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Sample records for additional signaling pathways

  1. The Wnt and Delta-Notch signalling pathways interact to direct pair-rule gene expression via caudal during segment addition in the spider Parasteatoda tepidariorum.

    PubMed

    Schönauer, Anna; Paese, Christian L B; Hilbrant, Maarten; Leite, Daniel J; Schwager, Evelyn E; Feitosa, Natália Martins; Eibner, Cornelius; Damen, Wim G M; McGregor, Alistair P

    2016-07-01

    In short-germ arthropods, posterior segments are added sequentially from a segment addition zone (SAZ) during embryogenesis. Studies in spiders such as Parasteatoda tepidariorum have provided insights into the gene regulatory network (GRN) underlying segment addition, and revealed that Wnt8 is required for dynamic Delta (Dl) expression associated with the formation of new segments. However, it remains unclear how these pathways interact during SAZ formation and segment addition. Here, we show that Delta-Notch signalling is required for Wnt8 expression in posterior SAZ cells, but represses the expression of this Wnt gene in anterior SAZ cells. We also found that these two signalling pathways are required for the expression of the spider orthologues of even-skipped (eve) and runt-1 (run-1), at least in part via caudal (cad). Moreover, it appears that dynamic expression of eve in this spider does not require a feedback loop with run-1, as is found in the pair-rule circuit of the beetle Tribolium Taken together, our results suggest that the development of posterior segments in Parasteatoda is directed by dynamic interactions between Wnt8 and Delta-Notch signalling that are read out by cad, which is necessary but probably not sufficient to regulate the expression of eve and run-1 Our study therefore provides new insights towards better understanding the evolution and developmental regulation of segmentation in other arthropods, including insects. PMID:27287802

  2. The Wnt and Delta-Notch signalling pathways interact to direct pair-rule gene expression via caudal during segment addition in the spider Parasteatoda tepidariorum.

    PubMed

    Schönauer, Anna; Paese, Christian L B; Hilbrant, Maarten; Leite, Daniel J; Schwager, Evelyn E; Feitosa, Natália Martins; Eibner, Cornelius; Damen, Wim G M; McGregor, Alistair P

    2016-07-01

    In short-germ arthropods, posterior segments are added sequentially from a segment addition zone (SAZ) during embryogenesis. Studies in spiders such as Parasteatoda tepidariorum have provided insights into the gene regulatory network (GRN) underlying segment addition, and revealed that Wnt8 is required for dynamic Delta (Dl) expression associated with the formation of new segments. However, it remains unclear how these pathways interact during SAZ formation and segment addition. Here, we show that Delta-Notch signalling is required for Wnt8 expression in posterior SAZ cells, but represses the expression of this Wnt gene in anterior SAZ cells. We also found that these two signalling pathways are required for the expression of the spider orthologues of even-skipped (eve) and runt-1 (run-1), at least in part via caudal (cad). Moreover, it appears that dynamic expression of eve in this spider does not require a feedback loop with run-1, as is found in the pair-rule circuit of the beetle Tribolium Taken together, our results suggest that the development of posterior segments in Parasteatoda is directed by dynamic interactions between Wnt8 and Delta-Notch signalling that are read out by cad, which is necessary but probably not sufficient to regulate the expression of eve and run-1 Our study therefore provides new insights towards better understanding the evolution and developmental regulation of segmentation in other arthropods, including insects.

  3. Retroactive Signaling in Short Signaling Pathways

    PubMed Central

    Sepulchre, Jacques-Alexandre; Merajver, Sofía D.; Ventura, Alejandra C.

    2012-01-01

    In biochemical signaling pathways without explicit feedback connections, the core signal transduction is usually described as a one-way communication, going from upstream to downstream in a feedforward chain or network of covalent modification cycles. In this paper we explore the possibility of a new type of signaling called retroactive signaling, offered by the recently demonstrated property of retroactivity in signaling cascades. The possibility of retroactive signaling is analysed in the simplest case of the stationary states of a bicyclic cascade of signaling cycles. In this case, we work out the conditions for which variables of the upstream cycle are affected by a change of the total amount of protein in the downstream cycle, or by a variation of the phosphatase deactivating the same protein. Particularly, we predict the characteristic ranges of the downstream protein, or of the downstream phosphatase, for which a retroactive effect can be observed on the upstream cycle variables. Next, we extend the possibility of retroactive signaling in short but nonlinear signaling pathways involving a few covalent modification cycles. PMID:22848403

  4. Signaling on the endocytic pathway.

    PubMed

    McPherson, P S; Kay, B K; Hussain, N K

    2001-06-01

    Ligand binding to receptor tyrosine kinases and G-protein-coupled receptors initiates signal transduction events and induces receptor endocytosis via clathrin-coated pits and vesicles. While receptor-mediated endocytosis has been traditionally considered an effective mechanism to attenuate ligand-activated responses, more recent studies demonstrate that signaling continues on the endocytic pathway. In fact, certain signaling events, such as the activation of the extracellular signal-regulated kinases, appear to require endocytosis. Protein components of signal transduction cascades can assemble at clathrin coated pits and remain associated with endocytic vesicles following their dynamin-dependent release from the plasma membrane. Thus, endocytic vesicles can function as a signaling compartment distinct from the plasma membrane. These observations demonstrate that endocytosis plays an important role in the activation and propagation of signaling pathways.

  5. Signaling on the endocytic pathway.

    PubMed

    McPherson, P S; Kay, B K; Hussain, N K

    2001-06-01

    Ligand binding to receptor tyrosine kinases and G-protein-coupled receptors initiates signal transduction events and induces receptor endocytosis via clathrin-coated pits and vesicles. While receptor-mediated endocytosis has been traditionally considered an effective mechanism to attenuate ligand-activated responses, more recent studies demonstrate that signaling continues on the endocytic pathway. In fact, certain signaling events, such as the activation of the extracellular signal-regulated kinases, appear to require endocytosis. Protein components of signal transduction cascades can assemble at clathrin coated pits and remain associated with endocytic vesicles following their dynamin-dependent release from the plasma membrane. Thus, endocytic vesicles can function as a signaling compartment distinct from the plasma membrane. These observations demonstrate that endocytosis plays an important role in the activation and propagation of signaling pathways. PMID:11389765

  6. Signaling Pathways in Melanogenesis

    PubMed Central

    D’Mello, Stacey A. N.; Finlay, Graeme J.; Baguley, Bruce C.; Askarian-Amiri, Marjan E.

    2016-01-01

    Melanocytes are melanin-producing cells found in skin, hair follicles, eyes, inner ear, bones, heart and brain of humans. They arise from pluripotent neural crest cells and differentiate in response to a complex network of interacting regulatory pathways. Melanins are pigment molecules that are endogenously synthesized by melanocytes. The light absorption of melanin in skin and hair leads to photoreceptor shielding, thermoregulation, photoprotection, camouflage and display coloring. Melanins are also powerful cation chelators and may act as free radical sinks. Melanin formation is a product of complex biochemical events that starts from amino acid tyrosine and its metabolite, dopa. The types and amounts of melanin produced by melanocytes are determined genetically and are influenced by a variety of extrinsic and intrinsic factors such as hormonal changes, inflammation, age and exposure to UV light. These stimuli affect the different pathways in melanogenesis. In this review we will discuss the regulatory mechanisms involved in melanogenesis and explain how intrinsic and extrinsic factors regulate melanin production. We will also explain the regulatory roles of different proteins involved in melanogenesis. PMID:27428965

  7. Signaling Pathways in Melanogenesis.

    PubMed

    D'Mello, Stacey A N; Finlay, Graeme J; Baguley, Bruce C; Askarian-Amiri, Marjan E

    2016-01-01

    Melanocytes are melanin-producing cells found in skin, hair follicles, eyes, inner ear, bones, heart and brain of humans. They arise from pluripotent neural crest cells and differentiate in response to a complex network of interacting regulatory pathways. Melanins are pigment molecules that are endogenously synthesized by melanocytes. The light absorption of melanin in skin and hair leads to photoreceptor shielding, thermoregulation, photoprotection, camouflage and display coloring. Melanins are also powerful cation chelators and may act as free radical sinks. Melanin formation is a product of complex biochemical events that starts from amino acid tyrosine and its metabolite, dopa. The types and amounts of melanin produced by melanocytes are determined genetically and are influenced by a variety of extrinsic and intrinsic factors such as hormonal changes, inflammation, age and exposure to UV light. These stimuli affect the different pathways in melanogenesis. In this review we will discuss the regulatory mechanisms involved in melanogenesis and explain how intrinsic and extrinsic factors regulate melanin production. We will also explain the regulatory roles of different proteins involved in melanogenesis. PMID:27428965

  8. Cancer stem cell signaling pathways.

    PubMed

    Matsui, William H

    2016-09-01

    Tissue development and homeostasis are governed by the actions of stem cells. Multipotent cells are capable of self-renewal during the course of one's lifetime. The accurate and appropriate regulation of stem cell functions is absolutely critical for normal biological activity. Several key developmental or signaling pathways have been shown to play essential roles in this regulatory capacity. Specifically, the Janus-activated kinase/signal transducer and activator of transcription, Hedgehog, Wnt, Notch, phosphatidylinositol 3-kinase/phosphatase and tensin homolog, and nuclear factor-κB signaling pathways have all been shown experimentally to mediate various stem cell properties, such as self-renewal, cell fate decisions, survival, proliferation, and differentiation. Unsurprisingly, many of these crucial signaling pathways are dysregulated in cancer. Growing evidence suggests that overactive or abnormal signaling within and among these pathways may contribute to the survival of cancer stem cells (CSCs). CSCs are a relatively rare population of cancer cells capable of self-renewal, differentiation, and generation of serially transplantable heterogeneous tumors of several types of cancer. PMID:27611937

  9. [Wnt signalling pathway and cervical cancer].

    PubMed

    Ramos-Solano, Moisés; Álvarez-Zavala, Monserrat; García-Castro, Beatriz; Jave-Suárez, Luis Felipe; Aguilar-Lemarroy, Adriana

    2015-01-01

    Cervical cancer (CC) is a pathology that arises in the cervical epithelium, whose major cause of risk is human papillomavirus (HPV) infection. Due to the fact that HPV infection per se is not enough to generate a carcinogenic process, it has been proposed that alterations in the Wnt signaling pathway are involved in cervical carcinogenesis. The Wnt family consists of 13 receptors and 19 ligands, and it is highly conserved phylogenetically due to its contribution in different biological processes, such as embryogenesis and tissue regeneration. Additionally, this signaling pathway modulates various cellular functions, for instance: cell proliferation, differentiation, migration and cell polarity. This paper describes the Wnt signaling pathways and alterations that have been found in members of this family in different cancer types and, especially, in CC.

  10. Pharmacology of intracellular signalling pathways

    PubMed Central

    Nahorski, Stefan R

    2006-01-01

    This article provides a brief and somewhat personalized review of the dramatic developments that have occurred over the last 45 years in our understanding of intracellular signalling pathways associated with G-protein-coupled receptor activation. Signalling via cyclic AMP, the phosphoinositides and Ca2+ is emphasized and these systems have already been revealed as new pharmacological targets. The therapeutic benefits of most of such targets are, however, yet to be realized, but it is certain that the discipline of pharmacology needs to widen its boundaries to meet these challenges in the future. PMID:16402119

  11. Signaling Pathways in Cartilage Repair

    PubMed Central

    Mariani, Erminia; Pulsatelli, Lia; Facchini, Andrea

    2014-01-01

    In adult healthy cartilage, chondrocytes are in a quiescent phase characterized by a fine balance between anabolic and catabolic activities. In ageing, degenerative joint diseases and traumatic injuries of cartilage, a loss of homeostatic conditions and an up-regulation of catabolic pathways occur. Since cartilage differentiation and maintenance of homeostasis are finely tuned by a complex network of signaling molecules and biophysical factors, shedding light on these mechanisms appears to be extremely relevant for both the identification of pathogenic key factors, as specific therapeutic targets, and the development of biological approaches for cartilage regeneration. This review will focus on the main signaling pathways that can activate cellular and molecular processes, regulating the functional behavior of cartilage in both physiological and pathological conditions. These networks may be relevant in the crosstalk among joint compartments and increased knowledge in this field may lead to the development of more effective strategies for inducing cartilage repair. PMID:24837833

  12. GA signalling and cross-talk with other signalling pathways.

    PubMed

    Lor, Vai S; Olszewski, Neil E

    2015-01-01

    Gibberellins (GAs) are phytohormones that regulate growth and development. DELLA proteins repress GA responses. GA binding to its receptor triggers a series of events that culminate in the destruction of DELLA proteins by the 26S proteasome, which removes the repression of GA signalling. DELLA proteins are transcription co-activators that induce the expression of genes which encode products that inhibit GA responses. In addition to repressing GA responses, DELLA proteins influence the activity of other signalling pathways and serve as a central hub from which other pathways influence GA signalling. In this role, DELLA proteins bind to and inhibit proteins, including transcription factors that act in the signalling pathways of other hormones and light. The binding of these proteins to DELLA proteins also inhibits DELLA activity. GA signalling is subject to homoeostatic regulation through GA-induced repression of GA biosynthesis gene expression, and increased production of the GA receptor and enzymes that catabolize bioactive GAs. This review also discusses the nature of mutant DELLA alleles that are used to produce high-yielding 'Green Revolution' cereal varieties, and highlights important gaps in our knowledge of GA signalling. PMID:26374886

  13. The inability of phosphatidylinositol 3-kinase activation to stimulate GLUT4 translocation indicates additional signaling pathways are required for insulin-stimulated glucose uptake.

    PubMed

    Isakoff, S J; Taha, C; Rose, E; Marcusohn, J; Klip, A; Skolnik, E Y

    1995-10-24

    Recent experimental evidence has focused attention to the role of two molecules, insulin receptor substrate 1 (IRS-1) and phosphatidylinositol 3-kinase (PI3-kinase), in linking the insulin receptor to glucose uptake; IRS-1 knockout mice are insulin resistant, and pharmacological inhibitors of PI3-kinase block insulin-stimulated glucose uptake. To investigate the role of PI3-kinase and IRS-1 in insulin-stimulated glucose uptake we examined whether stimulation of insulin-sensitive cells with platelet-derived growth factor (PDGF) or with interleukin 4 (IL-4) stimulates glucose uptake; the activated PDGF receptor (PDGFR) directly binds and activates PI3-kinase, whereas the IL-4 receptor (IL-4R) activates PI3-kinase via IRS-1 or the IRS-1-related molecule 4PS. We found that stimulation of 3T3-L1 adipocytes with PDGF resulted in tyrosine phosphorylation of the PDGFR and activation of PI3-kinase in these cells. To examine whether IL-4 stimulates glucose uptake, L6 myoblasts were engineered to overexpress GLUT4 as well as both chains of the IL-4R (L6/IL-4R/GLUT4); when these L6/IL-4R/GLUT4 myoblasts were stimulated with IL-4, IRS-1 became tyrosine phosphorylated and associated with PI3-kinase. Although PDGF and IL-4 can activate PI3-kinase in the respective cell lines, they do not possess insulin's ability to stimulate glucose uptake and GLUT4 translocation to the plasma membrane. These findings indicate that activation of PI3-kinase is not sufficient to stimulate GLUT4 translocation to the plasma membrane. We postulate that activation of a second signaling pathway by insulin, distinct from PI3-kinase, is necessary for the stimulation of glucose uptake in insulin-sensitive cells.

  14. Purinergic signaling pathways in endocrine system.

    PubMed

    Bjelobaba, Ivana; Janjic, Marija M; Stojilkovic, Stanko S

    2015-09-01

    Adenosine-5'-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5'-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5'-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5'-triphosphate hydrolysis to adenosine-5'-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling.

  15. Purinergic Signaling Pathways in Endocrine System

    PubMed Central

    Bjelobaba, Ivana; Janjic, Marija M.; Stojilkovic, Stanko S.

    2015-01-01

    Adenosine-5′-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5′-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5′-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5′-triphosphate hydrolysis to adenosine-5′-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling. PMID:25960051

  16. Leptin signalling pathways in hypothalamic neurons.

    PubMed

    Kwon, Obin; Kim, Ki Woo; Kim, Min-Seon

    2016-04-01

    Leptin is the most critical hormone in the homeostatic regulation of energy balance among those so far discovered. Leptin primarily acts on the neurons of the mediobasal part of hypothalamus to regulate food intake, thermogenesis, and the blood glucose level. In the hypothalamic neurons, leptin binding to the long form leptin receptors on the plasma membrane initiates multiple signaling cascades. The signaling pathways known to mediate the actions of leptin include JAK-STAT signaling, PI3K-Akt-FoxO1 signaling, SHP2-ERK signaling, AMPK signaling, and mTOR-S6K signaling. Recent evidence suggests that leptin signaling in hypothalamic neurons is also linked to primary cilia function. On the other hand, signaling molecules/pathways mitigating leptin actions in hypothalamic neurons have been extensively investigated in an effort to treat leptin resistance observed in obesity. These include SOCS3, tyrosine phosphatase PTP1B, and inflammatory signaling pathways such as IKK-NFκB and JNK signaling, and ER stress-mitochondrial signaling. In this review, we discuss leptin signaling pathways in the hypothalamus, with a particular focus on the most recently discovered pathways. PMID:26786898

  17. Leptin signalling pathways in hypothalamic neurons.

    PubMed

    Kwon, Obin; Kim, Ki Woo; Kim, Min-Seon

    2016-04-01

    Leptin is the most critical hormone in the homeostatic regulation of energy balance among those so far discovered. Leptin primarily acts on the neurons of the mediobasal part of hypothalamus to regulate food intake, thermogenesis, and the blood glucose level. In the hypothalamic neurons, leptin binding to the long form leptin receptors on the plasma membrane initiates multiple signaling cascades. The signaling pathways known to mediate the actions of leptin include JAK-STAT signaling, PI3K-Akt-FoxO1 signaling, SHP2-ERK signaling, AMPK signaling, and mTOR-S6K signaling. Recent evidence suggests that leptin signaling in hypothalamic neurons is also linked to primary cilia function. On the other hand, signaling molecules/pathways mitigating leptin actions in hypothalamic neurons have been extensively investigated in an effort to treat leptin resistance observed in obesity. These include SOCS3, tyrosine phosphatase PTP1B, and inflammatory signaling pathways such as IKK-NFκB and JNK signaling, and ER stress-mitochondrial signaling. In this review, we discuss leptin signaling pathways in the hypothalamus, with a particular focus on the most recently discovered pathways.

  18. Interleukin 4 signals through two related pathways.

    PubMed

    Pernis, A; Witthuhn, B; Keegan, A D; Nelms, K; Garfein, E; Ihle, J N; Paul, W E; Pierce, J H; Rothman, P

    1995-08-15

    The interleukin 4 (IL-4) signaling pathway involves activation, by tyrosine phosphorylation, of two distinct substrates, a signal-transducing factor (STF-IL4) and the IL-4-induced phosphotyrosine substrate (4PS). It is not known whether the IL-4-mediated activation of these substrates occurs via related or distinct signaling pathways. We report that 32D cells, an IL-3-dependent myeloid progenitor cell line in which no phosphorylated 4PS is found, activate high levels of STF-IL4 in response to IL-4. Consistent with the known requirement for 4PS or insulin receptor substrate 1 (IRS-1) in IL-4-mediated mitogenesis, activation of STF-IL4 in 32D cells is not sufficient for IL-4-inducible c-myc expression. In addition, we have examined the ability of 32D cells transfected with different truncation mutants of the human IL-4 receptor to activate Jak-3 kinase and STF-IL4 in response to human IL-4. As in the case of 4PS/IRS-1, we have found that activation of both Jak-3 and STF-IL4 requires the presence of the IL-4 receptor region comprising aa 437-557. The finding that the same region of the IL-4 receptor is required for the induction of both 4PS/IRS-1 and STF-IL4 suggests that the IL-4-stimulated activation of these two substrates might involve common factors.

  19. LXR signaling pathways and atherosclerosis

    PubMed Central

    Calkin, Anna; Tontonoz, Peter

    2010-01-01

    First discovered as orphan receptors, liver X receptors (LXRs) were subsequently identified as the nuclear receptor target of the cholesterol metabolites, oxysterols.1 There are 2 LXR receptors encoded by distinct genes: LXRα is most highly expressed in the liver, adipose, kidney, adrenal tissues and macrophages, and LXRβ is ubiquitously expressed. Despite differential tissue distribution, these isoforms have 78% homology in their ligand-binding domain and appear to respond to the same endogenous ligands. Work over the past 10 years has shown that the LXR pathway regulates lipid metabolism and inflammation via both the induction and repression of target genes. Given the importance of cholesterol regulation and inflammation in the development of cardiovascular disease, it is not surprising that activation of the LXR pathway attenuates various mechanisms underlying atherosclerotic plaque development.2 In this minireview we will discuss the impact of the LXR pathway on both cholesterol metabolism and atherosclerosis. PMID:20631351

  20. Modularized TGFbeta-Smad Signaling Pathway

    NASA Technical Reports Server (NTRS)

    Li, Yongfeng; Wang, M.; Carra, C.; Cucinotta, F. A.

    2011-01-01

    The Transforming Growth Factor beta (TGFbeta) signaling pathway is a prominent regulatory signaling pathway controlling various important cellular processes. It can be induced by several factors, including ionizing radiation. It is regulated by Smads in a negative feedback loop through promoting increases in the regulatory Smads in the cell nucleus, and subsequent expression of inhibitory Smad, Smad7 to form a ubiquitin ligase with Smurf targeting active TGF receptors for degradation. In this work, we proposed a mathematical model to study the radiation-induced Smad-regulated TGF signaling pathway. By modularization, we are able to analyze each module (subsystem) and recover the nonlinear dynamics of the entire network system. Meanwhile the excitability, a common feature observed in the biological systems, along the TGF signaling pathway is discussed by mathematical analysis and numerical simulation.

  1. Premetazoan origin of the Hippo signaling pathway

    PubMed Central

    Sebé-Pedrós, Arnau; Zheng, Yonggang; Ruiz-Trillo, Iñaki; Pan, Duojia

    2012-01-01

    Summary Non-aggregative multicellularity requires strict control of cell number. The Hippo signaling pathway coordinates cell proliferation and apoptosis and is a central regulator of organ size in animals. Recent studies have shown the presence of key members of the Hippo pathway in non-bilaterian animals, but failed to identify this pathway outside Metazoa. Through comparative analyses of recently sequenced holozoan genomes, we show that Hippo pathway components, such as the kinases Hippo and Warts, the co-activator Yorkie and the transcription factor Scalloped, were already present in the unicellular ancestors of animals. Remarkably, functional analysis of Hippo components of the amoeboid holozoan Capsaspora owczarzaki, performed in Drosophila, demonstrate that the growth-regulatory activity of the Hippo pathway is conserved in this unicellular lineage. Our findings show that the Hippo pathway evolved well before the origin of Metazoa and highlight the importance of Hippo signaling as a key developmental mechanism pre-dating the origin of Metazoa. PMID:22832104

  2. Optogenetic control of intracellular signaling pathways.

    PubMed

    Zhang, Kai; Cui, Bianxiao

    2015-02-01

    Cells employ a plethora of signaling pathways to make their life-and-death decisions. Extensive genetic, biochemical, and physiological studies have led to the accumulation of knowledge about signaling components and their interactions within signaling networks. These conventional approaches, although useful, lack the ability to control the spatial and temporal aspects of signaling processes. The recently emerged optogenetic tools open exciting opportunities by enabling signaling regulation with superior temporal and spatial resolution, easy delivery, rapid reversibility, fewer off-target side effects, and the ability to dissect complex signaling networks. Here we review recent achievements in using light to control intracellular signaling pathways and discuss future prospects for the field, including integration of new genetic approaches into optogenetics.

  3. Optogenetic control of intracellular signaling pathways

    PubMed Central

    Zhang, Kai; Cui, Bianxiao

    2014-01-01

    Cells employ a plethora of signaling pathways to make their life-and-death decisions. Extensive genetic, biochemical, and physiological studies have led to the accumulation of knowledge about signaling components and their interactions within signaling networks. These conventional approaches, though useful, lack the ability to control the spatial and temporal aspects of signaling processes. The recently emerged optogenetic tools open up exciting opportunities by enabling signaling regulation with superior temporal and spatial resolution, easy delivery, rapid reversibility, fewer off-target side effects, and the ability to dissect complex signaling networks. Here we review recent achievements in using light to control intracellular signaling pathways, and discuss future prospects for the field, including integration of new genetic approaches into optogenetics. PMID:25529484

  4. Signaling pathways take aim at neurotransmitter transporters.

    PubMed

    Robinson, Michael B

    2003-11-01

    Neurotransmitter transporters are the target of various pharmacological agents used to treat psychological or cognitive conditions, such as depression and attention-deficit disorder. In addition, some of the effects of stimulant-type drugs of abuse result from inhibition of neurotransmitter transporters. Robinson describes the intersection between neurotransmitter transporters and signaling pathways. Neurotransmitter transporters can be regulated by altering the rate of internalization and insertion into the plasma membrane to control cell surface expression or by altering the activity of the transporters within the membrane. As the mechanisms governing regulation of these transporters become elucidated, new potential therapeutic targets may be revealed, given the many processes affected by the activity of neurotransmitter transporters.

  5. Advances in Targeting Signal Transduction Pathways

    PubMed Central

    McCubrey, James A.; Steelman, Linda S.; Chappell, William H.; Sun, Lin; Davis, Nicole M.; Abrams, Stephen L.; Franklin, Richard A.; Cocco, Lucio; Evangelisti, Camilla; Chiarini, Francesca; Martelli, Alberto M.; Libra, Massimo; Candido, Saverio; Ligresti, Giovanni; Malaponte, Grazia; Mazzarino, Maria C.; Fagone, Paolo; Donia, Marco; Nicoletti, Ferdinando; Polesel, Jerry; Talamini, Renato; Bäsecke, Jörg; Mijatovic, Sanja; Maksimovic-Ivanic, Danijela; Milella, Michele; Tafuri, Agostino; Dulińska-Litewka, Joanna; Laidler, Piotr; D'Assoro, Antonio B.; Drobot, Lyudmyla; Umezawa, Kazuo; Montalto, Giuseppe; Cervello, Melchiorre; Demidenko, Zoya N.

    2012-01-01

    Over the past few years, significant advances have occurred in both our understanding of the complexity of signal transduction pathways as well as the isolation of specific inhibitors which target key components in those pathways. Furthermore critical information is being accrued regarding how genetic mutations can affect the sensitivity of various types of patients to targeted therapy. Finally, genetic mechanisms responsible for the development of resistance after targeted therapy are being discovered which may allow the creation of alternative therapies to overcome resistance. This review will discuss some of the highlights over the past few years on the roles of key signaling pathways in various diseases, the targeting of signal transduction pathways and the genetic mechanisms governing sensitivity and resistance to targeted therapies. PMID:23455493

  6. SPIKE: a database of highly curated human signaling pathways.

    PubMed

    Paz, Arnon; Brownstein, Zippora; Ber, Yaara; Bialik, Shani; David, Eyal; Sagir, Dorit; Ulitsky, Igor; Elkon, Ran; Kimchi, Adi; Avraham, Karen B; Shiloh, Yosef; Shamir, Ron

    2011-01-01

    The rapid accumulation of knowledge on biological signaling pathways and their regulatory mechanisms has highlighted the need for specific repositories that can store, organize and allow retrieval of pathway information in a way that will be useful for the research community. SPIKE (Signaling Pathways Integrated Knowledge Engine; http://www.cs.tau.ac.il/&~spike/) is a database for achieving this goal, containing highly curated interactions for particular human pathways, along with literature-referenced information on the nature of each interaction. To make database population and pathway comprehension straightforward, a simple yet informative data model is used, and pathways are laid out as maps that reflect the curator’s understanding and make the utilization of the pathways easy. The database currently focuses primarily on pathways describing DNA damage response, cell cycle, programmed cell death and hearing related pathways. Pathways are regularly updated, and additional pathways are gradually added. The complete database and the individual maps are freely exportable in several formats. The database is accompanied by a stand-alone software tool for analysis and dynamic visualization of pathways.

  7. Logical modelling of Drosophila signalling pathways.

    PubMed

    Mbodj, Abibatou; Junion, Guillaume; Brun, Christine; Furlong, Eileen E M; Thieffry, Denis

    2013-09-01

    A limited number of signalling pathways are involved in the specification of cell fate during the development of all animals. Several of these pathways were originally identified in Drosophila. To clarify their roles, and possible cross-talk, we have built a logical model for the nine key signalling pathways recurrently used in metazoan development. In each case, we considered the associated ligands, receptors, signal transducers, modulators, and transcription factors reported in the literature. Implemented using the logical modelling software GINsim, the resulting models qualitatively recapitulate the main characteristics of each pathway, in wild type as well as in various mutant situations (e.g. loss-of-function or gain-of-function). These models constitute pluggable modules that can be used to assemble comprehensive models of complex developmental processes. Moreover, these models of Drosophila pathways could serve as scaffolds for more complicated models of orthologous mammalian pathways. Comprehensive model annotations and GINsim files are provided for each of the nine considered pathways.

  8. The Hedgehog signalling pathway in bone formation

    PubMed Central

    Yang, Jing; Andre, Philipp; Ye, Ling; Yang, Ying-Zi

    2015-01-01

    The Hedgehog (Hh) signalling pathway plays many important roles in development, homeostasis and tumorigenesis. The critical function of Hh signalling in bone formation has been identified in the past two decades. Here, we review the evolutionarily conserved Hh signalling mechanisms with an emphasis on the functions of the Hh signalling pathway in bone development, homeostasis and diseases. In the early stages of embryonic limb development, Sonic Hedgehog (Shh) acts as a major morphogen in patterning the limb buds. Indian Hedgehog (Ihh) has an essential function in endochondral ossification and induces osteoblast differentiation in the perichondrium. Hh signalling is also involved intramembrane ossification. Interactions between Hh and Wnt signalling regulate cartilage development, endochondral bone formation and synovial joint formation. Hh also plays an important role in bone homeostasis, and reducing Hh signalling protects against age-related bone loss. Disruption of Hh signalling regulation leads to multiple bone diseases, such as progressive osseous heteroplasia. Therefore, understanding the signalling mechanisms and functions of Hh signalling in bone development, homeostasis and diseases will provide important insights into bone disease prevention, diagnoses and therapeutics. PMID:26023726

  9. Abnormalities in signaling pathways in diabetic nephropathy

    PubMed Central

    Brosius, Frank C; Khoury, Charbel C; Buller, Carolyn L; Chen, Sheldon

    2010-01-01

    Diabetic nephropathy (DN) is characterized by a plethora of signaling abnormalities that together ultimately result in the clinical and pathologic hallmarks of DN, namely progressive albuminuria followed by a gradual decline in glomerular filtration rate leading to kidney failure, and accompanied by podocyte loss, progressive glomerular sclerosis and, ultimately, progressive tubulointerstitial fibrosis. Over the past few years, the general understanding of the abnormalities in signaling pathways that lead to DN has expanded considerably. In this review, some of the important pathways that appear to be involved in driving this process are discussed, with special emphasis on newer findings and insights. Newer concepts regarding signaling changes in bradykinin, mTOR, JAK/STAT, MCP-1, VEGF, endothelial nitric oxide synthase, activated protein C and other pathways are discussed. PMID:20224802

  10. Aging of signal transduction pathways, and pathology

    PubMed Central

    Carlson, Morgan E.; Silva, Haroldo S.; Conboy, Irina M.

    2008-01-01

    The major cell signaling pathways, and their specific mechanisms of transduction, have been a subject of investigation for many years. As our understanding of these pathways advances, we find that they are evolutionarily well-conserved not only individually, but also at the level of their crosstalk and signal integration. Productive interactions within the key signal transduction networks determine success in embryonic organogenesis, and postnatal tissue repair throughout adulthood. However, aside from clues revealed through examining age-related degenerative diseases, much remains uncertain about imbalances within these pathways during normal aging. Further, little is known about the molecular mechanisms by which alterations in the major cell signal transduction networks cause age-related pathologies. The aim of this review is to describe the complex interplay between the Notch, TGFβ, WNT, RTK-Ras and Hh signaling pathways, with a specific focus on the changes introduced within these networks by the aging process, and those typical of age-associated human pathologies. PMID:18474281

  11. The Fibroblast Growth Factor signaling pathway

    PubMed Central

    Ornitz, David M; Itoh, Nobuyuki

    2015-01-01

    The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. © 2015 Wiley Periodicals, Inc. PMID:25772309

  12. Retinoic acid suppresses the canonical Wnt signaling pathway in embryonic stem cells and activates the noncanonical Wnt signaling pathway

    PubMed Central

    Osei-Sarfo, Kwame; Gudas, Lorraine J.

    2014-01-01

    Embryonic stem cells (ESCs) have both the ability to self-renew and to differentiate into various cell lineages. Retinoic acid (RA), a metabolite of Vitamin A, has a critical function in initiating lineage differentiation of ESCs through binding to the retinoic acid receptors (RARs). Additionally, the Wnt signaling pathway plays a role in pluripotency and differentiation, depending on the activation status of the canonical and noncanonical pathways. The activation of the canonical Wnt signaling pathway, which requires the nuclear accumulation of β-catenin and its interaction with Tcf1/Lef at Wnt response elements, is involved in ESC stemness maintenance. The noncanonical Wnt signaling pathway, through actions of Tcf3, can antagonize the canonical pathway. We show that RA activates the noncanonical Wnt signaling pathway, while concomitantly inhibiting the canonical pathway. RA increases the expression of ligands and receptors of the noncanonical Wnt pathway (Wnt 5a, 7a, Fzd2 and Fzd6), downstream signaling, and Tcf3 expression. RA reduces the phosphorylated β-catenin level by 4-fold, though total β-catenin levels don't change. We show that RA signaling increases the dissociation of Tcf1 and the association of Tcf3 at promoters of genes that regulate stemness (e.g. NR5A2,Lrh-1) or differentiation (eg. Cyr61, Zic5). Knockdown of Tcf3 increases Lrh-1 transcript levels in mESCs and prevents the RA-associated, ∼4-fold increase in Zic5, indicating that RA requires Tcf3 to effect changes in Zic5 levels. We demonstrate a novel role for RA in altering the activation of these two Wnt signaling pathways and show that Tcf3 mediates some actions of RA during differentiation. PMID:24648413

  13. Targeting RTK Signaling Pathways in Cancer

    PubMed Central

    Regad, Tarik

    2015-01-01

    The RAS/MAP kinase and the RAS/PI3K/AKT pathways play a key role in the regulation of proliferation, differentiation and survival. The induction of these pathways depends on Receptor Tyrosine Kinases (RTKs) that are activated upon ligand binding. In cancer, constitutive and aberrant activations of components of those pathways result in increased proliferation, survival and metastasis. For instance, mutations affecting RTKs, Ras, B-Raf, PI3K and AKT are common in perpetuating the malignancy of several types of cancers and from different tissue origins. Therefore, these signaling pathways became prime targets for cancer therapy. This review aims to provide an overview about the most frequently encountered mutations, the pathogenesis that results from such mutations and the known therapeutic strategies developed to counteract their aberrant functions. PMID:26404379

  14. The Fog signaling pathway: Insights into signaling in morphogenesis

    PubMed Central

    Manning, Alyssa J.; Rogers, Stephen L.

    2014-01-01

    Epithelia form the building blocks of many tissue and organ types. Epithelial cells often form a contiguous 2-dimensional sheet that is held together by strong adhesions. The mechanical properties conferred by these adhesions allow the cells to undergo dramatic three-dimensional morphogenetic movements while maintaining cell–cell contacts during embryogenesis and post-embryonic development. The Drosophila Folded gastrulation pathway triggers epithelial cell shape changes that drive gastrulation and tissue folding and is one of the most extensively studied examples of epithelial morphogenesis. This pathway has yielded key insights into the signaling mechanisms and cellular machinery involved in epithelial remodeling. In this review, we discuss principles of morphogenesis and signaling that have been discovered through genetic and cell biological examination of this pathway. We also consider various regulatory mechanisms and the system's relevance to mammalian development. We propose future directions that will continue to broaden our knowledge of morphogenesis across taxa. PMID:25127992

  15. The ethylene signal transduction pathway in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Kieber, J. J.; Evans, M. L. (Principal Investigator)

    1997-01-01

    The gaseous hormone ethylene is an important regulator of plant growth and development. Using a simple response of etiolated seedlings to ethylene as a genetic screen, genes involved in ethylene signal transduction have been identified in Arabidopsis. Analysis of two of these genes that have been cloned reveals that ethylene signalling involves a combination of a protein (ETR1) with similarity to bacterial histidine kinases and a protein (CTR1) with similarity to Raf-1, a protein kinase involved in multiple signalling cascades in eukaryotic cells. Several lines of investigation provide compelling evidence that ETR1 encodes an ethylene receptor. For the first time there is a glimpse of the molecular circuitry underlying the signal transduction pathway for a plant hormone.

  16. A multi-pathway hypothesis for human visual fear signaling

    PubMed Central

    Silverstein, David N.; Ingvar, Martin

    2015-01-01

    A hypothesis is proposed for five visual fear signaling pathways in humans, based on an analysis of anatomical connectivity from primate studies and human functional connectvity and tractography from brain imaging studies. Earlier work has identified possible subcortical and cortical fear pathways known as the “low road” and “high road,” which arrive at the amygdala independently. In addition to a subcortical pathway, we propose four cortical signaling pathways in humans along the visual ventral stream. All four of these traverse through the LGN to the visual cortex (VC) and branching off at the inferior temporal area, with one projection directly to the amygdala; another traversing the orbitofrontal cortex; and two others passing through the parietal and then prefrontal cortex, one excitatory pathway via the ventral-medial area and one regulatory pathway via the ventral-lateral area. These pathways have progressively longer propagation latencies and may have progressively evolved with brain development to take advantage of higher-level processing. Using the anatomical path lengths and latency estimates for each of these five pathways, predictions are made for the relative processing times at selective ROIs and arrival at the amygdala, based on the presentation of a fear-relevant visual stimulus. Partial verification of the temporal dynamics of this hypothesis might be accomplished using experimental MEG analysis. Possible experimental protocols are suggested. PMID:26379513

  17. Nongenomic Signaling Pathways of Estrogen Toxicity

    PubMed Central

    Watson, Cheryl S.; Jeng, Yow-Jiun; Kochukov, Mikhail Y.

    2010-01-01

    Xenoestrogens can affect the healthy functioning of a variety of tissues by acting as potent estrogens via nongenomic signaling pathways or by interfering with those actions of multiple physiological estrogens. Collectively, our and other studies have compared a wide range of estrogenic compounds, including some closely structurally related subgroups. The estrogens that have been studied include environmental contaminants of different subclasses, dietary estrogens, and several prominent physiological metabolites. By comparing the nongenomic signaling and functional responses to these compounds, we have begun to address the structural requirements for their actions through membrane estrogen receptors in the pituitary, in comparison to other tissues, and to gain insights into their typical non-monotonic dose-response behavior. Their multiple inputs into cellular signaling begin processes that eventually integrate at the level of mitogen-activated protein kinase activities to coordinately regulate broad cellular destinies, such as proliferation, apoptosis, or differentiation. PMID:19955490

  18. Pentagone internalises glypicans to fine-tune multiple signalling pathways.

    PubMed

    Norman, Mark; Vuilleumier, Robin; Springhorn, Alexander; Gawlik, Jennifer; Pyrowolakis, George

    2016-01-01

    Tight regulation of signalling activity is crucial for proper tissue patterning and growth. Here we investigate the function of Pentagone (Pent), a secreted protein that acts in a regulatory feedback during establishment and maintenance of BMP/Dpp morphogen signalling during Drosophila wing development. We show that Pent internalises the Dpp co-receptors, the glypicans Dally and Dally-like protein (Dlp), and propose that this internalisation is important in the establishment of a long range Dpp gradient. Pent-induced endocytosis and degradation of glypicans requires dynamin- and Rab5, but not clathrin or active BMP signalling. Thus, Pent modifies the ability of cells to trap and transduce BMP by fine-tuning the levels of the BMP reception system at the plasma membrane. In addition, and in accordance with the role of glypicans in multiple signalling pathways, we establish a requirement of Pent for Wg signalling. Our data propose a novel mechanism by which morphogen signalling is regulated. PMID:27269283

  19. Insulin signaling pathways in lepidopteran ecdysone secretion

    PubMed Central

    Smith, Wendy A.; Lamattina, Anthony; Collins, McKensie

    2014-01-01

    Molting and metamorphosis are stimulated by the secretion of ecdysteroid hormones from the prothoracic glands. Insulin-like hormones have been found to enhance prothoracic gland activity, providing a mechanism to link molting to nutritional state. In silk moths (Bombyx mori), the prothoracic glands are directly stimulated by insulin and the insulin-like hormone bombyxin. Further, in Bombyx, the neuropeptide prothoracicotropic hormone (PTTH) appears to act at least in part through the insulin-signaling pathway. In the prothoracic glands of Manduca sexta, while insulin stimulates the phosphorylation of the insulin receptor and Akt, neither insulin nor bombyxin II stimulate ecdysone secretion. Involvement of the insulin-signaling pathway in Manduca prothoracic glands was explored using two inhibitors of phosphatidylinositol-3-kinase (PI3K), LY294002 and wortmannin. PI3K inhibitors block the phosphorylation of Akt and 4EBP but have no effect on ecdysone secretion, or on the phosphorylation of the MAPkinase, ERK. Inhibitors that block phosphorylation of ERK, including the MEK inhibitor U0126, and high doses of the RSK inhibitor SL0101, effectively inhibit ecdysone secretion. The results highlight differences between the two lepidopteran insects most commonly used to directly study ecdysteroid secretion. In Bombyx, the PTTH and insulin-signaling pathways intersect; both insulin and PTTH enhance the phosphorylation of Akt and stimulate ecdysteroid secretion, and inhibition of PI3K reduces ecdysteroid secretion. By contrast, in Manduca, the action of PTTH is distinct from insulin. The results highlight species differences in the roles of translational regulators such as 4EBP, and members of the MAPkinase pathway such as ERK and RSK, in the regulation of insect ecdysone secretion, and in the impact of nutritionally-sensitive hormones such as insulin in the control of ecdysone secretion and molting. PMID:24550835

  20. Modulation of neurotrophic signaling pathways by polyphenols

    PubMed Central

    Moosavi, Fatemeh; Hosseini, Razieh; Saso, Luciano; Firuzi, Omidreza

    2016-01-01

    Polyphenols are an important class of phytochemicals, and several lines of evidence have demonstrated their beneficial effects in the context of a number of pathologies including neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. In this report, we review the studies on the effects of polyphenols on neuronal survival, growth, proliferation and differentiation, and the signaling pathways involved in these neurotrophic actions. Several polyphenols including flavonoids such as baicalein, daidzein, luteolin, and nobiletin as well as nonflavonoid polyphenols such as auraptene, carnosic acid, curcuminoids, and hydroxycinnamic acid derivatives including caffeic acid phentyl ester enhance neuronal survival and promote neurite outgrowth in vitro, a hallmark of neuronal differentiation. Assessment of underlying mechanisms, especially in PC12 neuronal-like cells, reveals that direct agonistic effect on tropomyosin receptor kinase (Trk) receptors, the main receptors of neurotrophic factors including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) explains the action of few polyphenols such as 7,8-dihydroxyflavone. However, several other polyphenolic compounds activate extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/Akt pathways. Increased expression of neurotrophic factors in vitro and in vivo is the mechanism of neurotrophic action of flavonoids such as scutellarin, daidzein, genistein, and fisetin, while compounds like apigenin and ferulic acid increase cyclic adenosine monophosphate response element-binding protein (CREB) phosphorylation. Finally, the antioxidant activity of polyphenols reflected in the activation of Nrf2 pathway and the consequent upregulation of detoxification enzymes such as heme oxygenase-1 as well as the contribution of these effects to the neurotrophic activity have also been discussed. In conclusion, a better understanding of the neurotrophic effects of polyphenols and

  1. Subpathway Analysis based on Signaling-Pathway Impact Analysis of Signaling Pathway

    PubMed Central

    Li, Xianbin; Shen, Liangzhong; Shang, Xuequn; Liu, Wenbin

    2015-01-01

    Pathway analysis is a common approach to gain insight from biological experiments. Signaling-pathway impact analysis (SPIA) is one such method and combines both the classical enrichment analysis and the actual perturbation on a given pathway. Because this method focuses on a single pathway, its resolution generally is not very high because the differentially expressed genes may be enriched in a local region of the pathway. In the present work, to identify cancer-related pathways, we incorporated a recent subpathway analysis method into the SPIA method to form the “sub-SPIA method.” The original subpathway analysis uses the k-clique structure to define a subpathway. However, it is not sufficiently flexible to capture subpathways with complex structure and usually results in many overlapping subpathways. We therefore propose using the minimal-spanning-tree structure to find a subpathway. We apply this approach to colorectal cancer and lung cancer datasets, and our results show that sub-SPIA can identify many significant pathways associated with each specific cancer that other methods miss. Based on the entire pathway network in the Kyoto Encyclopedia of Genes and Genomes, we find that the pathways identified by sub-SPIA not only have the largest average degree, but also are more closely connected than those identified by other methods. This result suggests that the abnormality signal propagating through them might be responsible for the specific cancer or disease. PMID:26207919

  2. A network map of Interleukin-10 signaling pathway.

    PubMed

    Verma, Renu; Balakrishnan, Lavanya; Sharma, Kusum; Khan, Aafaque Ahmad; Advani, Jayshree; Gowda, Harsha; Tripathy, Srikanth Prasad; Suar, Mrutyunjay; Pandey, Akhilesh; Gandotra, Sheetal; Prasad, T S Keshava; Shankar, Subramanian

    2016-03-01

    Interleukin-10 (IL-10) is an anti-inflammatory cytokine with important immunoregulatory functions. It is primarily secreted by antigen-presenting cells such as activated T-cells, monocytes, B-cells and macrophages. In biologically functional form, it exists as a homodimer that binds to tetrameric heterodimer IL-10 receptor and induces downstream signaling. IL-10 is associated with survival, proliferation and anti-apoptotic activities of various cancers such as Burkitt lymphoma, non-Hodgkins lymphoma and non-small scell lung cancer. In addition, it plays a central role in survival and persistence of intracellular pathogens such as Leishmania donovani, Mycobacterium tuberculosis and Trypanosoma cruzi inside the host. The signaling mechanisms of IL-10 cytokine are not well explored and a well annotated pathway map has been lacking. To this end, we developed a pathway resource by manually annotating the IL-10 induced signaling molecules derived from literature. The reactions were categorized under molecular associations, activation/inhibition, catalysis, transport and gene regulation. In all, 37 molecules and 76 reactions were annotated. The IL-10 signaling pathway can be freely accessed through NetPath, a resource of signal transduction pathways previously developed by our group. PMID:26253919

  3. The immune signaling pathways of Manduca sexta.

    PubMed

    Cao, Xiaolong; He, Yan; Hu, Yingxia; Wang, Yang; Chen, Yun-Ru; Bryant, Bart; Clem, Rollie J; Schwartz, Lawrence M; Blissard, Gary; Jiang, Haobo

    2015-07-01

    Signal transduction pathways and their coordination are critically important for proper functioning of animal immune systems. Our knowledge of the constituents of the intracellular signaling network in insects mainly comes from genetic analyses in Drosophila melanogaster. To facilitate future studies of similar systems in the tobacco hornworm and other lepidopteran insects, we have identified and examined the homologous genes in the genome of Manduca sexta. Based on 1:1 orthologous relationships in most cases, we hypothesize that the Toll, Imd, MAPK-JNK-p38 and JAK-STAT pathways are intact and operative in this species, as are most of the regulatory mechanisms. Similarly, cellular processes such as autophagy, apoptosis and RNA interference probably function in similar ways, because their mediators and modulators are mostly conserved in this lepidopteran species. We have annotated a total of 186 genes encoding 199 proteins, studied their domain structures and evolution, and examined their mRNA levels in tissues at different life stages. Such information provides a genomic perspective of the intricate signaling system in a non-drosophiline insect. PMID:25858029

  4. Schistosoma mansoni: TGF-β Signaling Pathways

    PubMed Central

    LoVerde, Philip T.; Osman, Ahmed; Hinck, Andrew

    2007-01-01

    Schistosome parasites have co-evolved an intricate relationship with their human and snail hosts as well as a novel interplay between the adult male and female parasites. We review the role of the TGF-β signaling pathway in parasite development, host-parasite interactions and male-female interactions. The data to date supports multiple roles for the TGF-β signaling pathway throughout schistosome development, in particular in the tegument which is at the interface with the host and between the male and female schistosome, development of vitelline cells in female worms whose genes and development are regulated by a stimulus from the male schistosome and embryogenesis of the egg. The human ligand TGF-β1 has been demonstrated to regulate the expression of a schistosome target gene that encodes a gynecophoric canal protein in the schistosome worm itself. Studies on signaling in schistosomes opens a new era for investigation of host-parasite and male-female interactions. PMID:17643432

  5. Mitochondrial Retrograde Signaling: Triggers, Pathways, and Outcomes

    PubMed Central

    da Cunha, Fernanda Marques; Torelli, Nicole Quesada; Kowaltowski, Alicia J.

    2015-01-01

    Mitochondria are essential organelles for eukaryotic homeostasis. Although these organelles possess their own DNA, the vast majority (>99%) of mitochondrial proteins are encoded in the nucleus. This situation makes systems that allow the communication between mitochondria and the nucleus a requirement not only to coordinate mitochondrial protein synthesis during biogenesis but also to communicate eventual mitochondrial malfunctions, triggering compensatory responses in the nucleus. Mitochondria-to-nucleus retrograde signaling has been described in various organisms, albeit with differences in effector pathways, molecules, and outcomes, as discussed in this review. PMID:26583058

  6. Building mammalian signalling pathways with RNAi screens.

    PubMed

    Moffat, Jason; Sabatini, David M

    2006-03-01

    Technological advances in mammalian systems are providing new tools to identify the molecular components of signalling pathways. Foremost among these tools is the ability to knock down gene function through the use of RNA interference (RNAi). The fact that RNAi can be scaled up for use in high-throughput techniques has motivated the creation of genome-wide RNAi reagents. We are now at the brink of being able to harness the power of RNAi for large-scale functional discovery in mammalian cells.

  7. The TAK1-TRAF6 signalling pathway.

    PubMed

    Landström, Marene

    2010-05-01

    Cellular responses to pathogens, growth factors, cytokines, extra- or intra-cellular stress, is a prerequisite for the cell to adapt to novel and potentially dangerous situations. If the changes in the extra- or intra-cellular milieu causes DNA-damage or revoke a signalling pathway utilized during morphogenesis, the epithelial cells might be forced to undergo programmed cell death (apoptosis) in the benefit for the whole organism or transform to a mesenchymal cell type (epithelial to mesenchymal transition; EMT), in respond to a specific stimuli. An overview is presented over the current knowledge for the key components in signal transduction in homeostasis, inflammation and cancer. A handful of transcription factors are crucial for the determination of the specific cellular responses, where the transforming growth factor-beta (TGF-beta) is an important factor as discussed in this review. PMID:20060931

  8. Signaling Pathways in Leiomyoma: Understanding Pathobiology and Implications for Therapy

    PubMed Central

    Borahay, Mostafa A; Al-Hendy, Ayman; Kilic, Gokhan S; Boehning, Darren

    2015-01-01

    Uterine leiomyomas are the most common tumors of the female genital tract, affecting 50% to 70% of females by the age of 50. Despite their prevalence and enormous medical and economic impact, no effective medical treatment is currently available. This is, in part, due to the poor understanding of their underlying pathobiology. Although they are thought to start as a clonal proliferation of a single myometrial smooth muscle cell, these early cytogenetic alterations are considered insufficient for tumor development and additional complex signaling pathway alterations are crucial. These include steroids, growth factors, transforming growth factor-beta (TGF-β)/Smad; wingless-type (Wnt)/β-catenin, retinoic acid, vitamin D, and peroxisome proliferator-activated receptor γ (PPARγ). An important finding is that several of these pathways converge in a summative way. For example, mitogen-activated protein kinase (MAPK) and Akt pathways seem to act as signal integrators, incorporating input from several signaling pathways, including growth factors, estrogen and vitamin D. This underlines the multifactorial origin and complex nature of these tumors. In this review, we aim to dissect these pathways and discuss their interconnections, aberrations and role in leiomyoma pathobiology. We also aim to identify potential targets for development of novel therapeutics. PMID:25879625

  9. MAPKs in development: insights from Dictyostelium signaling pathways

    PubMed Central

    Hadwiger, Jeffrey A.; Nguyen, Hoai-Nghia

    2011-01-01

    Mitogen activated protein kinases (MAPKs) play important roles in the development of eukaryotic organisms through the regulation of signal transduction pathways stimulated by external signals. MAPK signaling pathways have been associated with the regulation of cell growth, differentiation, and chemotaxis, indicating MAPKs contribute to a diverse set of developmental processes. In most eukaryotes, the diversity of external signals is likely to far exceed the diversity of MAPKs, suggesting that multiple signaling pathways might share MAPKs. Do different signaling pathways converge before MAPK function or can MAPKs maintain signaling specificity through interactions with specific proteins? The genetic and biochemical analysis of MAPK pathways in simple eukaryotes such as Dictyostelium offers opportunities to investigate functional specificity of MAPKs in G protein-mediated signal transduction pathways. This review considers the regulation and specificity of MAPK function in pathways that control Dictyostelium growth and development. PMID:21666837

  10. Gene expression analysis of aberrant signaling pathways in meningiomas

    PubMed Central

    TORRES-MARTÍN, MIGUEL; MARTINEZ-GLEZ, VICTOR; PEÑA-GRANERO, CAROLINA; ISLA, ALBERTO; LASSALETTA, LUIS; DE CAMPOS, JOSE M.; PINTO, GIOVANNY R.; BURBANO, ROMMEL R.; MELÉNDEZ, BÁRBARA; CASTRESANA, JAVIER S.; REY, JUAN A.

    2013-01-01

    Examining aberrant pathway alterations is one method for understanding the abnormal signals that are involved in tumorigenesis and tumor progression. In the present study, expression arrays were performed on tumor-related genes in meningiomas. The GE Array Q Series HS-006 was used to determine the expression levels of 96 genes that corresponded to six primary biological regulatory pathways in a series of 42 meningiomas, including 32 grade I, four recurrent grade I and six grade II tumors, in addition to three normal tissue controls. Results showed that 25 genes that were primarily associated with apoptosis and angiogenesis functions were downregulated and 13 genes frequently involving DNA damage repair functions were upregulated. In addition to the inactivation of the neurofibromin gene, NF2, which is considered to be an early step in tumorigenesis, variations of other biological regulatory pathways may play a significant role in the development of meningioma. PMID:23946817

  11. Gene expression analysis of aberrant signaling pathways in meningiomas.

    PubMed

    Torres-Martín, Miguel; Martinez-Glez, Victor; Peña-Granero, Carolina; Isla, Alberto; Lassaletta, Luis; DE Campos, Jose M; Pinto, Giovanny R; Burbano, Rommel R; Meléndez, Bárbara; Castresana, Javier S; Rey, Juan A

    2013-07-01

    Examining aberrant pathway alterations is one method for understanding the abnormal signals that are involved in tumorigenesis and tumor progression. In the present study, expression arrays were performed on tumor-related genes in meningiomas. The GE Array Q Series HS-006 was used to determine the expression levels of 96 genes that corresponded to six primary biological regulatory pathways in a series of 42 meningiomas, including 32 grade I, four recurrent grade I and six grade II tumors, in addition to three normal tissue controls. Results showed that 25 genes that were primarily associated with apoptosis and angiogenesis functions were downregulated and 13 genes frequently involving DNA damage repair functions were upregulated. In addition to the inactivation of the neurofibromin gene, NF2, which is considered to be an early step in tumorigenesis, variations of other biological regulatory pathways may play a significant role in the development of meningioma. PMID:23946817

  12. Exercise for the heart: signaling pathways

    PubMed Central

    Zhang, Haifeng; Xiao, Junjie; Li, Xinli

    2015-01-01

    Physical exercise, a potent functional intervention in protecting against cardiovascular diseases, is a hot topic in recent years. Exercise has been shown to reduce cardiac risk factors, protect against myocardial damage, and increase cardiac function. This improves quality of life and decreases mortality and morbidity in a variety of cardiovascular diseases, including myocardial infarction, cardiac ischemia/reperfusion injury, diabetic cardiomyopathy, cardiac aging, and pulmonary hypertension. The cellular adaptation to exercise can be associated with both endogenous and exogenous factors: 1) exercise induces cardiac growth via hypertrophy and renewal of cardiomyocytes, and 2) exercise induces endothelial progenitor cells to proliferate, migrate and differentiate into mature endothelial cells, giving rise to endothelial regeneration and angiogenesis. The cellular adaptations associated with exercise are due to the activation of several signaling pathways, in particular, the growth factor neuregulin1 (NRG1)-ErbB4-C/EBPβ and insulin-like growth factor (IGF)-1-PI3k-Akt signaling pathways. Of interest, microRNAs (miRNAs, miRs) such as miR-222 also play a major role in the beneficial effects of exercise. Thus, exploring the mechanisms mediating exercise-induced benefits will be instrumental for devising new effective therapies against cardiovascular diseases. PMID:26318584

  13. Current perspectives of the signaling pathways directing neural crest induction.

    PubMed

    Stuhlmiller, Timothy J; García-Castro, Martín I

    2012-11-01

    The neural crest is a migratory population of embryonic cells with a tremendous potential to differentiate and contribute to nearly every organ system in the adult body. Over the past two decades, an incredible amount of research has given us a reasonable understanding of how these cells are generated. Neural crest induction involves the combinatorial input of multiple signaling pathways and transcription factors, and is thought to occur in two phases from gastrulation to neurulation. In the first phase, FGF and Wnt signaling induce NC progenitors at the border of the neural plate, activating the expression of members of the Msx, Pax, and Zic families, among others. In the second phase, BMP, Wnt, and Notch signaling maintain these progenitors and bring about the expression of definitive NC markers including Snail2, FoxD3, and Sox9/10. In recent years, additional signaling molecules and modulators of these pathways have been uncovered, creating an increasingly complex regulatory network. In this work, we provide a comprehensive review of the major signaling pathways that participate in neural crest induction, with a focus on recent developments and current perspectives. We provide a simplified model of early neural crest development and stress similarities and differences between four major model organisms: Xenopus, chick, zebrafish, and mouse. PMID:22547091

  14. Current perspectives of the signaling pathways directing neural crest induction.

    PubMed

    Stuhlmiller, Timothy J; García-Castro, Martín I

    2012-11-01

    The neural crest is a migratory population of embryonic cells with a tremendous potential to differentiate and contribute to nearly every organ system in the adult body. Over the past two decades, an incredible amount of research has given us a reasonable understanding of how these cells are generated. Neural crest induction involves the combinatorial input of multiple signaling pathways and transcription factors, and is thought to occur in two phases from gastrulation to neurulation. In the first phase, FGF and Wnt signaling induce NC progenitors at the border of the neural plate, activating the expression of members of the Msx, Pax, and Zic families, among others. In the second phase, BMP, Wnt, and Notch signaling maintain these progenitors and bring about the expression of definitive NC markers including Snail2, FoxD3, and Sox9/10. In recent years, additional signaling molecules and modulators of these pathways have been uncovered, creating an increasingly complex regulatory network. In this work, we provide a comprehensive review of the major signaling pathways that participate in neural crest induction, with a focus on recent developments and current perspectives. We provide a simplified model of early neural crest development and stress similarities and differences between four major model organisms: Xenopus, chick, zebrafish, and mouse.

  15. Arbuscular Mycorrhiza–Specific Signaling in Rice Transcends the Common Symbiosis Signaling Pathway[W

    PubMed Central

    Gutjahr, Caroline; Banba, Mari; Croset, Vincent; An, Kyungsook; Miyao, Akio; An, Gynheung; Hirochika, Hirohiko; Imaizumi-Anraku, Haruko; Paszkowski, Uta

    2008-01-01

    Knowledge about signaling in arbuscular mycorrhizal (AM) symbioses is currently restricted to the common symbiosis (SYM) signaling pathway discovered in legumes. This pathway includes calcium as a second messenger and regulates both AM and rhizobial symbioses. Both monocotyledons and dicotyledons form symbiotic associations with AM fungi, and although they differ markedly in the organization of their root systems, the morphology of colonization is similar. To identify and dissect AM-specific signaling in rice (Oryza sativa), we developed molecular phenotyping tools based on gene expression patterns that monitor various steps of AM colonization. These tools were used to distinguish common SYM-dependent and -independent signaling by examining rice mutants of selected putative legume signaling orthologs predicted to be perturbed both upstream (CASTOR and POLLUX) and downstream (CCAMK and CYCLOPS) of the central, calcium-spiking signal. All four mutants displayed impaired AM interactions and altered AM-specific gene expression patterns, therefore demonstrating functional conservation of SYM signaling between distant plant species. In addition, differential gene expression patterns in the mutants provided evidence for AM-specific but SYM-independent signaling in rice and furthermore for unexpected deviations from the SYM pathway downstream of calcium spiking. PMID:19033527

  16. Signaling pathways in melanosome biogenesis and pathology.

    PubMed

    Schiaffino, Maria Vittoria

    2010-07-01

    Melanosomes are the specialized intracellular organelles of pigment cells devoted to the synthesis, storage and transport of melanin pigments, which are responsible for most visible pigmentation in mammals and other vertebrates. As a direct consequence, any genetic mutation resulting in alteration of melanosomal function, either because affecting pigment cell survival, migration and differentiation, or because interfering with melanosome biogenesis, transport and transfer to keratinocytes, is immediately translated into color variations of skin, fur, hair or eyes. Thus, over 100 genes and proteins have been identified as pigmentary determinants in mammals, providing us with a deep understanding of this biological system, which functions by using mechanisms and processes that have parallels in other tissues and organs. In particular, many genes implicated in melanosome biogenesis have been characterized, so that melanosomes represent an incredible source of information and a model for organelles belonging to the secretory pathway. Furthermore, the function of melanosomes can be associated with common physiological phenotypes, such as variation of pigmentation among individuals, and with rare pathological conditions, such as albinism, characterized by severe visual defects. Among the most relevant mechanisms operating in melanosome biogenesis are the signal transduction pathways mediated by two peculiar G protein-coupled receptors: the melanocortin-1 receptor (MC1R), involved in the fair skin/red hair phenotype and skin cancer; and OA1 (GPR143), whose loss-of-function results in X-linked ocular albinism. This review will focus on the most recent novelties regarding the functioning of these two receptors, by highlighting emerging signaling mechanisms and general implications for cell biology and pathology. PMID:20381640

  17. The Hippo-Salvador signaling pathway regulates renal tubulointerstitial fibrosis.

    PubMed

    Seo, Eunjeong; Kim, Wan-Young; Hur, Jeongmi; Kim, Hanbyul; Nam, Sun Ah; Choi, Arum; Kim, Yu-Mi; Park, Sang Hee; Chung, Chaeuk; Kim, Jin; Min, Soohong; Myung, Seung-Jae; Lim, Dae-Sik; Kim, Yong Kyun

    2016-08-23

    Renal tubulointerstitial fibrosis (TIF) is the final pathway of various renal injuries that result in chronic kidney disease. The mammalian Hippo-Salvador signaling pathway has been implicated in the regulation of cell proliferation, cell death, tissue regeneration, and tumorigenesis. Here, we report that the Hippo-Salvador pathway plays a role in disease development in patients with TIF and in a mouse model of TIF. Mice with tubular epithelial cell (TEC)-specific deletions of Sav1 (Salvador homolog 1) exhibited aggravated renal TIF, enhanced epithelial-mesenchymal transition-like phenotypic changes, apoptosis, and proliferation after unilateral ureteral obstruction (UUO). Moreover, Sav1 depletion in TECs increased transforming growth factor (TGF)-β and activated β-catenin expression after UUO, which likely accounts for the abovementioned enhanced TEC fibrotic phenotype. In addition, TAZ (transcriptional coactivator with PDZ-binding motif), a major downstream effector of the Hippo pathway, was significantly activated in Sav1-knockout mice in vivo. An in vitro study showed that TAZ directly regulates TGF-β and TGF-β receptor II expression. Collectively, our data indicate that the Hippo-Salvador pathway plays a role in the pathogenesis of TIF and that regulating this pathway may be a therapeutic strategy for reducing TIF.

  18. The Hippo-Salvador signaling pathway regulates renal tubulointerstitial fibrosis

    PubMed Central

    Seo, Eunjeong; Kim, Wan-Young; Hur, Jeongmi; Kim, Hanbyul; Nam, Sun Ah; Choi, Arum; Kim, Yu-Mi; Park, Sang Hee; Chung, Chaeuk; Kim, Jin; Min, Soohong; Myung, Seung-Jae; Lim, Dae-Sik; Kim, Yong Kyun

    2016-01-01

    Renal tubulointerstitial fibrosis (TIF) is the final pathway of various renal injuries that result in chronic kidney disease. The mammalian Hippo-Salvador signaling pathway has been implicated in the regulation of cell proliferation, cell death, tissue regeneration, and tumorigenesis. Here, we report that the Hippo-Salvador pathway plays a role in disease development in patients with TIF and in a mouse model of TIF. Mice with tubular epithelial cell (TEC)-specific deletions of Sav1 (Salvador homolog 1) exhibited aggravated renal TIF, enhanced epithelial-mesenchymal transition-like phenotypic changes, apoptosis, and proliferation after unilateral ureteral obstruction (UUO). Moreover, Sav1 depletion in TECs increased transforming growth factor (TGF)-β and activated β-catenin expression after UUO, which likely accounts for the abovementioned enhanced TEC fibrotic phenotype. In addition, TAZ (transcriptional coactivator with PDZ-binding motif), a major downstream effector of the Hippo pathway, was significantly activated in Sav1-knockout mice in vivo. An in vitro study showed that TAZ directly regulates TGF-β and TGF-β receptor II expression. Collectively, our data indicate that the Hippo-Salvador pathway plays a role in the pathogenesis of TIF and that regulating this pathway may be a therapeutic strategy for reducing TIF. PMID:27550469

  19. AlzPathway, an Updated Map of Curated Signaling Pathways: Towards Deciphering Alzheimer's Disease Pathogenesis.

    PubMed

    Ogishima, Soichi; Mizuno, Satoshi; Kikuchi, Masataka; Miyashita, Akinori; Kuwano, Ryozo; Tanaka, Hiroshi; Nakaya, Jun

    2016-01-01

    Alzheimer's disease (AD) is a complex neurodegenerative disorder in which loss of neurons and synaptic function causes dementia in the elderly. To clarify AD pathogenesis and develop drugs for AD, thousands of studies have elucidated signaling pathways involved. However, knowledge of AD signaling pathways has not been compiled as a pathway map. In this chapter, we introduce the manual construction of a pathway map in AD which we call "AlzPathway", that comprehensively catalogs signaling pathways in the field of AD. We have collected and manually curated over 100 review articles related to AD, and have built the AD pathway map. AlzPathway is currently composed of thousands of molecules and reactions in neurons, brain blood barrier, presynaptic, postsynaptic, astrocyte, and microglial cells, with their cellular localizations. AlzPathway provides a systems-biology platform of comprehensive AD signaling and related pathways which is expected to contribute to clarification of AD pathogenesis and AD drug development.

  20. [Psychiatric implications of PACAP signaling pathway].

    PubMed

    Hashimoto, Hitoshi

    2012-06-01

    Studies on genetically modified mice for investigating the role of pituitary adenylate cyclase-activating polypeptide (PACAP) in the brain have revealed a previously uncharacterized function of this neuropeptidergic signaling in the regulation of psychomotor behaviors. In addition, recent clinical studies investigating single nucleotide polymorphisms and copy number variations in the PACAP and its receptor genes have associated the variations with major psychiatric disorders and stress-dependent mental disorders. Here, I briefly review these recent advances in the field and make this an opportunity to consider future direction of research.

  1. Canonical RTK-Ras-ERK signaling and related alternative pathways

    PubMed Central

    Sundaram, Meera V.

    2013-01-01

    Receptor Tyrosine Kinase (RTK)-Ras-Extracellular signal-regulated kinase (ERK) signaling pathways control many aspects of C. elegans development and behavior. Studies in C. elegans helped elucidate the basic framework of the RTK-Ras-ERK pathway and continue to provide insights into its complex regulation, its biological roles, how it elicits cell-type appropriate responses, and how it interacts with other signaling pathways to do so. C. elegans studies have also revealed biological contexts in which alternative RTK- or Ras-dependent pathways are used instead of the canonical pathway. PMID:23908058

  2. The roles of signaling pathways in regulating kidney development.

    PubMed

    Xiao, Qiu; Rongfei, Wei; Lingqiang, Zhang; Fuchu, He

    2015-01-01

    The development of mammalian kidney is a complex process. The reciprocal inductive interactions between epithelial cells and metanephric mesenchymal cells determine cell fates including proliferation, growth, apoptosis, and eventually contribute to the formation of an intact kidney. Multiple signaling pathways, including the GDNF/Ret, Wnt and BMP signaling pathways, have been shown to regulate the development of kidney. A myriad of signaling pathways and their cross-talks form a precise spatiotemporal regulatory network, which ensures the kidney to be properly organized. In this review, we summarize the physiological process of kidney development as well as the involved signaling pathways and their interplay.

  3. Canonical WNT signaling pathway and human AREG.

    PubMed

    Katoh, Yuriko; Katoh, Masaru

    2006-06-01

    AREG (Amphiregulin), BTC (beta-cellulin), EGF, EPGN (Epigen), EREG (Epiregulin), HBEGF, NRG1, NRG2, NRG3, NRG4 and TGFA (TGFalpha) constitute EGF family ligands for ERBB family receptors. Cetuximab (Erbitux), Pertuzumab (Omnitarg) and Trastuzumab (Herceptin) are anti-cancer drugs targeted to EGF family ligands, while Gefitinib (Iressa), Erlotinib (Tarceva) and Lapatinib (GW572016) are anti-cancer drugs targeted to ERBB family receptors. AREG and TGFA are biomarkers for Gefitinib non-responders. The TCF/LEF binding sites within the promoter region of human EGF family members were searched for by using bioinformatics and human intelligence (Humint). Because three TCF/LEF-binding sites were identified within the 5'-promoter region of human AREG gene, comparative genomics analyses on AREG orthologs were further performed. The EPGN-EREG-AREG-BTC cluster at human chromosome 4q13.3 was linked to the PPBP-CXCL segmental duplicons. AREG was the paralog of HBEGF at human chromosome 5q31.2. Chimpanzee AREG gene, consisting of six exons, was located within NW_105918.1 genome sequence. Chimpanzee AREG was a type I transmembrane protein showing 98.0% and 71.4% total amino-acid identity with human AREG and mouse Areg, respectively. Three TCF/LEF-binding sites within human AREG promoter were conserved in chimpanzee AREG promoter, but not in rodent Areg promoters. Primate AREG promoters were significantly divergent from rodent Areg promoters. AREG mRNA was expressed in a variety of human tumors, such as colorectal cancer, liver cancer, gastric cancer, breast cancer, prostate cancer, esophageal cancer and myeloma. Because human AREG was characterized as potent target gene of WNT/beta-catenin signaling pathway, WNT signaling activation could lead to Gefitinib resistance through AREG upregulation. AREG is a target of systems medicine in the field of oncology. PMID:16685431

  4. Signaling through Rho GTPase pathway as viable drug target.

    PubMed

    Lu, Qun; Longo, Frank M; Zhou, Huchen; Massa, Stephen M; Chen, Yan-Hua

    2009-01-01

    Signaling through the Rho family of small GTPases has been increasingly investigated for their involvement in a wide variety of diseases such as cardiovascular, pulmonary, and neurological disorders as well as cancer. Rho GTPases are a subfamily of the Ras superfamily proteins which play essential roles in a number of biological processes, especially in the regulation of cell shape change, cytokinesis, cell adhesion, and cell migration. Many of these processes demonstrate a common theme: the rapid and dynamic reorganization of actin cytoskeleton of which Rho signaling has now emerged as a major switch control. The involvement of dynamic changes of Rho GTPases in disease states underscores the need to produce effective inhibitors for their therapeutic applications. Fasudil and Y-27632, with many newer additions, are two classes of widely used chemical compounds that inhibit Rho kinase (ROCK), an important downstream effector of RhoA subfamily GTPases. These inhibitors have been successful in many preclinical studies, indicating the potential benefit of clinical Rho pathway inhibition. On the other hand, except for Rac1 inhibitor NSC23766, there are few effective inhibitors directly targeting Rho GTPases, likely due to the lack of optimal structural information on individual Rho-RhoGEF, Rho-RhoGAP, or Rho-RhoGDI interaction to achieve specificity. Recently, LM11A-31 and other derivatives of peptide mimetic ligands for p75 neurotrophin receptor (p75(NTR)) show promising effects upstream of Rho GTPase signaling in neuronal regeneration. CCG-1423, a chemical compound showing profiles of inhibiting downstream of RhoA, is a further attempt for the development of novel pharmacological tools to disrupt Rho signaling pathway in cancer. Because of a rapidly growing number of studies deciphering the role of the Rho proteins in many diseases, specific and potent pharmaceutical modulators of various steps of Rho GTPase signaling pathway are critically needed to target for

  5. Cerebral insulin, insulin signaling pathway, and brain angiogenesis.

    PubMed

    Zeng, Yi; Zhang, Le; Hu, Zhiping

    2016-01-01

    Insulin performs unique non-metabolic functions within the brain. Broadly speaking, two major areas of these functions are those related to brain endothelial cells and the blood-brain barrier (BBB) function, and those related to behavioral effects, like cognition in disease states (Alzheimer's disease, AD) and in health. Recent studies showed that both these functions are associated with brain angiogenesis. These findings raise interesting questions such as how they are linked to each other and whether modifying brain angiogenesis by targeting certain insulin signaling pathways could be an effective strategy to treat dementia as in AD, or even to help secure healthy longevity. The two canonical downstream pathways involved in mediating the insulin signaling pathway, the phosphoinositide-3 kinase (PI3K), and mitogen-activated protein kinase (MAPK) cascades, in the brain are supposed to be similar to those in the periphery. PI3K and MAPK pathways play important roles in angiogenesis. Both are involved in stimulating hypoxia inducible factor (HIF) in angiogenesis and could be activated by the insulin signaling pathway. This suggests that PI3K and MAPK pathways might act as cross-talk between the insulin signaling pathway and the angiogenesis pathway in brain. But the cerebral insulin, insulin signaling pathway, and the detailed mechanism in the connection of insulin signaling pathway, brain angiogenesis pathway, and healthy aging or dementias are still mostly not clear and need further studies.

  6. Pentagone internalises glypicans to fine-tune multiple signalling pathways

    PubMed Central

    Norman, Mark; Vuilleumier, Robin; Springhorn, Alexander; Gawlik, Jennifer; Pyrowolakis, George

    2016-01-01

    Tight regulation of signalling activity is crucial for proper tissue patterning and growth. Here we investigate the function of Pentagone (Pent), a secreted protein that acts in a regulatory feedback during establishment and maintenance of BMP/Dpp morphogen signalling during Drosophila wing development. We show that Pent internalises the Dpp co-receptors, the glypicans Dally and Dally-like protein (Dlp), and propose that this internalisation is important in the establishment of a long range Dpp gradient. Pent-induced endocytosis and degradation of glypicans requires dynamin- and Rab5, but not clathrin or active BMP signalling. Thus, Pent modifies the ability of cells to trap and transduce BMP by fine-tuning the levels of the BMP reception system at the plasma membrane. In addition, and in accordance with the role of glypicans in multiple signalling pathways, we establish a requirement of Pent for Wg signalling. Our data propose a novel mechanism by which morphogen signalling is regulated. DOI: http://dx.doi.org/10.7554/eLife.13301.001 PMID:27269283

  7. Muscle redox signalling pathways in exercise. Role of antioxidants.

    PubMed

    Mason, Shaun A; Morrison, Dale; McConell, Glenn K; Wadley, Glenn D

    2016-09-01

    Recent research highlights the importance of redox signalling pathway activation by contraction-induced reactive oxygen species (ROS) and nitric oxide (NO) in normal exercise-related cellular and molecular adaptations in skeletal muscle. In this review, we discuss some potentially important redox signalling pathways in skeletal muscle that are involved in acute and chronic responses to contraction and exercise. Specifically, we discuss redox signalling implicated in skeletal muscle contraction force, mitochondrial biogenesis and antioxidant enzyme induction, glucose uptake and muscle hypertrophy. Furthermore, we review evidence investigating the impact of major exogenous antioxidants on these acute and chronic responses to exercise. Redox signalling pathways involved in adaptive responses in skeletal muscle to exercise are not clearly elucidated at present, and further research is required to better define important signalling pathways involved. Evidence of beneficial or detrimental effects of specific antioxidant compounds on exercise adaptations in muscle is similarly limited, particularly in human subjects. Future research is required to not only investigate effects of specific antioxidant compounds on skeletal muscle exercise adaptations, but also to better establish mechanisms of action of specific antioxidants in vivo. Although we feel it remains somewhat premature to make clear recommendations in relation to application of specific antioxidant compounds in different exercise settings, a bulk of evidence suggests that N-acetylcysteine (NAC) is ergogenic through its effects on maintenance of muscle force production during sustained fatiguing events. Nevertheless, a current lack of evidence from studies using performance tests representative of athletic competition and a potential for adverse effects with high doses (>70mg/kg body mass) warrants caution in its use for performance enhancement. In addition, evidence implicates high dose vitamin C (1g/day) and E

  8. The Hippo signaling pathway in stem cell biology and cancer.

    PubMed

    Mo, Jung-Soon; Park, Hyun Woo; Guan, Kun-Liang

    2014-06-01

    The Hippo signaling pathway, consisting of a highly conserved kinase cascade (MST and Lats) and downstream transcription coactivators (YAP and TAZ), plays a key role in tissue homeostasis and organ size control by regulating tissue-specific stem cells. Moreover, this pathway plays a prominent role in tissue repair and regeneration. Dysregulation of the Hippo pathway is associated with cancer development. Recent studies have revealed a complex network of upstream inputs, including cell density, mechanical sensation, and G-protein-coupled receptor (GPCR) signaling, that modulate Hippo pathway activity. This review focuses on the role of the Hippo pathway in stem cell biology and its potential implications in tissue homeostasis and cancer.

  9. Targeting the WNT Signaling Pathway in Cancer Therapeutics.

    PubMed

    Tai, David; Wells, Keith; Arcaroli, John; Vanderbilt, Chad; Aisner, Dara L; Messersmith, Wells A; Lieu, Christopher H

    2015-10-01

    The WNT signaling cascade is integral in numerous biological processes including embryonic development, cell cycle regulation, inflammation, and cancer. Hyperactivation of WNT signaling secondary to alterations to varying nodes of the pathway have been identified in multiple tumor types. These alterations converge into increased tumorigenicity, sustained proliferation, and enhanced metastatic potential. This review seeks to evaluate the evidence supporting the WNT pathway in cancer, the therapeutic strategies in modulating this pathway, and potential challenges in drug development.

  10. Signaling Pathways in Thyroid Cancer and Their Therapeutic Implications

    PubMed Central

    Jin, Shan; Borkhuu, Oyungerel; Bao, Wuyuntu; Yang, Yun-Tian

    2016-01-01

    Thyroid cancer is a common malignancy of endocrine system, and has now become the fastest increasing cancer among all the malignancies. The development, progression, invasion, and metastasis are closely associated with multiple signaling pathways and the functions of related molecules, such as Src, Janus kinase (JAK)-signal transducers and activators of transcription (STAT), mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/Akt, NF-κB, thyroid stimulating hormone receptor (TSHR), Wnt-β-catenin and Notch signaling pathways. Each of the signaling pathways could exert its function singly or through network with other pathways. These pathways could cooperate, promote, antagonize, or interact with each other to form a complex network for the regulation. Dysfunction of this network could increase the development, progression, invasion, and metastasis of thyroid cancer. Inoperable thyroid cancer still has a poor prognosis. However, signaling pathway-related targeted therapies offer the hope of longer quality of meaningful life for this small group of patients. Signaling pathway-related targets provide unprecedented opportunities for further research and clinical development of novel treatment strategies for this cancer. In the present work, the advances in these signaling pathways and targeted treatments of thyroid cancer were reviewed. PMID:26985248

  11. Distinct purinergic signaling pathways in prepubescent mouse spermatogonia.

    PubMed

    Fleck, David; Mundt, Nadine; Bruentgens, Felicitas; Geilenkirchen, Petra; Machado, Patricia A; Veitinger, Thomas; Veitinger, Sophie; Lipartowski, Susanne M; Engelhardt, Corinna H; Oldiges, Marco; Spehr, Jennifer; Spehr, Marc

    2016-09-01

    Spermatogenesis ranks among the most complex, yet least understood, developmental processes. The physiological principles that control male germ cell development in mammals are notoriously difficult to unravel, given the intricate anatomy and complex endo- and paracrinology of the testis. Accordingly, we lack a conceptual understanding of the basic signaling mechanisms within the testis, which control the seminiferous epithelial cycle and thus govern spermatogenesis. Here, we address paracrine signal transduction in undifferentiated male germ cells from an electrophysiological perspective. We identify distinct purinergic signaling pathways in prepubescent mouse spermatogonia, both in vitro and in situ. ATP-a dynamic, widespread, and evolutionary conserved mediator of cell to cell communication in various developmental contexts-activates at least two different spermatogonial purinoceptor isoforms. Both receptors operate within nonoverlapping stimulus concentration ranges, display distinct response kinetics and, in the juvenile seminiferous cord, are uniquely expressed in spermatogonia. We further find that spermatogonia express Ca(2+)-activated large-conductance K(+) channels that appear to function as a safeguard against prolonged ATP-dependent depolarization. Quantitative purine measurements additionally suggest testicular ATP-induced ATP release, a mechanism that could increase the paracrine radius of initially localized signaling events. Moreover, we establish a novel seminiferous tubule slice preparation that allows targeted electrophysiological recordings from identified testicular cell types in an intact epithelial environment. This unique approach not only confirms our in vitro findings, but also supports the notion of purinergic signaling during the early stages of spermatogenesis. PMID:27574293

  12. Validation of signalling pathways: Case study of the p16-mediated pathway.

    PubMed

    Akçay, Nimet İlke; Bashirov, Rza; Tüzmen, Şükrü

    2015-04-01

    p16 is recognized as a tumor suppressor gene due to the prevalence of its genetic inactivation in all types of human cancers. Additionally, p16 gene plays a critical role in controlling aging, regulating cellular senescence, detection and maintenance of DNA damage. The molecular mechanism behind these events involves p16-mediated signaling pathway (or p16- Rb pathway), the focus of our study. Understanding functional dependence between dynamic behavior of biological components involved in the p16-mediated pathway and aforesaid molecular-level events might suggest possible implications in the diagnosis, prognosis and treatment of human cancer. In the present work, we employ reverse-engineering approach to construct the most detailed computational model of p16-mediated pathway in higher eukaryotes. We implement experimental data from the literature to validate the model, and under various assumptions predict the dynamic behavior of p16 and other biological components by interpreting the simulation results. The quantitative model of p16-mediated pathway is created in a systematic manner in terms of Petri net technologies.

  13. Targeting Wnt signaling in colorectal cancer. A Review in the Theme: Cell Signaling: Proteins, Pathways and Mechanisms

    PubMed Central

    Novellasdemunt, Laura; Antas, Pedro

    2015-01-01

    The evolutionarily conserved Wnt signaling pathway plays essential roles during embryonic development and tissue homeostasis. Notably, comprehensive genetic studies in Drosophila and mice in the past decades have demonstrated the crucial role of Wnt signaling in intestinal stem cell maintenance by regulating proliferation, differentiation, and cell-fate decisions. Wnt signaling has also been implicated in a variety of cancers and other diseases. Loss of the Wnt pathway negative regulator adenomatous polyposis coli (APC) is the hallmark of human colorectal cancers (CRC). Recent advances in high-throughput sequencing further reveal many novel recurrent Wnt pathway mutations in addition to the well-characterized APC and β-catenin mutations in CRC. Despite attractive strategies to develop drugs for Wnt signaling, major hurdles in therapeutic intervention of the pathway persist. Here we discuss the Wnt-activating mechanisms in CRC and review the current advances and challenges in drug discovery. PMID:26289750

  14. Information processing in multi-step signaling pathways

    NASA Astrophysics Data System (ADS)

    Ganesan, Ambhi; Hamidzadeh, Archer; Zhang, Jin; Levchenko, Andre

    Information processing in complex signaling networks is limited by a high degree of variability in the abundance and activity of biochemical reactions (biological noise) operating in living cells. In this context, it is particularly surprising that many signaling pathways found in eukaryotic cells are composed of long chains of biochemical reactions, which are expected to be subject to accumulating noise and delayed signal processing. Here, we challenge the notion that signaling pathways are insulated chains, and rather view them as parts of extensively branched networks, which can benefit from a low degree of interference between signaling components. We further establish conditions under which this pathway organization would limit noise accumulation, and provide evidence for this type of signal processing in an experimental model of a calcium-activated MAPK cascade. These results address the long-standing problem of diverse organization and structure of signaling networks in live cells.

  15. The hypoxia signaling pathway and hypoxic adaptation in fishes.

    PubMed

    Xiao, Wuhan

    2015-02-01

    The hypoxia signaling pathway is an evolutionarily conserved cellular signaling pathway present in animals ranging from Caenorhabditis elegans to mammals. The pathway is crucial for oxygen homeostasis maintenance. Hypoxia-inducible factors (HIF-1α and HIF-2α) are master regulators in the hypoxia signaling pathway. Oxygen concentrations vary a lot in the aquatic environment. To deal with this, fishes have adapted and developed varying strategies for living in hypoxic conditions. Investigations into the strategies and mechanisms of hypoxia adaptation in fishes will allow us to understand fish speciation and breed hypoxia-tolerant fish species/strains. This review summarizes the process of the hypoxia signaling pathway and its regulation, as well as the mechanism of hypoxia adaptation in fishes.

  16. Miltefosine Suppresses Hepatic Steatosis by Activating AMPK Signal Pathway

    PubMed Central

    Zhu, Yaqin; Tong, Xing; Li, Kexue; Bai, Hui; Li, Xiaoyu; Ben, Jingjing; Zhang, Hanwen; Yang, Qing; Chen, Qi

    2016-01-01

    Background and Purpose It has been accepted that AMPK (Adenosine monophosphate–activated protein kinase) activation exhibits many beneficial effects on glucolipid metabolism. Lysophosphatidylcholine (LPC) is an important lysophospholipid which can improve blood glucose levels in diabetic mice and attenuate inflammation by activating AMPK signal pathway in macrophages. Synthetic alkylphospholipids (ALPs), such as miltefosine, is used as an alternate of LPC for the clinical application. Here, we investigated whether miltefosine could have an impact on hepatic steatosis and related metabolic disorders. Experimental Approach Mice were fed with high fat diet (HFD) for 16 weeks to generate an obese model. Next, the obese mice were randomly divided into three groups: saline-treated and miltefosine-treated (2.5 or 5 mg/kg/d) groups. Miltefosine was intraperitoneally administrated into mice for additional 4 weeks plus HFD treatment. Key Results It was shown that miltefosine treatment could substantially improve glucose metabolism, prevented hepatic lipid accumulation, and inhibited liver inflammation in HFD-fed mice by activating AMPK signal pathway. In vitro, miltefosine stimulated AMPKα phosphorylation both in time and dose dependent manner and decreased lipid accumulation in liver cells. When a specific AMPK inhibitor compound C was used to treat mice, the antagonistic effects of miltefosine on HFD-induced mouse hyperlipidaemia and liver steatosis were abolished. Treatment with miltefosine also dramatically inhibited the HFD-induced liver inflammation in mice. Conclusions and Implications Here we demonstrated that miltefosine might be a new activator of AMPK signal pathway in vivo and in vitro and be useful for treatment of hepatic steatosis and related metabolic disorders. PMID:27681040

  17. Evolutionary conservation of plant gibberellin signalling pathway components

    PubMed Central

    Vandenbussche, Filip; Fierro, Ana C; Wiedemann, Gertrud; Reski, Ralf; Van Der Straeten, Dominique

    2007-01-01

    Background: Gibberellins (GA) are plant hormones that can regulate germination, elongation growth, and sex determination. They ubiquitously occur in seed plants. The discovery of gibberellin receptors, together with advances in understanding the function of key components of GA signalling in Arabidopsis and rice, reveal a fairly short GA signal transduction route. The pathway essentially consists of GID1 gibberellin receptors that interact with F-box proteins, which in turn regulate degradation of downstream DELLA proteins, suppressors of GA-controlled responses. Results: Arabidopsis sequences of the gibberellin signalling compounds were used to screen databases from a variety of plants, including protists, for homologues, providing indications for the degree of conservation of the pathway. The pathway as such appears completely absent in protists, the moss Physcomitrella patens shares only a limited homology with the Arabidopsis proteins, thus lacking essential characteristics of the classical GA signalling pathway, while the lycophyte Selaginella moellendorffii contains a possible ortholog for each component. The occurrence of classical GA responses can as yet not be linked with the presence of homologues of the signalling pathway. Alignments and display in neighbour joining trees of the GA signalling components confirm the close relationship of gymnosperms, monocotyledonous and dicotyledonous plants, as suggested from previous studies. Conclusion: Homologues of the GA-signalling pathway were mainly found in vascular plants. The GA signalling system may have its evolutionary molecular onset in Physcomitrella patens, where GAs at higher concentrations affect gravitropism and elongation growth. PMID:18047669

  18. Targeting the Notch signaling pathway in cancer therapeutics

    PubMed Central

    Guo, Huajiao; Lu, Yi; Wang, Jianhua; Liu, Xia; Keller, Evan T; Liu, Qian; Zhou, Qinghua; Zhang, Jian

    2014-01-01

    Despite advances in surgery, imaging, chemotherapy, and radiotherapy, the poor overall cancer-related death rate remains unacceptable. Novel therapeutic strategies are desperately needed. Nowadays, targeted therapy has become the most promising therapy and a welcome asset to the cancer therapeutic arena. There is a large body of evidence demonstrating that the Notch signaling pathway is critically involved in the pathobiology of a variety of malignancies. In this review, we provide an overview of emerging data, highlight the mechanism of the Notch signaling pathway in the development of a wide range of cancers, and summarize recent progress in therapeutic targeting of the Notch signaling pathway. PMID:26767041

  19. Neurotrophin signalling pathways regulating neuronal apoptosis.

    PubMed

    Miller, F D; Kaplan, D R

    2001-07-01

    Recent evidence indicates that naturally occurring neuronal death in mammals is regulated by the interplay between receptor-mediated prosurvival and proapoptotic signals. The neurotrophins, a family of growth factors best known for their positive effects on neuronal biology, have now been shown to mediate both positive and negative survival signals, by signalling through the Trk and p75 neurotrophin receptors, respectively. The mechanisms whereby these two neurotrophin receptors interact to determine neuronal survival have been difficult to decipher, largely because both can signal independently or coincidentally, depending upon the cell or developmental context. Nonetheless, the past several years have seen significant advances in our understanding of this receptor signalling system. In this review, we focus on the proapoptotic actions of the p75 neurotrophin receptor (p75NTR), and on the interplay between Trk and p75NTR that determines neuronal survival.

  20. Neurotrophin signalling pathways regulating neuronal apoptosis.

    PubMed

    Miller, F D; Kaplan, D R

    2001-07-01

    Recent evidence indicates that naturally occurring neuronal death in mammals is regulated by the interplay between receptor-mediated prosurvival and proapoptotic signals. The neurotrophins, a family of growth factors best known for their positive effects on neuronal biology, have now been shown to mediate both positive and negative survival signals, by signalling through the Trk and p75 neurotrophin receptors, respectively. The mechanisms whereby these two neurotrophin receptors interact to determine neuronal survival have been difficult to decipher, largely because both can signal independently or coincidentally, depending upon the cell or developmental context. Nonetheless, the past several years have seen significant advances in our understanding of this receptor signalling system. In this review, we focus on the proapoptotic actions of the p75 neurotrophin receptor (p75NTR), and on the interplay between Trk and p75NTR that determines neuronal survival. PMID:11529497

  1. Intricacies of hedgehog signaling pathways: A perspective in tumorigenesis

    SciTech Connect

    Kar, Swayamsiddha; Deb, Moonmoon; Sengupta, Dipta; Shilpi, Arunima; Bhutia, Sujit Kumar; Patra, Samir Kumar

    2012-10-01

    The hedgehog (HH) signaling pathway is a crucial negotiator of developmental proceedings in the embryo governing a diverse array of processes including cell proliferation, differentiation, and tissue patterning. The overall activity of the pathway is significantly curtailed after embryogenesis as well as in adults, yet it retains many of its functional capacities. However, aberration in HH signaling mediates the initiation, proliferation and continued sustenance of malignancy in different tissues to varying degrees through different mechanisms. In this review, we provide an overview of the role of constitutively active aberrant HH signaling pathway in different types of human cancer and the underlying molecular and genetic mechanisms that drive tumorigenesis in that particular tissue. An insight into the various modes of anomalous HH signaling in different organs will provide a comprehensive knowledge of the pathway in these tissues and open a window for individually tailored, tissue-specific therapeutic interventions. The synergistic cross talking of HH pathway with many other regulatory molecules and developmentally inclined signaling pathways may offer many avenues for pharmacological advances. Understanding the molecular basis of abnormal HH signaling in cancer will provide an opportunity to inhibit the deregulated pathway in many aggressive and therapeutically challenging cancers where promising options are not available.

  2. UV signaling pathways within the skin

    PubMed Central

    Chen, Hongxiang; Weng, Qing Yu; Fisher, David E.

    2014-01-01

    The effects of UVR on the skin include tanning, carcinogenesis, immunomodulation, and synthesis of vitamin D, among others. Melanocortin 1 receptor polymorphisms correlate with skin pigmentation, UV sensitivity, and skin cancer risk. This article reviews pathways through which UVR induces cutaneous stress and the pigmentation response. Modulators of the UV tanning pathway include sunscreen agents, MC1R activators, adenylate cyclase activators, phosphodiesterase 4D3 inhibitors, T oligos, and MITF regulators such as histone deacetylase (HDAC)-inhibitors. UVR, as one of the most ubiquitous carcinogens, represents both a challenge and enormous opportunity in skin cancer prevention. PMID:24759085

  3. Text mining for metabolic pathways, signaling cascades, and protein networks.

    PubMed

    Hoffmann, Robert; Krallinger, Martin; Andres, Eduardo; Tamames, Javier; Blaschke, Christian; Valencia, Alfonso

    2005-05-10

    The complexity of the information stored in databases and publications on metabolic and signaling pathways, the high throughput of experimental data, and the growing number of publications make it imperative to provide systems to help the researcher navigate through these interrelated information resources. Text-mining methods have started to play a key role in the creation and maintenance of links between the information stored in biological databases and its original sources in the literature. These links will be extremely useful for database updating and curation, especially if a number of technical problems can be solved satisfactorily, including the identification of protein and gene names (entities in general) and the characterization of their types of interactions. The first generation of openly accessible text-mining systems, such as iHOP (Information Hyperlinked over Proteins), provides additional functions to facilitate the reconstruction of protein interaction networks, combine database and text information, and support the scientist in the formulation of novel hypotheses. The next challenge is the generation of comprehensive information regarding the general function of signaling pathways and protein interaction networks. PMID:15886388

  4. Dynamic signaling in the Hog1 MAPK pathway relies on high basal signal transduction.

    PubMed

    Macia, Javier; Regot, Sergi; Peeters, Tom; Conde, Núria; Solé, Ricard; Posas, Francesc

    2009-01-01

    Appropriate regulation of the Hog1 mitogen-activated protein kinase (MAPK) pathway is essential for cells to survive osmotic stress. Here, we show that the two sensing mechanisms upstream of Hog1 display different signaling properties. The Sho1 branch is an inducible nonbasal system, whereas the Sln1 branch shows high basal signaling that is restricted by a MAPK-mediated feedback mechanism. A two-dimensional mathematical model of the Snl1 branch, including high basal signaling and a Hog1-regulated negative feedback, shows that a system with basal signaling exhibits higher efficiency, with faster response times and higher sensitivity to variations in external signals, than would systems without basal signaling. Analysis of two other yeast MAPK pathways, the Fus3 and Kss1 signaling pathways, indicates that high intrinsic basal signaling may be a general property of MAPK pathways allowing rapid and sensitive responses to environmental changes. PMID:19318625

  5. UNDERSTANDING PATHWAYS OF TOXICITY: MAKING SENSE OF CHANGING SIGNALS

    EPA Science Inventory

    Title:
    Understanding Pathways of Toxicity: Making sense of changing signals
    Authors & affiliations:
    Sid Hunter, Maria Blanton, Edward Karoly, Ellen Rogers, Leonard Mole, Phillip Hartig, James Andrews. Reproductive Toxicology Division, National Health and Environmental Ef...

  6. Linear effects models of signaling pathways from combinatorial perturbation data

    PubMed Central

    Szczurek, Ewa; Beerenwinkel, Niko

    2016-01-01

    Motivation: Perturbations constitute the central means to study signaling pathways. Interrupting components of the pathway and analyzing observed effects of those interruptions can give insight into unknown connections within the signaling pathway itself, as well as the link from the pathway to the effects. Different pathway components may have different individual contributions to the measured perturbation effects, such as gene expression changes. Those effects will be observed in combination when the pathway components are perturbed. Extant approaches focus either on the reconstruction of pathway structure or on resolving how the pathway components control the downstream effects. Results: Here, we propose a linear effects model, which can be applied to solve both these problems from combinatorial perturbation data. We use simulated data to demonstrate the accuracy of learning the pathway structure as well as estimation of the individual contributions of pathway components to the perturbation effects. The practical utility of our approach is illustrated by an application to perturbations of the mitogen-activated protein kinase pathway in Saccharomyces cerevisiae. Availability and Implementation: lem is available as a R package at http://www.mimuw.edu.pl/∼szczurek/lem. Contact: szczurek@mimuw.edu.pl; niko.beerenwinkel@bsse.ethz.ch Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27307630

  7. Arrestins: ubiquitous regulators of cellular signaling pathways.

    PubMed

    Gurevich, Eugenia V; Gurevich, Vsevolod V

    2006-01-01

    In vertebrates, the arrestins are a family of four proteins that regulate the signaling and trafficking of hundreds of different G-protein-coupled receptors (GPCRs). Arrestin homologs are also found in insects, protochordates and nematodes. Fungi and protists have related proteins but do not have true arrestins. Structural information is available only for free (unbound) vertebrate arrestins, and shows that the conserved overall fold is elongated and composed of two domains, with the core of each domain consisting of a seven-stranded beta-sandwich. Two main intramolecular interactions keep the two domains in the correct relative orientation, but both of these interactions are destabilized in the process of receptor binding, suggesting that the conformation of bound arrestin is quite different. As well as binding to hundreds of GPCR subtypes, arrestins interact with other classes of membrane receptors and more than 20 surprisingly diverse types of soluble signaling protein. Arrestins thus serve as ubiquitous signaling regulators in the cytoplasm and nucleus.

  8. Role of Hedgehog Signaling Pathway in NASH

    PubMed Central

    Verdelho Machado, Mariana; Diehl, Anna Mae

    2016-01-01

    Non-alcoholic fatty liver disease (NAFLD) is the number one cause of chronic liver disease in the Western world. Although only a minority of patients will ultimately develop end-stage liver disease, it is not yet possible to efficiently predict who will progress and, most importantly, effective treatments are still unavailable. Better understanding of the pathophysiology of this disease is necessary to improve the clinical management of NAFLD patients. Epidemiological data indicate that NAFLD prognosis is determined by an individual’s response to lipotoxic injury, rather than either the severity of exposure to lipotoxins, or the intensity of liver injury. The liver responds to injury with a synchronized wound-healing response. When this response is abnormal, it leads to pathological scarring, resulting in progressive fibrosis and cirrhosis, rather than repair. The hedgehog pathway is a crucial player in the wound-healing response. In this review, we summarize the pre-clinical and clinical evidence, which demonstrate the role of hedgehog pathway dysregulation in NAFLD pathogenesis, and the preliminary data that place the hedgehog pathway as a potential target for the treatment of this disease. PMID:27258259

  9. Modeling Protein Expression and Protein Signaling Pathways

    PubMed Central

    Telesca, Donatello; Müller, Peter; Kornblau, Steven M.; Suchard, Marc A.; Ji, Yuan

    2015-01-01

    High-throughput functional proteomic technologies provide a way to quantify the expression of proteins of interest. Statistical inference centers on identifying the activation state of proteins and their patterns of molecular interaction formalized as dependence structure. Inference on dependence structure is particularly important when proteins are selected because they are part of a common molecular pathway. In that case, inference on dependence structure reveals properties of the underlying pathway. We propose a probability model that represents molecular interactions at the level of hidden binary latent variables that can be interpreted as indicators for active versus inactive states of the proteins. The proposed approach exploits available expert knowledge about the target pathway to define an informative prior on the hidden conditional dependence structure. An important feature of this prior is that it provides an instrument to explicitly anchor the model space to a set of interactions of interest, favoring a local search approach to model determination. We apply our model to reverse-phase protein array data from a study on acute myeloid leukemia. Our inference identifies relevant subpathways in relation to the unfolding of the biological process under study. PMID:26246646

  10. Estrogen Signaling Multiple Pathways to Impact Gene Transcription

    PubMed Central

    Marino, Maria; Galluzzo, Paola; Ascenzi, Paolo

    2006-01-01

    Steroid hormones exert profound effects on cell growth, development, differentiation, and homeostasis. Their effects are mediated through specific intracellular steroid receptors that act via multiple mechanisms. Among others, the action mechanism starting upon 17β-estradiol (E2) binds to its receptors (ER) is considered a paradigmatic example of how steroid hormones function. Ligand-activated ER dimerizes and translocates in the nucleus where it recognizes specific hormone response elements located in or near promoter DNA regions of target genes. Behind the classical genomic mechanism shared with other steroid hormones, E2 also modulates gene expression by a second indirect mechanism that involves the interaction of ER with other transcription factors which, in turn, bind their cognate DNA elements. In this case, ER modulates the activities of transcription factors such as the activator protein (AP)-1, nuclear factor-κB (NF-κB) and stimulating protein-1 (Sp-1), by stabilizing DNA-protein complexes and/or recruiting co-activators. In addition, E2 binding to ER may also exert rapid actions that start with the activation of a variety of signal transduction pathways (e.g. ERK/MAPK, p38/MAPK, PI3K/AKT, PLC/PKC). The debate about the contribution of different ER-mediated signaling pathways to coordinate the expression of specific sets of genes is still open. This review will focus on the recent knowledge about the mechanism by which ERs regulate the expression of target genes and the emerging field of integration of membrane and nuclear receptor signaling, giving examples of the ways by which the genomic and non-genomic actions of ERs on target genes converge. PMID:18369406

  11. Sonic Hedgehog Signalling Pathway and Ameloblastoma - A Review.

    PubMed

    Mishra, Pallavi; Panda, Abikshyeet; Bandyopadhyay, Alokenath; Kumar, Harish; Mohiddin, Gouse

    2015-11-01

    Ameloblastoma is a benign but aggressive odontogenic neoplasm arising from odontogenic epithelium. Many theories have been proposed to explain the pathogenesis of ameloblatoma. Numerous signalling pathways have been implicated to be associated in the development and progression of this neoplasm. Studies have found association of various signalling molecules of Sonic Hedgehog Pathway, namely SHH, PTCH1, SMO, Gli 1, Gli 2, Gli 3, with ameloblastoma. Knowledge about this pathway will help us to understand the nature and behaviour of this neoplasm. This will open the door towards new treatment modalities. PMID:26674664

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

    PubMed

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

    2016-09-15

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

  13. Sonic Hedgehog Signalling Pathway and Ameloblastoma – A Review

    PubMed Central

    Mishra, Pallavi; Bandyopadhyay, Alokenath; Kumar, Harish; Mohiddin, Gouse

    2015-01-01

    Ameloblastoma is a benign but aggressive odontogenic neoplasm arising from odontogenic epithelium. Many theories have been proposed to explain the pathogenesis of ameloblatoma. Numerous signalling pathways have been implicated to be associated in the development and progression of this neoplasm. Studies have found association of various signalling molecules of Sonic Hedgehog Pathway, namely SHH, PTCH1, SMO, Gli 1, Gli 2, Gli 3, with ameloblastoma. Knowledge about this pathway will help us to understand the nature and behaviour of this neoplasm. This will open the door towards new treatment modalities. PMID:26674664

  14. Signaling pathway networks mined from human pituitary adenoma proteomics data

    PubMed Central

    2010-01-01

    Background We obtained a series of pituitary adenoma proteomic expression data, including protein-mapping data (111 proteins), comparative proteomic data (56 differentially expressed proteins), and nitroproteomic data (17 nitroproteins). There is a pressing need to clarify the significant signaling pathway networks that derive from those proteins in order to clarify and to better understand the molecular basis of pituitary adenoma pathogenesis and to discover biomarkers. Here, we describe the significant signaling pathway networks that were mined from human pituitary adenoma proteomic data with the Ingenuity pathway analysis system. Methods The Ingenuity pathway analysis system was used to analyze signal pathway networks and canonical pathways from protein-mapping data, comparative proteomic data, adenoma nitroproteomic data, and control nitroproteomic data. A Fisher's exact test was used to test the statistical significance with a significance level of 0.05. Statistical significant results were rationalized within the pituitary adenoma biological system with literature-based bioinformatics analyses. Results For the protein-mapping data, the top pathway networks were related to cancer, cell death, and lipid metabolism; the top canonical toxicity pathways included acute-phase response, oxidative-stress response, oxidative stress, and cell-cycle G2/M transition regulation. For the comparative proteomic data, top pathway networks were related to cancer, endocrine system development and function, and lipid metabolism; the top canonical toxicity pathways included mitochondrial dysfunction, oxidative phosphorylation, oxidative-stress response, and ERK/MAPK signaling. The nitroproteomic data from a pituitary adenoma were related to cancer, cell death, lipid metabolism, and reproductive system disease, and the top canonical toxicity pathways mainly related to p38 MAPK signaling and cell-cycle G2/M transition regulation. Nitroproteins from a pituitary control related to

  15. Signal Transduction Pathways that Regulate CAB Gene Expression

    SciTech Connect

    Chory, Joanne

    2004-12-31

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  16. Signal Transduction Pathways that Regulate CAB Gene Expression

    SciTech Connect

    Chory, Joanne

    2006-01-16

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  17. Frontier of Epilepsy Research - mTOR signaling pathway

    PubMed Central

    2011-01-01

    Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism. PMID:21467839

  18. Oscillatory Dynamics of the Extracellular Signal-regulated Kinase Pathway

    SciTech Connect

    Shankaran, Harish; Wiley, H. S.

    2010-12-01

    The extracellular signal-regulated kinase (ERK) pathway is a central signaling pathway in development and disease and is regulated by multiple negative and positive feedback loops. Recent studies have shown negative feedback from ERK to upstream regulators can give rise to biochemical oscillations with a periodicity of between 15-30 minutes. Feedback due to the stimulated transcription of negative regulators of the ERK pathway can also give rise to transcriptional oscillations with a periodicity of 1-2h. The biological significance of these oscillations is not clear, but recent evidence suggests that transcriptional oscillations participate in developmental processes, such as somite formation. Biochemical oscillations are more enigmatic, but could provide a mechanism for encoding different types of inputs into a common signaling pathway.

  19. Functional roles for myosin 1c in cellular signaling pathways

    PubMed Central

    Bond, Lisa M.; Brandstaetter, Hemma; Kendrick-Jones, John; Buss, Folma

    2013-01-01

    Cellular signaling pathways underlie the transfer of information throughout the cell and to adjoining cells and so govern most critical cellular functions. Increasing evidence points to the molecular motor myosin 1c as a prominent player in many signaling cascades, from the integrin-dependent signaling involved in cell migration to the signaling events underlying insulin resistance. Myosin 1c functions on these pathways both via an important role in regulating lipid raft recycling and also via direct involvement in signaling cascades. This review provides an overview of the functional involvement of myosin 1c in cellular signaling and discusses the possible potential for myosin 1c as a target for drug-based treatments for human diseases. PMID:23022959

  20. IDO⁺ DCs and signalling pathways.

    PubMed

    Wang, Yue; Yang, Bao-Hong; Li, Hui; Cao, Shui; Ren, Xiu-Bao; Yu, Jin-Pu

    2013-03-01

    Dendritic cells (DCs) have traditionally been viewed as constituting an 'information management' system that functions solely to integrate a diverse array of incoming signals, in order to induce immune reactivity. In recent years, however, there has been a shift towards viewing these cells as key regulators in the orchestration of immunological tolerance, with increasing recognition that they are capable of suppressing T-cell responses depending on signalling processes and localised biochemical conditions. Indoleamine 2,3-dioxygenase (IDO) competent (IDO⁺) DCs are a subset of human DCs which are programmed to a tolerogenic state and play a vital role in establishing and maintaining a tumour-suppressing milieu. The expression of IDO in these DCs represents a key mechanism responsible for inducing the tolerogenic state. However, the mechanisms by which IDO becomes dysregulated in this subset of DCs have not yet been described. In this review, the function of IDO⁺ DCs within the cancer-tolerogenic milieu, as well as the signals responsible for expression of IDO in this subset, will be discussed.

  1. Role of the Neuregulin Signaling Pathway in Nicotine Dependence and Co-morbid Disorders

    PubMed Central

    Fisher, Miranda L.; Loukola, Anu; Kaprio, Jaakko; Turner, Jill R.

    2016-01-01

    Smoking is currently the leading cause of preventable death in the United States and is responsible for over four million deaths annually worldwide. Therefore, there is a vast clinical unmet need with regards to therapeutics targeting smoking cessation. This is even more apparent when examining smokers co-morbid with psychiatric illness, as rates of smoking in this population are ~4× higher than in the general population. Examining common genetic and molecular signaling pathways impinging upon both smoking behavior and psychiatric illness will lead to a better understanding of co-morbid disorders and potential development of novel therapeutics. Studies have implicated the Neuregulin Signaling Pathway in the pathophysiology of a number of psychiatric illnesses. Additionally, recent studies have also shown an association between the Neuregulin Signaling Pathway and smoking behaviors. This review outlines basic mechanisms of the Neuregulin Signaling Pathway and how it may be exploited for precision medicine approaches in treating nicotine dependence and mental illness. PMID:26472527

  2. Tight Junction–Associated Signaling Pathways Modulate Cell Proliferation in Uveal Melanoma

    PubMed Central

    Jayagopal, Ashwath; Yang, Jin-Long; Haselton, Frederick R.; Chang, Min S.

    2011-01-01

    Purpose. To investigate the role of tight junction (TJ)–associated signaling pathways in the proliferation of uveal melanoma. Methods. Human uveal melanoma cell lines overexpressing the TJ molecule blood vessel epicardial substance (Bves) were generated. The effects of Bves overexpression on TJ protein expression, cell proliferation, and cell cycle distribution were quantified. In addition, localization and transcription activity of the TJ-associated protein ZO-1–associated nucleic acid binding protein (ZONAB) were evaluated using immunofluorescence and bioluminescence reporter assays to study the involvement of Bves signaling in cell proliferation-associated pathways. Results. Bves overexpression in uveal melanoma cell lines resulted in increased expression of the TJ proteins occludin and ZO-1, reduced cell proliferation, and increased sequestration of ZONAB at TJs and reduced ZONAB transcriptional activity. Conclusions. TJ proteins are present in uveal melanoma, and TJ-associated signaling pathways modulate cell signaling pathways relevant to proliferation in uveal melanoma. PMID:20861479

  3. Role of the Neuregulin Signaling Pathway in Nicotine Dependence and Co-morbid Disorders.

    PubMed

    Fisher, Miranda L; Loukola, Anu; Kaprio, Jaakko; Turner, Jill R

    2015-01-01

    Smoking is currently the leading cause of preventable death in the United States and is responsible for over four million deaths annually worldwide. Therefore, there is a vast clinical unmet need with regards to therapeutics targeting smoking cessation. This is even more apparent when examining smokers co-morbid with psychiatric illness, as rates of smoking in this population are ~4× higher than in the general population. Examining common genetic and molecular signaling pathways impinging upon both smoking behavior and psychiatric illness will lead to a better understanding of co-morbid disorders and potential development of novel therapeutics. Studies have implicated the Neuregulin Signaling Pathway in the pathophysiology of a number of psychiatric illnesses. Additionally, recent studies have also shown an association between the Neuregulin Signaling Pathway and smoking behaviors. This review outlines basic mechanisms of the Neuregulin Signaling Pathway and how it may be exploited for precision medicine approaches in treating nicotine dependence and mental illness. PMID:26472527

  4. ERβ induces the differentiation of cultured osteoblasts by both Wnt/β-catenin signaling pathway and estrogen signaling pathways

    SciTech Connect

    Yin, Xinhua; Wang, Xiaoyuan; Hu, Xiongke; Chen, Yong; Zeng, Kefeng; Zhang, Hongqi

    2015-07-01

    Although 17β-estradial (E2) is known to stimulate bone formation, the underlying mechanisms are not fully understood. Recent studies have implicated the Wnt/β-catenin pathway as a major signaling cascade in bone biology. The interactions between Wnt/β-catenin signaling pathway and estrogen signaling pathways have been reported in many tissues. In this study, E2 significantly increased the expression of β-catenin by inducing phosphorylations of GSK3β at serine 9. ERβ siRNAs were transfected into MC3T3-E1 cells and revealed that ERβ involved E2-induced osteoblasts proliferation and differentiation via Wnt/β-catenin signaling. The osteoblast differentiation genes (BGP, ALP and OPN) and proliferation related gene (cyclin D1) expression were significantly induced by E2-mediated ERβ. Furthermore immunofluorescence and immunoprecipitation analysis demonstrated that E2 induced the accumulation of β-catenin protein in the nucleus which leads to interaction with T-cell-specific transcription factor/lymphoid enhancer binding factor (TCF/LEF) transcription factors. Taken together, these findings suggest that E2 promotes osteoblastic proliferation and differentiation by inducing proliferation-related and differentiation-related gene expression via ERβ/GSK-3β-dependent Wnt/β-catenin signaling pathway. Our findings provide novel insights into the mechanisms of action of E2 in osteoblastogenesis. - Highlights: • 17β-estradial (E2) promotes GSK3-β phosphorylation. • E2 activates the Wnt/β-catenin signaling pathway. • The Wnt/β-catenin signaling pathway interacts with estrogen signaling pathways. • E2-mediated ER induced osteoblast differentiation and proliferation related genes expression.

  5. Sex and hedgehog: roles of genes in the hedgehog signaling pathway in mammalian sexual differentiation.

    PubMed

    Franco, Heather L; Yao, Humphrey H-C

    2012-01-01

    The chromosome status of the mammalian embryo initiates a multistage process of sexual development in which the bipotential reproductive system establishes itself as either male or female. These events are governed by intricate cell-cell and interorgan communication that is regulated by multiple signaling pathways. The hedgehog signaling pathway was originally identified for its key role in the development of Drosophila, but is now recognized as a critical developmental regulator in many species, including humans. In addition to its developmental roles, the hedgehog signaling pathway also modulates adult organ function, and misregulation of this pathway often leads to diseases, such as cancer. The hedgehog signaling pathway acts through its morphogenetic ligands that signal from ligand-producing cells to target cells over a specified distance. The target cells then respond in a graded manner based on the concentration of the ligands that they are exposed to. Through this unique mechanism of action, the hedgehog signaling pathway elicits cell fate determination, epithelial-mesenchymal interactions, and cellular homeostasis. Here, we review current findings on the roles of hedgehog signaling in the sexually dimorphic development of the reproductive organs with an emphasis on mammals and comparative evidence in other species.

  6. Engineering key components in a synthetic eukaryotic signal transduction pathway

    PubMed Central

    Antunes, Mauricio S; Morey, Kevin J; Tewari-Singh, Neera; Bowen, Tessa A; Smith, J Jeff; Webb, Colleen T; Hellinga, Homme W; Medford, June I

    2009-01-01

    Signal transduction underlies how living organisms detect and respond to stimuli. A goal of synthetic biology is to rewire natural signal transduction systems. Bacteria, yeast, and plants sense environmental aspects through conserved histidine kinase (HK) signal transduction systems. HK protein components are typically comprised of multiple, relatively modular, and conserved domains. Phosphate transfer between these components may exhibit considerable cross talk between the otherwise apparently linear pathways, thereby establishing networks that integrate multiple signals. We show that sequence conservation and cross talk can extend across kingdoms and can be exploited to produce a synthetic plant signal transduction system. In response to HK cross talk, heterologously expressed bacterial response regulators, PhoB and OmpR, translocate to the nucleus on HK activation. Using this discovery, combined with modification of PhoB (PhoB-VP64), we produced a key component of a eukaryotic synthetic signal transduction pathway. In response to exogenous cytokinin, PhoB-VP64 translocates to the nucleus, binds a synthetic PlantPho promoter, and activates gene expression. These results show that conserved-signaling components can be used across kingdoms and adapted to produce synthetic eukaryotic signal transduction pathways. PMID:19455134

  7. Docosahexaenoic acid and signaling pathways in rabbit colon.

    PubMed

    Calderaro, V; Parrillo, C; Balestrieri, M L; Giovane, A; Filippelli, A; Rossi, F

    1994-04-01

    The effects of one of the main components of fish oil, docosahexaenoic acid (DHA), on prostaglandin (PG) and Ca2+ signaling pathways were examined in intact mucosa and freshly isolated crypt cells of rabbit descending colon. Preincubation of serosal mucosa for 20 min with 1 microM DHA fully suppressed the short-circuit and transepithelial conductance increase induced by serosal addition of 10 microM arachidonic acid (AA). DHA at 1 microM also prevented the Cl- secretion promoted by 10 microM AA, as estimated by unidirectional 36Cl flux measurements (net flux = 0.68 +/- 0.30 versus -1.91 +/- 0.20 microEq/hr/cm2, four experiments, p < 0.001), whereas it did not affect the electrophysiological and ion flux responses to PGE2. Addition of 1 microM DHA to the serosal side of the mucosa also inhibited the PG cascade activation elicited by AA (PG synthesis and second messenger cAMP increase). In vitro assays of colonic cyclooxygenase activity showed that 1 microM DHA inhibited (with a 20-min lag) cyclooxygenase activity to the same extent as 5 microM indomethacin (approximately 82% and 80%, respectively). DHA also affected the Ca2+ signaling pathway; in isolated crypt cells, the cytosolic free Ca2+ concentration ([Ca2+]i) dropped by 49 +/- 7.6% (mean +/- standard error, six experiments) after incubation with 1 microM DHA. The sustained phase of the [Ca2+]i response to 500 nM concentrations of the intracellular Ca(2+)-ATPase inhibitor thapsigargin was also inhibited within 150 sec upon 1 microM DHA addition (141 +/- 5.8 versus 243 +/- 8.2 nM [Ca2+]i mean +/- standard error, eight experiments, p < 0.01). The [Ca2+]i-lowering effect of DHA, which was not achieved by incubation with other free fatty acids, was not prevented by removal of Na+ from the incubation medium (-46 +/- 4.3% versus -47 +/- 3.8%, mean +/- standard error, four experiments), nor it was mediated by cAMP-, protein kinase C-, or calmodulin-dependent mechanisms. The incubation of highly purified basolateral

  8. A cyclic GMP-dependent signalling pathway regulates bacterial phytopathogenesis.

    PubMed

    An, Shi-Qi; Chin, Ko-Hsin; Febrer, Melanie; McCarthy, Yvonne; Yang, Jauo-Guey; Liu, Chung-Liang; Swarbreck, David; Rogers, Jane; Maxwell Dow, J; Chou, Shan-Ho; Ryan, Robert P

    2013-09-11

    Cyclic guanosine 3',5'-monophosphate (cyclic GMP) is a second messenger whose role in bacterial signalling is poorly understood. A genetic screen in the plant pathogen Xanthomonas campestris (Xcc) identified that XC_0250, which encodes a protein with a class III nucleotidyl cyclase domain, is required for cyclic GMP synthesis. Purified XC_0250 was active in cyclic GMP synthesis in vitro. The linked gene XC_0249 encodes a protein with a cyclic mononucleotide-binding (cNMP) domain and a GGDEF diguanylate cyclase domain. The activity of XC_0249 in cyclic di-GMP synthesis was enhanced by addition of cyclic GMP. The isolated cNMP domain of XC_0249 bound cyclic GMP and a structure-function analysis, directed by determination of the crystal structure of the holo-complex, demonstrated the site of cyclic GMP binding that modulates cyclic di-GMP synthesis. Mutation of either XC_0250 or XC_0249 led to a reduced virulence to plants and reduced biofilm formation in vitro. These findings describe a regulatory pathway in which cyclic GMP regulates virulence and biofilm formation through interaction with a novel effector that directly links cyclic GMP and cyclic di-GMP signalling.

  9. MAPK/JNK signalling: a potential autophagy regulation pathway

    PubMed Central

    Zhou, Yuan-Yuan; Li, Ying; Jiang, Wei-Qin; Zhou, Lin-Fu

    2015-01-01

    Autophagy refers to a lysosomal degradative pathway or a process of self-cannibalization. This pathway maintains nutrients levels for vital cellular functions during periods of starvation and it provides cells with survival advantages under various stress situations. However, the mechanisms responsible for the induction and regulation of autophagy are poorly understood. The c-Jun NH2-terminal kinase (JNK) signal transduction pathway functions to induce defence mechanisms that protect organisms against acute oxidative and xenobiotic insults. This pathway has also been repeatedly linked to the molecular events involved in autophagy regulation. The present review will focus on recent advances in understanding of the relationship between mitogen-activated protein kinase (MAPK)/JNK signalling and autophagic cell death. PMID:26182361

  10. Cancer stem cells and signaling pathways in radioresistance

    PubMed Central

    Chang, Lei; Graham, Peter; Hao, Jingli; Ni, Jie; Deng, Junli; Bucci, Joseph; Malouf, David; Gillatt, David; Li, Yong

    2016-01-01

    Radiation therapy (RT) is one of the most important strategies in cancer treatment. Radioresistance (the failure to RT) results in locoregional recurrence and metastasis. Therefore, it is critically important to investigate the mechanisms leading to cancer radioresistance to overcome this problem and increase patients' survival. Currently, the majority of the radioresistance-associated researches have focused on preclinical studies. Although the exact mechanisms of cancer radioresistance have not been fully uncovered, accumulating evidence supports that cancer stem cells (CSCs) and different signaling pathways play important roles in regulating radiation response and radioresistance. Therefore, targeting CSCs or signaling pathway proteins may hold promise for developing novel combination modalities and overcoming radioresistance. The present review focuses on the key evidence of CSC markers and several important signaling pathways in cancer radioresistance and explores innovative approaches for future radiation treatment. PMID:26716904

  11. Threshold detection in generalized non-additive signals and noise

    SciTech Connect

    Middleton, D., LLNL

    1997-12-22

    The classical theory of optimum (binary-on-off) threshold detection for additive signals and generalized (i.e. nongaussian) noise is extended to the canonical nonadditive threshold situation. In the important (and usual) applications where the noise is sampled independently, a canonical threshold optimum theory is outlined here, which is found formally to parallel the earlier additive theory, including the critical properties of locally optimum Bayes detection algorithms, which are asymptotically normal and optimum as well. The important Class A clutter model provides an explicit example of optimal threshold envelope detection, for the non-additive cases of signal and noise. Various extensions are noted in the concluding section, as are selected references.

  12. Triggering signaling pathways using F-actin self-organization

    PubMed Central

    Colin, A.; Bonnemay, L.; Gayrard, C.; Gautier, J.; Gueroui, Z.

    2016-01-01

    The spatiotemporal organization of proteins within cells is essential for cell fate behavior. Although it is known that the cytoskeleton is vital for numerous cellular functions, it remains unclear how cytoskeletal activity can shape and control signaling pathways in space and time throughout the cell cytoplasm. Here we show that F-actin self-organization can trigger signaling pathways by engineering two novel properties of the microfilament self-organization: (1) the confinement of signaling proteins and (2) their scaffolding along actin polymers. Using in vitro reconstitutions of cellular functions, we found that both the confinement of nanoparticle-based signaling platforms powered by F-actin contractility and the scaffolding of engineered signaling proteins along actin microfilaments can drive a signaling switch. Using Ran-dependent microtubule nucleation, we found that F-actin dynamics promotes the robust assembly of microtubules. Our in vitro assay is a first step towards the development of novel bottom-up strategies to decipher the interplay between cytoskeleton spatial organization and signaling pathway activity. PMID:27698406

  13. Dissecting Major Signaling Pathways throughout the Development of Prostate Cancer

    PubMed Central

    da Silva, Henrique B.; Amaral, Eduardo P.; Nolasco, Eduardo L.; de Victo, Nathalia C.; Atique, Rodrigo; Jank, Carina C.; Anschau, Valesca; Zerbini, Luiz F.; Correa, Ricardo G.

    2013-01-01

    Prostate cancer (PCa) is one of the most common malignancies found in males. The development of PCa involves several mutations in prostate epithelial cells, usually linked to developmental changes, such as enhanced resistance to apoptotic death, constitutive proliferation, and, in some cases, to differentiation into an androgen deprivation-resistant phenotype, leading to the appearance of castration-resistant PCa (CRPCa), which leads to a poor prognosis in patients. In this review, we summarize recent findings concerning the main deregulations into signaling pathways that will lead to the development of PCa and/or CRPCa. Key mutations in some pathway molecules are often linked to a higher prevalence of PCa, by directly affecting the respective cascade and, in some cases, by deregulating a cross-talk node or junction along the pathways. We also discuss the possible environmental and nonenvironmental inducers for these mutations, as well as the potential therapeutic strategies targeting these signaling pathways. A better understanding of how some risk factors induce deregulation of these signaling pathways, as well as how these deregulated pathways affect the development of PCa and CRPCa, will further help in the development of new treatments and prevention strategies for this disease. PMID:23738079

  14. Bone biology, signaling pathways, and therapeutic targets for osteoporosis.

    PubMed

    Iñiguez-Ariza, Nicole M; Clarke, Bart L

    2015-10-01

    Major advances have occurred recently in the treatment of osteoporosis in recent years. Most patients are currently treated with bisphosphonates, denosumab, raloxifene, or teriparatide, and in some countries, strontium ranelate. Strontium ranelate and calcitonin have recently had their use restricted due to cardiovascular concerns and malignancy, respectively. The available agents have generally provided excellent options that effectively reduce fracture risk. New targets are being sought based on appreciation of the bone biology and signaling pathways involved in bone formation and resorption. These agents will directly target these signaling pathways, and further expand the options available for treatment of osteoporosis. PMID:26255682

  15. The Hippo Signaling Pathway in Development and Cancer

    PubMed Central

    Pan, Duojia

    2011-01-01

    First discovered in Drosophila, the Hippo signaling pathway is a conserved regulator of organ size. Central to this pathway is a kinase cascade leading from the tumor suppressor Hippo (Mst1 and Mst2 in mammals) to the oncoprotein Yki (YAP and TAZ in mammals), a transcriptional coactivator of target genes involved in cell proliferation and survival. Here, I review recent progress in elucidating the molecular mechanism and physiological function of Hippo signaling in Drosophila and mammals. These studies suggest that the core Hippo kinase cascade integrates multiple upstream inputs, enabling dynamic regulation of tissue homeostasis in animal development and physiology. PMID:20951342

  16. POSTRANSLATIONAL MODIFICATIONS OF P53: UPSTREAM SIGNALING PATHWAYS.

    SciTech Connect

    ANDERSON,C.W.APPELLA,E.

    2003-10-23

    The p53 tumor suppressor is a tetrameric transcription factor that is posttranslational modified at >20 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review recent progress in characterizing the upstream signaling pathways whose activation in response to various genotoxic and non-genotoxic stresses result in p53 posttranslational modifications.

  17. The Notch signaling pathway as a mediator of tumor survival

    PubMed Central

    Pine, Sharon R.

    2013-01-01

    The Notch signaling pathway is evolutionarily conserved and responsible for cell fate determination in the developing embryo and mature tissue. At the molecular level, ligand binding activates Notch signaling by liberating the Notch intracellular domain, which then translocates into the nucleus and activates gene transcription. Despite the elegant simplicity of this pathway, which lacks secondary messengers or a signaling cascade, Notch regulates gene expression in a highly context- and cell-type-dependent manner. Notch signaling is frequently dysregulated, most commonly by overactivation, across many cancers and confers a survival advantage on tumors, leading to poorer outcomes for patients. Recent studies demonstrate how Notch signaling increases tumor cell proliferation and provide evidence that active Notch signaling maintains the cancer stem-cell pool, induces epithelial–mesenchymal transition and promotes chemoresistance. These studies imply that pharmacological inhibition of Notch signaling may refine control of cancer therapy and improve patient survival. Gamma secretase inhibitors (GSIs) are drugs that inhibit Notch signaling and may be successful in controlling cancer cell growth in conjunction with standard chemotherapy, but substantial side effects have hampered their widespread use. Recent efforts have been aimed at the development of antibodies against specific Notch receptors and ligands with the hope of limiting side effects while providing the same therapeutic benefit as GSIs. Together, studies characterizing Notch signaling and modulation have offered hope that refined methods targeting Notch may become powerful tools in anticancer therapeutics. PMID:23585460

  18. The Notch signaling pathway as a mediator of tumor survival.

    PubMed

    Capaccione, Kathleen M; Pine, Sharon R

    2013-07-01

    The Notch signaling pathway is evolutionarily conserved and responsible for cell fate determination in the developing embryo and mature tissue. At the molecular level, ligand binding activates Notch signaling by liberating the Notch intracellular domain, which then translocates into the nucleus and activates gene transcription. Despite the elegant simplicity of this pathway, which lacks secondary messengers or a signaling cascade, Notch regulates gene expression in a highly context- and cell-type-dependent manner. Notch signaling is frequently dysregulated, most commonly by overactivation, across many cancers and confers a survival advantage on tumors, leading to poorer outcomes for patients. Recent studies demonstrate how Notch signaling increases tumor cell proliferation and provide evidence that active Notch signaling maintains the cancer stem-cell pool, induces epithelial-mesenchymal transition and promotes chemoresistance. These studies imply that pharmacological inhibition of Notch signaling may refine control of cancer therapy and improve patient survival. Gamma secretase inhibitors (GSIs) are drugs that inhibit Notch signaling and may be successful in controlling cancer cell growth in conjunction with standard chemotherapy, but substantial side effects have hampered their widespread use. Recent efforts have been aimed at the development of antibodies against specific Notch receptors and ligands with the hope of limiting side effects while providing the same therapeutic benefit as GSIs. Together, studies characterizing Notch signaling and modulation have offered hope that refined methods targeting Notch may become powerful tools in anticancer therapeutics. PMID:23585460

  19. A lateral signalling pathway coordinates shape volatility during cell migration

    PubMed Central

    Zhang, Liang; Luga, Valbona; Armitage, Sarah K.; Musiol, Martin; Won, Amy; Yip, Christopher M.; Plotnikov, Sergey V.; Wrana, Jeffrey L.

    2016-01-01

    Cell migration is fundamental for both physiological and pathological processes. Migrating cells usually display high dynamics in morphology, which is orchestrated by an integrative array of signalling pathways. Here we identify a novel pathway, we term lateral signalling, comprised of the planar cell polarity (PCP) protein Pk1 and the RhoGAPs, Arhgap21/23. We show that the Pk1–Arhgap21/23 complex inhibits RhoA, is localized on the non-protrusive lateral membrane cortex and its disruption leads to the disorganization of the actomyosin network and altered focal adhesion dynamics. Pk1-mediated lateral signalling confines protrusive activity and is regulated by Smurf2, an E3 ubiquitin ligase in the PCP pathway. Furthermore, we demonstrate that dynamic interplay between lateral and protrusive signalling generates cyclical fluctuations in cell shape that we quantify here as shape volatility, which strongly correlates with migration speed. These studies uncover a previously unrecognized lateral signalling pathway that coordinates shape volatility during productive cell migration. PMID:27226243

  20. Redefining Signaling Pathways with an Expanding Single-Cell Toolbox.

    PubMed

    Gaudet, Suzanne; Miller-Jensen, Kathryn

    2016-06-01

    Genetically identical cells respond heterogeneously to uniform environmental stimuli. Consequently, investigating the signaling networks that control these cell responses using 'average' bulk cell measurements can obscure underlying mechanisms and misses information emerging from cell-to-cell variability. Here we review recent technological advances including live-cell fluorescence imaging-based approaches and microfluidic devices that enable measurements of signaling networks, dynamics, and responses in single cells. We discuss how these single-cell tools have uncovered novel mechanistic insights for canonical signaling pathways that control cell proliferation (ERK), DNA-damage responses (p53), and innate immune and stress responses (NF-κB). Future improvements in throughput and multiplexing, analytical pipelines, and in vivo applicability will all significantly expand the biological information gained from single-cell measurements of signaling pathways. PMID:26968612

  1. Redefining Signaling Pathways with an Expanding Single-Cell Toolbox.

    PubMed

    Gaudet, Suzanne; Miller-Jensen, Kathryn

    2016-06-01

    Genetically identical cells respond heterogeneously to uniform environmental stimuli. Consequently, investigating the signaling networks that control these cell responses using 'average' bulk cell measurements can obscure underlying mechanisms and misses information emerging from cell-to-cell variability. Here we review recent technological advances including live-cell fluorescence imaging-based approaches and microfluidic devices that enable measurements of signaling networks, dynamics, and responses in single cells. We discuss how these single-cell tools have uncovered novel mechanistic insights for canonical signaling pathways that control cell proliferation (ERK), DNA-damage responses (p53), and innate immune and stress responses (NF-κB). Future improvements in throughput and multiplexing, analytical pipelines, and in vivo applicability will all significantly expand the biological information gained from single-cell measurements of signaling pathways.

  2. Phylogenetic diversity of stress signalling pathways in fungi

    PubMed Central

    Nikolaou, Elissavet; Agrafioti, Ino; Stumpf, Michael; Quinn, Janet; Stansfield, Ian; Brown, Alistair JP

    2009-01-01

    Background Microbes must sense environmental stresses, transduce these signals and mount protective responses to survive in hostile environments. In this study we have tested the hypothesis that fungal stress signalling pathways have evolved rapidly in a niche-specific fashion that is independent of phylogeny. To test this hypothesis we have compared the conservation of stress signalling molecules in diverse fungal species with their stress resistance. These fungi, which include ascomycetes, basidiomycetes and microsporidia, occupy highly divergent niches from saline environments to plant or mammalian hosts. Results The fungi displayed significant variation in their resistance to osmotic (NaCl and sorbitol), oxidative (H2O2 and menadione) and cell wall stresses (Calcofluor White and Congo Red). There was no strict correlation between fungal phylogeny and stress resistance. Rather, the human pathogens tended to be more resistant to all three types of stress, an exception being the sensitivity of Candida albicans to the cell wall stress, Calcofluor White. In contrast, the plant pathogens were relatively sensitive to oxidative stress. The degree of conservation of osmotic, oxidative and cell wall stress signalling pathways amongst the eighteen fungal species was examined. Putative orthologues of functionally defined signalling components in Saccharomyces cerevisiae were identified by performing reciprocal BLASTP searches, and the percent amino acid identities of these orthologues recorded. This revealed that in general, central components of the osmotic, oxidative and cell wall stress signalling pathways are relatively well conserved, whereas the sensors lying upstream and transcriptional regulators lying downstream of these modules have diverged significantly. There was no obvious correlation between the degree of conservation of stress signalling pathways and the resistance of a particular fungus to the corresponding stress. Conclusion Our data are consistent with

  3. Copper as a key regulator of cell signalling pathways.

    PubMed

    Grubman, Alexandra; White, Anthony R

    2014-05-22

    Copper is an essential element in many biological processes. The critical functions associated with copper have resulted from evolutionary harnessing of its potent redox activity. This same property also places copper in a unique role as a key modulator of cell signal transduction pathways. These pathways are the complex sequence of molecular interactions that drive all cellular mechanisms and are often associated with the interplay of key enzymes including kinases and phosphatases but also including intracellular changes in pools of smaller molecules. A growing body of evidence is beginning to delineate the how, when and where of copper-mediated control over cell signal transduction. This has been driven by research demonstrating critical changes to copper homeostasis in many disorders including cancer and neurodegeneration and therapeutic potential through control of disease-associated cell signalling changes by modulation of copper-protein interactions. This timely review brings together for the first time the diverse actions of copper as a key regulator of cell signalling pathways and discusses the potential strategies for controlling disease-associated signalling processes using copper modulators. It is hoped that this review will provide a valuable insight into copper as a key signal regulator and stimulate further research to promote our understanding of copper in disease and therapy.

  4. YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

    SciTech Connect

    Lin, Yi-Ting; Ding, Jing-Ya; Li, Ming-Yang; Yeh, Tien-Shun; Wang, Tsu-Wei; Yu, Jenn-Yah

    2012-09-10

    Tight regulation of cell numbers by controlling cell proliferation and apoptosis is important during development. Recently, the Hippo pathway has been shown to regulate tissue growth and organ size in Drosophila. In mammalian cells, it also affects cell proliferation and differentiation in various tissues, including the nervous system. Interplay of several signaling cascades, such as Notch, Wnt, and Sonic Hedgehog (Shh) pathways, control cell proliferation during neuronal differentiation. However, it remains unclear whether the Hippo pathway coordinates with other signaling cascades in regulating neuronal differentiation. Here, we used P19 cells, a mouse embryonic carcinoma cell line, as a model to study roles of YAP, a core component of the Hippo pathway, in neuronal differentiation. P19 cells can be induced to differentiate into neurons by expressing a neural bHLH transcription factor gene Ascl1. Our results showed that YAP promoted cell proliferation and inhibited neuronal differentiation. Expression of Yap activated Shh but not Wnt or Notch signaling activity during neuronal differentiation. Furthermore, expression of Yap increased the expression of Patched homolog 1 (Ptch1), a downstream target of the Shh signaling. Knockdown of Gli2, a transcription factor of the Shh pathway, promoted neuronal differentiation even when Yap was over-expressed. We further demonstrated that over-expression of Yap inhibited neuronal differentiation in primary mouse cortical progenitors and Gli2 knockdown rescued the differentiation defect in Yap over-expressing cells. In conclusion, our study reveals that Shh signaling acts downstream of YAP in regulating neuronal differentiation. -- Highlights: Black-Right-Pointing-Pointer YAP promotes cell proliferation and inhibits neuronal differentiation in P19 cells. Black-Right-Pointing-Pointer YAP promotes Sonic hedgehog signaling activity during neuronal differentiation. Black-Right-Pointing-Pointer Knockdown of Gli2 rescues the Yap

  5. Genetic/molecular alterations of meningiomas and the signaling pathways targeted

    PubMed Central

    Domingues, Patrícia; González-Tablas, María; Otero, Álvaro; Pascual, Daniel; Ruiz, Laura; Miranda, David; Sousa, Pablo; Gonçalves, Jesús María; Lopes, María Celeste; Orfao, Alberto; Tabernero, María Dolores

    2015-01-01

    Meningiomas are usually considered to be benign central nervous system tumors; however, they show heterogenous clinical, histolopathological and cytogenetic features associated with a variable outcome. In recent years important advances have been achieved in the identification of the genetic/molecular alterations of meningiomas and the signaling pathways involved. Thus, monosomy 22, which is often associated with mutations of the NF2 gene, has emerged as the most frequent alteration of meningiomas; in addition, several other genes (e.g. AKT1, KLF4, TRAF7, SMO) and chromosomes have been found to be recurrently altered often in association with more complex karyotypes and involvement of multiple signaling pathways. Here we review the current knowledge about the most relevant genes involved and the signaling pathways targeted by such alterations. In addition, we summarize those proposals that have been made so far for classification and prognostic stratification of meningiomas based on their genetic/genomic features. PMID:25965831

  6. Folding and signaling share the same pathway in a photoreceptor protein

    NASA Astrophysics Data System (ADS)

    Hoff, Wouter D.

    2002-03-01

    The photoreceptor photoactive yellow protein (PYP) was used as a model system to study receptor activation and protein folding. Refolding was studied by stopped-flow absorbance spectroscopy for PYP with either a trans or a cis chromophore. Chromophore trans to cis isomerization, the mechanism of light detection by PYP, greatly affects the protein folding process. When the cis chromophore is present, the unfolded state refolding proceeds through the putative signaling state of PYP as an on-pathway intermediate. In addition, moderate denaturant concentrations result in the specific unfolding of the signaling state of PYP. Thus, the signaling state is common to the pathways of folding and signaling. This provides a novel avenue for the study of protein folding. We demonstrate how this approach can be used to establish whether a folding intermediate is on-pathway or off-pathway. The results also reveal transient partial unfolding as a molecular mechanism for signaling. The signaling intermediate of PYP exhibits properties characteristic of a molten globule, providing a challenge for the current paradigm for the relay of signals along a signal transduction chain by highly specific interactions between fully folded proteins.

  7. The Hippo signaling pathway in liver regeneration and tumorigenesis.

    PubMed

    Hong, Lixin; Cai, Yabo; Jiang, Mingting; Zhou, Dawang; Chen, Lanfen

    2015-01-01

    The Hippo signaling pathway is an evolutionarily conserved signaling module that plays critical roles in liver size control and tumorigenesis. The Hippo pathway consists of a core kinase cascade in which the mammalian Ste20-like kinases (Mst1/2, orthologs of Drosophila Hippo) and their cofactor Salvador (Sav1) form a complex to phosphorylate and activate the large tumor suppressor (Lats1/2). Lats1/2 kinases in turn phosphorylate and inhibit the transcription co-activators, the Yes-associated protein (YAP) and the transcriptional co-activator with PDZ-binding motif (TAZ), two major downstream effectors of the Hippo pathway. Losses of the Hippo pathway components induce aberrant hepatomegaly and tumorigenesis, in which YAP coordinates regulation of cell proliferation and apoptosis and plays an essential role. This review summarizes the current findings of the regulation of Hippo signaling in liver regeneration and tumorigenesis, focusing on how the loss of tumor suppressor components of the Hippo pathway results in liver cancers and discussing the molecular mechanisms that regulate the expression and activation of its downstream effector YAP in liver tumorigenesis.

  8. 29 CFR 1926.1421 - Signals-voice signals-additional requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Signals-voice signals-additional requirements. 1926.1421 Section 1926.1421 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Cranes...

  9. 29 CFR 1926.1421 - Signals-voice signals-additional requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Cranes and Derricks in Construction § 1926.1421 Signals—voice signals—additional requirements. (a) Prior to beginning... agree on the voice signals that will be used. Once the voice signals are agreed upon, these workers...

  10. 29 CFR 1926.1421 - Signals-voice signals-additional requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Cranes and Derricks in Construction § 1926.1421 Signals—voice signals—additional requirements. (a) Prior to beginning... agree on the voice signals that will be used. Once the voice signals are agreed upon, these workers...

  11. Targeting stem cell signaling pathways for drug discovery: advances in the Notch and Wnt pathways.

    PubMed

    An, Songzhu Michael; Ding, Qiang; Zhang, Jie; Xie, JingYi; Li, LingSong

    2014-06-01

    Signaling pathways transduce extracellular stimuli into cells through molecular cascades to regulate cellular functions. In stem cells, a small number of pathways, notably those of TGF-β/BMP, Hedgehog, Notch, and Wnt, are responsible for the regulation of pluripotency and differentiation. During embryonic development, these pathways govern cell fate specifications as well as the formation of tissues and organs. In adulthood, their normal functions are important for tissue homeostasis and regeneration, whereas aberrations result in diseases, such as cancer and degenerative disorders. In complex biological systems, stem cell signaling pathways work in concert as a network and exhibit crosstalk, such as the negative crosstalk between Wnt and Notch. Over the past decade, genetic and genomic studies have identified a number of potential drug targets that are involved in stem cell signaling pathways. Indeed, discovery of new targets and drugs for these pathways has become one of the most active areas in both the research community and pharmaceutical industry. Remarkable progress has been made and several promising drug candidates have entered into clinical trials. This review focuses on recent advances in the discovery of novel drugs which target the Notch and Wnt pathways.

  12. Regulation of insect behavior via the insulin-signaling pathway

    PubMed Central

    Erion, Renske; Sehgal, Amita

    2013-01-01

    The insulin/insulin-like growth factor signaling (IIS) pathway is well-established as a critical regulator of growth and metabolic homeostasis across the animal kingdom. Insulin-like peptides (ILPs), the functional analogs of mammalian insulin, were initially discovered in the silkmoth Bombyx mori and subsequently identified in many other insect species. Initial research focused on the role of insulin signaling in metabolism, cell proliferation, development, reproduction and aging. More recently however, increasing attention has been given to the role of insulin in the regulation of neuronal function and behavior. Here we review the role of insulin signaling in two specific insect behaviors: feeding and locomotion. PMID:24348428

  13. Cellular metabolic and autophagic pathways: traffic control by redox signaling.

    PubMed

    Dodson, Matthew; Darley-Usmar, Victor; Zhang, Jianhua

    2013-10-01

    It has been established that the key metabolic pathways of glycolysis and oxidative phosphorylation are intimately related to redox biology through control of cell signaling. Under physiological conditions glucose metabolism is linked to control of the NADH/NAD redox couple, as well as providing the major reductant, NADPH, for thiol-dependent antioxidant defenses. Retrograde signaling from the mitochondrion to the nucleus or cytosol controls cell growth and differentiation. Under pathological conditions mitochondria are targets for reactive oxygen and nitrogen species and are critical in controlling apoptotic cell death. At the interface of these metabolic pathways, the autophagy-lysosomal pathway functions to maintain mitochondrial quality and generally serves an important cytoprotective function. In this review we will discuss the autophagic response to reactive oxygen and nitrogen species that are generated from perturbations of cellular glucose metabolism and bioenergetic function.

  14. New Insights into Reelin-Mediated Signaling Pathways

    PubMed Central

    Lee, Gum Hwa; D’Arcangelo, Gabriella

    2016-01-01

    Reelin, a multifunctional extracellular protein that is important for mammalian brain development and function, is secreted by different cell types in the prenatal or postnatal brain. The spatiotemporal regulation of Reelin expression and distribution during development relates to its multifaceted function in the brain. Prenatally Reelin controls neuronal radial migration and proper positioning in cortical layers, whereas postnatally Reelin promotes neuronal maturation, synaptic formation and plasticity. The molecular mechanisms underlying the distinct biological functions of Reelin during and after brain development involve unique and overlapping signaling pathways that are activated following Reelin binding to its cell surface receptors. Distinct Reelin ligand isoforms, such as the full-length protein or fragments generated by proteolytic cleavage differentially affect the activity of downstream signaling pathways. In this review, we discuss recent advances in our understanding of the signaling transduction pathways activated by Reelin that regulate different aspects of brain development and function. A core signaling machinery, including ApoER2/VLDLR receptors, Src/Fyn kinases, and the adaptor protein Dab1, participates in all known aspects of Reelin biology. However, distinct downstream mechanisms, such as the Crk/Rap1 pathway and cell adhesion molecules, play crucial roles in the control of neuronal migration, whereas the PI3K/Akt/mTOR pathway appears to be more important for dendrite and spine development. Finally, the NMDA receptor (NMDAR) and an unidentified receptor contribute to the activation of the MEK/Erk1/2 pathway leading to the upregulation of genes involved in synaptic plasticity and learning. This knowledge may provide new insight into neurodevelopmental or neurodegenerative disorders that are associated with Reelin dysfunction. PMID:27242434

  15. Key cancer cell signal transduction pathways as therapeutic targets.

    PubMed

    Bianco, Roberto; Melisi, Davide; Ciardiello, Fortunato; Tortora, Giampaolo

    2006-02-01

    Growth factor signals are propagated from the cell surface, through the action of transmembrane receptors, to intracellular effectors that control critical functions in human cancer cells, such as differentiation, growth, angiogenesis, and inhibition of cell death and apoptosis. Several kinases are involved in transduction pathways via sequential signalling activation. These kinases include transmembrane receptor kinases (e.g., epidermal growth factor receptor EGFR); or cytoplasmic kinases (e.g., PI3 kinase). In cancer cells, these signalling pathways are often altered and results in a phenotype characterized by uncontrolled growth and increased capability to invade surrounding tissue. Therefore, these crucial transduction molecules represent attractive targets for cancer therapy. This review will summarize current knowledge of key signal transduction pathways, that are altered in cancer cells, as therapeutic targets for novel selective inhibitors. The most advanced targeted agents currently under development interfere with function and expression of several signalling molecules, including the EGFR family; the vascular endothelial growth factor and its receptors; and cytoplasmic kinases such as Ras, PI3K and mTOR.

  16. Pentoxifylline inhibits liver fibrosis via hedgehog signaling pathway.

    PubMed

    Li, Hui; Hua, Juan; Guo, Chun-Xia; Wang, Wei-Xian; Wang, Bao-Ju; Yang, Dong-Liang; Wei, Ping; Lu, Yin-Ping

    2016-06-01

    Infection of schistosomiasis japonica may eventually lead to liver fibrosis, and no effective antifibrotic therapies are available but liver transplantation. Hedgehog (HH) signaling pathway has been involved in the process and is a promising target for treating liver fibrosis. This study aimed to explore the effects of pentoxifylline (PTX) on liver fibrosis induced by schistosoma japonicum infection by inhibiting the HH signaling pathway. Phorbol12-myristate13-acetate (PMA) was used to induce human acute mononuclear leukemia cells THP-1 to differentiate into macrophages. The THP-1-derived macrophages were stimulated by soluble egg antigen (SEA), and the culture supernatants were collected for detection of activation of macrophages. Cell Counting Kit-8 (CCK-8) was used to detect the cytotoxicity of the culture supernatant and PTX on the LX-2 cells. The LX-2 cells were administered with activated culture supernatant from macrophages and(or) PTX to detect the transforming growth factor-β gene expression. The mRNA expression of shh and gli-1, key parts in HH signaling pathway, was detected. The mRNA expression of shh and gli-1 was increased in LX-2 cells treated with activated macrophages-derived culture supernatant, suggesting HH signaling pathway may play a key role in the activation process of hepatic stellate cells (HSCs). The expression of these genes decreased in LX-2 cells co-cultured with both activated macrophages-derived culture supernatant and PTX, indicating PTX could suppress the activation process of HSCs. In conclusion, these data provide evidence that PTX prevents liver fibrogenesis in vitro by the suppression of HH signaling pathway. PMID:27376806

  17. Signaling Pathways That Control mRNA Turnover

    PubMed Central

    Thapar, Roopa; Denmon, Andria P.

    2013-01-01

    Cells regulate their genomes mainly at the level of transcription and at the level of mRNA decay. While regulation at the level of transcription is clearly important, the regulation of mRNA turnover by signaling networks is essential for a rapid response to external stimuli. Signaling pathways result in posttranslational modification of RNA binding proteins by phosphorylation, ubiquitination, methylation, acetylation etc. These modifications are important for rapid remodeling of dynamic ribonucleoprotein complexes and triggering mRNA decay. Understanding how these posttranslational modifications alter gene expression is therefore a fundamental question in biology. In this review we highlight recent findings on how signaling pathways and cell cycle checkpoints involving phosphorylation, ubiquitination, and arginine methylation affect mRNA turnover. PMID:23602935

  18. Stress Signaling Pathways for the Pathogenicity of Cryptococcus

    PubMed Central

    Jung, Kwang-Woo

    2013-01-01

    Sensing, responding, and adapting to the surrounding environment are crucial for all living organisms to survive, proliferate, and differentiate in their biological niches. This ability is also essential for Cryptococcus neoformans and its sibling species Cryptococcus gattii, as these pathogens have saprobic and parasitic life cycles in natural and animal host environments. The ability of Cryptococcus to cause fatal meningoencephalitis is highly related to its capability to remodel and optimize its metabolic and physiological status according to external cues. These cues act through multiple stress signaling pathways through a panoply of signaling components, including receptors/sensors, small GTPases, secondary messengers, kinases, transcription factors, and other miscellaneous adaptors or regulators. In this minireview, we summarize and highlight the importance of several stress signaling pathways that influence the pathogenicity of Cryptococcus and discuss future challenges in these areas. PMID:24078305

  19. Feedback Regulation of Kinase Signaling Pathways by AREs and GREs

    PubMed Central

    Vlasova-St. Louis, Irina; Bohjanen, Paul R.

    2016-01-01

    In response to environmental signals, kinases phosphorylate numerous proteins, including RNA-binding proteins such as the AU-rich element (ARE) binding proteins, and the GU-rich element (GRE) binding proteins. Posttranslational modifications of these proteins lead to a significant changes in the abundance of target mRNAs, and affect gene expression during cellular activation, proliferation, and stress responses. In this review, we summarize the effect of phosphorylation on the function of ARE-binding proteins ZFP36 and ELAVL1 and the GRE-binding protein CELF1. The networks of target mRNAs that these proteins bind and regulate include transcripts encoding kinases and kinase signaling pathways (KSP) components. Thus, kinase signaling pathways are involved in feedback regulation, whereby kinases regulate RNA-binding proteins that subsequently regulate mRNA stability of ARE- or GRE-containing transcripts that encode components of KSP. PMID:26821046

  20. Asymptotic Analysis of the Wnt/β Signaling Pathway

    NASA Astrophysics Data System (ADS)

    Maris, D. T.; Goussis, D. A.

    2015-01-01

    The Wnt/β-catenin pathway is a signal transduction pathway made of proteins, which plays an important role in oncogenesis. Ethan Lee and and co-workers introduced in 2003 a detailed mathematical model of this pathway, incorporating the kinetics of protein-protein interactions, protein synthesis/degradation and phosphorylation/dephosphorylation. The fast/slow dynamics of Lee's system are examined here, by employing the Computational Singular Perturbation (CSP) algorithm. CSP reproduces the results of the classical singular perturbation analysis in an algorithmic fashion, producing an approximation of (i) the low dimensional Slow Invariant Manifold (SIM), where the solution evolves and (ii) the reduced model that governs the flow there. The temporal variation of the dimensions of the SIM will be presented and the components of the pathway that are responsible (i) for the generation of the SIM and (ii) for driving the system on it will be identified.

  1. ent-Steroids: novel tools for studies of signaling pathways.

    PubMed

    Covey, Douglas F

    2009-07-01

    Membrane receptors are often modulated by steroids and it is necessary to distinguish the effects of steroids at these receptors from effects occurring at nuclear receptors. Additionally, it may also be mechanistically important to distinguish between direct effects caused by binding of steroids to membrane receptors and indirect effects on membrane receptor function caused by steroid perturbation of the membrane containing the receptor. In this regard, ent-steroids, the mirror images of naturally occurring steroids, are novel tools for distinguishing between these various actions of steroids. The review provides a background for understanding the different actions that can be expected of steroids and ent-steroids in biological systems, references for the preparation of ent-steroids, a short discussion about relevant forms of stereoisomerism and the requirements that need to be fulfilled for the interaction between two molecules to be enantioselective. The review then summarizes results of biophysical, biochemical and pharmacological studies published since 1992 in which ent-steroids have been used to investigate the actions of steroids in membranes and/or receptor-mediated signaling pathways.

  2. Expanding the Interactome of the Noncanonical NF-κB Signaling Pathway.

    PubMed

    Willmann, Katharina L; Sacco, Roberto; Martins, Rui; Garncarz, Wojciech; Krolo, Ana; Knapp, Sylvia; Bennett, Keiryn L; Boztug, Kaan

    2016-09-01

    NF-κB signaling is a central pathway of immunity and integrates signal transduction upon a wide array of inflammatory stimuli. Noncanonical NF-κB signaling is activated by a small subset of TNF family receptors and characterized by NF-κB2/p52 transcriptional activity. The medical relevance of this pathway has recently re-emerged from the discovery of primary immunodeficiency patients that have loss-of-function mutations in the MAP3K14 gene encoding NIK. Nevertheless, knowledge of protein interactions that regulate noncanonical NF-κB signaling is sparse. Here we report a detailed state-of-the-art mass spectrometry-based protein-protein interaction network including the noncanonical NF-κB signaling nodes TRAF2, TRAF3, IKKα, NIK, and NF-κB2/p100. The value of the data set was confirmed by the identification of interactions already known to regulate this pathway. In addition, a remarkable number of novel interactors were identified. We provide validation of the novel NIK and IKKα interactor FKBP8, which may regulate processes downstream of noncanonical NF-κB signaling. To understand perturbed noncanonical NF-κB signaling in the context of misregulated NIK in disease, we also provide a differential interactome of NIK mutants that cause immunodeficiency. Altogether, this data set not only provides critical insight into how protein-protein interactions can regulate immune signaling but also offers a novel resource on noncanonical NF-κB signaling.

  3. Systematic identification of signaling pathways with potential to confer anticancer drug resistance.

    PubMed

    Martz, Colin A; Ottina, Kathleen A; Singleton, Katherine R; Jasper, Jeff S; Wardell, Suzanne E; Peraza-Penton, Ashley; Anderson, Grace R; Winter, Peter S; Wang, Tim; Alley, Holly M; Kwong, Lawrence N; Cooper, Zachary A; Tetzlaff, Michael; Chen, Pei-Ling; Rathmell, Jeffrey C; Flaherty, Keith T; Wargo, Jennifer A; McDonnell, Donald P; Sabatini, David M; Wood, Kris C

    2014-12-23

    Cancer cells can activate diverse signaling pathways to evade the cytotoxic action of drugs. We created and screened a library of barcoded pathway-activating mutant complementary DNAs to identify those that enhanced the survival of cancer cells in the presence of 13 clinically relevant, targeted therapies. We found that activation of the RAS-MAPK (mitogen-activated protein kinase), Notch1, PI3K (phosphoinositide 3-kinase)-mTOR (mechanistic target of rapamycin), and ER (estrogen receptor) signaling pathways often conferred resistance to this selection of drugs. Activation of the Notch1 pathway promoted acquired resistance to tamoxifen (an ER-targeted therapy) in serially passaged breast cancer xenografts in mice, and treating mice with a γ-secretase inhibitor to inhibit Notch signaling restored tamoxifen sensitivity. Markers of Notch1 activity in tumor tissue correlated with resistance to tamoxifen in breast cancer patients. Similarly, activation of Notch1 signaling promoted acquired resistance to MAPK inhibitors in BRAF(V600E) melanoma cells in culture, and the abundance of Notch1 pathway markers was increased in tumors from a subset of melanoma patients. Thus, Notch1 signaling may be a therapeutic target in some drug-resistant breast cancers and melanomas. Additionally, multiple resistance pathways were activated in melanoma cell lines with intrinsic resistance to MAPK inhibitors, and simultaneous inhibition of these pathways synergistically induced drug sensitivity. These data illustrate the potential for systematic identification of the signaling pathways controlling drug resistance that could inform clinical strategies and drug development for multiple types of cancer. This approach may also be used to advance clinical options in other disease contexts. PMID:25538079

  4. Activation of the Canonical Wnt Signaling Pathway Induces Cementum Regeneration.

    PubMed

    Han, Pingping; Ivanovski, Saso; Crawford, Ross; Xiao, Yin

    2015-07-01

    Canonical Wnt signaling is important in tooth development but it is unclear whether it can induce cementogenesis and promote the regeneration of periodontal tissues lost because of disease. Therefore, the aim of this study is to investigate the influence of canonical Wnt signaling enhancers on human periodontal ligament cell (hPDLCs) cementogenic differentiation in vitro and cementum repair in a rat periodontal defect model. Canonical Wnt signaling was induced by (1) local injection of lithium chloride; (2) local injection of sclerostin antibody; and (3) local injection of a lentiviral construct overexpressing β-catenin. The results showed that the local activation of canonical Wnt signaling resulted in significant new cellular cementum deposition and the formation of well-organized periodontal ligament fibers, which was absent in the control group. In vitro experiments using hPDLCs showed that the Wnt signaling pathway activators significantly increased mineralization, alkaline phosphatase (ALP) activity, and gene and protein expression of the bone and cementum markers osteocalcin (OCN), osteopontin (OPN), cementum protein 1 (CEMP1), and cementum attachment protein (CAP). Our results show that the activation of the canonical Wnt signaling pathway can induce in vivo cementum regeneration and in vitro cementogenic differentiation of hPDLCs.

  5. Neural signal transduction aided by noise in multisynaptic excitatory and inhibitory pathways with saturation

    NASA Astrophysics Data System (ADS)

    Duan, Fabing; Chapeau-Blondeau, François; Abbott, Derek

    2011-08-01

    We study the stochastic resonance phenomenon in saturating dynamical models of neural signal transduction, at the synaptic stage, wherein the noise in multipathways enhances the processing of neuronal information integrated by excitatory and inhibitory synaptic currents. For an excitatory synaptic pathway, the additive intervention of an inhibitory pathway reduces the stochastic resonance effect. However, as the number of synaptic pathways increases, the signal transduction is greatly improved for parallel multipathways that feature both excitation and inhibition. The obtained results lead us to the realization that the collective property of inhibitory synapses assists neural signal transmission, and a parallel array of neurons can enhance their responses to multiple synaptic currents by adjusting the contributions of excitatory and inhibitory currents.

  6. Structure–Activity Relationships for Side Chain Oxysterol Agonists of the Hedgehog Signaling Pathway

    PubMed Central

    2012-01-01

    Oxysterols (OHCs) are byproducts of cholesterol oxidation that are known to activate the Hedeghog (Hh) signaling pathway. While OHCs that incorporate hydroxyl groups throughout the scaffold are known, those that act as agonists of Hh signaling primarily contain a single hydroxyl on the alkyl side chain. We sought to further explore how side chain hydroxylation patterns affect oxysterol-mediated Hh activation, by performing a structure–activity relationship study on a series of synthetic OHCs. The most active analogue, 23(R)-OHC (35), demonstrated potent activation of Hh signaling in two Hh-dependent cell lines (EC50 values 0.54–0.65 μM). In addition, OHC 35 was approximately 3-fold selective for the Hh pathway as compared to the liver X receptor, a nuclear receptor that is also activated by endogenous OHCs. Finally, 35 induced osteogenic differentiation and osteoblast formation in cultured cells, indicating functional agonism of the Hh pathway. PMID:24900386

  7. The Ectodysplasin and NFkappaB signalling pathways in odontogenesis.

    PubMed

    Courtney, Jo-Maree; Blackburn, James; Sharpe, Paul T

    2005-02-01

    Hypohidrotic ectodermal dysplasia (HED) is a congenital disorder affecting organs of ectodermal origin including teeth, hair and sweat glands. Defects in Ectodysplasin (tabby), Edar (downless) and Edar associated death domain (Edaradd) (crinkled) cause HED in both humans and mice. Ectodysplasin is a tumour necrosis factor (TNF) superfamily member whose downstream signalling is transduced by the inhibitor of kappaB kinase (IKK) complex and inhibitors of kappaB (IkappaB) to activate the transcription factor NFkappaB. NFkappaB signalling is involved in a wide range of cellular processes and at each stage the different family members must be tightly regulated for each function. Recent data have demonstrated the importance of this signalling pathway in odontogenesis, particularly in the formation of cusps. Here we review recent advances in our understanding of Ectodysplasin/NFkappaB signalling in tooth development and in particular the central role of the IKK complex.

  8. Expression pattern of the Hedgehog signaling pathway in pituitary adenomas.

    PubMed

    Yavropoulou, Maria P; Maladaki, Anna; Topouridou, Konstantina; Kotoula, Vasiliki; Poulios, Chris; Daskalaki, Emily; Foroglou, Nikolaos; Karkavelas, George; Yovos, John G

    2016-01-12

    Several studies have demonstrated the role of Wnt and Notch signaling in the pathogenesis of pituitary adenomas, but data are scarce regarding the role of Hedgehog signaling. In this study we investigated the differential expression of gene targets of the Hedgehog signaling pathway. Formalin-fixed, paraffin-embedded specimens from adult patients who underwent transphenoidal resection and normal human pituitary tissues that were obtained from autopsies were used. Clinical information and data from pre-operative MRI scan (extracellular tumor extension, tumor size, displacement of the optic chiasm) were retrieved from the Hospital's database. We used a customized RT(2) Profiler PCR Array, to investigate the expression of genes related to Notch and Hedgehog signaling pathways (PTCH1, PTCH2, GLI1, GLI3, NOTCH3, JAG1, HES1, and HIP). A total of 52 pituitary adenomas (32 non-functioning adenomas, 15 somatotropinomas and 5 prolactinomas) were used in the final analysis. In non-functioning pituitary adenomas there was a significant decrease (approximately 75%) in expression of all Hedgehog related genes that were tested, while Notch3 and Jagged-1 expression was found significantly increased, compared with normal pituitary tissue controls. In contrast, somatotropinomas demonstrated a significant increase in expression of all Hedgehog related genes and a decrease in the expression of Notch3 and Jagged-1. There was no significant difference in the expression of Hedgehog and Notch related genes between prolactinomas and healthy pituitary tissues. Hedgehog signalling appears to be activated in somatotropinomas but not in non-functioning pituitary adenomas in contrast to the expression pattern of Notch signalling pathway. PMID:26620835

  9. Homocysteine enhances MMP-9 production in murine macrophages via ERK and Akt signaling pathways

    SciTech Connect

    Lee, Seung Jin; Lee, Yi Sle; Seo, Kyo Won; Bae, Jin Ung; Kim, Gyu Hee; Park, So Youn; Kim, Chi Dae

    2012-04-01

    Homocysteine (Hcy) at elevated levels is an independent risk factor of cardiovascular diseases, including atherosclerosis. In the present study, we investigated the effect of Hcy on the production of matrix metalloproteinases (MMP) in murine macrophages. Among the MMP known to regulate the activities of collagenase and gelatinase, Hcy exclusively increased the gelatinolytic activity of MMP-9 in J774A.1 cells as well as in mouse peritoneal macrophages. Furthermore, this activity was found to be correlated with Western blot findings in J774A.1 cells, which showed that MMP-9 expression was concentration- and time-dependently increased by Hcy. Inhibition of the ERK and Akt pathways led to a significant decrease in Hcy-induced MMP-9 expression, and combined treatment with inhibitors of the ERK and Akt pathways showed an additive effects. Activity assays for ERK and Akt showed that Hcy increased the phosphorylation of both, but these phosphorylation were not affected by inhibitors of the Akt and ERK pathways. In line with these findings, the molecular inhibition of ERK and Akt using siRNA did not affect the Hcy-induced phosphorylation of Akt and ERK, respectively. Taken together, these findings suggest that Hcy enhances MMP-9 production in murine macrophages by separately activating the ERK and Akt signaling pathways. -- Highlights: ► Homocysteine (Hcy) induced MMP-9 production in murine macrophages. ► Hcy induced MMP-9 production through ERK and Akt signaling pathways. ► ERK and Akt signaling pathways were activated by Hcy in murine macrophages. ► ERK and Akt pathways were additively act on Hcy-induced MMP-9 production. ► Hcy enhances MMP-9 production in macrophages via activation of ERK and Akt signaling pathways in an independent manner.

  10. Preface: cardiac control pathways: signaling and transport phenomena.

    PubMed

    Sideman, Samuel

    2008-03-01

    Signaling is part of a complex system of communication that governs basic cellular functions and coordinates cellular activity. Transfer of ions and signaling molecules and their interactions with appropriate receptors, transmembrane transport, and the consequent intracellular interactions and functional cellular response represent a complex system of interwoven phenomena of transport, signaling, conformational changes, chemical activation, and/or genetic expression. The well-being of the cell thus depends on a harmonic orchestration of all these events and the existence of control mechanisms that assure the normal behavior of the various parameters involved and their orderly expression. The ability of cells to sustain life by perceiving and responding correctly to their microenvironment is the basis for development, tissue repair, and immunity, as well as normal tissue homeostasis. Natural deviations, or human-induced interference in the signaling pathways and/or inter- and intracellular transport and information transfer, are responsible for the generation, modulation, and control of diseases. The present overview aims to highlight some major topics of the highly complex cellular information transfer processes and their control mechanisms. Our goal is to contribute to the understanding of the normal and pathophysiological phenomena associated with cardiac functions so that more efficient therapeutic modalities can be developed. Our objective in this volume is to identify and enhance the study of some basic passive and active physical and chemical transport phenomena, physiological signaling pathways, and their biological consequences.

  11. Signal transduction pathways involved in mechanotransduction in bone cells

    SciTech Connect

    Liedert, Astrid . E-mail: astrid.liedert@uni-ulm.de; Kaspar, Daniela; Blakytny, Robert; Claes, Lutz; Ignatius, Anita

    2006-10-13

    Several in vivo and in vitro studies with different loading regimens showed that mechanical stimuli have an influence on proliferation and differentiation of bone cells. Prerequisite for this influence is the transduction of mechanical signals into the cell, a phenomenon that is termed mechanotransduction, which is essential for the maintenance of skeletal homeostasis in adults. Mechanoreceptors, such as the integrins, cadherins, and stretch-activated Ca{sup 2+} channels, together with various signal transduction pathways, are involved in the mechanotransduction process that ultimately regulates gene expression in the nucleus. Mechanotransduction itself is considered to be regulated by hormones, the extracellular matrix of the osteoblastic cells and the mode of the mechanical stimulus.

  12. SNIP1: a new activator of HSE signaling pathway.

    PubMed

    Li, Qiang; An, Jian; Liu, Xianghua; Zhang, Mingjun; Ling, Yichen; Wang, Chenji; Zhao, Jing; Yu, Long

    2012-03-01

    In the last 10 years, more and more attention has been focused on SNIP1 (Smad nuclear interacting protein 1), which functions as a transcriptional coactivator. We report here that through quantitative real-time PCR analysis in 18 different human tissues, SNIP1 was found to be expressed ubiquitously. When overexpressed in HeLa cells, SNIP1-EGFP fused protein exhibited a nuclear localization with a characteristic subnuclear distribution in speckles or formed larger discrete nuclear bodies in some cells. Reporter gene assay showed that overexpression of SNIP1 in HEK 293 cells or H1299 cells strongly activated the HSE signaling pathway. Moreover, SNIP1 could selectively regulate the transcription of HSP70A1A and HSP27. Taken together, our findings suggest that SNIP1 might also be a positive regulator of HSE signaling pathway.

  13. Estrogen Stimulation of Cell Migration Involves Multiple Signaling Pathway Interactions

    PubMed Central

    Li, Yan; Wang, Ji-Ping; Santen, Richard J.; Kim, Tae-Hyun; Park, Hoyong; Fan, Ping; Yue, Wei

    2010-01-01

    Hormone-dependent breast cancers respond to inhibitors of estrogen synthesis or action with tumor regression and with a reduction of new metastases. The mechanisms underlying the effects of estrogen on metastasis likely differ from those on tumor regression. Cell migration is a key first step in the metastatic process. Based on our prior work and other published data, we designed and tested a working model that suggested that estrogen receptor α, epidermal growth factor receptor, focal adhesion kinase (FAK), paxillin, phosphatidylinositol 3 kinase, p60 Src tyrosine kinase (c-Src), c-Jun N-terminal kinase, and MAPK interact to facilitate estradiol (E2)-induced cell migration. Accordingly, we examined the effect of E2 on activation of these pathways and demonstrated mechanistic effects by blocking each component and assessing cell migration as a biologic endpoint. Initial studies validated a robust cell migration assay characterized by highly reproducible, dose-dependent responses to E2. Examining various mechanisms involved in migration, we showed that E2 induced activation of c-Src, FAK, and paxillin with early peaks within 5–30 min and later peaks at 24 h. ERK and protein kinase B phosphorylation exhibited only early peaks. Blockade of various steps in these signaling pathways with use of small interfering RNA or specific inhibitors demonstrated mechanistic effects of these signaling molecules on cell migration. Our results suggest that the effects of E2 on cell migration involve multiple, interacting signaling pathways. Important effects are mediated by the MAPK, phosphatidylinositol 3 kinase, and c-Jun N-terminal kinase pathways and use FAK, paxillin, and c-Src for activation. Each pathway represents a potential target for blocking cell migration and metastasis of breast cancer cells. PMID:20861240

  14. RNAi Induces Innate Immunity through Multiple Cellular Signaling Pathways

    PubMed Central

    Wu, Jun; Pei, Rongjuan; Xu, Yang; Yang, Dongliang; Roggendorf, Michael; Lu, Mengji

    2013-01-01

    Background & Aims Our previous results showed that the knockdown of woodchuck hepatitis virus (WHV) by RNA interference (RNAi) led to upregulation of interferon stimulated genes (ISGs) in primary hepatocytes. In the present study, we tested the hypothesis that the cellular signaling pathways recognizing RNA molecules may be involved the ISG stimulation by RNAi. Methods Primary murine hepatocytes (PMHs) from wild type mice and WHV transgenic (Tg) mice were prepared and treated with defined siRNAs. The mRNA levels of target genes and ISGs were detected by real-time RT-PCR. The involvement of the signaling pathways including RIG-I/MDA5, PKR, and TLR3/7/8/9 was examined by specific inhibition and the analysis of their activation by Western blotting. Results In PMHs from WHV Tg mice, specific siRNAs targeting WHV, mouse β-actin, and GAPDH reduced the levels of targeted mRNAs and increased the mRNA expression of IFN-β, MxA, and IP-10. The enhanced ISG expression by siRNA transfection were abolished by siRNA-specific 2′-O-methyl antisense RNA and the inhibitors 2-AP and chloroquine blocking PKR and other TLR-mediated signaling pathways. Furthermore, Western blotting revealed that RNAi results in an increase in PKR phosphorylation and nuclear translocation of IRF3 and NF-êB, indicating the possible role of IRF3 in the RNAi-directed induction of ISGs. In contrast, silencing of RIG-I and MDA5 failed to block RNAi-mediated MxA induction. Conclusions RNAi is capable of enhancing innate immune responses through the PKR- and TLR-dependent signaling pathways in primary hepatocytes. The immune stimulation by RNAi may contribute to the antiviral activity of siRNAs in vivo. PMID:23700487

  15. PI3K/Akt signalling pathway and cancer.

    PubMed

    Fresno Vara, Juan Angel; Casado, Enrique; de Castro, Javier; Cejas, Paloma; Belda-Iniesta, Cristóbal; González-Barón, Manuel

    2004-04-01

    Phosphatidylinositol-3 kinases, PI3Ks, constitute a lipid kinase family characterized by their ability to phosphorylate inositol ring 3'-OH group in inositol phospholipids to generate the second messenger phosphatidylinositol-3,4,5-trisphosphate (PI-3,4,5-P(3)). RPTK activation results in PI(3,4,5)P(3) and PI(3,4)P(2) production by PI3K at the inner side of the plasma membrane. Akt interacts with these phospholipids, causing its translocation to the inner membrane, where it is phosphorylated and activated by PDK1 and PDK2. Activated Akt modulates the function of numerous substrates involved in the regulation of cell survival, cell cycle progression and cellular growth. In recent years, it has been shown that PI3K/Akt signalling pathway components are frequently altered in human cancers. Cancer treatment by chemotherapy and gamma-irradiation kills target cells primarily by the induction of apoptosis. However, the development of resistance to therapy is an important clinical problem. Failure to activate the apoptotic programme represents an important mode of drug resistance in tumor cells. Survival signals induced by several receptors are mediated mainly by PI3K/Akt, hence this pathway may decisively contribute to the resistant phenotype. Many of the signalling pathways involved in cellular transformation have been elucidated and efforts are underway to develop treatment strategies that target these specific signalling molecules or their downstream effectors. The PI3K/Akt pathway is involved in many of the mechanisms targeted by these new drugs, thus a better understanding of this crossroad can help to fully exploit the potential benefits of these new agents. PMID:15023437

  16. Nutrient shortage triggers the hexosamine biosynthetic pathway via the GCN2-ATF4 signalling pathway.

    PubMed

    Chaveroux, Cédric; Sarcinelli, Carmen; Barbet, Virginie; Belfeki, Sofiane; Barthelaix, Audrey; Ferraro-Peyret, Carole; Lebecque, Serge; Renno, Toufic; Bruhat, Alain; Fafournoux, Pierre; Manié, Serge N

    2016-06-03

    The hexosamine biosynthetic pathway (HBP) is a nutrient-sensing metabolic pathway that produces the activated amino sugar UDP-N-acetylglucosamine, a critical substrate for protein glycosylation. Despite its biological significance, little is known about the regulation of HBP flux during nutrient limitation. Here, we report that amino acid or glucose shortage increase GFAT1 production, the first and rate-limiting enzyme of the HBP. GFAT1 is a transcriptional target of the activating transcription factor 4 (ATF4) induced by the GCN2-eIF2α signalling pathway. The increased production of GFAT1 stimulates HBP flux and results in an increase in O-linked β-N-acetylglucosamine protein modifications. Taken together, these findings demonstrate that ATF4 provides a link between nutritional stress and the HBP for the regulation of the O-GlcNAcylation-dependent cellular signalling.

  17. Nutrient shortage triggers the hexosamine biosynthetic pathway via the GCN2-ATF4 signalling pathway

    PubMed Central

    Chaveroux, Cédric; Sarcinelli, Carmen; Barbet, Virginie; Belfeki, Sofiane; Barthelaix, Audrey; Ferraro-Peyret, Carole; Lebecque, Serge; Renno, Toufic; Bruhat, Alain; Fafournoux, Pierre; Manié, Serge N.

    2016-01-01

    The hexosamine biosynthetic pathway (HBP) is a nutrient-sensing metabolic pathway that produces the activated amino sugar UDP-N-acetylglucosamine, a critical substrate for protein glycosylation. Despite its biological significance, little is known about the regulation of HBP flux during nutrient limitation. Here, we report that amino acid or glucose shortage increase GFAT1 production, the first and rate-limiting enzyme of the HBP. GFAT1 is a transcriptional target of the activating transcription factor 4 (ATF4) induced by the GCN2-eIF2α signalling pathway. The increased production of GFAT1 stimulates HBP flux and results in an increase in O-linked β-N-acetylglucosamine protein modifications. Taken together, these findings demonstrate that ATF4 provides a link between nutritional stress and the HBP for the regulation of the O-GlcNAcylation-dependent cellular signalling. PMID:27255611

  18. E-cadherin mediates contact inhibition of proliferation through Hippo signaling-pathway components

    PubMed Central

    Kim, Nam-Gyun; Koh, Eunjin; Chen, Xiao; Gumbiner, Barry M.

    2011-01-01

    Contact inhibition of cell growth is essential for embryonic development and maintenance of tissue architecture in adult organisms, and the growth of tumors is characterized by a loss of contact inhibition of proliferation. The recently identified Hippo signaling pathway has been implicated in contact inhibition of proliferation as well as organ size control. The modulation of the phosphorylation and nuclear localization of Yes-associated protein (YAP) by the highly conserved kinase cascade of the Hippo signaling pathway has been intensively studied. However, cell-surface receptors regulating the Hippo signaling pathway in mammals are not well understood. In this study, we show that Hippo signaling pathway components are required for E-cadherin–dependent contact inhibition of proliferation. Knockdown of the Hippo signaling components or overexpression of YAP inhibits the decrease in cell proliferation caused by E-cadherin homophilic binding at the cell surface, independent of other cell–cell interactions. We also demonstrate that the E-cadherin/catenin complex functions as an upstream regulator of the Hippo signaling pathway in mammalian cells. Expression of E-cadherin in MDA-MB-231 cells restores the density-dependent regulation of YAP nuclear exclusion. Knockdown of β-catenin in densely cultured MCF10A cells, which mainly depletes E-cadherin–bound β-catenin, induces a decrease in the phosphorylation of S127 residue of YAP and its nuclear accumulation. Moreover, E-cadherin homophilic binding independent of other cell interactions is sufficient to control the subcellular localization of YAP. Therefore, Our results indicate that, in addition to its role in cell–cell adhesion, E-cadherin-mediated cell–cell contact directly regulates the Hippo signaling pathway to control cell proliferation. PMID:21730131

  19. Regression of Pathological Cardiac Hypertrophy: Signaling Pathways and Therapeutic Targets

    PubMed Central

    Hou, Jianglong; Kang, Y. James

    2012-01-01

    Pathological cardiac hypertrophy is a key risk factor for heart failure. It is associated with increased interstitial fibrosis, cell death and cardiac dysfunction. The progression of pathological cardiac hypertrophy has long been considered as irreversible. However, recent clinical observations and experimental studies have produced evidence showing the reversal of pathological cardiac hypertrophy. Left ventricle assist devices used in heart failure patients for bridging to transplantation not only improve peripheral circulation but also often cause reverse remodeling of the geometry and recovery of the function of the heart. Dietary supplementation with physiologically relevant levels of copper can reverse pathological cardiac hypertrophy in mice. Angiogenesis is essential and vascular endothelial growth factor (VEGF) is a constitutive factor for the regression. The action of VEGF is mediated by VEGF receptor-1, whose activation is linked to cyclic GMP-dependent protein kinase-1 (PKG-1) signaling pathways, and inhibition of cyclic GMP degradation leads to regression of pathological cardiac hypertrophy. Most of these pathways are regulated by hypoxia-inducible factor. Potential therapeutic targets for promoting the regression include: promotion of angiogenesis, selective enhancement of VEGF receptor-1 signaling pathways, stimulation of PKG-1 pathways, and sustention of hypoxia-inducible factor transcriptional activity. More exciting insights into the regression of pathological cardiac hypertrophy are emerging. The time of translating the concept of regression of pathological cardiac hypertrophy to clinical practice is coming. PMID:22750195

  20. Association between FOXM1 and hedgehog signaling pathway in human cervical carcinoma by tissue microarray analysis

    PubMed Central

    Chen, Hong; Wang, Jingjing; Yang, Hong; Chen, Dan; Li, Panpan

    2016-01-01

    Forkhead box M1 (FOXM1) and hedgehog (Hh) signaling pathway are implicated in the formation and development of human tumors, including cervical cancer. Previous studies have indicated that FOXM1 may be a downstream target gene of the Hh signaling pathway, but their association in cervical cancer is largely unknown. In the present study, the expression of FOXM1 and Hh signaling molecules was evaluated by immunohistochemical analysis in a tissue microarray that contained 70 cervical cancer tissues and 10 normal cervical tissues. In addition, the association of these molecules with clinicopathological parameters, and the association between FOXM1 and various molecules involved in the Hh signaling pathway was investigated. The results indicated that FOXM1 and Hh signaling molecules were overexpressed in cervical cancer tissues. The protein expression levels of FOXM1, glioma-associated oncogene 1 (GLI1) and smoothened (SMO) correlated with the clinical stage of the tumors, while the protein expression levels of Sonic Hh (SHh), patched 1 (PTCH1) and GLI1 correlated with the pathological grade of the tumors. The expression levels of GLI1 were lower in tissues without lymph node metastasis than in tissues with lymph node metastasis. In addition, FOXM1 expression correlated with GLI1, SHh and PTCH1 expression in cancer tissues. These findings confirmed the participation of FOXM1 and the Hh signaling pathway in cervical cancer. Furthermore, the finding that FOXM1 may be a downstream target gene of the Hh signaling pathway in cervical cancer provides a potential novel diagnostic and therapeutic target for cervical cancer.

  1. Association between FOXM1 and hedgehog signaling pathway in human cervical carcinoma by tissue microarray analysis

    PubMed Central

    Chen, Hong; Wang, Jingjing; Yang, Hong; Chen, Dan; Li, Panpan

    2016-01-01

    Forkhead box M1 (FOXM1) and hedgehog (Hh) signaling pathway are implicated in the formation and development of human tumors, including cervical cancer. Previous studies have indicated that FOXM1 may be a downstream target gene of the Hh signaling pathway, but their association in cervical cancer is largely unknown. In the present study, the expression of FOXM1 and Hh signaling molecules was evaluated by immunohistochemical analysis in a tissue microarray that contained 70 cervical cancer tissues and 10 normal cervical tissues. In addition, the association of these molecules with clinicopathological parameters, and the association between FOXM1 and various molecules involved in the Hh signaling pathway was investigated. The results indicated that FOXM1 and Hh signaling molecules were overexpressed in cervical cancer tissues. The protein expression levels of FOXM1, glioma-associated oncogene 1 (GLI1) and smoothened (SMO) correlated with the clinical stage of the tumors, while the protein expression levels of Sonic Hh (SHh), patched 1 (PTCH1) and GLI1 correlated with the pathological grade of the tumors. The expression levels of GLI1 were lower in tissues without lymph node metastasis than in tissues with lymph node metastasis. In addition, FOXM1 expression correlated with GLI1, SHh and PTCH1 expression in cancer tissues. These findings confirmed the participation of FOXM1 and the Hh signaling pathway in cervical cancer. Furthermore, the finding that FOXM1 may be a downstream target gene of the Hh signaling pathway in cervical cancer provides a potential novel diagnostic and therapeutic target for cervical cancer. PMID:27698840

  2. Color signals through dorsal and ventral visual pathways

    PubMed Central

    Conway, Bevil R.

    2014-01-01

    Explanations for color phenomena are often sought in the retina, LGN and V1, yet it is becoming increasingly clear that a complete account will take us further along the visual-processing pathway. Working out which areas are involved is not trivial. Responses to S-cone activation are often assumed to indicate that an area or neuron is involved in color perception. However, work tracing S-cone signals into extrastriate cortex has challenged this assumption: S-cone responses have been found in brain regions, such as MT, not thought to play a major role in color perception. Here we review the processing of S-cone signals across cortex and present original data on S-cone responses measured with fMRI in alert macaque, focusing on one area in which S-cone signals seem likely to contribute to color (V4/posterior inferior temporal cortex), and on one area in which S signals are unlikely to play a role in color (MT). We advance a hypothesis that the S-cone signals in color-computing areas are required to achieve a balanced neural representation of perceptual color space, while the S-cone signals in non-color-areas provide a cue to illumination (not luminance) and confer sensitivity to the chromatic contrast generated by natural daylight (shadows, illuminated by ambient sky, surrounded by direct sunlight). This sensitivity would facilitate the extraction of shape-from-shadow signals to benefit global scene analysis and motion perception. PMID:24103417

  3. Extreme-longevity mutations orchestrate silencing of multiple signaling pathways.

    PubMed

    Shmookler Reis, Robert J; Bharill, Puneet; Tazearslan, Cagdas; Ayyadevara, Srinivas

    2009-10-01

    Long-lived mutants provide unique insights into the genetic factors that limit lifespan in wild-type animals. Most mutants and RNA interference targets found to extend life, typically by 1.5- to 2.5-fold, were discovered in C. elegans. Several longevity-assurance pathways are conserved across widely divergent taxa, indicating that mechanisms of lifespan regulation evolved several hundred million years ago. Strong mutations to the C. elegans gene encoding AGE-1/PI3KCS achieve unprecedented longevity by orchestrating the modulation (predominantly silencing) of multiple signaling pathways. This is evident in a profound attenuation of total kinase activity, leading to reduced phosphoprotein content. Mutations to the gene encoding the catalytic subunit of PI3K (phosphatidylinositol 3-kinase) have the potential to modulate all enzymes that depend on its product, PIP3, for membrane tethering or activation by other kinases. Remarkably, strong mutants inactivating PI3K also silence multiple signaling pathways at the transcript level, partially but not entirely mediated by the DAF-16/FOXO transcription factor. Mammals have a relatively large proportion of somatic cells, and survival depends on their replication, whereas somatic cell divisions in nematodes are limited to development and reproductive tissues. Thus, translation of longevity gains from nematodes to mammals requires disentangling the downstream consequences of signaling mutations, to avoid their deleterious consequences.

  4. PI3K/Akt/mTOR signaling pathway in cancer stem cells: from basic research to clinical application

    PubMed Central

    Xia, Pu; Xu, Xiao-Yan

    2015-01-01

    Cancer stem cells (CSCs) are a subpopulation of tumor cells that possess unique self-renewal activity and mediate tumor initiation and propagation. The PI3K/Akt/mTOR signaling pathway can be considered as a master regulator for cancer. More and more recent studies have shown the links between PI3K/Akt/mTOR signaling pathway and CSC biology. Herein, we provide a comprehensive review on the role of signaling components upstream and downstream of PI3K/Akt/mTOR signaling in CSC. In addition, we also summarize various classes of small molecule inhibitors of PI3K/Akt/mTOR signaling pathway and their clinical potential in CSC. Overall, the current available data suggest that the PI3K/Akt/mTOR signaling pathway could be a promising target for development of CSC-target drugs. PMID:26175931

  5. From tyrosine to melanin: Signaling pathways and factors regulating melanogenesis.

    PubMed

    Rzepka, Zuzanna; Buszman, Ewa; Beberok, Artur; Wrześniok, Dorota

    2016-01-01

    Melanins are natural pigments of skin, hair and eyes and can be classified into two main types: brown to black eumelanin and yellow to reddish-brown pheomelanin. Biosynthesis of melanins takes place in melanosomes, which are specialized cytoplasmic organelles of melanocytes - dendritic cells located in the basal layer of the epidermis, uveal tract of the eye, hair follicles, as well as in the inner ear, central nervous system and heart. Melanogenesis is a multistep process and begins with the conversion of amino acid L-tyrosine to DOPAquinone. The addition of cysteine or glutathione to DOPAquinone leads to the intermediates formation, followed by subsequent transformations and polymerization to the final product, pheomelanin. In the absence of thiol compounds DOPAquinone undergoes an intramolecular cyclization and oxidation to form DOPAchrome, which is then converted to 5,6-dihydroksyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Eumelanin is formed by polymerization of DHI and DHICA and their quinones. Regulation of melanogenesis is achieved by physical and biochemical factors. The article presents the intracellular signaling pathways: cAMP/PKA/CREB/MITF cascade, MAP kinases cascade, PLC/DAG/PKCβ cascade and NO/cGMP/PKG cascade, which are involved in the regulation of expression and activity of the melanogenesis-related proteins by ultraviolet radiation and endogenous agents (cytokines, hormones). Activity of the key melanogenic enzyme, tyrosinase, is also affected by pH and temperature. Many pharmacologically active substances are able to inhibit or stimulate melanin biosynthesis, as evidenced by in vitro studies on cultured pigment cells. PMID:27356601

  6. Multiplicity and plasticity of natural killer cell signaling pathways

    PubMed Central

    Chiesa, Sabrina; Mingueneau, Michael; Fuseri, Nicolas; Malissen, Bernard; Raulet, David H.; Malissen, Marie; Vivier, Eric; Tomasello, Elena

    2006-01-01

    Natural killer (NK) cells express an array of activating receptors that associate with DAP12 (KARAP), CD3ζ, and/or FcRγ ITAM (immunoreceptor tyrosine-based activation motif)–bearing signaling subunits. In T and mast cells, ITAM-dependent signals are integrated by critical scaffolding elements such as LAT (linker for activation of T cells) and NTAL (non–T-cell activation linker). Using mice that are deficient for ITAM-bearing molecules, LAT or NTAL, we show that NK cell cytotoxicity and interferon-γ secretion are initiated by ITAM-dependent and -independent as well as LAT/NTAL-dependent and -independent pathways. The role of these various signaling circuits depends on the target cell as well as on the activation status of the NK cell. The multiplicity and the plasticity of the pathways that initiate NK cell effector functions contrast with the situation in T cells and B cells and provide an explanation for the resiliency of NK cell effector functions to various pharmacologic inhibitors and genetic mutations in signaling molecules. PMID:16291591

  7. Signaling Pathways and Gene Regulatory Networks in Cardiomyocyte Differentiation

    PubMed Central

    Parikh, Abhirath; Wu, Jincheng; Blanton, Robert M.

    2015-01-01

    Strategies for harnessing stem cells as a source to treat cell loss in heart disease are the subject of intense research. Human pluripotent stem cells (hPSCs) can be expanded extensively in vitro and therefore can potentially provide sufficient quantities of patient-specific differentiated cardiomyocytes. Although multiple stimuli direct heart development, the differentiation process is driven in large part by signaling activity. The engineering of hPSCs to heart cell progeny has extensively relied on establishing proper combinations of soluble signals, which target genetic programs thereby inducing cardiomyocyte specification. Pertinent differentiation strategies have relied as a template on the development of embryonic heart in multiple model organisms. Here, information on the regulation of cardiomyocyte development from in vivo genetic and embryological studies is critically reviewed. A fresh interpretation is provided of in vivo and in vitro data on signaling pathways and gene regulatory networks (GRNs) underlying cardiopoiesis. The state-of-the-art understanding of signaling pathways and GRNs presented here can inform the design and optimization of methods for the engineering of tissues for heart therapies. PMID:25813860

  8. SEPT4 is regulated by the Notch signaling pathway.

    PubMed

    Liu, Wenbin

    2012-04-01

    Notch receptor-mediated signaling is an evolutionarily conserved pathway that regulates diverse developmental processes and its dysregulation has been implicated in a variety of developmental disorders and cancers. Notch functions in these processes by activating expression of its target genes. Septin 4 (SEPT4) is a polymerizing GTP-binding protein that serves as scaffold for diverse molecules and is involved in cell proliferation and apoptosis. After activation of the Notch signal, the expression of SEPT4 is up-regulated and cell proliferation is inhibited. When the Notch signal is inhibited by the CSL (CBF1/Su(H)/Lag-1)-binding-domain-negative Mastermind-like protein 1, the expression of SEPT4 is down-regulated, proliferation and colony formation of cells are promoted, but cell adhesion ability is decreased. Nevertheless, the SEPT4 expression is not affected after knock-down of CSL. Meanwhile, if SEPT4 activity is inhibited through RNA interference, the protein level and activity of NOTCH1 remains unchanged, but cell proliferation is dysregulated. This indicates that SEPT4 is a Notch target gene. This relationship between Notch signaling pathway and SEPT4 offers a potential basis for further study of developmental control and carcinogenesis. PMID:21938432

  9. Mechanisms of disease: signaling pathways and immunobiology of inflammatory myopathies.

    PubMed

    Dalakas, Marinos C

    2006-04-01

    The signaling pathways involved in the immunobiology of polymyositis, dermatomyositis, and inclusion-body myositis are outlined in this Review, which is based on research performed during the past 10 years. In dermatomyositis, the complement cascade is activated and the expression of cytokines and chemokines is upregulated. In polymyositis and inclusion-body myositis, autoinvasive CD8+ T cells are clonally expanded. This T-cell subset possesses conserved amino-acid sequences in complementarity-determining region 3 of the T-cell receptor and, via the perforin pathway, exerts a myotoxic effect on muscle fibers that express major histocompatibility complex (MHC) class I molecules. In all inflammatory myopathies, molecules associated with T-cell transmigration and cytokine signaling, as well as chemokines and their receptors, are strongly expressed by endothelial and inflammatory cells. Early in the pathogenesis of polymyositis and inclusion-body myositis, expression of MHC class I molecules on muscle fibers is upregulated, even in the absence of autoinvasive CD8+ T cells. Emerging data indicate that such continuous upregulation of the expression of MHC class I molecules on muscle fibers leads to an endoplasmic reticulum stress response, intracellular accumulation of misfolded glycoproteins, and activation of nuclear factor kappaB pathways, which can further stimulate formation of MHC class I-CD8 complexes, resulting in a self-sustaining inflammatory response. Advances in our understanding of the signaling pathways involved in the pathogenesis of these inflammatory myopathies are expected to result in the identification of novel therapeutic targets for these diseases.

  10. Dynamic alterations in Hippo signaling pathway and YAP activation during liver regeneration.

    PubMed

    Grijalva, James L; Huizenga, Megan; Mueller, Kaly; Rodriguez, Steven; Brazzo, Joseph; Camargo, Fernando; Sadri-Vakili, Ghazaleh; Vakili, Khashayar

    2014-07-15

    The Hippo signaling pathway has been implicated in mammalian organ size regulation and tumor suppression. Specifically, the Hippo pathway plays a critical role regulating the activity of transcriptional coactivator Yes-associated protein (YAP), which modulates a proliferative transcriptional program. Recent investigations have demonstrated that while this pathway is activated in quiescent livers, its inhibition leads to liver overgrowth and tumorigenesis. However, the role of the Hippo pathway during the natural process of liver regeneration remains unknown. Here we investigated alterations in the Hippo signaling pathway and YAP activation during liver regeneration using a 70% partial hepatectomy (PH) rat model. Our results indicate an increase in YAP activation by 1 day following PH as demonstrated by increased YAP nuclear localization and increased YAP target gene expression. Investigation of the Hippo pathway revealed a decrease in the activation of core kinases Mst1/2 by 1 day as well as Lats1/2 and its adapter protein Mob1 by 3 days following PH. Evaluation of liver-to-body weight ratios indicated that the liver reaches its near normal size by 7 days following PH, which correlated with a return to baseline YAP nuclear levels and target gene expression. Additionally, when liver size was restored, Mst1/2 kinase activation returned to levels observed in quiescent livers indicating reactivation of the Hippo signaling pathway. These findings illustrate the dynamic changes in the Hippo signaling pathway and YAP activation during liver regeneration, which stabilize when the liver-to-body weight ratio reaches homeostatic levels.

  11. 78 FR 41703 - Regulation of Fuels and Fuel Additives: Additional Qualifying Renewable Fuel Pathways Under the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-11

    ... renewable fuels they produce through approved fuel pathways. See 75 FR 14670 (March 26, 2010); 75 FR 26026 (May 10, 2010); 75 FR 37733 (June 30, 2010); 75 FR 59622 (September 28, 2010); 75 FR 76790 (December 9, 2010); 75 FR 79964 (December 21, 2010); 77 FR 1320 (January 9, 2012); 77 FR 74592 (December 17,...

  12. Molecular mechanism for the interaction between gibberellin and brassinosteroid signaling pathways in Arabidopsis.

    PubMed

    Gallego-Bartolomé, Javier; Minguet, Eugenio G; Grau-Enguix, Federico; Abbas, Mohamad; Locascio, Antonella; Thomas, Stephen G; Alabadí, David; Blázquez, Miguel A

    2012-08-14

    Plant development is modulated by the convergence of multiple environmental and endogenous signals, and the mechanisms that allow the integration of different signaling pathways is currently being unveiled. A paradigmatic case is the concurrence of brassinosteroid (BR) and gibberellin (GA) signaling in the control of cell expansion during photomorphogenesis, which is supported by physiological observations in several plants but for which no molecular mechanism has been proposed. In this work, we show that the integration of these two signaling pathways occurs through the physical interaction between the DELLA protein GAI, which is a major negative regulator of the GA pathway, and BRASSINAZOLE RESISTANT1 (BZR1), a transcription factor that broadly regulates gene expression in response to BRs. We provide biochemical evidence, both in vitro and in vivo, indicating that GAI inactivates the transcriptional regulatory activity of BZR1 upon their interaction by inhibiting the ability of BZR1 to bind to target promoters. The physiological relevance of this interaction was confirmed by the observation that the dominant gai-1 allele interferes with BR-regulated gene expression, whereas the bzr1-1D allele displays enhanced resistance to DELLA accumulation during hypocotyl elongation. Because DELLA proteins mediate the response to multiple environmental signals, our results provide an initial molecular framework for the integration with BRs of additional pathways that control plant development.

  13. Molecular characterization of the Akt-TOR signaling pathway in rainbow trout: potential role in muscle growth/degradation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Akt-TOR signaling pathway plays a key role in cellular metabolism and muscle growth. Hormone, nutrition and stress factors affect the Akt-TOR pathway by regulating gene transcription, protein synthesis and degradation. In addition, we previously showed that energetic demands elevate during vit...

  14. Connecting proline metabolism and signaling pathways in plant senescence

    PubMed Central

    Zhang, Lu; Becker, Donald F.

    2015-01-01

    The amino acid proline has a unique biological role in stress adaptation. Proline metabolism is manipulated under stress by multiple and complex regulatory pathways and can profoundly influence cell death and survival in microorganisms, plants, and animals. Though the effects of proline are mediated by diverse signaling pathways, a common theme appears to be the generation of reactive oxygen species (ROS) due to proline oxidation being coupled to the respiratory electron transport chain. Considerable research has been devoted to understand how plants exploit proline metabolism in response to abiotic and biotic stress. Here, we review potential mechanisms by which proline metabolism influences plant senescence, namely in the petal and leaf. Recent studies of petal senescence suggest proline content is manipulated to meet energy demands of senescing cells. In the flower and leaf, proline metabolism may influence ROS signaling pathways that delay senescence progression. Future studies focusing on the mechanisms by which proline metabolic shifts occur during senescence may lead to novel methods to rescue crops under stress and to preserve post-harvest agricultural products. PMID:26347750

  15. Signaling Pathways Involved in Lunar Dust Induced Cytotoxicity

    NASA Technical Reports Server (NTRS)

    Zhang, Ye; Lam, Chiu-Wing; Scully, Robert R.; Williams, Kyle; Zalesak, Selina; Wu, Honglu; James, John T.

    2014-01-01

    The Moon's surface is covered by a layer of fine, reactive dust. Lunar dust contain about 1-2% of very fine dust (< 3 micron), that is respirable. The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents to assess the health risk of dust exposures to humans. One of the particular interests in the study is to evaluate dust-induced changes of the expression of fibrosis-related genes, and to identify specific signaling pathways involved in lunar dust-induced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose-only inhalation chambers to concentrations of 0 (control air), 2.1, 6.1, 21, and 61 mg/m(exp 3) of lunar dust. Five rats per group were euthanized 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The total RNAs were isolated from the blood or lung tissue after being lavaged, using the Qigen RNeasy kit. The Rat Fibrosis RT2 Profile PCR Array was used to profile the expression of 84 genes relevant to fibrosis. The genes with significant expression changes are identified and the gene expression data were further analyzed using IPA pathway analysis tool to determine the signaling pathways with significant changes.

  16. The Gq signalling pathway inhibits brown and beige adipose tissue

    PubMed Central

    Klepac, Katarina; Kilić, Ana; Gnad, Thorsten; Brown, Loren M.; Herrmann, Beate; Wilderman, Andrea; Balkow, Aileen; Glöde, Anja; Simon, Katharina; Lidell, Martin E.; Betz, Matthias J.; Enerbäck, Sven; Wess, Jürgen; Freichel, Marc; Blüher, Matthias; König, Gabi; Kostenis, Evi; Insel, Paul A.; Pfeifer, Alexander

    2016-01-01

    Brown adipose tissue (BAT) dissipates nutritional energy as heat via the uncoupling protein-1 (UCP1) and BAT activity correlates with leanness in human adults. Here we profile G protein-coupled receptors (GPCRs) in brown adipocytes to identify druggable regulators of BAT. Twenty-one per cent of the GPCRs link to the Gq family, and inhibition of Gq signalling enhances differentiation of human and murine brown adipocytes. In contrast, activation of Gq signalling abrogates brown adipogenesis. We further identify the endothelin/Ednra pathway as an autocrine activator of Gq signalling in brown adipocytes. Expression of a constitutively active Gq protein in mice reduces UCP1 expression in BAT, whole-body energy expenditure and the number of brown-like/beige cells in white adipose tissue (WAT). Furthermore, expression of Gq in human WAT inversely correlates with UCP1 expression. Thus, our data indicate that Gq signalling regulates brown/beige adipocytes and inhibition of Gq signalling may be a novel therapeutic approach to combat obesity. PMID:26955961

  17. Ca2+ signal is generated only once in the mating pheromone response pathway in Saccharomyces cerevisiae.

    PubMed

    Nakajima-Shimada, J; Sakaguchi, S; Tsuji, F I; Anraku, Y; Iida, H

    2000-04-01

    The mating pheromone, alpha-factor, of the yeast Saccharomyces cerevisiae binds to the heterotrimeric G protein-coupled cell surface receptor of MATa cells and induces cellular responses necessary for mating. In higher eukaryotic cells, many hormones and growth factors rapidly mobilize a second messenger, Ca2+, by means of receptor-G protein signaling. Although striking similarities between the mechanisms of the receptor-G protein signaling in yeast and higher eukaryotes have long been known, it is still uncertain whether the pheromone rapidly mobilizes Ca2+ necessary for early events of the pheromone response. Here we reexamine this problem using sensitive methods for detecting Ca2+ fluxes and mobilization, and find no evidence that there is rapid Ca2+ influx leading to a rapid increase in the cytosolic free Ca2+ concentration. In addition, the yeast PLC1 deletion mutant lacking phosphoinositide-specific phospholipase C, a key enzyme for generating Ca2+ signals in higher eukaryotic cells, responds normally to the pheromone. These findings suggest that the receptor-G protein signaling does not utilize Ca2+ as a second messenger in the early stage of the pheromone response pathway. Since the receptor-G protein signaling does stimulate Ca2+ influx after early events have finished and this stimulation is essential for late events in the pheromone response pathway [Iida et al., (1990) J. Biol. Chem., 265: 13391-13399] Ca2+ may be used only once in the signal transduction pathway in unicellular eukaryotes such as yeast. PMID:10885582

  18. Emerging Role and Therapeutic Implication of Wnt Signaling Pathways in Autoimmune Diseases

    PubMed Central

    Shi, Juan; Chi, Shuhong; Xue, Jing; Yang, Jiali; Li, Feng; Liu, Xiaoming

    2016-01-01

    The Wnt signaling pathway plays a key role in many biological aspects, such as cellular proliferation, tissue regeneration, embryonic development, and other systemic effects. Under a physiological condition, it is tightly controlled at different layers and arrays, and a dysregulated activation of this signaling has been implicated into the pathogenesis of various human disorders, including autoimmune diseases. Despite the fact that therapeutic interventions are available for ameliorating disease manifestations, there is no curative therapy currently available for autoimmune disorders. Increasing lines of evidence have suggested a crucial role of Wnt signaling during the pathogenesis of many autoimmune diseases; in addition, some of microRNAs (miRNAs), a class of small, noncoding RNA molecules capable of transcriptionally regulating gene expression, have also recently been demonstrated to possess both physiological and pathological roles in autoimmune diseases by regulating the Wnt signaling pathway. This review summarizes currently our understanding of the pathogenic roles of Wnt signaling in several major autoimmune disorders and miRNAs, those targeting Wnt signaling in autoimmune diseases, with a focus on the implication of the Wnt signaling as potential biomarkers and therapeutic targets in immune diseases, as well as miRNA-mediated regulation of Wnt signaling activation in the development of autoimmune diseases. PMID:27110577

  19. Biphasic Role of Calcium in Mouse Sperm Capacitation Signaling Pathways

    PubMed Central

    Alvau, Antonio; Escoffier, Jessica; Krapf, Dario; Sánchez-Cárdenas, Claudia; Salicioni, Ana M.; Darszon, Alberto; Visconti, Pablo E.

    2016-01-01

    Mammalian sperm acquire fertilizing ability in the female tract in a process known as capacitation. At the molecular level, capacitation is associated with up-regulation of a cAMP-dependent pathway, changes in intracellular pH, intracellular Ca2+ and an increase in tyrosine phosphorylation. How these signaling systems interact during capacitation is not well understood. Results presented in this study indicate that Ca2+ ions have a biphasic role in the regulation of cAMP-dependent signaling. Media without added Ca2+ salts (nominal zero Ca2+) still contain micromolar concentrations of this ion. Sperm incubated in this medium did not undergo PKA activation or the increase in tyrosine phosphorylation suggesting that these phosphorylation pathways require Ca2+. However, chelation of the extracellular Ca2+ traces by EGTA induced both cAMP-dependent phosphorylation and the increase in tyrosine phosphorylation. The EGTA effect in nominal zero Ca2+ media was mimicked by two calmodulin antagonists, W7 and calmidazolium, and by the calcineurin inhibitor cyclosporine A. These results suggest that Ca2+ ions regulate sperm cAMP and tyrosine phosphorylation pathways in a biphasic manner and that some of its effects are mediated by calmodulin. Interestingly, contrary to wild type mouse sperm, sperm from CatSper1 KO mice underwent PKA activation and an increase in tyrosine phosphorylation upon incubation in nominal zero Ca2+ media. Therefore, sperm lacking Catsper Ca2+ channels behave as wild-type sperm incubated in the presence of EGTA. This latter result suggests that Catsper transports the Ca2+ involved in the regulation of cAMP-dependent and tyrosine phosphorylation pathways required for sperm capacitation. PMID:25597298

  20. Involvement of Notch1/Hes signaling pathway in ankylosing spondylitis

    PubMed Central

    Xu, Wei; Liang, Chao-Ge; Li, Yi-Fan; Ji, Yun-Han; Qiu, Wen-Jun; Tang, Xian-Zhong

    2015-01-01

    We aimed to investigate the role of Notch1/Hes signaling pathway in the pathogenesis of abnormal ossification of hip ligament in patients with ankylosing spondylitis (AS). 22 AS patients scheduled for artificial hip arthroplasty were randomly chosen as AS group. As controls, we used 4 patients diagnosed with transcervical fracture who underwent hip replacement surgery. Notch1 and Hes mRNA expressions were detected by real-time fluorescent quantitative polymerase chain reaction (RFQ-PCR). Immunohistochemistry (IHC) was used to detect Notch1 and Hes protein expression. Correlation analyses of Notch-l and Hes with AS-related clinical factors were conducted with spearman’s correlation analysis and partial correlation analysis. RFQ-PCR results showed significant differences in Notch1 and Hes mRNA expressions between AS group and the control group (all P < 0.05). IHC analysis further indicated positive nuclear signals of Notch1 and Hes protein, indicating functional activation of the Notch1 and Hes pathways. Semi-quantitative IHC showed a higher Notch1 and Hes expression levels in AS group compared to the control group (all P < 0.05). Correlation analysis suggested that Hes protein expression was positively associated with the clinical course of the disease in AS patients. In conclusion, Notch1 and Hes overexpression was clearly detected in hip joint ligaments of AS patients, Hes protein expression was associated with the clinical course of AS. Taken together, we suggest that signaling pathways mediated by Notch1-Hes may contribute to ligament ossification of hip joints in AS patients. PMID:26045779

  1. Colony-stimulating Factor-1 Receptor Utilizes Multiple Signaling Pathways to Induce Cyclin D2 Expression

    PubMed Central

    Dey, Arunangsu; She, Hongyun; Kim, Leopold; Boruch, Allan; Guris, Deborah L.; Carlberg, Kristen; Sebti, Saïd M.; Woodley, David T.; Imamoto, Akira; Li, Wei

    2000-01-01

    Colony-stimulating factor-1 (CSF-1) induces expression of immediate early gene, such as c-myc and c-fos and delayed early genes such as D-type cyclins (D1 and D2), whose products play essential roles in the G1 to S phase transition of the cell cycle. Little is known, however, about the cytoplasmic signal transduction pathways that connect the surface CSF-1 receptor to these genes in the nucleus. We have investigated the signaling mechanism of CSF-1-induced D2 expression. Analyses of CSF-1 receptor autophosphorylation mutants show that, although certain individual mutation has a partial inhibitory effect, only multiple combined mutations completely block induction of D2 in response to CSF-1. We report that at least three parallel pathways, the Src pathway, the MAPK/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway, and the c-myc pathway, are involved. Induction of D2 is partially inhibited in Src−/− bone marrow-derived macrophages and by Src inhibitor PP1 and is enhanced in v-Src-overexpressing cells. Activation of myc's transactivating activity selectively induces D2 but not D1. Blockade of c-myc expression partially blocks CSF-1-induced D2 expression. Complete inhibition of the MEK/ERK pathway causes 50% decrease of D2 expression. Finally, simultaneous inhibition of Src, MEK activation, and c-myc expression additively blocks CSF-1-induced D2 expression. This study indicates that multiple signaling pathways are involved in full induction of a single gene, and this finding may also apply broadly to other growth factor-inducible genes. PMID:11071910

  2. Multiparticle collision dynamics for diffusion-influenced signaling pathways

    NASA Astrophysics Data System (ADS)

    Strehl, R.; Rohlf, K.

    2016-08-01

    An efficient yet accurate simulation method for modeling diffusion-influenced reaction networks is presented. The method extends existing reactive multiparticle collision dynamics by incorporating species-dependent diffusion coefficients, and developing theoretical expressions for the reactant-dependent diffusion control. This off-lattice particle-based mesoscopic simulation tool is particularly suited for problems in which detailed descriptions of particle trajectories and local reactions are required. Numerical simulations of an intracellular signaling pathway for bacterial chemotaxis are carried out to validate our approach, and to demonstrate its efficiency.

  3. Signaling pathways mediating chemotaxis in the social amoeba, Dictyostelium discoideum.

    PubMed

    Willard, Stacey S; Devreotes, Peter N

    2006-09-01

    Chemotaxis, or cell migration guided by chemical cues, is critical for a multitude of biological processes in a diverse array of organisms. Dictyostelium discoideum amoebae rely on chemotaxis to find food and to survive starvation conditions, and we have taken advantage of this system to study the molecular regulation of this vital cell behavior. Previous work has identified phosphoinositide signaling as one mechanism which may contribute to directional sensing and actin polymerization during chemotaxis; a mechanism which is conserved in mammalian neutrophils. In this review, we will discuss recent data on genes and pathways governing directional sensing and actin polymerization, with a particular emphasis on contributions from our laboratory. PMID:16962888

  4. To build a synapse: signaling pathways in neuromuscular junction assembly

    PubMed Central

    Wu, Haitao; Xiong, Wen C.; Mei, Lin

    2010-01-01

    Synapses, as fundamental units of the neural circuitry, enable complex behaviors. The neuromuscular junction (NMJ) is a synapse type that forms between motoneurons and skeletal muscle fibers and that exhibits a high degree of subcellular specialization. Aided by genetic techniques and suitable animal models, studies in the past decade have brought significant progress in identifying NMJ components and assembly mechanisms. This review highlights recent advances in the study of NMJ development, focusing on signaling pathways that are activated by diffusible cues, which shed light on synaptogenesis in the brain and contribute to a better understanding of muscular dystrophy. PMID:20215342

  5. [Current understanding of signaling transduction pathway and biological functions of Karrikins].

    PubMed

    Luo, Xiaofeng; Qi, Ying; Meng, Yongjie; Shuai, Haiwei; Chen, Feng; Yang, Wenyu; Shu, Kai

    2016-01-01

    Karrikins are a class of signaling molecules discovered in wildfire smoke, which can significantly promote seed germination in some species (such as Arabidopsis and Avena fatua). The structures of Karrikins were first elucidated in 2004. At present, six different types of Karrikins have been documented, and their biological activities vary significantly. So far, studies for Karrikins have become a hot spot in the plant molecular biology field. Recent advances demonstrate that Karrikins regulate plant photomorphogenesis and leaf differentiation effectively, in addition to the effect on seed germination. Furthermore, Karrikins share highly similar molecular structures and signaling transduction pathways with strigolactone. In this review, we summarize the history of discovery, signaling transduction pathways, physiological functions and ecological significance of Karrikins, and further discuss the future research directions. PMID:26787523

  6. Metabolic control of signalling pathways and metabolic auto-regulation.

    PubMed

    Lorendeau, Doriane; Christen, Stefan; Rinaldi, Gianmarco; Fendt, Sarah-Maria

    2015-08-01

    Metabolic alterations have emerged as an important hallmark in the development of various diseases. Thus, understanding the complex interplay of metabolism with other cellular processes such as cell signalling is critical to rationally control and modulate cellular physiology. Here, we review in the context of mammalian target of rapamycin, AMP-activated protein kinase and p53, the orchestrated interplay between metabolism and cellular signalling as well as transcriptional regulation. Moreover, we discuss recent discoveries in auto-regulation of metabolism (i.e. how metabolic parameters such as metabolite levels activate or inhibit enzymes and thus metabolic pathways). Finally, we review functional consequences of post-translational modification on metabolic enzyme abundance and/or activities.

  7. Hypergravity Stimulates Osteoblast Proliferation Via Matrix-Integrin-Signaling Pathways

    NASA Technical Reports Server (NTRS)

    Vercoutere, W.; Parra, M.; Roden, C.; DaCosta, M.; Wing, A.; Damsky, C.; Holton, E.; Searby, N.; Globus, R.; Almeida, E.

    2003-01-01

    Extensive characterizations of the physiologic consequences of microgravity and gravity indicate that lack of weight-bearing may cause tissue atrophy through cellular and subcellular level mechanisms. We hypothesize that gravity is needed for the efficient transduction of cell growth and survival signals from the extra-cellular matrix (ECM) in mechanosensitive tissues. Recent work from our laboratory and from others shows that an increase of gravity increases bone cell growth and survival. We found that 50-g hypergravity stimulation increased osteoblast proliferation for cells grown on Collagen Type I and Fibronectin, but not on Laminin or uncoated plastic. This may be a tissue-specific response, because 50-g hypergravity stimulation caused no increase in proliferation for primary rat fibroblasts. These results combined with RT-PCR for all possible integrins indicate that beta1 integrin subunit may be involved. The osteoblast proliferation response on Collagen Type I was greater at 25-g than at 10-g or 50-g; 24-h duration of hypergravity was necessary to see an increase in proliferation. Survival was enhanced during hypergravity stimulation by the presence of matrix. Flow cytometry analysis indicated that cell cycle may be altered; BrdU incorporation in proliferating cells showed an increase in the number of actively dividing cells from about 60% at 1-g to over 90% at 25-g. To further investigate the molecular components involved, we applied fluorescence labeling of cytoskeletal and signaling molecules to cells after 2 to 30 minutes of hypergravity stimulation. While structural components did not appear to be altered, phosphorylation increased, indicating that signaling pathways may be activated. These data indicate that gravity mechanostimulation of osteoblast proliferation involves specific matrix-integrin signaling pathways which are sensitive to duration and g-level.

  8. Signaling pathways involved in PDGF-evoked cellular responses in human RPE cells

    SciTech Connect

    Hollborn, Margrit . E-mail: hollbm@medizin.uni-leipzig.de; Bringmann, Andreas; Faude, Frank; Wiedemann, Peter; Kohen, Leon

    2006-06-09

    We examined whether PDGF may directly stimulate the expression of VEGF by retinal pigment epithelial (RPE) cells in vitro, and the involvement of three signal transduction pathways in the regulation of PDGF-evoked cell proliferation, migration, and production of VEGF-A was investigated. PDGF stimulated the gene and protein expression of VEGF-A by RPE cells, and increased cell proliferation and chemotaxis. PDGF activated all signaling pathways investigated, as determined by increased phosphorylation levels of ERK1/2, p38, and Akt proteins. The three signaling pathways were involved in the mediation of PDGF-evoked cell proliferation, while p38 and PI3K mediated cell migration, and PI3K mediated secretion of VEGF-A. In addition to VEGF-A, the cells expressed mRNAs for various members of the VEGF family and for their receptors, including VEGF-B, -C, -D, flt-1, and KDR. The data indicate that PDGF selectively stimulates the expression of VEGF-A in RPE cells. PDGF evokes at least three signal transduction pathways which are differentially involved in various cellular responses.

  9. Approaches and tools for modeling signaling pathways and calcium dynamics in neurons

    PubMed Central

    Blackwell, KT

    2013-01-01

    Signaling pathways are cascades of intracellular biochemical reactions that are activated by transmembrane receptors, and ultimately lead to transcription in the nucleus. In neurons, both calcium permeable synaptic and ionic channels as well as G protein coupled receptors initiate activation of signaling pathway molecules that interact with electrical activity at multiple spatial and time scales. At small temporal and spatial scales, calcium modifies the properties of ionic channels, whereas at larger temporal and spatial scales, various kinases and phosphatases modify the properties of ionic channels, producing phenomena such as synaptic plasticity and homeostatic plasticity. The elongated structure of neuronal dendrites and the organization of multi-protein complexes by anchoring proteins implies that the spatial dimension must be explicit. Therefore, modeling signaling pathways in neurons utilizes algorithms for both diffusion and reactions. The small size of spines coupled with small concentrations of some molecules implies that some reactions occur stochastically. The need for stochastic simulation of many reaction and diffusion events coupled with the multiple temporal and spatial scales makes modeling of signaling pathways a difficult problem. Several different software programs have achieved different aspects of these capabilities. This review explains some of the mathematical formulas used for modeling reactions and diffusion. In addition, it briefly presents the simulators used for modeling reaction-diffusion systems in neurons, together with scientific problems addressed. PMID:23743449

  10. The Inositide Signaling Pathway As a Target for Treating Gastric Cancer and Colorectal Cancer

    PubMed Central

    Kim, Hong Jun; Lee, Suk-young; Oh, Sang Cheul

    2016-01-01

    Gastric cancer and colorectal cancer are the leading cause of cancer mortality and have a dismal prognosis. The introduction of biological agents to treat these cancers has resulted in improved outcomes, and combination chemotherapy with targeted agents and conventional chemotherapeutic agents is regarded as standard therapy. Additional newly clarified mechanisms of oncogenesis and resistance to targeted agents require the development of new biologic agents. Aberrant activation of the inositide signaling pathway by a loss of function PTEN mutation or gain of function mutation/amplification of PIK3CA is an oncogenic mechanism in gastric cancer and colorectal cancer. Clinical trials with biologic agents that target the inositide signaling pathway are being performed to further improve treatment outcomes of patients with advanced gastric cancer and metastatic colorectal cancer (CRC). In this review we summarize the inositide signaling pathway, the targeted agents that inhibit abnormal activation of this signaling pathway and the clinical trials currently being performed in patients with advanced or metastatic gastric cancer and metastatic CRC using these targeted agents. PMID:27242542

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

    PubMed

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

    2002-09-01

    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.

  12. Expanding the Interactome of the Noncanonical NF-κB Signaling Pathway.

    PubMed

    Willmann, Katharina L; Sacco, Roberto; Martins, Rui; Garncarz, Wojciech; Krolo, Ana; Knapp, Sylvia; Bennett, Keiryn L; Boztug, Kaan

    2016-09-01

    NF-κB signaling is a central pathway of immunity and integrates signal transduction upon a wide array of inflammatory stimuli. Noncanonical NF-κB signaling is activated by a small subset of TNF family receptors and characterized by NF-κB2/p52 transcriptional activity. The medical relevance of this pathway has recently re-emerged from the discovery of primary immunodeficiency patients that have loss-of-function mutations in the MAP3K14 gene encoding NIK. Nevertheless, knowledge of protein interactions that regulate noncanonical NF-κB signaling is sparse. Here we report a detailed state-of-the-art mass spectrometry-based protein-protein interaction network including the noncanonical NF-κB signaling nodes TRAF2, TRAF3, IKKα, NIK, and NF-κB2/p100. The value of the data set was confirmed by the identification of interactions already known to regulate this pathway. In addition, a remarkable number of novel interactors were identified. We provide validation of the novel NIK and IKKα interactor FKBP8, which may regulate processes downstream of noncanonical NF-κB signaling. To understand perturbed noncanonical NF-κB signaling in the context of misregulated NIK in disease, we also provide a differential interactome of NIK mutants that cause immunodeficiency. Altogether, this data set not only provides critical insight into how protein-protein interactions can regulate immune signaling but also offers a novel resource on noncanonical NF-κB signaling. PMID:27416764

  13. Sorting and targeting of melanosomal membrane proteins: signals, pathways, and mechanisms.

    PubMed

    Setaluri, V

    2000-06-01

    Newly synthesized melanosomal proteins, like many other cellular proteins, traverse through a series of intracellular compartments en route to melanosomes. Entry and exit of proteins through these compartments is orchestrated by cellular sorting machinery that recognize specific sorting signals. Melanosomal membrane proteins begin their intracellular journey upon co-translational importation into the endoplasmic reticulum (ER). The biosynthetic output of tyrosinase, the key melanogenic enzyme, appears to be regulated by quality-control events at the ER, the 'port of entry' to the secretory pathway. Following maturation in the ER and through the Golgi, the sorting of these proteins in the trans-Golgi network for intracellular retention and transport along endosome/lysosome pathway requires cytoplasmically exposed signals. A di-leucine motif, present in the cytoplasmic tails of most melanosomal proteins, and its interaction with adaptor protein (AP) complexes, specifically AP-3, are critical for these events. Defects in sorting signals and the cytosolic components that interact with these signals result in a number of murine coat color phenotypes and cause human pigmentary disorders. Thus, missense or frame-shift mutations that produce truncated tyrosinase lacking the melanosomal sorting signal(s) appear to be responsible for murine platinum coat color phenotypes and a proportion of human oculocutaneous albinism-1; mutations in AP-3 appear to be responsible for the mocha phenotype in mice and Hermansky-Pudlak-like syndrome in man. Additional signals and sorting steps downstream of AP-3 appear to be required for endosomal sorting and targeting proteins to melanosomes. Signals and mechanisms that sequester melanosomal proteins from endosomes/lysosomes are not understood. Potential candidates that mediate such processes include proteins encoded by lyst and pallid genes. The common occurrence of abnormalities in melanosomes in many storage-pool disorders suggests that

  14. Signaling pathway cross talk in Alzheimer’s disease

    PubMed Central

    2014-01-01

    Numerous studies suggest energy failure and accumulative intracellular waste play a causal role in the pathogenesis of several neurodegenerative disorders and Alzheimer’s disease (AD) in particular. AD is characterized by extracellular amyloid deposits, intracellular neurofibrillary tangles, cholinergic deficits, synaptic loss, inflammation and extensive oxidative stress. These pathobiological changes are accompanied by significant behavioral, motor, and cognitive impairment leading to accelerated mortality. Currently, the potential role of several metabolic pathways associated with AD, including Wnt signaling, 5' adenosine monophosphate-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), Sirtuin 1 (Sirt1, silent mating-type information regulator 2 homolog 1), and peroxisome proliferator-activated receptor gamma co-activator 1-α (PGC-1α) have widened, with recent discoveries that they are able to modulate several pathological events in AD. These include reduction of amyloid-β aggregation and inflammation, regulation of mitochondrial dynamics, and increased availability of neuronal energy. This review aims to highlight the involvement of these new set of signaling pathways, which we have collectively termed “anti-ageing pathways”, for their potentiality in multi-target therapies against AD where cellular metabolic processes are severely impaired. PMID:24679124

  15. Wnt-signalling pathways and microRNAs network in carcinogenesis: experimental and bioinformatics approaches.

    PubMed

    Onyido, Emenike K; Sweeney, Eloise; Nateri, Abdolrahman Shams

    2016-01-01

    Over the past few years, microRNAs (miRNAs) have not only emerged as integral regulators of gene expression at the post-transcriptional level but also respond to signalling molecules to affect cell function(s). miRNAs crosstalk with a variety of the key cellular signalling networks such as Wnt, transforming growth factor-β and Notch, control stem cell activity in maintaining tissue homeostasis, while if dysregulated contributes to the initiation and progression of cancer. Herein, we overview the molecular mechanism(s) underlying the crosstalk between Wnt-signalling components (canonical and non-canonical) and miRNAs, as well as changes in the miRNA/Wnt-signalling components observed in the different forms of cancer. Furthermore, the fundamental understanding of miRNA-mediated regulation of Wnt-signalling pathway and vice versa has been significantly improved by high-throughput genomics and bioinformatics technologies. Whilst, these approaches have identified a number of specific miRNA(s) that function as oncogenes or tumour suppressors, additional analyses will be necessary to fully unravel the links among conserved cellular signalling pathways and miRNAs and their potential associated components in cancer, thereby creating therapeutic avenues against tumours. Hence, we also discuss the current challenges associated with Wnt-signalling/miRNAs complex and the analysis using the biomedical experimental and bioinformatics approaches. PMID:27590724

  16. A divergent canonical WNT-signaling pathway regulates microtubule dynamics

    PubMed Central

    Ciani, Lorenza; Krylova, Olga; Smalley, Matthew J.; Dale, Trevor C.; Salinas, Patricia C.

    2004-01-01

    Dishevelled (DVL) is associated with axonal microtubules and regulates microtubule stability through the inhibition of the serine/threonine kinase, glycogen synthase kinase 3β (GSK-3β). In the canonical WNT pathway, the negative regulator Axin forms a complex with β-catenin and GSK-3β, resulting in β-catenin degradation. Inhibition of GSK-3β by DVL increases β-catenin stability and TCF transcriptional activation. Here, we show that Axin associates with microtubules and unexpectedly stabilizes microtubules through DVL. In turn, DVL stabilizes microtubules by inhibiting GSK-3β through a transcription- and β-catenin–independent pathway. More importantly, axonal microtubules are stabilized after DVL localizes to axons. Increased microtubule stability is correlated with a decrease in GSK-3β–mediated phosphorylation of MAP-1B. We propose a model in which Axin, through DVL, stabilizes microtubules by inhibiting a pool of GSK-3β, resulting in local changes in the phosphorylation of cellular targets. Our data indicate a bifurcation in the so-called canonical WNT-signaling pathway to regulate microtubule stability. PMID:14734535

  17. Romidepsin targets multiple survival signaling pathways in malignant T cells

    PubMed Central

    Valdez, B C; Brammer, J E; Li, Y; Murray, D; Liu, Y; Hosing, C; Nieto, Y; Champlin, R E; Andersson, B S

    2015-01-01

    Romidepsin is a cyclic molecule that inhibits histone deacetylases. It is Food and Drug Administration-approved for treatment of cutaneous and peripheral T-cell lymphoma, but its precise mechanism of action against malignant T cells is unknown. To better understand the biological effects of romidepsin in these cells, we exposed PEER and SUPT1 T-cell lines, and a primary sample from T-cell lymphoma patient (Patient J) to romidepsin. We then examined the consequences in some key oncogenic signaling pathways. Romidepsin displayed IC50 values of 10.8, 7.9 and 7.0 nm in PEER, SUPT1 and Patient J cells, respectively. Strong inhibition of histone deacetylases and demethylases, increased production of reactive oxygen species and decreased mitochondrial membrane potential were observed, which may contribute to the observed DNA-damage response and apoptosis. The stress-activated protein kinase/c-Jun N-terminal kinase signaling pathway and unfolded protein response in the endoplasmic reticulum were activated, whereas the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) and β-catenin pro-survival pathways were inhibited. The decreased level of β-catenin correlated with the upregulation of its inhibitor SFRP1 through romidepsin-mediated hypomethylation of its gene promoter. Our results provide new insights into how romidepsin invokes malignant T-cell killing, show evidence of its associated DNA hypomethylating activity and offer a rationale for the development of romidepsin-containing combination therapies. PMID:26473529

  18. Romidepsin targets multiple survival signaling pathways in malignant T cells.

    PubMed

    Valdez, B C; Brammer, J E; Li, Y; Murray, D; Liu, Y; Hosing, C; Nieto, Y; Champlin, R E; Andersson, B S

    2015-10-16

    Romidepsin is a cyclic molecule that inhibits histone deacetylases. It is Food and Drug Administration-approved for treatment of cutaneous and peripheral T-cell lymphoma, but its precise mechanism of action against malignant T cells is unknown. To better understand the biological effects of romidepsin in these cells, we exposed PEER and SUPT1 T-cell lines, and a primary sample from T-cell lymphoma patient (Patient J) to romidepsin. We then examined the consequences in some key oncogenic signaling pathways. Romidepsin displayed IC50 values of 10.8, 7.9 and 7.0 nm in PEER, SUPT1 and Patient J cells, respectively. Strong inhibition of histone deacetylases and demethylases, increased production of reactive oxygen species and decreased mitochondrial membrane potential were observed, which may contribute to the observed DNA-damage response and apoptosis. The stress-activated protein kinase/c-Jun N-terminal kinase signaling pathway and unfolded protein response in the endoplasmic reticulum were activated, whereas the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) and β-catenin pro-survival pathways were inhibited. The decreased level of β-catenin correlated with the upregulation of its inhibitor SFRP1 through romidepsin-mediated hypomethylation of its gene promoter. Our results provide new insights into how romidepsin invokes malignant T-cell killing, show evidence of its associated DNA hypomethylating activity and offer a rationale for the development of romidepsin-containing combination therapies.

  19. Identification of a neurovascular signaling pathway regulating seizures in mice

    PubMed Central

    Fredriksson, Linda; Stevenson, Tamara K; Su, Enming J; Ragsdale, Margaret; Moore, Shannon; Craciun, Stefan; Schielke, Gerald P; Murphy, Geoffrey G; Lawrence, Daniel A

    2015-01-01

    Objective A growing body of evidence suggests that increased blood–brain barrier (BBB) permeability can contribute to the development of seizures. The protease tissue plasminogen activator (tPA) has been shown to promote BBB permeability and susceptibility to seizures. In this study, we examined the pathway regulated by tPA in seizures. Methods An experimental model of kainate-induced seizures was used in genetically modified mice, including mice deficient in tPA (tPA−/−), its inhibitor neuroserpin (Nsp−/−), or both (Nsp:tPA−/−), and in mice conditionally deficient in the platelet-derived growth factor receptor alpha (PDGFRα). Results Compared to wild-type (WT) mice, Nsp−/− mice have significantly reduced latency to seizure onset and generalization; whereas tPA−/− mice have the opposite phenotype, as do Nsp:tPA−/− mice. Furthermore, interventions that maintain BBB integrity delay seizure propagation, whereas osmotic disruption of the BBB in seizure-resistant tPA−/− mice dramatically reduces the time to seizure onset and accelerates seizure progression. The phenotypic differences in seizure progression between WT, tPA−/−, and Nsp−/− mice are also observed in electroencephalogram recordings in vivo, but absent in ex vivo electrophysiological recordings where regulation of the BBB is no longer necessary to maintain the extracellular environment. Finally, we demonstrate that these effects on seizure progression are mediated through signaling by PDGFRα on perivascular astrocytes. Interpretation Together, these data identify a specific molecular pathway involving tPA-mediated PDGFRα signaling in perivascular astrocytes that regulates seizure progression through control of the BBB. Inhibition of PDGFRα signaling and maintenance of BBB integrity might therefore offer a novel clinical approach for managing seizures. PMID:26273685

  20. Directed random walks and constraint programming reveal active pathways in hepatocyte growth factor signaling.

    PubMed

    Kittas, Aristotelis; Delobelle, Aurélien; Schmitt, Sabrina; Breuhahn, Kai; Guziolowski, Carito; Grabe, Niels

    2016-01-01

    An effective means to analyze mRNA expression data is to take advantage of established knowledge from pathway databases, using methods such as pathway-enrichment analyses. However, pathway databases are not case-specific and expression data could be used to infer gene-regulation patterns in the context of specific pathways. In addition, canonical pathways may not always describe the signaling mechanisms properly, because interactions can frequently occur between genes in different pathways. Relatively few methods have been proposed to date for generating and analyzing such networks, preserving the causality between gene interactions and reasoning over the qualitative logic of regulatory effects. We present an algorithm (MCWalk) integrated with a logic programming approach, to discover subgraphs in large-scale signaling networks by random walks in a fully automated pipeline. As an exemplary application, we uncover the signal transduction mechanisms in a gene interaction network describing hepatocyte growth factor-stimulated cell migration and proliferation from gene-expression measured with microarray and RT-qPCR using in-house perturbation experiments in a keratinocyte-fibroblast co-culture. The resulting subgraphs illustrate possible associations of hepatocyte growth factor receptor c-Met nodes, differentially expressed genes and cellular states. Using perturbation experiments and Answer Set programming, we are able to select those which are more consistent with the experimental data. We discover key regulator nodes by measuring the frequency with which they are traversed when connecting signaling between receptors and significantly regulated genes and predict their expression-shift consistently with the measured data. The Java implementation of MCWalk is publicly available under the MIT license at: https://bitbucket.org/akittas/biosubg.

  1. Phytochrome and retrograde signalling pathways coverage to antogonistically regulate a light-induced transcription network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plastid-to-nucleus retrograde signals emitted by dysfunctional chloroplasts impact photomorphogenic development, but the molecular link between retrograde and photosensory-receptor signaling has remained undefined. Here, we show that the phytochrome (phy) and retrograde signaling pathways converge a...

  2. Phosphoproteomic Analyses Reveal Signaling Pathways That Facilitate Lytic Gammaherpesvirus Replication

    PubMed Central

    Stahl, James A.; Chavan, Shweta S.; Sifford, Jeffrey M.; MacLeod, Veronica; Voth, Daniel E.; Edmondson, Ricky D.; Forrest, J. Craig

    2013-01-01

    Lytic gammaherpesvirus (GHV) replication facilitates the establishment of lifelong latent infection, which places the infected host at risk for numerous cancers. As obligate intracellular parasites, GHVs must control and usurp cellular signaling pathways in order to successfully replicate, disseminate to stable latency reservoirs in the host, and prevent immune-mediated clearance. To facilitate a systems-level understanding of phosphorylation-dependent signaling events directed by GHVs during lytic replication, we utilized label-free quantitative mass spectrometry to interrogate the lytic replication cycle of murine gammaherpesvirus-68 (MHV68). Compared to controls, MHV68 infection regulated by 2-fold or greater ca. 86% of identified phosphopeptides – a regulatory scale not previously observed in phosphoproteomic evaluations of discrete signal-inducing stimuli. Network analyses demonstrated that the infection-associated induction or repression of specific cellular proteins globally altered the flow of information through the host phosphoprotein network, yielding major changes to functional protein clusters and ontologically associated proteins. A series of orthogonal bioinformatics analyses revealed that MAPK and CDK-related signaling events were overrepresented in the infection-associated phosphoproteome and identified 155 host proteins, such as the transcription factor c-Jun, as putative downstream targets. Importantly, functional tests of bioinformatics-based predictions confirmed ERK1/2 and CDK1/2 as kinases that facilitate MHV68 replication and also demonstrated the importance of c-Jun. Finally, a transposon-mutant virus screen identified the MHV68 cyclin D ortholog as a viral protein that contributes to the prominent MAPK/CDK signature of the infection-associated phosphoproteome. Together, these analyses enhance an understanding of how GHVs reorganize and usurp intracellular signaling networks to facilitate infection and replication. PMID:24068923

  3. Phosphoproteomic analyses reveal signaling pathways that facilitate lytic gammaherpesvirus replication.

    PubMed

    Stahl, James A; Chavan, Shweta S; Sifford, Jeffrey M; MacLeod, Veronica; Voth, Daniel E; Edmondson, Ricky D; Forrest, J Craig

    2013-09-01

    Lytic gammaherpesvirus (GHV) replication facilitates the establishment of lifelong latent infection, which places the infected host at risk for numerous cancers. As obligate intracellular parasites, GHVs must control and usurp cellular signaling pathways in order to successfully replicate, disseminate to stable latency reservoirs in the host, and prevent immune-mediated clearance. To facilitate a systems-level understanding of phosphorylation-dependent signaling events directed by GHVs during lytic replication, we utilized label-free quantitative mass spectrometry to interrogate the lytic replication cycle of murine gammaherpesvirus-68 (MHV68). Compared to controls, MHV68 infection regulated by 2-fold or greater ca. 86% of identified phosphopeptides - a regulatory scale not previously observed in phosphoproteomic evaluations of discrete signal-inducing stimuli. Network analyses demonstrated that the infection-associated induction or repression of specific cellular proteins globally altered the flow of information through the host phosphoprotein network, yielding major changes to functional protein clusters and ontologically associated proteins. A series of orthogonal bioinformatics analyses revealed that MAPK and CDK-related signaling events were overrepresented in the infection-associated phosphoproteome and identified 155 host proteins, such as the transcription factor c-Jun, as putative downstream targets. Importantly, functional tests of bioinformatics-based predictions confirmed ERK1/2 and CDK1/2 as kinases that facilitate MHV68 replication and also demonstrated the importance of c-Jun. Finally, a transposon-mutant virus screen identified the MHV68 cyclin D ortholog as a viral protein that contributes to the prominent MAPK/CDK signature of the infection-associated phosphoproteome. Together, these analyses enhance an understanding of how GHVs reorganize and usurp intracellular signaling networks to facilitate infection and replication.

  4. Spatio-temporal dynamics of a cell signal pathway with negative feedbacks: the MAPK/ERK pathway.

    PubMed

    Maya-Bernal, José Luis; Ramírez-Santiago, Guillermo

    2016-03-01

    We studied the spatio-temporal dynamics of a cell signal cascade with negative feedback that quantitatively emulates the regulative process that occurs in the Mitogen Activated Protein Kinase/Extracellular Regulated Kinase (MAPK/ERK) pathway. The model consists of a set of six coupled reaction-diffusion equations that describes the dynamics of the six-module pathway. In the basic module the active form of the protein transmits the signal to the next pathway’s module. As suggested by experiments, the model considers that the fifth module's kinase down-regulates the first and third modules. The feedback parameter is defined as, μ(r)( j)= k(kin)5/k(kin)(j), (j = 1, 3). We analysed the pathway's dynamics for μ(r)( j) = 0.10, 1.0, and 10 in the kinetic regimes: i) saturation of both kinases and phosphatases, ii) saturation of the phosphatases and iii) saturation of the kinases. For a regulated pathway the Total Activated Protein Profiles (TAPPs) as a function of time develop a maximum during the transient stage in the three kinetic regimes. These maxima become higher and their positions shift to longer times downstream. This scenario also applies to the TAPP's regulatory kinase that sums up its inhibitory action to that of the phosphatases leading to a maximum. Nevertheless, when μ(r)(j)= 1.0 , the TAPPs develop two maxima, with the second maximum being almost imperceptible. These results are in qualitative agreement with experimental data obtained from NIH 3T3 mouse fibroblasts. In addition, analyses of the stationary states as a function of position indicate that in the kinetic regime i) which is of physiological interest, signal transduction occurs with a relatively large propagation length for the three values of the regulative parameter. However, for μ(r)(j)= 0.10 , the sixth module concentration profile is transmitted with approximately 45% of its full value. The results obtained for μ(r)(j) = 10 , indicate that the first five concentration profiles are

  5. Peroxiredoxins in Regulation of MAPK Signalling Pathways; Sensors and Barriers to Signal Transduction

    PubMed Central

    Latimer, Heather R.; Veal, Elizabeth A.

    2016-01-01

    Peroxiredoxins are highly conserved and abundant peroxidases. Although the thioredoxin peroxidase activity of peroxiredoxin (Prx) is important to maintain low levels of endogenous hydrogen peroxide, Prx have also been shown to promote hydrogen peroxide-mediated signalling. Mitogen activated protein kinase (MAPK) signalling pathways mediate cellular responses to a variety of stimuli, including reactive oxygen species (ROS). Here we review the evidence that Prx can act as both sensors and barriers to the activation of MAPK and discuss the underlying mechanisms involved, focusing in particular on the relationship with thioredoxin. PMID:26813660

  6. Small molecules intercept Notch signaling and the early secretory pathway.

    PubMed

    Krämer, Andreas; Mentrup, Torben; Kleizen, Bertrand; Rivera-Milla, Eric; Reichenbach, Daniela; Enzensperger, Christoph; Nohl, Richard; Täuscher, Eric; Görls, Helmar; Ploubidou, Aspasia; Englert, Christoph; Werz, Oliver; Arndt, Hans-Dieter; Kaether, Christoph

    2013-11-01

    Notch signaling has a pivotal role in numerous cell-fate decisions, and its aberrant activity leads to developmental disorders and cancer. To identify molecules that influence Notch signaling, we screened nearly 17,000 compounds using automated microscopy to monitor the trafficking and processing of a ligand-independent Notch-enhanced GFP (eGFP) reporter. Characterization of hits in vitro by biochemical and cellular assays and in vivo using zebrafish led to five validated compounds, four of which induced accumulation of the reporter at the plasma membrane by inhibiting γ-secretase. One compound, the dihydropyridine FLI-06, disrupted the Golgi apparatus in a manner distinct from that of brefeldin A and golgicide A. FLI-06 inhibited general secretion at a step before exit from the endoplasmic reticulum (ER), which was accompanied by a tubule-to-sheet morphological transition of the ER, rendering FLI-06 the first small molecule acting at such an early stage in secretory traffic. These data highlight the power of phenotypic screening to enable investigations of central cellular signaling pathways. PMID:24077179

  7. Hippo signaling pathway in liver and pancreas: the potential drug target for tumor therapy.

    PubMed

    Kong, Delin; Zhao, Yicheng; Men, Tong; Teng, Chun-Bo

    2015-02-01

    Cell behaviors, including proliferation, differentiation and apoptosis, are intricately controlled during organ development and tissue regeneration. In the past 9 years, the Hippo signaling pathway has been delineated to play critical roles in organ size control, tissue regeneration and tumorigenesis through regulating cell behaviors. In mammals, the core modules of the Hippo signaling pathway include the MST1/2-LATS1/2 kinase cascade and the transcriptional co-activators YAP/TAZ. The activity of YAP/TAZ is suppressed by cytoplasmic retention due to phosphorylation in the canonical MST1/2-LATS1/2 kinase cascade-dependent manner or the non-canonical MST1/2- and/or LATS1/2-independent manner. Hippo signaling pathway, which can be activated or inactivated by cell polarity, contact inhibition, mechanical stretch and extracellular factors, has been demonstrated to be involved in development and tumorigenesis of liver and pancreas. In addition, we have summarized several small molecules currently available that can target Hippo-YAP pathway for potential treatment of hepatic and pancreatic cancers, providing clues for other YAP initiated cancers therapy as well.

  8. Lovastatin inhibits the extracellular-signal-regulated kinase pathway in immortalized rat brain neuroblasts

    PubMed Central

    Cerezo-Guisado, Maria Isabel; GarcíA-Román, Natalia; García-MaríN, Luis Jesús; Álvarez-Barrientos, Alberto; Bragado, Maria Julia; Lorenzo, Maria Jesús

    2006-01-01

    We have shown previously that lovastatin, a 3-hydroxy-3-methyl- glutaryl coenzyme A reductase inhibitor, induces apoptosis in spontaneously immortalized rat brain neuroblasts. In the present study, we analysed the intracellular signal transduction pathways by which lovastatin induces neuroblast apoptosis. We showed that lovastatin efficiently inhibited Ras activation, which was associ-ated with a significant decrease in ERK1/2 (extracellular-signal-regulated kinase 1/2) phosphorylation. Lovastatin also decreased CREB phosphorylation and CREB-mediated gene expression. The effects of lovastatin on the Ras/ERK1/2/CREB pathway were time- and concentration-dependent and fully prevented by meva-lonate. In addition, we showed that two MEK [MAPK (mitogen-activated protein kinase)/ERK kinase] inhibitors, PD98059 and PD184352, were poor inducers of apoptosis in serum-treated neuroblasts. However, these inhibitors significantly increased apop-tosis induced by lovastatin treatment. Furthermore, we showed that pharmacological inhibition of both MEK and phosphoinos-itide 3-kinase activities was able to induce neuroblast apoptosis with similar efficacy as lovastatin. Our results suggest that lovast-atin triggers neuroblast apoptosis by regulating several signalling pathways, including the Ras/ERK1/2 pathway. These findings might also contribute to elucidate the intracellular mechanisms involved in the central nervous system side effects associated with statin therapy. PMID:16952276

  9. Capping protein integrates multiple MAMP signalling pathways to modulate actin dynamics during plant innate immunity.

    PubMed

    Li, Jiejie; Henty-Ridilla, Jessica L; Staiger, Benjamin H; Day, Brad; Staiger, Christopher J

    2015-01-01

    Plants and animals perceive diverse microbe-associated molecular patterns (MAMPs) via pattern recognition receptors and activate innate immune signalling. The actin cytoskeleton has been suggested as a target for innate immune signalling and a key transducer of cellular responses. However, the molecular mechanisms underlying actin remodelling and the precise functions of these rearrangements during innate immunity remain largely unknown. Here we demonstrate rapid actin remodelling in response to several distinct MAMP signalling pathways in plant epidermal cells. The regulation of actin dynamics is a convergence point for basal defence machinery, such as cell wall fortification and transcriptional reprogramming. Our quantitative analyses of actin dynamics and genetic studies reveal that MAMP-stimulated actin remodelling is due to the inhibition of capping protein (CP) by the signalling lipid, phosphatidic acid. In addition, CP promotes resistance against bacterial and fungal phytopathogens. These findings demonstrate that CP is a central target for the plant innate immune response. PMID:26018794

  10. Integration of Signaling Pathways with the Epigenetic Machinery in the Maintenance of Stem Cells

    PubMed Central

    Fagnocchi, Luca; Mazzoleni, Stefania; Zippo, Alessio

    2016-01-01

    Stem cells balance their self-renewal and differentiation potential by integrating environmental signals with the transcriptional regulatory network. The maintenance of cell identity and/or cell lineage commitment relies on the interplay of multiple factors including signaling pathways, transcription factors, and the epigenetic machinery. These regulatory modules are strongly interconnected and they influence the pattern of gene expression of stem cells, thus guiding their cellular fate. Embryonic stem cells (ESCs) represent an invaluable tool to study this interplay, being able to indefinitely self-renew and to differentiate towards all three embryonic germ layers in response to developmental cues. In this review, we highlight those mechanisms of signaling to chromatin, which regulate chromatin modifying enzymes, histone modifications, and nucleosome occupancy. In addition, we report the molecular mechanisms through which signaling pathways affect both the epigenetic and the transcriptional state of ESCs, thereby influencing their cell identity. We propose that the dynamic nature of oscillating signaling and the different regulatory network topologies through which those signals are encoded determine specific gene expression programs, leading to the fluctuation of ESCs among multiple pluripotent states or to the establishment of the necessary conditions to exit pluripotency. PMID:26798364

  11. Signaling pathways relevant to cognition-enhancing drug targets.

    PubMed

    Ménard, Caroline; Gaudreau, Pierrette; Quirion, Rémi

    2015-01-01

    Aging is generally associated with a certain cognitive decline. However, individual differences exist. While age-related memory deficits can be observed in humans and rodents in the absence of pathological conditions, some individuals maintain intact cognitive functions up to an advanced age. The mechanisms underlying learning and memory processes involve the recruitment of multiple signaling pathways and gene expression, leading to adaptative neuronal plasticity and long-lasting changes in brain circuitry. This chapter summarizes the current understanding of how these signaling cascades could be modulated by cognition-enhancing agents favoring memory formation and successful aging. It focuses on data obtained in rodents, particularly in the rat as it is the most common animal model studied in this field. First, we will discuss the role of the excitatory neurotransmitter glutamate and its receptors, downstream signaling effectors [e.g., calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase C (PKC), extracellular signal-regulated kinases (ERK), mammalian target of rapamycin (mTOR), cAMP response element-binding protein (CREB)], associated immediate early gene (e.g., Homer 1a, Arc and Zif268), and growth factors [insulin-like growth factors (IGFs) and brain-derived neurotrophic factor (BDNF)] in synaptic plasticity and memory formation. Second, the impact of the cholinergic system and related modulators on memory will be briefly reviewed. Finally, since dynorphin neuropeptides have recently been associated with memory impairments in aging, it is proposed as an attractive target to develop novel cognition-enhancing agents. PMID:25977080

  12. Kinetic insulation as an effective mechanism for achieving pathway specificity in intracellular signaling networks

    PubMed Central

    Behar, Marcelo; Dohlman, Henrik G.; Elston, Timothy C.

    2007-01-01

    Intracellular signaling pathways that share common components often elicit distinct physiological responses. In most cases, the biochemical mechanisms responsible for this signal specificity remain poorly understood. Protein scaffolds and cross-inhibition have been proposed as strategies to prevent unwanted cross-talk. Here, we report a mechanism for signal specificity termed “kinetic insulation.” In this approach signals are selectively transmitted through the appropriate pathway based on their temporal profile. In particular, we demonstrate how pathway architectures downstream of a common component can be designed to efficiently separate transient signals from signals that increase slowly over time. Furthermore, we demonstrate that upstream signaling proteins can generate the appropriate input to the common pathway component regardless of the temporal profile of the external stimulus. Our results suggest that multilevel signaling cascades may have evolved to modulate the temporal profile of pathway activity so that stimulus information can be efficiently encoded and transmitted while ensuring signal specificity. PMID:17913886

  13. Interferons, Signal Transduction Pathways, and the Central Nervous System

    PubMed Central

    Nallar, Shreeram C.

    2014-01-01

    The interferon (IFN) family of cytokines participates in the development of innate and acquired immune defenses against various pathogens and pathogenic stimuli. Discovered originally as a proteinaceous substance secreted from virus-infected cells that afforded immunity to neighboring cells from virus infection, these cytokines are now implicated in various human pathologies, including control of tumor development, cell differentiation, and autoimmunity. It is now believed that the IFN system (IFN genes and the genes induced by them, and the factors that regulate these processes) is a generalized alarm of cellular stress, including DNA damage. IFNs exert both beneficial and deleterious effects on the central nervous system (CNS). Our knowledge of the IFN-regulated processes in the CNS is far from being clear. In this article, we reviewed the current understanding of IFN signal transduction pathways and gene products that might have potential relevance to diseases of the CNS. PMID:25084173

  14. Interferons, signal transduction pathways, and the central nervous system.

    PubMed

    Nallar, Shreeram C; Kalvakolanu, Dhan V

    2014-08-01

    The interferon (IFN) family of cytokines participates in the development of innate and acquired immune defenses against various pathogens and pathogenic stimuli. Discovered originally as a proteinaceous substance secreted from virus-infected cells that afforded immunity to neighboring cells from virus infection, these cytokines are now implicated in various human pathologies, including control of tumor development, cell differentiation, and autoimmunity. It is now believed that the IFN system (IFN genes and the genes induced by them, and the factors that regulate these processes) is a generalized alarm of cellular stress, including DNA damage. IFNs exert both beneficial and deleterious effects on the central nervous system (CNS). Our knowledge of the IFN-regulated processes in the CNS is far from being clear. In this article, we reviewed the current understanding of IFN signal transduction pathways and gene products that might have potential relevance to diseases of the CNS.

  15. DAMP Signaling is a Key Pathway Inducing Immune Modulation after Brain Injury

    PubMed Central

    Dalpke, Alexander; Mracsko, Eva; Antoine, Daniel J.; Roth, Stefan; Zhou, Wei; Yang, Huan; Na, Shin-Young; Akhisaroglu, Mustafa; Fleming, Thomas; Eigenbrod, Tatjana; Nawroth, Peter P.; Tracey, Kevin J.

    2015-01-01

    Acute brain lesions induce profound alterations of the peripheral immune response comprising the opposing phenomena of early immune activation and subsequent immunosuppression. The mechanisms underlying this brain-immune signaling are largely unknown. We used animal models for experimental brain ischemia as a paradigm of acute brain lesions and additionally investigated a large cohort of stroke patients. We analyzed release of HMGB1 isoforms by mass spectrometry and investigated its inflammatory potency and signaling pathways by immunological in vivo and in vitro techniques. Features of the complex behavioral sickness behavior syndrome were characterized by homecage behavior analysis. HMGB1 downstream signaling, particularly with RAGE, was studied in various transgenic animal models and by pharmacological blockade. Our results indicate that the cytokine-inducing, fully reduced isoform of HMGB1 was released from the ischemic brain in the hyperacute phase of stroke in mice and patients. Cytokines secreted in the periphery in response to brain injury induced sickness behavior, which could be abrogated by inhibition of the HMGB1-RAGE pathway or direct cytokine neutralization. Subsequently, HMGB1-release induced bone marrow egress and splenic proliferation of bone marrow-derived suppressor cells, inhibiting the adaptive immune responses in vivo and vitro. Furthermore, HMGB1-RAGE signaling resulted in functional exhaustion of mature monocytes and lymphopenia, the hallmarks of immune suppression after extensive ischemia. This study introduces the HMGB1-RAGE-mediated pathway as a key mechanism explaining the complex postischemic brain-immune interactions. PMID:25589753

  16. The effects of hispidulin on bupivacaine-induced neurotoxicity: role of AMPK signaling pathway.

    PubMed

    Niu, Xinhuan; Chen, Jie; Wang, Ping; Zhou, Hui; Li, Song; Zhang, Mengyuan

    2014-09-01

    Bupivacaine is a sodium channel blocker, which is widely used for local infiltration nerve block, epidural and intrathecal anesthesia. However, bupivacaine could cause nerve damage. Hispidulin was shown to be able to penetrate the blood-brain barrier and possess antiepileptic activity. In this study, we investigate whether hispidulin administration could attenuate bupivacaine-induced neurotoxicity. Bupivacaine-challenged mouse neuroblastoma N2a cells were treated with hispidulin. The neuron injury was assessed by examination of cell viability and apoptosis. The levels of activation of AMP-activated protein kinase (AMPK) signaling pathway were examined along with the effect of blocking AMPK signaling on cell viability in the presence of hispidulin and bupivacaine. Our results showed that Bupivacaine treatment significantly decreased cell viability and induced apoptosis. Treatment with hispidulin significantly attenuated bupivacaine-induced cell injury. In addition, hispidulin treatment increased the levels of phospho-AMPK and phospho-GSK3β and attenuated bupivacaine-induced loss in mitochondrial membrane potential. Furthermore, we found that blocking AMPK signaling pathway significantly abolished the cytoprotective effect of hispidulin against bupivacaine-induced cell injury. Our findings suggest that treatment of neuroblastoma cells with hispidulin-protected neural cells from Bupivacaine-induced injury via the activation of the AMPK/GSK3β signaling pathway.

  17. Mechanisms by which the inhibition of specific intracellular signaling pathways increase osteoblast proliferation on apatite surfaces.

    PubMed

    Yang, Seungwon; Tian, Yu-Shun; Lee, Yun-Jung; Yu, Frank H; Kim, Hyun-Man

    2011-04-01

    Osteoblasts proliferate slowly on the surface of calcium phosphate apatite which is widely used as a substrate biomaterial in bone regeneration. Owing to poor adhesion signaling in the cells grown on the calcium phosphate surface, inadequate growth factor signaling is generated to trigger cell cycle progression. The present study investigated an intracellular signal transduction pathway involved in the slow cell proliferation in osteoblasts grown on the calcium phosphate surface. Small GTPase RhoA and phosphatase and tensin homolog (PTEN) were more activated in cells grown on the surface of calcium phosphate apatite than on tissue culture plate. Specific inhibition of RhoA and PTEN induced the cells on calcium phosphate apatite surface to proliferate at a similar rate as cells on tissue culture plate surface. Specific inhibition of ROCK, which is a downstream effector of RhoA and an upstream activator of PTEN also increased proliferation of these osteoblasts. Present results indicate that physical property of calcium phosphate crystals that impede cell proliferation may be surmounted by the inhibition of the RhoA/ROCK/PTEN pathway to rescue delayed proliferation of osteoblasts on the calcium phosphate apatite surface. In addition, specific inhibition of ROCK promoted cell migration and osteoblast differentiation. Inhibition of the RhoA/ROCK/PTEN intracellular signaling pathway is expected to enhance cell activity to promote and accelerate bone regeneration on the calcium phosphate apatite surface.

  18. Actionable pathways: interactive discovery of therapeutic targets using signaling pathway models

    PubMed Central

    Salavert, Francisco; Hidago, Marta R.; Amadoz, Alicia; Çubuk, Cankut; Medina, Ignacio; Crespo, Daniel; Carbonell-Caballero, Jose; Dopazo, Joaquín

    2016-01-01

    The discovery of actionable targets is crucial for targeted therapies and is also a constituent part of the drug discovery process. The success of an intervention over a target depends critically on its contribution, within the complex network of gene interactions, to the cellular processes responsible for disease progression or therapeutic response. Here we present PathAct, a web server that predicts the effect that interventions over genes (inhibitions or activations that simulate knock-outs, drug treatments or over-expressions) can have over signal transmission within signaling pathways and, ultimately, over the cell functionalities triggered by them. PathAct implements an advanced graphical interface that provides a unique interactive working environment in which the suitability of potentially actionable genes, that could eventually become drug targets for personalized or individualized therapies, can be easily tested. The PathAct tool can be found at: http://pathact.babelomics.org. PMID:27137885

  19. Ginsenoside Rb1 inhibits matrix metalloproteinase 13 through down-regulating Notch signaling pathway in osteoarthritis

    PubMed Central

    Wang, Wei; Zeng, Li; Wang, Ze-ming; Zhang, Sihan; Rong, Xiao-Feng

    2015-01-01

    Mounting evidence suggests that an excess of matrix metalloproteinase-13 (MMP-13) plays an important role in the breakdown of extracellular matrix in osteoarthritis (OA). Here, the effects of ginsenoside Rb1 (GRb1) on the expression of MMP-13 in IL-1β-induced SW 1353 chondrosarcoma cells and an experimental rat model of OA induced by anterior cruciate ligament transection (ACLT) were investigated. SW1353 chondrosarcoma cells were pretreated with or without GRb1 and Notch signaling pathway inhibitor, DAPT, then were stimulated with IL-1β. In rats, experimental OA was induced by ACLT. These rats then received intra-articular injections of vehicle, an inhibitor of γ-secretase, DAPT, and/or GRb1. Expression of MMP-13, collagen type II (CII), Notch1, and jagged 1 (JAG1) were verified by western blotting and immunohistochemistry. In addition, levels of MMP-13 mRNA were detected using quantitative real-time PCR. In histological analyses, treatment with DAPT reduced the number of cartilage lesions present and the expressions of MMP-13, CII, Notch1, and JAG1. In addition, treatment with GRb1 was associated with lower levels of Notch1 and JAG1 in both IL-1β-induced SW1353 chondrosarcoma cells and in the rat OA model. Furthermore, the suppressive effect of GRb1 on MMP-13 was greater than that exhibited by the signaling pathway inhibitor. In conclusion, GRb1 inhibits MMP-13 through down-regulating Notch signaling pathway in OA. PMID:26062798

  20. Caytaxin Deficiency Disrupts Signaling Pathways in Cerebellar Cortex

    PubMed Central

    Xiao, Jianfeng; Gong, Suzhen; LeDoux, Mark S.

    2007-01-01

    The genetically dystonic (dt) rat, an autosomal recessive model of generalized dystonia, harbors an insertional mutation in Atcay. As a result, dt rats are deficient in Atcay transcript and the neuronally-restricted protein caytaxin. Previous electrophysiological and biochemical studies have defined olivocerebellar pathways, particularly the climbing fiber projection to Purkinje cells, as a site of significant functional abnormality in dt rats. In normal rats, Atcay transcript is abundantly expressed in the granular and Purkinje cell layers of cerebellar cortex. To better understand the consequences of caytaxin deficiency in cerebellar cortex, differential gene expression was examined in dt rats and their normal littermates. Data from oligonucleotide microarrays and quantitative real-time RT-PCR (QRT-PCR) identified phosphatidylinositol signaling pathways, calcium homeostasis, and extracellular matrix interactions as domains of cellular dysfunction in dt rats. In dt rats, genes encoding the corticotropin-releasing hormone receptor 1 (CRH-R1, Crhr1) and calcium-transporting plasma membrane ATPase 4 (PMCA4, Atp2b4) showed the greatest up-regulation with QRT-PCR. Immunocytochemical experiments demonstrated that CRH-R1, CRH, and PMCA4 were up-regulated in cerebellar cortex of mutant rats. Along with previous electrophysiological and pharmacological studies, our data indicate that caytaxin plays a critical role in the molecular response of Purkinje cells to climbing fiber input. Caytaxin may also contribute to maturational events in cerebellar cortex. PMID:17092653

  1. Osteocytic signalling pathways as therapeutic targets for bone fragility.

    PubMed

    Plotkin, Lilian I; Bellido, Teresita

    2016-10-01

    Osteocytes are differentiated osteoblasts that become surrounded by matrix during the process of bone formation. Acquisition of the osteocyte phenotype is achieved by profound changes in gene expression that facilitate adaptation to the changing cellular environment and constitute the molecular signature of osteocytes. During osteocytogenesis, the expression of genes that are characteristic of the osteoblast are altered and the expression of genes and/or proteins that impart dendritic cellular morphology, regulate matrix mineralization and control the function of cells at the bone surface are ordely modulated. The discovery of mutations in human osteocytic genes has contributed, in a large part, to our understanding of the role of osteocytes in bone homeostasis. Osteocytes are targets of the mechanical force imposed on the skeleton and have a critical role in integrating mechanosensory pathways with the action of hormones, which thereby leads to the orchestrated response of bone to environmental cues. Current, therapeutic approaches harness this accumulating knowledge by targeting osteocytic signalling pathways and messengers to improve skeletal health.

  2. Osteocytic signalling pathways as therapeutic targets for bone fragility.

    PubMed

    Plotkin, Lilian I; Bellido, Teresita

    2016-10-01

    Osteocytes are differentiated osteoblasts that become surrounded by matrix during the process of bone formation. Acquisition of the osteocyte phenotype is achieved by profound changes in gene expression that facilitate adaptation to the changing cellular environment and constitute the molecular signature of osteocytes. During osteocytogenesis, the expression of genes that are characteristic of the osteoblast are altered and the expression of genes and/or proteins that impart dendritic cellular morphology, regulate matrix mineralization and control the function of cells at the bone surface are ordely modulated. The discovery of mutations in human osteocytic genes has contributed, in a large part, to our understanding of the role of osteocytes in bone homeostasis. Osteocytes are targets of the mechanical force imposed on the skeleton and have a critical role in integrating mechanosensory pathways with the action of hormones, which thereby leads to the orchestrated response of bone to environmental cues. Current, therapeutic approaches harness this accumulating knowledge by targeting osteocytic signalling pathways and messengers to improve skeletal health. PMID:27230951

  3. Cyclic AMP signalling pathways in the regulation of uterine relaxation

    PubMed Central

    Yuan, Wei; López Bernal, Andrés

    2007-01-01

    Studying the mechanism(s) of uterine relaxation is important and will be helpful in the prevention of obstetric difficulties such as preterm labour, which remains a major cause of perinatal mortality and morbidity. Multiple signalling pathways regulate the balance between maintaining relative uterine quiescence during gestation, and the transition to the contractile state at the onset of parturition. Elevation of intracellular cyclic AMP promotes myometrial relaxation, and thus quiescence, via effects on multiple intracellular targets including calcium channels, potassium channels and myosin light chain kinase. A complete understanding of cAMP regulatory pathways (synthesis and hydrolysis) would assist in the development of better tocolytics to delay or inhibit preterm labour. Here we review the enzymes involved in cAMP homoeostasis (adenylyl cyclases and phosphodiesterases) and possible myometrial substrates for the cAMP dependent protein kinase. We must emphasise the need to identify novel pharmacological targets in human pregnant myometrium to achieve safe and selective uterine relaxation when this is indicated in preterm labour or other obstetric complications. PMID:17570154

  4. CREB pathway links PGE2 signaling with macrophage polarization.

    PubMed

    Luan, Bing; Yoon, Young-Sil; Le Lay, John; Kaestner, Klaus H; Hedrick, Susan; Montminy, Marc

    2015-12-22

    Obesity is thought to promote insulin resistance in part via activation of the innate immune system. Increases in proinflammatory cytokine production by M1 macrophages inhibit insulin signaling in white adipose tissue. In contrast, M2 macrophages have been found to enhance insulin sensitivity in part by reducing adipose tissue inflammation. The paracrine hormone prostaglandin E2 (PGE2) enhances M2 polarization in part through activation of the cAMP pathway, although the underlying mechanism is unclear. Here we show that PGE2 stimulates M2 polarization via the cyclic AMP-responsive element binding (CREB)-mediated induction of Krupple-like factor 4 (KLF4). Targeted disruption of CREB or the cAMP-regulated transcriptional coactivators 2 and 3 (CRTC2/3) in macrophages down-regulated M2 marker gene expression and promoted insulin resistance in the context of high-fat diet feeding. As re-expression of KLF4 rescued M2 marker gene expression in CREB-depleted cells, our results demonstrate the importance of the CREB/CRTC pathway in maintaining insulin sensitivity in white adipose tissue via its effects on the innate immune system.

  5. CREB pathway links PGE2 signaling with macrophage polarization

    PubMed Central

    Luan, Bing; Yoon, Young-Sil; Le Lay, John; Kaestner, Klaus H.; Hedrick, Susan; Montminy, Marc

    2015-01-01

    Obesity is thought to promote insulin resistance in part via activation of the innate immune system. Increases in proinflammatory cytokine production by M1 macrophages inhibit insulin signaling in white adipose tissue. In contrast, M2 macrophages have been found to enhance insulin sensitivity in part by reducing adipose tissue inflammation. The paracrine hormone prostaglandin E2 (PGE2) enhances M2 polarization in part through activation of the cAMP pathway, although the underlying mechanism is unclear. Here we show that PGE2 stimulates M2 polarization via the cyclic AMP-responsive element binding (CREB)-mediated induction of Krupple-like factor 4 (KLF4). Targeted disruption of CREB or the cAMP-regulated transcriptional coactivators 2 and 3 (CRTC2/3) in macrophages down-regulated M2 marker gene expression and promoted insulin resistance in the context of high-fat diet feeding. As re-expression of KLF4 rescued M2 marker gene expression in CREB-depleted cells, our results demonstrate the importance of the CREB/CRTC pathway in maintaining insulin sensitivity in white adipose tissue via its effects on the innate immune system. PMID:26644581

  6. Targeting cancer by binding iron: Dissecting cellular signaling pathways

    PubMed Central

    Lui, Goldie Y.L.; Kovacevic, Zaklina; Richardson, Vera; Merlot, Angelica M.; Kalinowski, Danuta S.; Richardson, Des R.

    2015-01-01

    Newer and more potent therapies are urgently needed to effectively treat advanced cancers that have developed resistance and metastasized. One such strategy is to target cancer cell iron metabolism, which is altered compared to normal cells and may facilitate their rapid proliferation. This is supported by studies reporting the anti-neoplastic activities of the clinically available iron chelators, desferrioxamine and deferasirox. More recently, ligands of the di-2-pyridylketone thiosemicarbazone (DpT) class have demonstrated potent and selective anti-proliferative activity across multiple cancer-types in vivo, fueling studies aimed at dissecting their molecular mechanisms of action. In the past five years alone, significant advances have been made in understanding how chelators not only modulate cellular iron metabolism, but also multiple signaling pathways implicated in tumor progression and metastasis. Herein, we discuss recent research on the targeting of iron in cancer cells, with a focus on the novel and potent DpT ligands. Several key studies have revealed that iron chelation can target the AKT, ERK, JNK, p38, STAT3, TGF-β, Wnt and autophagic pathways to subsequently inhibit cellular proliferation, the epithelial-mesenchymal transition (EMT) and metastasis. These developments emphasize that these novel therapies could be utilized clinically to effectively target cancer. PMID:26125440

  7. Targeting cancer by binding iron: Dissecting cellular signaling pathways.

    PubMed

    Lui, Goldie Y L; Kovacevic, Zaklina; Richardson, Vera; Merlot, Angelica M; Kalinowski, Danuta S; Richardson, Des R

    2015-08-01

    Newer and more potent therapies are urgently needed to effectively treat advanced cancers that have developed resistance and metastasized. One such strategy is to target cancer cell iron metabolism, which is altered compared to normal cells and may facilitate their rapid proliferation. This is supported by studies reporting the anti-neoplastic activities of the clinically available iron chelators, desferrioxamine and deferasirox. More recently, ligands of the di-2-pyridylketone thiosemicarbazone (DpT) class have demonstrated potent and selective anti-proliferative activity across multiple cancer-types in vivo, fueling studies aimed at dissecting their molecular mechanisms of action. In the past five years alone, significant advances have been made in understanding how chelators not only modulate cellular iron metabolism, but also multiple signaling pathways implicated in tumor progression and metastasis. Herein, we discuss recent research on the targeting of iron in cancer cells, with a focus on the novel and potent DpT ligands. Several key studies have revealed that iron chelation can target the AKT, ERK, JNK, p38, STAT3, TGF-β, Wnt and autophagic pathways to subsequently inhibit cellular proliferation, the epithelial-mesenchymal transition (EMT) and metastasis. These developments emphasize that these novel therapies could be utilized clinically to effectively target cancer. PMID:26125440

  8. mTOR signaling pathway genes in focal epilepsies.

    PubMed

    Baulac, S

    2016-01-01

    Focal epilepsies, where seizures initiate in spatially limited networks, are the most frequent epilepsy type, accounting for two-thirds of patients. Focal epilepsies have long been thought to be acquired disorders; several focal epilepsy syndromes are now proven to be (genetically heterogeneous) monogenic disorders. While earlier genetic studies have demonstrated a strong contribution of ion channel and neurotransmitter receptor genes, or synaptic secreted protein genes, later work has revealed a new class of genes encoding components of the mechanistic target of rapamycin (mTOR) signal transduction pathway. The mTOR pathway controls a myriad of biological processes among which cell growth and protein synthesis in response to several extracellular and intracellular. Recently, germline mutations have been found in genes encoding the components of the GATOR1 complex (DEPDC5, NPRL2, NPRL3), a repressor of mTORC1. These mutations are increasingly recognized as causing a wide and yet evolving spectrum of focal epilepsy syndromes, with and without cortical structural abnormalities (usually focal cortical dysplasia). Brain somatic mutations in the gene encoding mTOR (MTOR) have recently been linked to focal cortical dysplasia and other associated brain pathologies including hemimegalencephaly. This chapter reviews the genetics and neurobiology of DEPDC5, NPRL2, and NPRL3, and summarizes the clinical and molecular spectrum of GATOR1-related epilepsies. PMID:27323939

  9. The Ras/Raf/MEK/extracellular signal-regulated kinase pathway induces autocrine-paracrine growth inhibition via the leukemia inhibitory factor/JAK/STAT pathway.

    PubMed

    Park, Jong-In; Strock, Christopher J; Ball, Douglas W; Nelkin, Barry D

    2003-01-01

    Sustained activation of the Ras/Raf/MEK/extracellular signal-regulated kinase (ERK) pathway can lead to cell cycle arrest in many cell types. We have found, with human medullary thyroid cancer (MTC) cells, that activated Ras or c-Raf-1 can induce growth arrest by producing and secreting an autocrine-paracrine factor. This protein was purified from cell culture medium conditioned by Raf-activated MTC cells and was identified by mass spectrometry as leukemia inhibitory factor (LIF). LIF expression upon Raf activation and subsequent activation of JAK-STAT3 was also observed in small cell lung carcinoma cells, suggesting that this autocrine-paracrine signaling may be a common response to Ras/Raf activation. LIF was sufficient to induce growth arrest and differentiation of MTC cells. This effect was mediated through the gp130/JAK/STAT3 pathway, since anti-gp130 blocking antibody or dominant-negative STAT3 blocked the effects of LIF. Thus, LIF expression provides a novel mechanism allowing Ras/Raf signaling to activate the JAK-STAT3 pathway. In addition to this cell-extrinsic growth inhibitory pathway, we find that the Ras/Raf/MEK/ERK pathway induces an intracellular growth inhibitory signal, independent of the LIF/JAK/STAT3 pathway. Therefore, activation of the Ras/Raf/MEK/ERK pathway can lead to growth arrest and differentiation via at least two different signaling pathways. This use of multiple pathways may be important for "fail-safe" induction and maintenance of cell cycle arrest.

  10. The Ras/Raf/MEK/Extracellular Signal-Regulated Kinase Pathway Induces Autocrine-Paracrine Growth Inhibition via the Leukemia Inhibitory Factor/JAK/STAT Pathway

    PubMed Central

    Park, Jong-In; Strock, Christopher J.; Ball, Douglas W.; Nelkin, Barry D.

    2003-01-01

    Sustained activation of the Ras/Raf/MEK/extracellular signal-regulated kinase (ERK) pathway can lead to cell cycle arrest in many cell types. We have found, with human medullary thyroid cancer (MTC) cells, that activated Ras or c-Raf-1 can induce growth arrest by producing and secreting an autocrine-paracrine factor. This protein was purified from cell culture medium conditioned by Raf-activated MTC cells and was identified by mass spectrometry as leukemia inhibitory factor (LIF). LIF expression upon Raf activation and subsequent activation of JAK-STAT3 was also observed in small cell lung carcinoma cells, suggesting that this autocrine-paracrine signaling may be a common response to Ras/Raf activation. LIF was sufficient to induce growth arrest and differentiation of MTC cells. This effect was mediated through the gp130/JAK/STAT3 pathway, since anti-gp130 blocking antibody or dominant-negative STAT3 blocked the effects of LIF. Thus, LIF expression provides a novel mechanism allowing Ras/Raf signaling to activate the JAK-STAT3 pathway. In addition to this cell-extrinsic growth inhibitory pathway, we find that the Ras/Raf/MEK/ERK pathway induces an intracellular growth inhibitory signal, independent of the LIF/JAK/STAT3 pathway. Therefore, activation of the Ras/Raf/MEK/ERK pathway can lead to growth arrest and differentiation via at least two different signaling pathways. This use of multiple pathways may be important for “fail-safe” induction and maintenance of cell cycle arrest. PMID:12509453

  11. Neovibsanin B increases extracellular matrix proteins in optic nerve head cells via activation of Smad signalling pathway.

    PubMed

    Wang, Zhen; Xu, Wei; Rong, Ao; Lin, Yan; Qiu, Xu-Ling; Qu, Shen; Lan, Xian-Hai

    2015-01-01

    The present study demonstrates the effect of neovibsanin B on the synthesis and deposition of ECM proteins and the signalling pathways used in optic nerve head (ONH) astrocytes and lamina cribrosa (LC) cells. For investigation of the signalling pathway used by neovibsanin B, ONH cells were treated with neovibsanin B. Western blot and immunostaining analyses were used to examine the phosphorylation of proteins involved in Smad and non-Smad signalling pathway. The results revealed that ONH cells on treatment with neovibsanin B showed enhanced synthesis of extracellular matrix (ECM) proteins. Neovibsanin B induced phosphorylation of canonical signalling proteins, Smad2/3. However phosphorylation of non-canonical signalling proteins, extracellular signal-regulated kinases, p38, and c-Jun N-terminal kinases (JNK) 1/2 remained unaffected. There was also increase in co-localization of pSmad2/3 with Co-Smad4 in the nucleus of ONH astrocytes and LC cells indicating activation of the canonical Smad signalling pathway. Treatment of ONH cells with SIS3, inhibitor of Smad3 phosphorylation reversed the neovibsanin B stimulated ECM expression as well as activation of canonical pathway signalling molecules. In addition, inhibition of Smad2 or Smad3 using small interfering RNA (siRNA) also suppressed neovibsanin B stimulated ECM protein synthesis in ONH astrocytes and LC cells. Thus neovibsanin B utilizes the canonical Smad signalling pathway to stimulate ECM synthesis in human ONH cells. The neovibsanin B induced ECM synthesis and activation of the canonical Smad signalling pathway may be due to its effect on transforming growth factor-β2 (TGF-β2). However, further studies are under process to understand the mechanism.

  12. Phosphate-responsive signaling pathway is a novel component of NAD+ metabolism in Saccharomyces cerevisiae.

    PubMed

    Lu, Shu-Ping; Lin, Su-Ju

    2011-04-22

    Nicotinamide adenine dinucleotide (NAD(+)) is an essential cofactor involved in various cellular biochemical reactions. To date the signaling pathways that regulate NAD(+) metabolism remain unclear due to the dynamic nature and complexity of the NAD(+) metabolic pathways and the difficulty of determining the levels of the interconvertible pyridine nucleotides. Nicotinamide riboside (NmR) is a key pyridine metabolite that is excreted and re-assimilated by yeast and plays important roles in the maintenance of NAD(+) pool. In this study we establish a NmR-specific reporter system and use it to identify yeast mutants with altered NmR/NAD(+) metabolism. We show that the phosphate-responsive signaling (PHO) pathway contributes to control NAD(+) metabolism. Yeast strains with activated PHO pathway show increases in both the release rate and internal concentration of NmR. We further identify Pho8, a PHO-regulated vacuolar phosphatase, as a potential NmR production factor. We also demonstrate that Fun26, a homolog of human ENT (equilibrative nucleoside transporter), localizes to the vacuolar membrane and establishes the size of the vacuolar and cytosolic NmR pools. In addition, the PHO pathway responds to depletion of cellular nicotinic acid mononucleotide (NaMN) and mediates nicotinamide mononucleotide (NMN) catabolism, thereby contributing to both NmR salvage and phosphate acquisition. Therefore, NaMN is a putative molecular link connecting the PHO signaling and NAD(+) metabolic pathways. Our findings may contribute to the understanding of the molecular basis and regulation of NAD(+) metabolism in higher eukaryotes. PMID:21349851

  13. Advances in mechanisms and signaling pathways of carbon nanotube toxicity.

    PubMed

    Dong, Jie; Ma, Qiang

    2015-01-01

    Carbon nanotubes (CNT) have been developed into new materials with a variety of industrial and commercial applications. In contrast, the physicochemical properties of CNT at the nanoscale render them the potency to generate toxic effects. Indeed, the potential health impacts of CNT have drawn a great deal of attention in recent years, owing to their identified toxicological and pathological consequences including cytotoxicity, inflammation, fibrosis, genotoxicity, tumorigenesis, and immunotoxicity. Understanding the mechanisms by which CNT induce toxicity and pathology is thus urgently needed for accurate risk assessment of CNT exposure in humans, and for safe and responsible development and commercialization of nanotechnology. Here, we summarize and discuss recent advances in this area with a focus on the molecular interactions between CNT and mammalian systems, and the signaling pathways important for the development of CNT toxicity such as the NF-κB, NLRP3 inflammasome, TGF-β1, MAPK, and p53 signaling cascades. With the current mechanistic evidence summarized in this review, we expect to provide new insights into CNT toxicology at the molecular level and offer new clues to the prevention of health effects resulting from CNT exposure. Moreover, we disclose questions and issues that remain in this rapidly advancing field of nanotoxicology, which would facilitate ascertaining future research directions. PMID:25676622

  14. Advances in mechanisms and signaling pathways of carbon nanotube toxicity

    PubMed Central

    Dong, Jie; Ma, Qiang

    2015-01-01

    Carbon nanotubes (CNT) have been developed into new materials with a variety of industrial and commercial applications. In contrast, the physicochemical properties of CNT at the nanoscale render them the potency to generate toxic effects. Indeed, the potential health impacts of CNT have drawn a great deal of attention in recent years, owing to their identified toxicological and pathological consequences including cytotoxicity, inflammation, fibrosis, genotoxicity, tumorigenesis, and immunotoxicity. Understanding the mechanisms by which CNT induce toxicity and pathology is thus urgently needed for accurate risk assessment of CNT exposure in humans, and for safe and responsible development and commercialization of nanotechnology. Here, we summarize and discuss recent advances in this area with a focus on the molecular interactions between CNT and mammalian systems, and the signaling pathways important for the development of CNT toxicity such as the NF-κB, NLRP3 inflammasome, TGF-β1, MAPK, and p53 signaling cascades. With the current mechanistic evidence summarized in this review, we expect to provide new insights into CNT toxicology at the molecular level and offer new clues to the prevention of health effects resulting from CNT exposure. Moreover, we disclose questions and issues that remain in this rapidly advancing field of nanotoxicology, which would facilitate ascertaining future research directions. PMID:25676622

  15. Targeting the VEGF and PDGF signaling pathway in glioblastoma treatment

    PubMed Central

    Popescu, Alisa Madalina; Alexandru, Oana; Brindusa, Corina; Purcaru, Stefana Oana; Tache, Daniela Elise; Tataranu, Ligia Gabriela; Taisescu, Citto; Dricu, Anica

    2015-01-01

    Growth factor receptors dysfunction has previously been correlated with glioma cell proliferation, ability to evade apoptosis, neo-angiogenesis and resistance to therapy. Antineoplastic molecules targeting growth factor receptors are in clinical handling, however the efficacy of these compounds has often been limited by the signaling redundancy. Here, we analyzed the effect of AG1433 (a PDGFR inhibitor), SU1498 (a VEGFR inhibitor) and BEZ235 (a PI3K/Akt/mTOR signaling pathways inhibitor) on glioblastoma cells in vitro. For this study, we used a low passage glioblastoma cell line (GB9B). Assessment of cell number over 72 h showed that the growth rate was 0.3024 and the doubling time of GB9B was 2.29 days. Similar cytotoxic effects were observed by using AG1433 and SU1498 treatment, while dual PI3K/Akt/mTOR inhibition by BEZ235 was more efficient in killing glioblastoma cells than individual PDGFR or VEGFR targeting. In SU1498 treated cells, caspase 3 activity was detected 3 hours after the treatment, while activation of caspase 8 and 9 was detected 48 hours later. AG1433 treatment induced caspase 3, 8 and 9, 3 hours after the treatment. BEZ235 treatment resulted in early caspase 3 and 8 activation, 3 hours after the treatment and an activation of caspase 9, 8 hours later. PMID:26339347

  16. Signaling pathways activated by a protease allergen in basophils

    PubMed Central

    Rosenstein, Rachel K.; Bezbradica, Jelena S.; Yu, Shuang; Medzhitov, Ruslan

    2014-01-01

    Allergic diseases represent a significant burden in industrialized countries, but why and how the immune system responds to allergens remain largely unknown. Because many clinically significant allergens have proteolytic activity, and many helminths express proteases that are necessary for their life cycles, host mechanisms likely have evolved to detect the proteolytic activity of helminth proteases, which may be incidentally activated by protease allergens. A cysteine protease, papain, is a prototypic protease allergen that can directly activate basophils and mast cells, leading to the production of cytokines, including IL-4, characteristic of the type 2 immune response. The mechanism of papain’s immunogenic activity remains unknown. Here we have characterized the cellular response activated by papain in basophils. We find that papain-induced IL-4 production requires calcium flux and activation of PI3K and nuclear factor of activated T cells. Interestingly, papain-induced IL-4 production was dependent on the immunoreceptor tyrosine-based activation motif (ITAM) adaptor protein Fc receptor γ-chain, even though the canonical ITAM signaling was not activated by papain. Collectively, these data characterize the downstream signaling pathway activated by a protease allergen in basophils. PMID:25369937

  17. Cysteine and cysteine-related signaling pathways in Arabidopsis thaliana.

    PubMed

    Romero, Luis C; Aroca, M Ángeles; Laureano-Marín, Ana M; Moreno, Inmaculada; García, Irene; Gotor, Cecilia

    2014-02-01

    Cysteine occupies a central position in plant metabolism because it is a reduced sulfur donor molecule involved in the synthesis of essential biomolecules and defense compounds. Moreover, cysteine per se and its derivative molecules play roles in the redox signaling of processes occurring in various cellular compartments. Cysteine is synthesized during the sulfate assimilation pathway via the incorporation of sulfide to O-acetylserine, catalyzed by O-acetylserine(thiol)lyase (OASTL). Plant cells contain OASTLs in the mitochondria, chloroplasts, and cytosol, resulting in a complex array of isoforms and subcellular cysteine pools. In recent years, significant progress has been made in Arabidopsis, in determining the specific roles of the OASTLs and the metabolites produced by them. Thus, the discovery of novel enzymatic activities of the less-abundant, like DES1 with L-cysteine desulfhydrase activity and SCS with S-sulfocysteine synthase activity, has provided new perspectives on their roles, besides their metabolic functions. Thereby, the research has been demonstrated that cytosolic sulfide and chloroplastic S-sulfocysteine act as signaling molecules regulating autophagy and protecting the photosystems, respectively. In the cytosol, cysteine plays an essential role in plant immunity; in the mitochondria, this molecule plays a central role in the detoxification of cyanide, which is essential for root hair development and plant responses to pathogens.

  18. Tubedown regulation of retinal endothelial permeability signaling pathways

    PubMed Central

    Ho, Nhu; Gendron, Robert L.; Grozinger, Kindra; Whelan, Maria A.; Hicks, Emily Anne; Tennakoon, Bimal; Gardiner, Danielle; Good, William V.; Paradis, Hélène

    2015-01-01

    ABSTRACT Tubedown (Tbdn; Naa15), a subunit of the N-terminal acetyltransferase NatA, complexes with the c-Src substrate Cortactin and supports adult retinal homeostasis through regulation of vascular permeability. Here we investigate the role of Tbdn expression on signaling components of retinal endothelial permeability to understand how Tbdn regulates the vasculature and supports retinal homeostasis. Tbdn knockdown-induced hyperpermeability to Albumin in retinal endothelial cells was associated with an increase in the levels of activation of the Src family kinases (SFK) c-Src, Fyn and Lyn and phospho-Cortactin (Tyr421). The knockdown of Cortactin expression reduced Tbdn knockdown-induced permeability to Albumin and the levels of activated SFK. Inhibition of SFK in retinal endothelial cells decreased Tbdn knockdown-induced permeability to Albumin and phospho-Cortactin (Tyr421) levels. Retinal lesions of endothelial-specific Tbdn knockdown mice, with tissue thickening, fibrovascular growth, and hyperpermeable vessels displayed an increase in the levels of activated c-Src. Moreover, the retinal lesions of patients with proliferative diabetic retinopathy (PDR) associated with a loss of Tbdn expression and hyperpermeability to Albumin displayed increased levels of activated SFK in retinal blood vessels. Taken together, these results implicate Tbdn as an important regulator of retinal endothelial permeability and homeostasis by modulating a signaling pathway involving c-Src and Cortactin. PMID:26142315

  19. Mechanistic pathways and biological roles for receptor-independent activators of G-protein signaling.

    PubMed

    Blumer, Joe B; Smrcka, Alan V; Lanier, Stephen M

    2007-03-01

    Signal processing via heterotrimeric G-proteins in response to cell surface receptors is a central and much investigated aspect of how cells integrate cellular stimuli to produce coordinated biological responses. The system is a target of numerous therapeutic agents and plays an important role in adaptive processes of organs; aberrant processing of signals through these transducing systems is a component of various disease states. In addition to G-protein coupled receptor (GPCR)-mediated activation of G-protein signaling, nature has evolved creative ways to manipulate and utilize the Galphabetagamma heterotrimer or Galpha and Gbetagamma subunits independent of the cell surface receptor stimuli. In such situations, the G-protein subunits (Galpha and Gbetagamma) may actually be complexed with alternative binding partners independent of the typical heterotrimeric Galphabetagamma. Such regulatory accessory proteins include the family of regulator of G-protein signaling (RGS) proteins that accelerate the GTPase activity of Galpha and various entities that influence nucleotide binding properties and/or subunit interaction. The latter group of proteins includes receptor-independent activators of G-protein signaling (AGS) proteins that play surprising roles in signal processing. This review provides an overview of our current knowledge regarding AGS proteins. AGS proteins are indicative of a growing number of accessory proteins that influence signal propagation, facilitate cross talk between various types of signaling pathways, and provide a platform for diverse functions of both the heterotrimeric Galphabetagamma and the individual Galpha and Gbetagamma subunits.

  20. Activation of ERK and JNK signaling pathways by mycotoxin citrinin in human cells

    SciTech Connect

    Chang, C.-H.; Yu, F.-Y.; Wang, L.-T.; Lin, Y.-S.; Liu, B.-H.

    2009-06-15

    Mycotoxin citrinin (CTN) is commonly found in foods and feeds that are contaminated/inoculated with Penicillium, Aspergillus and Monascus species. The exposure of human embryonic kidney (HEK293) and HeLa cells to CTN resulted in a dose-dependent increase in the phosphorylation of two major mitogen-activated protein kinases (MAPKs), ERK1/2 and JNK. In HEK293 cultures, the administering of CTN increased both the mRNA and protein levels of egr-1, c-fos and c-jun genes; additionally, the ERK1/2 pathway contributed to the upregulation of Egr-1 and c-Fos protein expression. CTN treatment also induced the transcription activity of Egr-1 and AP-1 proteins, as evidenced by luciferase reporter assays. Bioinformatic analyses indicated two genes Gadd45{beta} and MMP3 have Egr-1 and AP-1 response elements in their promoters, respectively. Furthermore, co-exposure of HEK293 cells to CTN and MAPK pathway inhibitors demonstrated that CTN increased the levels of Gadd45{beta} mRNA through ERK1/2 signaling pathway and up-regulated the MMP3 transcripts majorly via JNK pathway. Finally, CTN-triggered caspase 3 activity was significantly reduced in the presence of MAPK inhibitors. Our results suggest that CTN positively regulates ERK1/2 and JNK pathways as well as their downstream effectors in human cells; activated MAPK pathways are also involved in CTN-induced apoptosis.

  1. Signals controlling un-differentiated states in embryonic stem and cancer cells: role of the phosphatidylinositol 3' kinase pathway.

    PubMed

    Voskas, Daniel; Ling, Ling Sunny; Woodgett, James Robert

    2014-10-01

    The capacity of embryonic stem (ES) cells to differentiate into cell lineages comprising the three germ layers makes them powerful tools for studying mammalian early embryonic development in vitro. The human body consists of approximately 210 different somatic cell types, the majority of which have limited proliferative capacity. However, both stem cells and cancer cells bypass this replicative barrier and undergo symmetric division indefinitely when cultured under defined conditions. Several signal transduction pathways play important roles in regulating stem cell development, and aberrant expression of components of these pathways is linked to cancer. Among signaling systems, the critical role of leukemia inhibitory factor (LIF) coupled to the Jak/STAT3 (signal transduction and activation of transcription-3) pathway in maintaining stem cell self-renewal has been extensively reviewed. This pathway additionally plays multiple roles in tumorigenesis. Likewise, the phosphatidylinositide 3-kinase (PI3K)/protein kinase B (PKB/Akt) pathway has been determined to play an important role in both stem cell maintenance and tumor development. This pathway is often induced in cancer with frequent mutational activation of the catalytic subunit of PI3K or loss of a primary PI3K antagonist, phosphatase and tensin homolog deleted on chromosome ten (PTEN). This review focusses on roles of the PI3K signal transduction pathway components, with emphasis on functions in stem cell maintenance and cancer. Since the PI3K pathway impinges on and collaborates with other signaling pathways in regulating stem cell development and/or cancer, aspects of the canonical Wnt, Ras/mitogen-activated protein kinase (MAPK), and TGF-β signaling pathways are also discussed.

  2. Targeting the PDGF signaling pathway in tumor treatment

    PubMed Central

    2013-01-01

    Platelet-derived growth factor (PDGF) isoforms and PDGF receptors have important functions in the regulation of growth and survival of certain cell types during embryonal development and e.g. tissue repair in the adult. Overactivity of PDGF receptor signaling, by overexpression or mutational events, may drive tumor cell growth. In addition, pericytes of the vasculature and fibroblasts and myofibroblasts of the stroma of solid tumors express PDGF receptors, and PDGF stimulation of such cells promotes tumorigenesis. Inhibition of PDGF receptor signaling has proven to useful for the treatment of patients with certain rare tumors. Whether treatment with PDGF/PDGF receptor antagonists will be beneficial for more common malignancies is the subject for ongoing studies. PMID:24359404

  3. FGF signaling inhibitor, SPRY4, is evolutionarily conserved target of WNT signaling pathway in progenitor cells.

    PubMed

    Katoh, Yuriko; Katoh, Masaru

    2006-03-01

    WNT, FGF and Hedgehog signaling pathways network together during embryogenesis, tissue regeneration, and carcinogenesis. FGF16, FGF18, and FGF20 genes are targets of WNT-mediated TCF/LEF-beta-catenin-BCL9/BCL9L-PYGO transcriptional complex. SPROUTY (SPRY) and SPRED family genes encode inhibitors for receptor tyrosine kinase signaling cascades, such as those of FGF receptor family members and EGF receptor family members. Here, transcriptional regulation of SPRY1, SPRY2, SPRY3, SPRY4, SPRED1, SPRED2, and SPRED3 genes by WNT/beta-catenin signaling cascade was investigated by using bioinformatics and human intelligence (humint). Because double TCF/LEF-binding sites were identified within the 5'-promoter region of human SPRY4 gene, comparative genomics analyses on SPRY4 orthologs were further performed. SPRY4-FGF1 locus at human chromosome 5q31.3 and FGF2-NUDT6-SPATA5-SPRY1 locus at human chromosome 4q27-q28.1 were paralogous regions within the human genome. Chimpanzee SPRY4 gene was identified within NW_107083.1 genome sequence. Human, chimpanzee, rat and mouse SPRY4 orthologs, consisting of three exons, were well conserved. SPRY4 gene was identified as the evolutionarily conserved target of WNT/beta-catenin signaling pathway based on the conservation of double TCF/LEF-binding sites within 5'-promoter region of mammalian SPRY4 orthologs. Human SPRY4 mRNA was expressed in embryonic stem (ES) cells, brain, pancreatic islet, colon cancer, head and neck tumor, melanoma, and pancreatic cancer. WNT signaling activation in progenitor cells leads to the growth regulation of progenitor cells themselves through SPRY4 induction, and also to the growth stimulation of proliferating cells through FGF secretion. Epigenetic silencing and loss-of-function mutations of SPRY4 gene in progenitor cells could lead to carcinogenesis. SPRY4 is the pharmacogenomics target in the fields of oncology and regenerative medicine. PMID:16465403

  4. Cherry Valley Ducks Mitochondrial Antiviral-Signaling Protein-Mediated Signaling Pathway and Antiviral Activity Research

    PubMed Central

    Li, Ning; Hong, Tianqi; Li, Rong; Wang, Yao; Guo, Mengjiao; Cao, Zongxi; Cai, Yumei; Liu, Sidang; Chai, Tongjie; Wei, Liangmeng

    2016-01-01

    Mitochondrial antiviral-signaling protein (MAVS), an adaptor protein of retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs)-mediated signal pathway, is involved in innate immunity. In this study, Cherry Valley duck MAVS (duMAVS) was cloned from the spleen and analyzed. duMAVS was determined to have a caspase activation and recruitment domain at N-terminal, followed by a proline-rich domain and a transmembrane domain at C-terminal. Quantitative real-time PCR indicated that duMAVS was expressed in all tissues tested across a broad expression spectrum. The expression of duMAVS was significantly upregulated after infection with duck Tembusu virus (DTMUV). Overexpression of duMAVS could drive the activation of interferon (IFN)-β, nuclear factor-κB, interferon regulatory factor 7, and many downstream factors (such as Mx, PKR, OAS, and IL-8) in duck embryo fibroblast cells. What is more, RNA interference further confirmed that duMAVS was an important adaptor for IFN-β activation. The antiviral assay showed that duMAVS could suppress the various viral replications (DTMUV, novel reovirus, and duck plague virus) at early stages of infection. Overall, these results showed that the main signal pathway mediated by duMAVS and it had a broad-spectrum antiviral ability. This research will be helpful to better understanding the innate immune system of ducks. PMID:27708647

  5. Early mouse caudal development relies on crosstalk between retinoic acid, Shh and Fgf signalling pathways.

    PubMed

    Ribes, Vanessa; Le Roux, Isabelle; Rhinn, Muriel; Schuhbaur, Brigitte; Dollé, Pascal

    2009-02-01

    The progressive generation of embryonic trunk structures relies on the proper patterning of the caudal epiblast, which involves the integration of several signalling pathways. We have investigated the function of retinoic acid (RA) signalling during this process. We show that, in addition to posterior mesendoderm, primitive streak and node cells transiently express the RA-synthesizing enzyme Raldh2 prior to the headfold stage. RA-responsive cells (detected by the RA-activated RARE-lacZ transgene) are additionally found in the epiblast layer. Analysis of RA-deficient Raldh2(-/-) mutants reveals early caudal patterning defects, with an expansion of primitive streak and mesodermal markers at the expense of markers of the prospective neuroepithelium. As a result, many genes involved in neurogenesis and/or patterning of the embryonic spinal cord are affected in their expression. We demonstrate that RA signalling is required at late gastrulation stages for mesodermal and neural progenitors to respond to the Shh signal. Whole-embryo culture experiments indicate that the proper response of cells to Shh requires two RA-dependent mechanisms: (1) a balanced antagonism between Fgf and RA signals, and (2) a RA-mediated repression of Gli2 expression. Thus, an interplay between RA, Fgf and Shh signalling is likely to be an important mechanism underpinning the tight regulation of caudal embryonic development. PMID:19168680

  6. Interferon gamma induces protective non-canonical signaling pathways in primary neurons.

    PubMed

    O'Donnell, Lauren A; Henkins, Kristen M; Kulkarni, Apurva; Matullo, Christine M; Balachandran, Siddharth; Pattisapu, Anil K; Rall, Glenn F

    2015-10-01

    The signal transduction molecule, Stat1, is critical for the expression of type I and II interferon (IFN)-responsive genes in most cells; however, we previously showed that primary hippocampal mouse neurons express low basal Stat1, with delayed and attenuated expression of IFN-responsive genes. Moreover, IFNγ-dependent resolution of a neurotropic viral challenge in permissive mice is Stat1-independent. Here, we show that exogenous IFNγ has no deleterious impact on neuronal viability, and staurosporine-induced apoptosis in neurons is significantly blunted by the addition of IFNγ, suggesting that IFNγ confers a pro-survival signal in neurons. To identify the pathways induced by IFNγ in neurons, the activation of alternative signal transducers associated with IFNγ signaling was assessed. Rapid and pronounced activation of extracellular signal regulated kinase (Erk1/2) was observed in neurons, compared to a modest response in fibroblasts. Moreover, the absence of Stat1 in primary fibroblasts led to enhanced Erk activation following IFNγ addition, implying that the cell-specific availability of signal transducers can diversify the cellular response following IFN engagement.

  7. Activation of the Notch signaling pathway promotes neurovascular repair after traumatic brain injury

    PubMed Central

    Ran, Qi-shan; Yu, Yun-hu; Fu, Xiao-hong; Wen, Yuan-chao

    2015-01-01

    The Notch signaling pathway plays a key role in angiogenesis and endothelial cell formation, but it remains unclear whether it is involved in vascular repair by endothelial progenitor cells after traumatic brain injury. Therefore, in the present study, we controlled the Notch signaling pathway using overexpression and knockdown constructs. Activation of the Notch signaling pathway by Notch1 or Jagged1 overexpression enhanced the migration, invasiveness and angiogenic ability of endothelial progenitor cells. Suppression of the Notch signaling pathway with Notch1 or Jagged1 siRNAs reduced the migratory capacity, invasiveness and angiogenic ability of endothelial progenitor cells. Activation of the Notch signaling pathway in vivo in a rat model of mild traumatic brain injury promoted neurovascular repair. These findings suggest that the activation of the Notch signaling pathway promotes blood vessel formation and tissue repair after brain trauma. PMID:26487853

  8. The merged basins of signal transduction pathways in spatiotemporal cell biology.

    PubMed

    Hou, Yingchun; Hou, Yang; He, Siyu; Ma, Caixia; Sun, Mengyao; He, Huimin; Gao, Ning

    2014-03-01

    Numerous evidences have indicated that a signal system is composed by signal pathways, each pathway is composed by sub-pathways, and the sub-pathway is composed by the original signal terminals initiated with a protein/gene. We infer the terminal signals merged signal transduction system as "signal basin". In this article, we discussed the composition and regulation of signal basins, and the relationship between the signal basin control and triple W of spatiotemporal cell biology. Finally, we evaluated the importance of the systemic regulation to gene expression by signal basins under triple W. We hope our discussion will be the beginning to cause the attention for this area from the scientists of life science.

  9. Signalling pathways involved in the control of sperm cell volume.

    PubMed

    Petrunkina, A M; Harrison, R A P; Tsolova, M; Jebe, E; Töpfer-Petersen, E

    2007-01-01

    The ability to maintain cellular volume is an important general physiological function, which is achieved by specific molecular mechanisms. Hypotonically induced swelling results in the opening of K+ and Cl- ion channels, through which these ions exit with accompanying water loss. This process is known as regulatory volume decrease (RVD). The molecular mechanisms that control the opening of the ion channels in spermatozoa are as yet poorly understood. The present study investigated pathways of osmo-signalling using boar spermatozoa as a model. Spermatozoa were diluted into isotonic and hypotonic Hepes-buffered saline in the presence or absence of effector drugs, and at predetermined intervals volume measurements were performed electronically. Treatment with protein kinase C (PKC) inhibitors staurosporine, bismaleimide I and bismaleimide X led to dose-dependent increases of both isotonic and hypotonic volumes (P<0.05). However, as the isotonic volume was affected more than the hypotonic volume, the kinase inhibitors appeared to improve RVD, whereas activation of PKC with phorbol dibutyrate blocked RVD. The increase in isotonic cell volume induced by bismaleimide X was observed in chloride-containing medium but not in the medium in which chloride was replaced by sulphate, implying that PKC was involved in the control of chloride channel activity, e.g. by closing the channel after volume adjustment. The protein phosphatase PP1/PP2 inhibitors calyculin and okadaic acid increased the isotonic volume only slightly but they greatly increased the relative cell volume and blocked RVD. The activation of RVD processes was found to be cAMP-dependent; incubation with forskolin and papaverine improved volume regulation. Moreover, papaverine was able to overcome the negative effect of protein phosphatase inhibitors. The mechanism of sperm RVD appears to involve (a) alterations in protein phosphorylation/dephosphorylation balance brought about by PKC and PP1 and (b) a c

  10. Oncogenic mutant of Galpha12 stimulates cell proliferation through cycloxygenase-2 signaling pathway.

    PubMed

    Dermott, J M; Reddy, M R; Onesime, D; Reddy, E P; Dhanasekaran, N

    1999-12-01

    Expression of the GTPase-deficient, activated mutant alpha-subunit of the heterotrimeric G protein G12 (Galpha12QL) leads to the neoplastic transformation of fibroblast cell lines. The mitogenic pathway regulated by Galpha12QL includes an extensive signaling network involving several small GTPases and various kinases. In addition, Galpha12QL has been shown to potentiate the serum-induced phospholipase-A2 activity in NIH3T3 cells. In the present study, we demonstrate that cycloxygenase-2 (COX-2) pathway is involved in the mitogenic pathway activated by Galpha12QL. Expression of Galpha12QL and not Galpha13QL, stimulates the serum-induced release of arachidonic acid in NIH3T3 cells. Furthermore, expression of Galpha12QL or the stimulation of wild-type Galpha12 induces the expression of COX-2. Our results also indicate that the COX-2 inhibitor acutely disrupts the DNA-synthesis stimulated by Galpha12QL in NIH3T3 cells. These studies, for the first time, identify the crucial role of COX-2 in Galpha12-mediated regulation of cell proliferation and suggest a role for prostaglandin-derived autocrine loop in Galpha12-mediated signaling pathways. PMID:10602471

  11. Three WRKY transcription factors additively repress abscisic acid and gibberellin signaling in aleurone cells.

    PubMed

    Zhang, Liyuan; Gu, Lingkun; Ringler, Patricia; Smith, Stanley; Rushton, Paul J; Shen, Qingxi J

    2015-07-01

    Members of the WRKY transcription factor superfamily are essential for the regulation of many plant pathways. Functional redundancy due to duplications of WRKY transcription factors, however, complicates genetic analysis by allowing single-mutant plants to maintain wild-type phenotypes. Our analyses indicate that three group I WRKY genes, OsWRKY24, -53, and -70, act in a partially redundant manner. All three showed characteristics of typical WRKY transcription factors: each localized to nuclei and yeast one-hybrid assays indicated that they all bind to W-boxes, including those present in their own promoters. Quantitative real time-PCR (qRT-PCR) analyses indicated that the expression levels of the three WRKY genes varied in the different tissues tested. Particle bombardment-mediated transient expression analyses indicated that all three genes repress the GA and ABA signaling in a dosage-dependent manner. Combination of all three WRKY genes showed additive antagonism of ABA and GA signaling. These results suggest that these WRKY proteins function as negative transcriptional regulators of GA and ABA signaling. However, different combinations of these WRKY genes can lead to varied strengths in suppression of their targets.

  12. Elabela-apelin receptor signaling pathway is functional in mammalian systems.

    PubMed

    Wang, Zhi; Yu, Daozhan; Wang, Mengqiao; Wang, Qilong; Kouznetsova, Jennifer; Yang, Rongze; Qian, Kun; Wu, Wenjun; Shuldiner, Alan; Sztalryd, Carole; Zou, Minghui; Zheng, Wei; Gong, Da-Wei

    2015-02-02

    Elabela (ELA) or Toddler is a recently discovered hormone which is required for normal development of heart and vasculature through activation of apelin receptor (APJ), a G protein-coupled receptor (GPCR), in zebrafish. The present study explores whether the ELA-APJ signaling pathway is functional in the mammalian system. Using reverse-transcription PCR, we found that ELA is restrictedly expressed in human pluripotent stem cells and adult kidney whereas APJ is more widely expressed. We next studied ELA-APJ signaling pathway in reconstituted mammalian cell systems. Addition of ELA to HEK293 cells over-expressing GFP-AJP fusion protein resulted in rapid internalization of the fusion receptor. In Chinese hamster ovarian (CHO) cells over-expressing human APJ, ELA suppresses cAMP production with EC50 of 11.1 nM, stimulates ERK1/2 phosphorylation with EC50 of 14.3 nM and weakly induces intracellular calcium mobilization. Finally, we tested ELA biological function in human umbilical vascular endothelial cells and showed that ELA induces angiogenesis and relaxes mouse aortic blood vessel in a dose-dependent manner through a mechanism different from apelin. Collectively, we demonstrate that the ELA-AJP signaling pathways are functional in mammalian systems, indicating that ELA likely serves as a hormone regulating the circulation system in adulthood as well as in embryonic development.

  13. The Calcium Ion Is a Second Messenger in the Nitrate Signaling Pathway of Arabidopsis.

    PubMed

    Riveras, Eleodoro; Alvarez, José M; Vidal, Elena A; Oses, Carolina; Vega, Andrea; Gutiérrez, Rodrigo A

    2015-10-01

    Understanding how plants sense and respond to changes in nitrogen availability is the first step toward developing strategies for biotechnological applications, such as improvement of nitrogen use efficiency. However, components involved in nitrogen signaling pathways remain poorly characterized. Calcium is a second messenger in signal transduction pathways in plants, and it has been indirectly implicated in nitrate responses. Using aequorin reporter plants, we show that nitrate treatments transiently increase cytoplasmic Ca(2+) concentration. We found that nitrate also induces cytoplasmic concentration of inositol 1,4,5-trisphosphate. Increases in inositol 1,4,5-trisphosphate and cytoplasmic Ca(2+) levels in response to nitrate treatments were blocked by U73122, a pharmacological inhibitor of phospholipase C, but not by the nonfunctional phospholipase C inhibitor analog U73343. In addition, increase in cytoplasmic Ca(2+) levels in response to nitrate treatments was abolished in mutants of the nitrate transceptor NITRATE TRANSPORTER1.1/Arabidopsis (Arabidopsis thaliana) NITRATE TRANSPORTER1 PEPTIDE TRANSPORTER FAMILY6.3. Gene expression of nitrate-responsive genes was severely affected by pretreatments with Ca(2+) channel blockers or phospholipase C inhibitors. These results indicate that Ca(2+) acts as a second messenger in the nitrate signaling pathway of Arabidopsis. Our results suggest a model where NRT1.1/AtNPF6.3 and a phospholipase C activity mediate the increase of Ca(2+) in response to nitrate required for changes in expression of prototypical nitrate-responsive genes. PMID:26304850

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

    PubMed

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

    2015-01-30

    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.

  15. Elabela-Apelin Receptor Signaling Pathway is Functional in Mammalian Systems

    PubMed Central

    Wang, Zhi; Yu, Daozhan; Wang, Mengqiao; Wang, Qilong; Kouznetsova, Jennifer; Yang, Rongze; Qian, Kun; Wu, Wenjun; Shuldiner, Alan; Sztalryd, Carole; Zou, Minghui; Zheng, Wei; Gong, Da-Wei

    2015-01-01

    Elabela (ELA) or Toddler is a recently discovered hormone which is required for normal development of heart and vasculature through activation of apelin receptor (APJ), a G protein-coupled receptor (GPCR), in zebrafish. The present study explores whether the ELA-APJ signaling pathway is functional in the mammalian system. Using reverse-transcription PCR, we found that ELA is restrictedly expressed in human pluripotent stem cells and adult kidney whereas APJ is more widely expressed. We next studied ELA-APJ signaling pathway in reconstituted mammalian cell systems. Addition of ELA to HEK293 cells over-expressing GFP-AJP fusion protein resulted in rapid internalization of the fusion receptor. In Chinese hamster ovarian (CHO) cells over-expressing human APJ, ELA suppresses cAMP production with EC50 of 11.1 nM, stimulates ERK1/2 phosphorylation with EC50 of 14.3 nM and weakly induces intracellular calcium mobilization. Finally, we tested ELA biological function in human umbilical vascular endothelial cells and showed that ELA induces angiogenesis and relaxes mouse aortic blood vessel in a dose-dependent manner through a mechanism different from apelin. Collectively, we demonstrate that the ELA-AJP signaling pathways are functional in mammalian systems, indicating that ELA likely serves as a hormone regulating the circulation system in adulthood as well as in embryonic development. PMID:25639753

  16. The Calcium Ion Is a Second Messenger in the Nitrate Signaling Pathway of Arabidopsis1

    PubMed Central

    Riveras, Eleodoro; Alvarez, José M.; Vidal, Elena A.; Oses, Carolina; Vega, Andrea; Gutiérrez, Rodrigo A.

    2015-01-01

    Understanding how plants sense and respond to changes in nitrogen availability is the first step toward developing strategies for biotechnological applications, such as improvement of nitrogen use efficiency. However, components involved in nitrogen signaling pathways remain poorly characterized. Calcium is a second messenger in signal transduction pathways in plants, and it has been indirectly implicated in nitrate responses. Using aequorin reporter plants, we show that nitrate treatments transiently increase cytoplasmic Ca2+ concentration. We found that nitrate also induces cytoplasmic concentration of inositol 1,4,5-trisphosphate. Increases in inositol 1,4,5-trisphosphate and cytoplasmic Ca2+ levels in response to nitrate treatments were blocked by U73122, a pharmacological inhibitor of phospholipase C, but not by the nonfunctional phospholipase C inhibitor analog U73343. In addition, increase in cytoplasmic Ca2+ levels in response to nitrate treatments was abolished in mutants of the nitrate transceptor NITRATE TRANSPORTER1.1/Arabidopsis (Arabidopsis thaliana) NITRATE TRANSPORTER1 PEPTIDE TRANSPORTER FAMILY6.3. Gene expression of nitrate-responsive genes was severely affected by pretreatments with Ca2+ channel blockers or phospholipase C inhibitors. These results indicate that Ca2+ acts as a second messenger in the nitrate signaling pathway of Arabidopsis. Our results suggest a model where NRT1.1/AtNPF6.3 and a phospholipase C activity mediate the increase of Ca2+ in response to nitrate required for changes in expression of prototypical nitrate-responsive genes. PMID:26304850

  17. G-Protein–Coupled Receptors Signaling Pathways in New Antiplatelet Drug Development

    PubMed Central

    Gurbel, Paul A.; Kuliopulos, Athan; Tantry, Udaya S.

    2016-01-01

    Platelet G-protein–coupled receptors influence platelet function by mediating the response to various agonists, including ADP, thromboxane A2, and thrombin. Blockade of the ADP receptor, P2Y12, in combination with cyclooxygenase-1 inhibition by aspirin has been among the most widely used pharmacological strategies to reduce cardiovascular event occurrence in high-risk patients. The latter dual pathway blockade strategy is one of the greatest advances in the field of cardiovascular medicine. In addition to P2Y12, the platelet thrombin receptor, protease activated receptor-1, has also been recently targeted for inhibition. Blockade of protease activated receptor-1 has been associated with reduced thrombotic event occurrence when added to a strategy using P2Y12 and cyclooxygenase-1 inhibition. At this time, the relative contributions of these G-protein–coupled receptor signaling pathways to in vivo thrombosis remain incompletely defined. The observation of treatment failure in ≈10% of high-risk patients treated with aspirin and potent P2Y12 inhibitors provides the rationale for targeting novel pathways mediating platelet function. Targeting intracellular signaling downstream from G-protein–coupled receptor receptors with phosphotidylionisitol 3-kinase and Gq inhibitors are among the novel strategies under investigation to prevent arterial ischemic event occurrence. Greater understanding of the mechanisms of G-protein–coupled receptor–mediated signaling may allow the tailoring of antiplatelet therapy. PMID:25633316

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

    PubMed Central

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

    2014-01-01

    Cellular fate depends on the spatio-temporal separation and integration of signaling processes which can be provided by phosphorylation events. In this study we identify the crucial points in signaling crosstalk which 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 on 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 or 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 have 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

  19. Costal2 Functions as a Microtubule-Dependent Motor in the Hedgehog Signal Transduction Pathway

    PubMed Central

    Farzan, Shohreh F.; Ascano, Manuel; Ogden, Stacey K.; Sanial, Matthieu; Brigui, Amira; Plessis, Anne; Robbins, David J.

    2009-01-01

    SUMMARY The Hedgehog (Hh) signaling pathway initiates an evolutionarily conserved developmental program required for the proper patterning of many tissues. Costal2 (Cos2) is a requisite component of the Hh pathway, whose mechanistic role is not well understood. Cos2 was initially predicted, based on its primary sequence, to function as a microtubule-associated (MT) molecular motor. However, despite being identified over a decade ago, evidence showing that Cos2 function might require kinesin-like properties has for the most part been lacking. Thus the prevailing dogma in the field is that Cos2 functions solely as a scaffolding protein during Hh signal transduction. Here, we provide the first evidence that Cos2 motility is required for its biological function, and that this motility may be Hh regulated. We show that Cos2 motility requires an active motor domain, ATP and microtubules. Additionally, Cos2 recruits and transports other components of the Hh signaling pathway, including the transcription factor Cubitus interruptus (Ci), throughout the cell. Drosophila expressing cos2 mutations that encode proteins that lack motility are attenuated in their ability to regulate Ci activity and exhibit phenotypes consistent with attenuated Cos2 function. Combined, these results demonstrate that Cos2 motility plays an important role in its function, regulating the amounts and activity of Ci that ultimately interpret the level of Hh to which cells are exposed. PMID:18691888

  20. The Tor and PKA signaling pathways independently target the Atg1/Atg13 protein kinase complex to control autophagy

    PubMed Central

    Stephan, Joseph S.; Yeh, Yuh-Ying; Ramachandran, Vidhya; Deminoff, Stephen J.; Herman, Paul K.

    2009-01-01

    Macroautophagy (or autophagy) is a conserved degradative pathway that has been implicated in a number of biological processes, including organismal aging, innate immunity, and the progression of human cancers. This pathway was initially identified as a cellular response to nutrient deprivation and is essential for cell survival during these periods of starvation. Autophagy is highly regulated and is under the control of a number of signaling pathways, including the Tor pathway, that coordinate cell growth with nutrient availability. These pathways appear to target a complex of proteins that contains the Atg1 protein kinase. The data here show that autophagy in Saccharomyces cerevisiae is also controlled by the cAMP-dependent protein kinase (PKA) pathway. Elevated levels of PKA activity inhibited autophagy and inactivation of the PKA pathway was sufficient to induce a robust autophagy response. We show that in addition to Atg1, PKA directly phosphorylates Atg13, a conserved regulator of Atg1 kinase activity. This phosphorylation regulates Atg13 localization to the preautophagosomal structure, the nucleation site from which autophagy pathway transport intermediates are formed. Atg13 is also phosphorylated in a Tor-dependent manner, but these modifications appear to occur at positions distinct from the PKA phosphorylation sites identified here. In all, our data indicate that the PKA and Tor pathways function independently to control autophagy in S. cerevisiae, and that the Atg1/Atg13 kinase complex is a key site of signal integration within this degradative pathway. PMID:19805182

  1. Partial Decay of Thiamine Signal Transduction Pathway Alters Growth Properties of Candida glabrata.

    PubMed

    Iosue, Christine L; Attanasio, Nicholas; Shaik, Noor F; Neal, Erin M; Leone, Sarah G; Cali, Brian J; Peel, Michael T; Grannas, Amanda M; Wykoff, Dennis D

    2016-01-01

    The phosphorylated form of thiamine (Vitamin B1), thiamine pyrophosphate (TPP) is essential for the metabolism of amino acids and carbohydrates in all organisms. Plants and microorganisms, such as yeast, synthesize thiamine de novo whereas animals do not. The thiamine signal transduction (THI) pathway in Saccharomyces cerevisiae is well characterized. The ~10 genes required for thiamine biosynthesis and uptake are transcriptionally upregulated during thiamine starvation by THI2, THI3, and PDC2. Candida glabrata, a human commensal and opportunistic pathogen, is closely related to S. cerevisiae but is missing half of the biosynthetic pathway, which limits its ability to make thiamine. We investigated the changes to the THI pathway in C. glabrata, confirming orthologous functions. We found that C. glabrata is unable to synthesize the pyrimidine subunit of thiamine as well as the thiamine precursor vitamin B6. In addition, THI2 (the gene encoding a transcription factor) is not present in C. glabrata, indicating a difference in the transcriptional regulation of the pathway. Although the pathway is upregulated by thiamine starvation in both species, C. glabrata appears to upregulate genes involved in thiamine uptake to a greater extent than S. cerevisiae. However, the altered regulation of the THI pathway does not alter the concentration of thiamine and its vitamers in the two species as measured by HPLC. Finally, we demonstrate potential consequences to having a partial decay of the THI biosynthetic and regulatory pathway. When the two species are co-cultured, the presence of thiamine allows C. glabrata to rapidly outcompete S. cerevisiae, while absence of thiamine allows S. cerevisiae to outcompete C. glabrata. This simplification of the THI pathway in C. glabrata suggests its environment provides thiamine and/or its precursors to cells, whereas S. cerevisiae is not as reliant on environmental sources of thiamine.

  2. Partial Decay of Thiamine Signal Transduction Pathway Alters Growth Properties of Candida glabrata

    PubMed Central

    Shaik, Noor F.; Neal, Erin M.; Leone, Sarah G.; Cali, Brian J.; Peel, Michael T.; Grannas, Amanda M.; Wykoff, Dennis D.

    2016-01-01

    The phosphorylated form of thiamine (Vitamin B1), thiamine pyrophosphate (TPP) is essential for the metabolism of amino acids and carbohydrates in all organisms. Plants and microorganisms, such as yeast, synthesize thiamine de novo whereas animals do not. The thiamine signal transduction (THI) pathway in Saccharomyces cerevisiae is well characterized. The ~10 genes required for thiamine biosynthesis and uptake are transcriptionally upregulated during thiamine starvation by THI2, THI3, and PDC2. Candida glabrata, a human commensal and opportunistic pathogen, is closely related to S. cerevisiae but is missing half of the biosynthetic pathway, which limits its ability to make thiamine. We investigated the changes to the THI pathway in C. glabrata, confirming orthologous functions. We found that C. glabrata is unable to synthesize the pyrimidine subunit of thiamine as well as the thiamine precursor vitamin B6. In addition, THI2 (the gene encoding a transcription factor) is not present in C. glabrata, indicating a difference in the transcriptional regulation of the pathway. Although the pathway is upregulated by thiamine starvation in both species, C. glabrata appears to upregulate genes involved in thiamine uptake to a greater extent than S. cerevisiae. However, the altered regulation of the THI pathway does not alter the concentration of thiamine and its vitamers in the two species as measured by HPLC. Finally, we demonstrate potential consequences to having a partial decay of the THI biosynthetic and regulatory pathway. When the two species are co-cultured, the presence of thiamine allows C. glabrata to rapidly outcompete S. cerevisiae, while absence of thiamine allows S. cerevisiae to outcompete C. glabrata. This simplification of the THI pathway in C. glabrata suggests its environment provides thiamine and/or its precursors to cells, whereas S. cerevisiae is not as reliant on environmental sources of thiamine. PMID:27015653

  3. Partial Decay of Thiamine Signal Transduction Pathway Alters Growth Properties of Candida glabrata.

    PubMed

    Iosue, Christine L; Attanasio, Nicholas; Shaik, Noor F; Neal, Erin M; Leone, Sarah G; Cali, Brian J; Peel, Michael T; Grannas, Amanda M; Wykoff, Dennis D

    2016-01-01

    The phosphorylated form of thiamine (Vitamin B1), thiamine pyrophosphate (TPP) is essential for the metabolism of amino acids and carbohydrates in all organisms. Plants and microorganisms, such as yeast, synthesize thiamine de novo whereas animals do not. The thiamine signal transduction (THI) pathway in Saccharomyces cerevisiae is well characterized. The ~10 genes required for thiamine biosynthesis and uptake are transcriptionally upregulated during thiamine starvation by THI2, THI3, and PDC2. Candida glabrata, a human commensal and opportunistic pathogen, is closely related to S. cerevisiae but is missing half of the biosynthetic pathway, which limits its ability to make thiamine. We investigated the changes to the THI pathway in C. glabrata, confirming orthologous functions. We found that C. glabrata is unable to synthesize the pyrimidine subunit of thiamine as well as the thiamine precursor vitamin B6. In addition, THI2 (the gene encoding a transcription factor) is not present in C. glabrata, indicating a difference in the transcriptional regulation of the pathway. Although the pathway is upregulated by thiamine starvation in both species, C. glabrata appears to upregulate genes involved in thiamine uptake to a greater extent than S. cerevisiae. However, the altered regulation of the THI pathway does not alter the concentration of thiamine and its vitamers in the two species as measured by HPLC. Finally, we demonstrate potential consequences to having a partial decay of the THI biosynthetic and regulatory pathway. When the two species are co-cultured, the presence of thiamine allows C. glabrata to rapidly outcompete S. cerevisiae, while absence of thiamine allows S. cerevisiae to outcompete C. glabrata. This simplification of the THI pathway in C. glabrata suggests its environment provides thiamine and/or its precursors to cells, whereas S. cerevisiae is not as reliant on environmental sources of thiamine. PMID:27015653

  4. Signal transduction in the activation of spermatozoa compared to other signalling pathways: a biological networks study.

    PubMed

    Bernabò, Nicola; Mattioli, Mauro; Barboni, Barbara

    2015-01-01

    In this paper we represented Spermatozoa Activation (SA) the process that leads male gametes to reach their fertilising ability of sea urchin, Caenorhabditis elegans and human as biological networks, i.e. as networks of nodes (molecules) linked by edges (their interactions). Then, we compared them with networks representing ten pathways of relevant physio-pathological importance and with a computer-generated network. We have found that the number of nodes and edges composing each network is not related with the amount of published papers on each specific topic and that all the topological parameters examined are similar in all the networks, thus conferring them a scale free topology and small world behaviour. In conclusion, SA topology, independently from the reproductive biology of considered organism, as others signalling networks is characterised by robustness against random failure, controllability and efficiency in signal transmission. PMID:26489142

  5. An Integrative Model for Representation of Signaling Pathways on the Basis of Device Ontology

    NASA Astrophysics Data System (ADS)

    Takai-Igarashi, Takako; Mizoguchi, Riichiro

    Signaling pathways are causal sequences of chemical reactions that end up by achieving cellular functions. Much information has been accumulated in databases for signaling pathways and ontologies have been built for sharing and reusing the information in community. However, we still have difficulties in consistent representation of signaling pathways. We still fail to have an intrinsic definition of a signaling pathway. We also fail to specify cooperative actions of molecules in dynamical construction of molecular complexes. We have developed Cell Signaling Networks Ontology (CSNO) based on device ontology to address theses difficulties. CSNO explicates that "signal" carries two kinds of information such as "identity" and "causality" of a signaling pathway. Identity is coded into "molecular recognition" predetermined in a cell, whereas causality is coded into "activity" processed along a pathway progressively and is essential for two-layered functions of cooperative molecules: to let activities flow (elementary function) and to control the flow of activities (mechanical function). CSNO defines roles of complex formation as dynamical construction of a device that performs a mechanical function generating cooperation in actions of molecules. Based on the definitions of signaling pathways, CSNO provides us with a base of integrative and consistent representation of signaling pathways, inducing a viewpoint in which not molecules but pathways are focused in the knowledge representation.

  6. Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways

    PubMed Central

    Becnel, Lauren B.; Darlington, Yolanda F.; Ochsner, Scott A.; Easton-Marks, Jeremy R.; Watkins, Christopher M.; McOwiti, Apollo; Kankanamge, Wasula H.; Wise, Michael W.; DeHart, Michael; Margolis, Ronald N.; McKenna, Neil J.

    2015-01-01

    Signaling pathways involving nuclear receptors (NRs), their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA) is a Consortium focused around a Hub website (www.nursa.org) that annotates and integrates diverse ‘omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs). These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy “Web 2.0” technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA’s Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field. PMID:26325041

  7. Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways.

    PubMed

    Becnel, Lauren B; Darlington, Yolanda F; Ochsner, Scott A; Easton-Marks, Jeremy R; Watkins, Christopher M; McOwiti, Apollo; Kankanamge, Wasula H; Wise, Michael W; DeHart, Michael; Margolis, Ronald N; McKenna, Neil J

    2015-01-01

    Signaling pathways involving nuclear receptors (NRs), their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA) is a Consortium focused around a Hub website (www.nursa.org) that annotates and integrates diverse 'omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs). These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy "Web 2.0" technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA's Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field.

  8. Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways.

    PubMed

    Becnel, Lauren B; Darlington, Yolanda F; Ochsner, Scott A; Easton-Marks, Jeremy R; Watkins, Christopher M; McOwiti, Apollo; Kankanamge, Wasula H; Wise, Michael W; DeHart, Michael; Margolis, Ronald N; McKenna, Neil J

    2015-01-01

    Signaling pathways involving nuclear receptors (NRs), their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA) is a Consortium focused around a Hub website (www.nursa.org) that annotates and integrates diverse 'omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs). These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy "Web 2.0" technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA's Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field. PMID:26325041

  9. Genetically encoded optical probes for imaging cellular signaling pathways.

    PubMed

    Umezawa, Yoshio

    2005-06-15

    The intracellular signaling can be monitored in vivo in living cells by genetically encoded intracellular fluorescent and bioluminescent probes or indicators, which include second messengers, protein phosphorylation, protein conformational changes, protein-protein interactions, and protein localizations. These probes are of general use not only for fundamental biological studies, but also for assay and screening of possible pharmaceutical or toxic chemicals that inhibit or facilitate cellular signaling pathways. In this review, two examples of such indicators were briefly introduced. First, a genetically encoded fluorescent indicator was described for the detection and characterization of estrogen agonists and antagonists. The indicator was named SCCoR (single cell-coactivator recruitment). The high sensitivity of the present indicator made it possible to distinguish between estrogen strong and weak agonists in a dose-dependent fashion, immediately after adding a ligand to live cells. Discrimination of agonists from antagonists was efficiently achieved using the indicator. The approach described here can be applied to develop biosensors for other hormone receptors as well. Another example herein is a genetically encoded bioluminescent indicator for monitoring the nuclear trafficking of target proteins in vitro and in vivo. We demonstrated quantitative cell-based in vitro sensing of ligand-induced translocation of androgen receptor, which allowed high-throughput screening of exo- and endogenous agonists and antagonists. Furthermore, the indicator enabled noninvasive in vivo imaging of the androgen receptor translocation in the brains of living mice with a charge-coupled device imaging system. These rapid and quantitative analyses in vitro and in vivo provide a wide variety of applications for screening pharmacological or toxicological compounds and testing them in living animals.

  10. Phosphatidic acid mediates activation of mTORC1 through the ERK signaling pathway

    PubMed Central

    Winter, Jeremiah N.; Fox, Todd E.; Kester, Mark; Jefferson, Leonard S.

    2010-01-01

    The mammalian target of rapamycin (mTOR) assembles into two distinct multiprotein complexes known as mTORC1 and mTORC2. Of the two complexes, mTORC1 acts to integrate a variety of positive and negative signals to downstream targets that regulate cell growth. The lipid second messenger, phosphatidic acid (PA), represents one positive input to mTORC1, and it is thought to act by binding directly to mTOR, thereby enhancing the protein kinase activity of mTORC1. Support for this model includes findings that PA binds directly to mTOR and addition of PA to the medium of cells in culture results in activation of mTORC1. In contrast, the results of the present study do not support a model in which PA activates mTORC1 through direct interaction with the protein kinase but, instead, show that the lipid promotes mTORC1 signaling through activation of the ERK pathway. Moreover, rather than acting directly on mTORC1, the results suggest that exogenous PA must be metabolized to lysophosphatidic acid (LPA), which subsequently activates the LPA receptor endothelial differentiation gene (EDG-2). Finally, in contrast to previous studies, the results of the present study demonstrate that leucine does not act through phospholipase D and PA to activate mTORC1 and, instead, show that the two mediators act through parallel upstream signaling pathways to activate mTORC1. Overall, the results demonstrate that leucine and PA signal through parallel pathways to activate mTORC1 and that PA mediates its effect through the ERK pathway, rather than through direct binding to mTOR. PMID:20427710

  11. Global microRNA profiles and signaling pathways in the development of cardiac hypertrophy.

    PubMed

    Feng, H J; Ouyang, W; Liu, J H; Sun, Y G; Hu, R; Huang, L H; Xian, J L; Jing, C F; Zhou, M J

    2014-05-01

    Hypertrophy is a major predictor of progressive heart disease and has an adverse prognosis. MicroRNAs (miRNAs) that accumulate during the course of cardiac hypertrophy may participate in the process. However, the nature of any interaction between a hypertrophy-specific signaling pathway and aberrant expression of miRNAs remains unclear. In this study, Spague Dawley male rats were treated with transverse aortic constriction (TAC) surgery to mimic pathological hypertrophy. Hearts were isolated from TAC and sham operated rats (n=5 for each group at 5, 10, 15, and 20 days after surgery) for miRNA microarray assay. The miRNAs dysexpressed during hypertrophy were further analyzed using a combination of bioinformatics algorithms in order to predict possible targets. Increased expression of the target genes identified in diverse signaling pathways was also analyzed. Two sets of miRNAs were identified, showing different expression patterns during hypertrophy. Bioinformatics analysis suggested the miRNAs may regulate multiple hypertrophy-specific signaling pathways by targeting the member genes and the interaction of miRNA and mRNA might form a network that leads to cardiac hypertrophy. In addition, the multifold changes in several miRNAs suggested that upregulation of rno-miR-331*, rno-miR-3596b, rno-miR-3557-5p and downregulation of rno-miR-10a, miR-221, miR-190, miR-451 could be seen as biomarkers of prognosis in clinical therapy of heart failure. This study described, for the first time, a potential mechanism of cardiac hypertrophy involving multiple signaling pathways that control up- and downregulation of miRNAs. It represents a first step in the systematic discovery of miRNA function in cardiovascular hypertrophy.

  12. Modeling of Non-Steroidal Anti-Inflammatory Drug Effect within Signaling Pathways and miRNA-Regulation Pathways

    PubMed Central

    Li, Jian; Mansmann, Ulrich R.

    2013-01-01

    To date, it is widely recognized that Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) can exert considerable anti-tumor effects regarding many types of cancers. The prolonged use of NSAIDs is highly associated with diverse side effects. Therefore, tailoring down the NSAID application onto individual patients has become a necessary and relevant step towards personalized medicine. This study conducts the systemsbiological approach to construct a molecular model (NSAID model) containing a cyclooxygenase (COX)-pathway and its related signaling pathways. Four cancer hallmarks are integrated into the model to reflect different developmental aspects of tumorigenesis. In addition, a Flux-Comparative-Analysis (FCA) based on Petri net is developed to transfer the dynamic properties (including drug responsiveness) of individual cellular system into the model. The gene expression profiles of different tumor-types with available drug-response information are applied to validate the predictive ability of the NSAID model. Moreover, two therapeutic developmental strategies, synthetic lethality and microRNA (miRNA) biomarker discovery, are investigated based on the COX-pathway. In conclusion, the result of this study demonstrates that the NSAID model involving gene expression, gene regulation, signal transduction, protein interaction and other cellular processes, is able to predict the individual cellular responses for different therapeutic interventions (such as NS-398 and COX-2 specific siRNA inhibition). This strongly indicates that this type of model is able to reflect the physiological, developmental and pathological processes of an individual. The approach of miRNA biomarker discovery is demonstrated for identifying miRNAs with oncogenic and tumor suppressive functions for individual cell lines of breast-, colon- and lung-tumor. The achieved results are in line with different independent studies that investigated miRNA biomarker related to diagnostics of cancer treatments

  13. Neuroplasticity Signaling Pathways Linked to the Pathophysiology of Schizophrenia

    PubMed Central

    Balu, Darrick T.; Coyle, Joseph T.

    2010-01-01

    Schizophrenia is a severe mental illness that afflicts nearly 1% of the world's population. One of the cardinal pathological features of schizophrenia is perturbation in synaptic connectivity. Although the etiology of schizophrenia is unknown, it appears to be a developmental disorder involving the interaction of a potentially large number of risk genes, with no one gene producing a strong effect except rare, highly penetrant copy number variants. The purpose of this review is to detail how putative schizophrenia risk genes (DISC-1, neuregulin/ErbB4, dysbindin, Akt1, BDNF, and NMDA receptor) are involved in regulating neuroplasticity and how alterations in their expression may contribute to the disconnectivity observed in schizophrenia. Moreover, this review highlights how many of these risk genes converge to regulate common neurotransmitter systems and signaling pathways. Future studies aimed at elucidating the functions of these risk genes will provide new insights into the pathophysiology of schizophrenia and will likely lead to the nomination of novel therapeutic targets for restoring proper synaptic connectivity in the brain in schizophrenia and related disorders. PMID:20951727

  14. Targeting signaling pathways in acute lymphoblastic leukemia: new insights.

    PubMed

    Harrison, Christine J

    2013-01-01

    The genetics of acute lymphoblastic leukemia are becoming well understood and the incidence of individual chromosomal abnormalities varies considerably with age. Cytogenetics provide reliable risk stratification for treatment: high hyperdiploidy and ETV6-RUNX1 are good risk, whereas BCR-ABL1, MLL rearrangements, and hypodiploidy are poor risk. Nevertheless, some patients within the good- and intermediate-risk groups will unpredictably relapse. With advancing technologies in array-based approaches (single nucleotide polymorphism arrays) and next-generation sequencing to study the genome, increasing numbers of new genetic changes are being discovered. These include deletions of B-cell differentiation and cell cycle control genes, as well as mutations of genes in key signaling pathways. Their associations and interactions with established cytogenetic subgroups and with each other are becoming elucidated. Whether they have a link to outcome is the most important factor for refinement of risk factors in relation to clinical trials. For several newly identified abnormalities, including intrachromosomal amplification of chromosome 21 (iAMP21), that are associated with a poor prognosis with standard therapy, appropriately modified treatment has significantly improved outcome. After the successful use of tyrosine kinase inhibitors in the treatment of BCR-ABL1-positive acute lymphoblastic leukemia, patients with alternative ABL1 translocations and rearrangements involving PDGFRB may benefit from treatment with tyrosine kinase inhibitors. Other aberrations, for example, CRLF2 overexpression and JAK2 mutations, are also providing potential novel therapeutic targets with the prospect of reduced toxicity.

  15. Generation and application of signaling pathway reporter lines in zebrafish.

    PubMed

    Moro, Enrico; Vettori, Andrea; Porazzi, Patrizia; Schiavone, Marco; Rampazzo, Elena; Casari, Alessandro; Ek, Olivier; Facchinello, Nicola; Astone, Matteo; Zancan, Ilaria; Milanetto, Martina; Tiso, Natascia; Argenton, Francesco

    2013-06-01

    In the last years, we have seen the emergence of different tools that have changed the face of biology from a simple modeling level to a more systematic science. The transparent zebrafish embryo is one of the living models in which, after germline transformation with reporter protein-coding genes, specific fluorescent cell populations can be followed at single-cell resolution. The genetically modified embryos, larvae and adults, resulting from the transformation, are individuals in which time lapse analysis, digital imaging quantification, FACS sorting and next-generation sequencing can be performed in specific times and tissues. These multifaceted genetic and cellular approaches have permitted to dissect molecular interactions at the subcellular, intercellular, tissue and whole-animal level, thus allowing integration of cellular and developmental genetics with molecular imaging in the resulting frame of modern biology. In this review, we describe a new step in the zebrafish road to system biology, based on the use of transgenic biosensor animals expressing fluorescent proteins under the control of signaling pathway-responsive cis-elements. In particular, we provide here the rationale and details of this powerful tool, trying to focus on its huge potentialities in basic and applied research, while also discussing limits and potential technological evolutions of this approach. PMID:23674148

  16. Generation and application of signaling pathway reporter lines in zebrafish.

    PubMed

    Moro, Enrico; Vettori, Andrea; Porazzi, Patrizia; Schiavone, Marco; Rampazzo, Elena; Casari, Alessandro; Ek, Olivier; Facchinello, Nicola; Astone, Matteo; Zancan, Ilaria; Milanetto, Martina; Tiso, Natascia; Argenton, Francesco

    2013-06-01

    In the last years, we have seen the emergence of different tools that have changed the face of biology from a simple modeling level to a more systematic science. The transparent zebrafish embryo is one of the living models in which, after germline transformation with reporter protein-coding genes, specific fluorescent cell populations can be followed at single-cell resolution. The genetically modified embryos, larvae and adults, resulting from the transformation, are individuals in which time lapse analysis, digital imaging quantification, FACS sorting and next-generation sequencing can be performed in specific times and tissues. These multifaceted genetic and cellular approaches have permitted to dissect molecular interactions at the subcellular, intercellular, tissue and whole-animal level, thus allowing integration of cellular and developmental genetics with molecular imaging in the resulting frame of modern biology. In this review, we describe a new step in the zebrafish road to system biology, based on the use of transgenic biosensor animals expressing fluorescent proteins under the control of signaling pathway-responsive cis-elements. In particular, we provide here the rationale and details of this powerful tool, trying to focus on its huge potentialities in basic and applied research, while also discussing limits and potential technological evolutions of this approach.

  17. Host insulin stimulates Echinococcus multilocularis insulin signalling pathways and larval development

    PubMed Central

    2014-01-01

    Background The metacestode of the tapeworm Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a lethal zoonosis. Infections are initiated through establishment of parasite larvae within the intermediate host’s liver, where high concentrations of insulin are present, followed by tumour-like growth of the metacestode in host organs. The molecular mechanisms determining the organ tropism of E. multilocularis or the influences of host hormones on parasite proliferation are poorly understood. Results Using in vitro cultivation systems for parasite larvae we show that physiological concentrations (10 nM) of human insulin significantly stimulate the formation of metacestode larvae from parasite stem cells and promote asexual growth of the metacestode. Addition of human insulin to parasite larvae led to increased glucose uptake and enhanced phosphorylation of Echinococcus insulin signalling components, including an insulin receptor-like kinase, EmIR1, for which we demonstrate predominant expression in the parasite’s glycogen storage cells. We also characterized a second insulin receptor family member, EmIR2, and demonstrated interaction of its ligand binding domain with human insulin in the yeast two-hybrid system. Addition of an insulin receptor inhibitor resulted in metacestode killing, prevented metacestode development from parasite stem cells, and impaired the activation of insulin signalling pathways through host insulin. Conclusions Our data indicate that host insulin acts as a stimulant for parasite development within the host liver and that E. multilocularis senses the host hormone through an evolutionarily conserved insulin signalling pathway. Hormonal host-parasite cross-communication, facilitated by the relatively close phylogenetic relationship between E. multilocularis and its mammalian hosts, thus appears to be important in the pathology of alveolar echinococcosis. This contributes to a closer understanding of organ tropism and

  18. CXC Chemokine Receptor 3 Alternative Splice Variants Selectively Activate Different Signaling Pathways.

    PubMed

    Berchiche, Yamina A; Sakmar, Thomas P

    2016-10-01

    The G protein-coupled receptor (GPCR) C-X-C chemokine receptor 3 (CXCR3) is a potential drug target that mediates signaling involved in cancer metastasis and inflammatory diseases. The CXCR3 primary transcript has three potential alternative splice variants and cell-type specific expression results in receptor variants that are believed to have different functional characteristics. However, the molecular pharmacology of ligand binding to CXCR3 alternative splice variants and their downstream signaling pathways remain poorly explored. To better understand the role of the functional consequences of alternative splicing of CXCR3, we measured signaling in response to four different chemokine ligands (CXCL4, CXCL9, CXCL10, and CXCL11) with agonist activity at CXCR3. Both CXCL10 and CXCL11 activated splice variant CXCR3A. Whereas CXCL10 displayed full agonistic activity for Gαi activation and extracellular signal regulated kinase (ERK) 1/2 phosphorylation and partial agonist activity for β-arrestin recruitment, CXCL9 triggered only modest ERK1/2 phosphorylation. CXCL11 induced CXCR3B-mediated β-arrestin recruitment and little ERK phosphorylation. CXCR3Alt signaling was limited to modest ligand-induced receptor internalization and ERK1/2 phosphorylation in response to chemokines CXCL11, CXCL10, and CXCL9. These results show that CXCR3 splice variants activate different signaling pathways and that CXCR3 variant function is not redundant, suggesting a mechanism for tissue specific biased agonism. Our data show an additional layer of complexity for chemokine receptor signaling that might be exploited to target specific CXCR3 splice variants. PMID:27512119

  19. Signal Transduction Pathways of EMT Induced by TGF-β, SHH, and WNT and Their Crosstalks

    PubMed Central

    Zhang, Jingyu; Tian, Xiao-Jun; Xing, Jianhua

    2016-01-01

    Epithelial-to-mesenchymal transition (EMT) is a key step in development, wound healing, and cancer development. It involves cooperation of signaling pathways, such as transformation growth factor-β (TGF-β), Sonic Hedgehog (SHH), and WNT pathways. These signaling pathways crosstalk to each other and converge to key transcription factors (e.g., SNAIL1) to initialize and maintain the process of EMT. The functional roles of multi-signaling pathway crosstalks in EMT are sophisticated and, thus, remain to be explored. In this review, we focused on three major signal transduction pathways that promote or regulate EMT in carcinoma. We discussed the network structures, and provided a brief overview of the current therapy strategies and drug development targeted to these three signal transduction pathways. Finally, we highlighted systems biology approaches that can accelerate the process of deconstructing complex networks and drug discovery. PMID:27043642

  20. SAMP8 mice have altered hippocampal gene expression in long term potentiation, phosphatidylinositol signaling, and endocytosis pathways.

    PubMed

    Armbrecht, Harvey J; Siddiqui, Akbar M; Green, Michael; Farr, Susan A; Kumar, Vijaya B; Banks, William A; Patrick, Ping; Shah, Gul N; Morley, John E

    2014-01-01

    The senescence-accelerated mouse (SAMP8) strain exhibits decreased learning and memory and increased amyloid beta (Aβ) peptide accumulation at 12 months. To detect differences in gene expression in SAMP8 mice, we used a control mouse that was a 50% cross between SAMP8 and CD-1 mice and which showed no memory deficits (50% SAMs). We then compared gene expression in the hippocampus of 4- and 12-month-old SAMP8 and control mice using Affymetrix gene arrays. At 12 months, but not at 4 months, pathway analysis revealed significant differences in the long term potentiation (6 genes), phosphatidylinositol signaling (6 genes), and endocytosis (10 genes) pathways. The changes in long term potentiation included mitogen-activated protein kinase (MAPK) signaling (N-ras, cAMP responsive element binding protein [CREB], protein phosphatase inhibitor 1) and Ca-dependent signaling (inositol triphosphate [ITP] receptors 1 and 2 and phospholipase C). Changes in phosphatidylinositol signaling genes suggested altered signaling through phosphatidylinositol-3-kinase, and Western blotting revealed phosphorylation changes in serine/threonine protein kinase AKT and 70S6K. Changes in the endocytosis pathway involved genes related to clathrin-mediated endocytosis (dynamin and clathrin). Endocytosis is required for receptor recycling, is involved in Aβ metabolism, and is regulated by phosphatidylinositol signaling. In summary, these studies demonstrate altered gene expression in 3 SAMP8 hippocampal pathways associated with memory formation and consolidation. These pathways might provide new therapeutic targets in addition to targeting Aβ metabolism itself.

  1. How the Wnt signaling pathway protects from neurodegeneration: the mitochondrial scenario

    PubMed Central

    Arrázola, Macarena S.; Silva-Alvarez, Carmen; Inestrosa, Nibaldo C.

    2015-01-01

    Alzheimer’s disease (AD) is the most common neurodegenerative disorder and is characterized by progressive memory loss and cognitive decline. One of the hallmarks of AD is the overproduction of amyloid-beta aggregates that range from the toxic soluble oligomer (Aβo) form to extracellular accumulations in the brain. Growing evidence indicates that mitochondrial dysfunction is a common feature of neurodegenerative diseases and is observed at an early stage in the pathogenesis of AD. Reports indicate that mitochondrial structure and function are affected by Aβo and can trigger neuronal cell death. Mitochondria are highly dynamic organelles, and the balance between their fusion and fission processes is essential for neuronal function. Interestingly, in AD, the process known as “mitochondrial dynamics” is also impaired by Aβo. On the other hand, the activation of the Wnt signaling pathway has an essential role in synaptic maintenance and neuronal functions, and its deregulation has also been implicated in AD. We have demonstrated that canonical Wnt signaling, through the Wnt3a ligand, prevents the permeabilization of mitochondrial membranes through the inhibition of the mitochondrial permeability transition pore (mPTP), induced by Aβo. In addition, we showed that non-canonical Wnt signaling, through the Wnt5a ligand, protects mitochondria from fission-fusion alterations in AD. These results suggest new approaches by which different Wnt signaling pathways protect neurons in AD, and support the idea that mitochondria have become potential therapeutic targets for the treatment of neurodegenerative disorders. Here we discuss the neuroprotective role of the canonical and non-canonical Wnt signaling pathways in AD and their differential modulation of mitochondrial processes, associated with mitochondrial dysfunction and neurodegeneration. PMID:25999816

  2. How the Wnt signaling pathway protects from neurodegeneration: the mitochondrial scenario.

    PubMed

    Arrázola, Macarena S; Silva-Alvarez, Carmen; Inestrosa, Nibaldo C

    2015-01-01

    Alzheimer's disease (AD) is the most common neurodegenerative disorder and is characterized by progressive memory loss and cognitive decline. One of the hallmarks of AD is the overproduction of amyloid-beta aggregates that range from the toxic soluble oligomer (Aβo) form to extracellular accumulations in the brain. Growing evidence indicates that mitochondrial dysfunction is a common feature of neurodegenerative diseases and is observed at an early stage in the pathogenesis of AD. Reports indicate that mitochondrial structure and function are affected by Aβo and can trigger neuronal cell death. Mitochondria are highly dynamic organelles, and the balance between their fusion and fission processes is essential for neuronal function. Interestingly, in AD, the process known as "mitochondrial dynamics" is also impaired by Aβo. On the other hand, the activation of the Wnt signaling pathway has an essential role in synaptic maintenance and neuronal functions, and its deregulation has also been implicated in AD. We have demonstrated that canonical Wnt signaling, through the Wnt3a ligand, prevents the permeabilization of mitochondrial membranes through the inhibition of the mitochondrial permeability transition pore (mPTP), induced by Aβo. In addition, we showed that non-canonical Wnt signaling, through the Wnt5a ligand, protects mitochondria from fission-fusion alterations in AD. These results suggest new approaches by which different Wnt signaling pathways protect neurons in AD, and support the idea that mitochondria have become potential therapeutic targets for the treatment of neurodegenerative disorders. Here we discuss the neuroprotective role of the canonical and non-canonical Wnt signaling pathways in AD and their differential modulation of mitochondrial processes, associated with mitochondrial dysfunction and neurodegeneration.

  3. How the Wnt signaling pathway protects from neurodegeneration: the mitochondrial scenario.

    PubMed

    Arrázola, Macarena S; Silva-Alvarez, Carmen; Inestrosa, Nibaldo C

    2015-01-01

    Alzheimer's disease (AD) is the most common neurodegenerative disorder and is characterized by progressive memory loss and cognitive decline. One of the hallmarks of AD is the overproduction of amyloid-beta aggregates that range from the toxic soluble oligomer (Aβo) form to extracellular accumulations in the brain. Growing evidence indicates that mitochondrial dysfunction is a common feature of neurodegenerative diseases and is observed at an early stage in the pathogenesis of AD. Reports indicate that mitochondrial structure and function are affected by Aβo and can trigger neuronal cell death. Mitochondria are highly dynamic organelles, and the balance between their fusion and fission processes is essential for neuronal function. Interestingly, in AD, the process known as "mitochondrial dynamics" is also impaired by Aβo. On the other hand, the activation of the Wnt signaling pathway has an essential role in synaptic maintenance and neuronal functions, and its deregulation has also been implicated in AD. We have demonstrated that canonical Wnt signaling, through the Wnt3a ligand, prevents the permeabilization of mitochondrial membranes through the inhibition of the mitochondrial permeability transition pore (mPTP), induced by Aβo. In addition, we showed that non-canonical Wnt signaling, through the Wnt5a ligand, protects mitochondria from fission-fusion alterations in AD. These results suggest new approaches by which different Wnt signaling pathways protect neurons in AD, and support the idea that mitochondria have become potential therapeutic targets for the treatment of neurodegenerative disorders. Here we discuss the neuroprotective role of the canonical and non-canonical Wnt signaling pathways in AD and their differential modulation of mitochondrial processes, associated with mitochondrial dysfunction and neurodegeneration. PMID:25999816

  4. IFT80 is essential for chondrocyte differentiation by regulating hedgehog and Wnt signaling pathways

    PubMed Central

    Wang, Changdong; Yuan, Xue; Yang, Shuying

    2013-01-01

    Partial mutation of intraflagellar transport 80 (IFT80) in humans causes Jeune asphyxiating thoracic dystrophy (JATD) and short-rib polydactyly (SRP) syndrome type III. These diseases are autosomal recessive chondrodysplasias that share clinical similarities, including shortened long bones and constricted thoracic cage. However, the role and mechanism of IFT80 in the regulation of chondrocyte differentiation and function remain largely unknown. We hypothesize that IFT80 is required for the formation and function of cilia and plays a critical role in chondrogenic differentiation by regulating Hedgehog (Hh) and Wingless (Wnt) signaling pathways. To test this hypothesis, we first analyzed the IFT80 expression pattern and found that IFT80 was predominantly expressed in growth plate chondrocytes and during chondrogenic differentiation. Silencing IFT80 impaired cilia formation and chondrogenic differentiation in mouse bone marrow derived stromal cells (BMSCs), and decreased the expression of chondrocyte marker genes—collagen II and aggrecan. Additionally, silencing IFT80 down-regulated Hh signaling activity whereas up-regulated Wnt signaling activity. The overexpression of Gli2 in IFT80-silenced cells promoted chondrogenesis and recovered the chondrogenic deficiency from IFT80 silencing. Overall, our results demonstrate that IFT80 is essential for chondrocyte differentiation by regulating the Hh and Wnt signaling pathways. PMID:23333501

  5. Curcumol suppresses RANKL-induced osteoclast formation by attenuating the JNK signaling pathway

    SciTech Connect

    Yu, Mingxiang; Chen, Xianying; Lv, Chaoyang; Yi, Xilu; Zhang, Yao; Xue, Mengjuan; He, Shunmei; Zhu, Guoying; Wang, Hongfu

    2014-05-02

    Highlights: • Curcumol suppresses osteoclasts differentiation in vitro. • Curcumol impairs JNK/AP-1 signaling pathway. • Curcumol may be used for treating osteoclast related diseases. - Abstract: Osteoclasts, derived from hemopoietic progenitors of the monocyte/macrophage lineage, have a unique role in bone resorption, and are considered a potential therapeutic target in the treatment of such pathologic bone diseases as osteoporosis, rheumatoid arthritis, and periodontitis. In the present study, we demonstrate that curcumol, one of the major components of the essential oil of Rhizoma Curcumae, exhibits an inhibitory effect on receptor activator of nuclear factor kappaB ligand (RANKL)-induced osteoclast differentiation with both bone marrow-derived macrophages and RAW264.7 cells in a dose-dependent manner. In addition, RANKL-induced mRNA expression of osteoclast-specific genes, such as tartrate-resistant acid phosphatase, calcitonin receptor, and cathepsin K, is prominently reduced in the presence of curcumol. Furthermore, the molecular mechanism of action was investigated, and curcumol inhibited osteoclastogenesis by specifically impairing RANKL-induced c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) signaling, which was further identified in rescue studies by means of anisomycin, a JNK signaling-specific activator. Taken together, these findings suggest that curcumol suppresses RANKL-induced osteoclast differentiation through the JNK/AP-1 signaling pathway, and may be useful as a therapeutic treatment for bone resorption-associated diseases.

  6. 29 CFR 1926.1421 - Signals-voice signals-additional requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... operations, the operator, signal person and lift director (if there is one), must contact each other and....), direction; distance and/or speed; function, stop command. (c) The operator, signal person and lift...

  7. Wnt/β-Catenin Signaling Pathway in Skin Carcinogenesis and Therapy

    PubMed Central

    Li, Jing; Ji, Ling; Chen, Jieping; Zhang, Wengeng; Ye, Zhijia

    2015-01-01

    Cooperating with other signaling pathways, Wnt signaling controls cell proliferation, morphology, motility, and embryonic development destination and maintains the homeostasis of tissues including skin, blood, intestine, and brain by regulating somatic stem cells and their niches throughout adult life. Abnormal regulation of Wnt pathways leads to neoplastic proliferation in these tissues. Recent research shows that Wnt signaling is also associated with the regulation of cancer stem cells (CSCs) through a similar mechanism to that observed in normal adult stem cells. Thus, the Wnt/β-catenin signaling pathway has been intensively studied and characterized. For this review, we will focus on the regulation of the Wnt/β-catenin signaling pathway in skin cancer. With the important role in stemness and skin CSC proliferation, the Wnt/β-catenin signaling pathway and its elements have the potential to be targets for skin cancer therapy. PMID:26078973

  8. Signal transduction pathways in FSH regulation of rat Sertoli cell proliferation.

    PubMed

    Riera, María F; Regueira, Mariana; Galardo, María N; Pellizzari, Eliana H; Meroni, Silvina B; Cigorraga, Selva B

    2012-04-15

    The final number of Sertoli cells reached during the proliferative periods determines sperm production capacity in adulthood. It is well known that FSH is the major Sertoli cell mitogen; however, little is known about the signal transduction pathways that regulate the proliferation of Sertoli cells. The hypothesis of this investigation was that FSH regulates proliferation through a PI3K/Akt/mTORC1 pathway, and additionally, AMPK-dependent mechanisms counteract FSH proliferative effects. The present study was performed in 8-day-old rat Sertoli cell cultures. The results presented herein show that FSH, in addition to increasing p-Akt, p-mTOR, and p-p70S6K levels, increases p-PRAS40 levels, probably contributing to improving mTORC1 signaling. Furthermore, the decrease in FSH-stimulated p-Akt, p-mTOR, p-p70S6K, and p-PRAS40 levels in the presence of wortmannin emphasizes the participation of PI3K in FSH signaling. Additionally, the inhibition of FSH-stimulated Sertoli cell proliferation by the effect of wortmannin and rapamycin point to the relevance of the PI3K/Akt/mTORC1 signaling pathway in the mitotic activity of FSH. On the other hand, by activating AMPK, several interesting observations were made. Activation of AMPK produced an increase in Raptor phosphorylation, a decrease in p70S6K phosphorylation, and a decrease in FSH-stimulated Sertoli cell proliferation. The decrease in FSH-stimulated cell proliferation was accompanied by an increased expression of the cyclin-dependent kinase inhibitors (CDKIs) p19INK4d, p21Cip1, and p27Kip1. In summary, it is concluded that FSH regulates Sertoli cell proliferation with the participation of a PI3K/Akt/mTORC1 pathway and that AMPK activation may be involved in the detention of proliferation by, at least in part, a decrease in mTORC1 signaling and an increase in CDKI expression.

  9. The role of the extracellular signal-regulated kinase signaling pathway in mood modulation.

    PubMed

    Einat, Haim; Yuan, Peixiong; Gould, Todd D; Li, Jianling; Du, JianHua; Zhang, Lei; Manji, Husseini K; Chen, Guang

    2003-08-13

    The neurobiological underpinnings of mood modulation, molecular pathophysiology of manic-depressive illness, and therapeutic mechanism of mood stabilizers are largely unknown. The extracellular signal-regulated kinase (ERK) pathway is activated by neurotrophins and other neuroactive chemicals to produce their effects on neuronal differentiation, survival, regeneration, and structural and functional plasticity. We found that lithium and valproate, commonly used mood stabilizers for the treatment of manic-depressive illness, stimulated the ERK pathway in the rat hippocampus and frontal cortex. Both drugs increased the levels of activated phospho-ERK44/42, activated phospho-ribosomal protein S6 kinase-1 (RSK1) (a substrate of ERK), phospho-CREB (cAMP response element-binding protein) and phospho-B cell lymphoma protein-2 antagonist of cell death (substrates of RSK), and BDNF. Inhibiting the ERK pathway with the blood-brain barrier-penetrating mitogen-activated protein kinase (MAP kinase)/ERK kinase (MEK) kinase inhibitor SL327, but not with the nonblood-brain barrier-penetrating MEK inhibitor U0126, decreased immobility time and increased swimming time of rats in the forced-swim test. SL327, but not U0126, also increased locomotion time and distance traveled in a large open field. The behavioral changes in the open field were prevented with chronic lithium pretreatment. SL327-induced behavioral changes are qualitatively similar to the changes induced by amphetamine, a compound that induces relapse in remitted manic patients and mood elevation in normal subjects. These data suggest that the ERK pathway may mediate the antimanic effects of mood stabilizers.

  10. Resveratrol augments the canonical Wnt signaling pathway in promoting osteoblastic differentiation of multipotent mesenchymal cells

    SciTech Connect

    Zhou, Haibin; Shang, Linshan; Li, Xi; Zhang, Xiyu; Gao, Guimin; Guo, Chenhong; Chen, Bingxi; Liu, Qiji; Gong, Yaoqin; Shao, Changshun

    2009-10-15

    Resveratrol has been shown to possess many health-benefiting effects, including the promotion of bone formation. In this report we investigated the mechanism by which resveratrol promotes osteoblastic differentiation from pluripotent mesenchymal cells. Since Wnt signaling is well documented to induce osteoblastogenesis and bone formation, we characterized the factors involved in Wnt signaling in response to resveratrol treatment. Resveratrol treatment of mesenchymal cells led to an increase in stabilization and nuclear accumulation of {beta}-catenin dose-dependently and time-dependently. As a consequence of the increased nuclear accumulation of {beta}-catenin, the ability to activate transcription of {beta}-catenin-TCF/LEF target genes that are required for osteoblastic differentiation was upregulated. However, resveratrol did not affect the initial step of the Wnt signaling pathway, as resveratrol was as effective in upregulating the activity of {beta}-catenin in cells in which Lrp5 was knocked down as in control cells. In addition, while conditioned medium enriched in Wnt signaling antagonist Dkk1 was able to inhibit Wnt3a-induced {beta}-catenin upregulation, this inhibitory effect can be abolished in resveratrol-treated cells. Furthermore, we showed that the level of glycogen synthase kinase 3{beta} (GSK-3{beta}), which phosphorylates and destabilizes {beta}-catenin, was reduced in response to resveratrol treatment. The phosphorylation of GSK-3{beta} requires extracellular signal-regulated kinase (ERK)1/2. Together, our data indicate that resveratrol promotes osteoblastogenesis and bone formation by augmenting Wnt signaling.

  11. Signaling pathways in spermatogonial stem cells and their disruption by toxicants.

    PubMed

    Lucas, Benjamin; Fields, Christopher; Hofmann, Marie-Claude

    2009-03-01

    Spermatogenesis is a complex biological process that is particularly sensitive to environmental insults such as chemicals and physical stressors. Exposure to specific chemicals has been shown to inhibit fertility through a negative impact on germ cell proliferation and differentiation that can lower sperm count. In addition, toxicants might produce DNA damages that could have negative consequences on the development of the offspring. This review describes spermatogonial stem cell development in the testis, signaling pathways that are crucial for self-renewal, and possible target molecules for environmental toxicants such as phthalate esters and nanoparticles.

  12. Hippocampus ghrelin signaling mediates appetite through lateral hypothalamic orexin pathways

    PubMed Central

    Hsu, Ted M; Hahn, Joel D; Konanur, Vaibhav R; Noble, Emily E; Suarez, Andrea N; Thai, Jessica; Nakamoto, Emily M; Kanoski, Scott E

    2015-01-01

    Feeding behavior rarely occurs in direct response to metabolic deficit, yet the overwhelming majority of research on the biology of food intake control has focused on basic metabolic and homeostatic neurobiological substrates. Most animals, including humans, have habitual feeding patterns in which meals are consumed based on learned and/or environmental factors. Here we illuminate a novel neural system regulating higher-order aspects of feeding through which the gut-derived hormone ghrelin communicates with ventral hippocampus (vHP) neurons to stimulate meal-entrained conditioned appetite. Additional results show that the lateral hypothalamus (LHA) is a critical downstream substrate for vHP ghrelin-mediated hyperphagia and that vHP ghrelin activated neurons communicate directly with neurons in the LHA that express the neuropeptide, orexin. Furthermore, activation of downstream orexin-1 receptors is required for vHP ghrelin-mediated hyperphagia. These findings reveal novel neurobiological circuitry regulating appetite through which ghrelin signaling in hippocampal neurons engages LHA orexin signaling. DOI: http://dx.doi.org/10.7554/eLife.11190.001 PMID:26745307

  13. Characterization of signalling pathways by reverse phase protein arrays.

    PubMed

    Malinowsky, Katharina; Wolff, Claudia; Schott, Christina; Becker, Karl-Friedrich

    2013-01-01

    Reverse phase protein array (RPPA) is a very suitable technique to analyze large numbers of proteins in small samples like for example tumor biopsies. Beside their small size another major hindrance for the analysis of proteins from biopsies is the extraction of proteins from formalin-fixed and paraffin-embedded (FFPE) tissues. Here we describe a protocol, allowing quantitative extraction of large numbers of proteins from FFPE tissues and their subsequent analysis by RPPA. To elucidate the role of epidermal growth factor receptor (EGFR) signalling in ovarian cancer, we analyzed 23 primary tumors and corresponding metastases for the expression of 25 proteins involved in EGFR signalling with special emphasis on epithelial-mesenchymal transition (EMT). We found a significant correlation of Snail with EGFR((Tyr1086)) and p38 MAPK((Thr180/Tyr182)) in primary ovarian carcinoma and with EGFR((Tyr1086)) in their corresponding metastases. Additionally, we showed that high expression levels of the E-cadherin repressor Snail in primary tumors combined with high expression levels of the pp38 MAPK((Thr180/Tyr182)) in metastasis lead to an increased risk for death in ovarian carcinoma patients.

  14. Hippocampus ghrelin signaling mediates appetite through lateral hypothalamic orexin pathways.

    PubMed

    Hsu, Ted M; Hahn, Joel D; Konanur, Vaibhav R; Noble, Emily E; Suarez, Andrea N; Thai, Jessica; Nakamoto, Emily M; Kanoski, Scott E

    2015-12-15

    Feeding behavior rarely occurs in direct response to metabolic deficit, yet the overwhelming majority of research on the biology of food intake control has focused on basic metabolic and homeostatic neurobiological substrates. Most animals, including humans, have habitual feeding patterns in which meals are consumed based on learned and/or environmental factors. Here we illuminate a novel neural system regulating higher-order aspects of feeding through which the gut-derived hormone ghrelin communicates with ventral hippocampus (vHP) neurons to stimulate meal-entrained conditioned appetite. Additional results show that the lateral hypothalamus (LHA) is a critical downstream substrate for vHP ghrelin-mediated hyperphagia and that vHP ghrelin activated neurons communicate directly with neurons in the LHA that express the neuropeptide, orexin. Furthermore, activation of downstream orexin-1 receptors is required for vHP ghrelin-mediated hyperphagia. These findings reveal novel neurobiological circuitry regulating appetite through which ghrelin signaling in hippocampal neurons engages LHA orexin signaling.

  15. Pathway connectivity and signaling coordination in the yeast stress-activated signaling network

    PubMed Central

    Chasman, Deborah; Ho, Yi-Hsuan; Berry, David B; Nemec, Corey M; MacGilvray, Matthew E; Hose, James; Merrill, Anna E; Lee, M Violet; Will, Jessica L; Coon, Joshua J; Ansari, Aseem Z; Craven, Mark; Gasch, Audrey P

    2014-01-01

    Stressed cells coordinate a multi-faceted response spanning many levels of physiology. Yet knowledge of the complete stress-activated regulatory network as well as design principles for signal integration remains incomplete. We developed an experimental and computational approach to integrate available protein interaction data with gene fitness contributions, mutant transcriptome profiles, and phospho-proteome changes in cells responding to salt stress, to infer the salt-responsive signaling network in yeast. The inferred subnetwork presented many novel predictions by implicating new regulators, uncovering unrecognized crosstalk between known pathways, and pointing to previously unknown ‘hubs’ of signal integration. We exploited these predictions to show that Cdc14 phosphatase is a central hub in the network and that modification of RNA polymerase II coordinates induction of stress-defense genes with reduction of growth-related transcripts. We find that the orthologous human network is enriched for cancer-causing genes, underscoring the importance of the subnetwork's predictions in understanding stress biology. PMID:25411400

  16. Wnt and the Wnt signaling pathway in bone development and disease

    PubMed Central

    Wang, Yiping; Li, Yi-Ping; Paulson, Christie; Shao, Jian-Zhong; Zhang, Xiaoling; Wu, Mengrui; Chen, Wei

    2014-01-01

    Wnt signaling affects both bone modeling, which occurs during development, and bone remodeling, which is a lifelong process involving tissue renewal. Wnt signals are especially known to affect the differentiation of osteoblasts. In this review, we summarize recent advances in understanding the mechanisms of Wnt signaling, which is divided into two major branches: the canonical pathway and the noncanonical pathway. The canonical pathway is also called the Wnt/β-catenin pathway. There are two major noncanonical pathways: the Wnt-planar cell polarity pathway (Wnt-PCP pathway) and the Wnt-calcium pathway (Wnt-Ca2+ pathway). This review also discusses how Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists affect both the bone modeling and bone remodeling processes. We also review the role of Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists in bone as demonstrated in mouse models. Disrupted Wnt signaling is linked to several bone diseases, including osteoporosis, van Buchem disease, and sclerosteosis. Studying the mechanism of Wnt signaling and its interactions with other signaling pathways in bone will provide potential therapeutic targets to treat these bone diseases. PMID:24389191

  17. Targeting Apoptosis and Multiple Signaling Pathways with Icariside II in Cancer Cells

    PubMed Central

    Khan, Muhammad; Maryam, Amara; Qazi, Javed Iqbal; Ma, Tonghui

    2015-01-01

    Cancer is the second leading cause of deaths worldwide. Despite concerted efforts to improve the current therapies, the prognosis of cancer remains dismal. Highly selective or specific blocking of only one of the signaling pathways has been associated with limited or sporadic responses. Using targeted agents to inhibit multiple signaling pathways has emerged as a new paradigm for anticancer treatment. Icariside II, a flavonol glycoside, is one of the major components of Traditional Chinese Medicine Herba epimedii and possesses multiple biological and pharmacological properties including anti-inflammatory, anti-osteoporosis, anti-oxidant, anti-aging, and anticancer activities. Recently, the anticancer activity of Icariside II has been extensively investigated. Here, in this review, our aim is to give our perspective on the current status of Icariside II, and discuss its natural sources, anticancer activity, molecular targets and the mechanisms of action with specific emphasis on apoptosis pathways which may help the further design and conduct of preclinical and clinical trials. Icariside II has been found to induce apoptosis in various human cancer cell lines of different origin by targeting multiple signaling pathways including STAT3, PI3K/AKT, MAPK/ERK, COX-2/PGE2 and β-Catenin which are frequently deregulated in cancers, suggesting that this collective activity rather than just a single effect may play an important role in developing Icariside II into a potential lead compound for anticancer therapy. This review suggests that Icariside II provides a novel opportunity for treatment of cancers, but additional investigations and clinical trials are still required to fully understand the mechanism of therapeutic effects to further validate it in anti-tumor therapy. PMID:26221076

  18. New signaling pathways govern the host response to C. albicans infection in various niches.

    PubMed

    Liu, Yaoping; Shetty, Amol C; Schwartz, Jennifer A; Bradford, L Latey; Xu, Wenjie; Phan, Qyunh T; Kumari, Priti; Mahurkar, Anup; Mitchell, Aaron P; Ravel, Jacques; Fraser, Claire M; Filler, Scott G; Bruno, Vincent M

    2015-05-01

    Candida albicans, the major invasive fungal pathogen of humans, can cause both debilitating mucosal infections and fatal invasive infections. Understanding the complex nature of the host-pathogen interaction in each of these contexts is essential to developing desperately needed therapies to treat fungal infections. RNA-seq enables a systems-level understanding of infection by facilitating comprehensive analysis of transcriptomes from multiple species (e.g., host and pathogen) simultaneously. We used RNA-seq to characterize the transcriptomes of both C. albicans and human endothelial cells or oral epithelial cells during in vitro infection. Network analysis of the differentially expressed genes identified the activation of several signaling pathways that have not previously been associated with the host response to fungal pathogens. Using an siRNA knockdown approach, we demonstrate that two of these pathways-platelet-derived growth factor BB (PDGF BB) and neural precursor-cell-expressed developmentally down-regulated protein 9 (NEDD9)-govern the host-pathogen interaction by regulating the uptake of C. albicans by host cells. Using RNA-seq analysis of a mouse model of hematogenously disseminated candidiasis (HDC) and episodes of vulvovaginal candidiasis (VVC) in humans, we found evidence that many of the same signaling pathways are activated during mucosal (VVC) and/or disseminated (HDC) infections in vivo. Our analyses have uncovered several signaling pathways at the interface between C. albicans and host cells in various contexts of infection, and suggest that PDGF BB and NEDD9 play important roles in this interaction. In addition, these data provide a valuable community resource for better understanding host-fungal pathogen interactions.

  19. Wrangling Phosphoproteomic Data to Elucidate Cancer Signaling Pathways

    PubMed Central

    Grimes, Mark L.; Lee, Wan-Jui; van der Maaten, Laurens; Shannon, Paul

    2013-01-01

    The interpretation of biological data sets is essential for generating hypotheses that guide research, yet modern methods of global analysis challenge our ability to discern meaningful patterns and then convey results in a way that can be easily appreciated. Proteomic data is especially challenging because mass spectrometry detectors often miss peptides in complex samples, resulting in sparsely populated data sets. Using the R programming language and techniques from the field of pattern recognition, we have devised methods to resolve and evaluate clusters of proteins related by their pattern of expression in different samples in proteomic data sets. We examined tyrosine phosphoproteomic data from lung cancer samples. We calculated dissimilarities between the proteins based on Pearson or Spearman correlations and on Euclidean distances, whilst dealing with large amounts of missing data. The dissimilarities were then used as feature vectors in clustering and visualization algorithms. The quality of the clusterings and visualizations were evaluated internally based on the primary data and externally based on gene ontology and protein interaction networks. The results show that t-distributed stochastic neighbor embedding (t-SNE) followed by minimum spanning tree methods groups sparse proteomic data into meaningful clusters more effectively than other methods such as k-means and classical multidimensional scaling. Furthermore, our results show that using a combination of Spearman correlation and Euclidean distance as a dissimilarity representation increases the resolution of clusters. Our analyses show that many clusters contain one or more tyrosine kinases and include known effectors as well as proteins with no known interactions. Visualizing these clusters as networks elucidated previously unknown tyrosine kinase signal transduction pathways that drive cancer. Our approach can be applied to other data types, and can be easily adopted because open source software

  20. BLM promotes the activation of Fanconi Anemia signaling pathway

    PubMed Central

    Panneerselvam, Jayabal; Wang, Hong; Zhang, Jun; Che, Raymond; Yu, Herbert; Fei, Peiwen

    2016-01-01

    Mutations in the human RecQ helicase, BLM, causes Bloom Syndrome, which is a rare autosomal recessive disorder and characterized by genomic instability and an increased risk of cancer. Fanconi Anemia (FA), resulting from mutations in any of the 19 known FA genes and those yet to be known, is also characterized by chromosomal instability and a high incidence of cancer. BLM helicase and FA proteins, therefore, may work in a common tumor-suppressor signaling pathway. To date, it remains largely unclear as to how BLM and FA proteins work concurrently in the maintenance of genome stability. Here we report that BLM is involved in the early activation of FA group D2 protein (FANCD2). We found that FANCD2 activation is substantially delayed and attenuated in crosslinking agent-treated cells harboring deficient Blm compared to similarly treated control cells with sufficient BLM. We also identified that the domain VI of BLM plays an essential role in promoting FANCD2 activation in cells treated with DNA crosslinking agents, especially ultraviolet B. The similar biological effects performed by ΔVI-BLM and inactivated FANCD2 further confirm the relationship between BLM and FANCD2. Mutations within the domain VI of BLM detected in human cancer samples demonstrate the functional importance of this domain, suggesting human tumorigenicity resulting from mtBLM may be at least partly attributed to mitigated FANCD2 activation. Collectively, our data show a previously unknown regulatory liaison in advancing our understanding of how the cancer susceptibility gene products act in concert to maintain genome stability. PMID:27083049

  1. Neuronal Profilin Isoforms Are Addressed by Different Signalling Pathways

    PubMed Central

    Michaelsen-Preusse, Kristin; Dresbach, Thomas; Schoenenberger, Cora-Ann; Korte, Martin; Jockusch, Brigitte M.; Rothkegel, Martin

    2012-01-01

    Profilins are prominent regulators of actin dynamics. While most mammalian cells express only one profilin, two isoforms, PFN1 and PFN2a are present in the CNS. To challenge the hypothesis that the expression of two profilin isoforms is linked to the complex shape of neurons and to the activity-dependent structural plasticity, we analysed how PFN1 and PFN2a respond to changes of neuronal activity. Simultaneous labelling of rodent embryonic neurons with isoform-specific monoclonal antibodies revealed both isoforms in the same synapse. Immunoelectron microscopy on brain sections demonstrated both profilins in synapses of the mature rodent cortex, hippocampus and cerebellum. Both isoforms were significantly more abundant in postsynaptic than in presynaptic structures. Immunofluorescence showed PFN2a associated with gephyrin clusters of the postsynaptic active zone in inhibitory synapses of embryonic neurons. When cultures were stimulated in order to change their activity level, active synapses that were identified by the uptake of synaptotagmin antibodies, displayed significantly higher amounts of both isoforms than non-stimulated controls. Specific inhibition of NMDA receptors by the antagonist APV in cultured rat hippocampal neurons resulted in a decrease of PFN2a but left PFN1 unaffected. Stimulation by the brain derived neurotrophic factor (BDNF), on the other hand, led to a significant increase in both synaptic PFN1 and PFN2a. Analogous results were obtained for neuronal nuclei: both isoforms were localized in the same nucleus, and their levels rose significantly in response to KCl stimulation, whereas BDNF caused here a higher increase in PFN1 than in PFN2a. Our results strongly support the notion of an isoform specific role for profilins as regulators of actin dynamics in different signalling pathways, in excitatory as well as in inhibitory synapses. Furthermore, they suggest a functional role for both profilins in neuronal nuclei. PMID:22470532

  2. Mast Cell Chemotaxis – Chemoattractants and Signaling Pathways

    PubMed Central

    Halova, Ivana; Draberova, Lubica; Draber, Petr

    2012-01-01

    Migration of mast cells is essential for their recruitment within target tissues where they play an important role in innate and adaptive immune responses. These processes rely on the ability of mast cells to recognize appropriate chemotactic stimuli and react to them by a chemotactic response. Another level of intercellular communication is attained by production of chemoattractants by activated mast cells, which results in accumulation of mast cells and other hematopoietic cells at the sites of inflammation. Mast cells express numerous surface receptors for various ligands with properties of potent chemoattractants. They include the stem cell factor (SCF) recognized by c-Kit, antigen, which binds to immunoglobulin E (IgE) anchored to the high affinity IgE receptor (FcεRI), highly cytokinergic (HC) IgE recognized by FcεRI, lipid mediator sphingosine-1-phosphate (S1P), which binds to G protein-coupled receptors (GPCRs). Other large groups of chemoattractants are eicosanoids [prostaglandin E2 and D2, leukotriene (LT) B4, LTD4, and LTC4, and others] and chemokines (CC, CXC, C, and CX3C), which also bind to various GPCRs. Further noteworthy chemoattractants are isoforms of transforming growth factor (TGF) β1–3, which are sensitively recognized by TGF-β serine/threonine type I and II β receptors, adenosine, C1q, C3a, and C5a components of the complement, 5-hydroxytryptamine, neuroendocrine peptide catestatin, tumor necrosis factor-α, and others. Here we discuss the major types of chemoattractants recognized by mast cells, their target receptors, as well as signaling pathways they utilize. We also briefly deal with methods used for studies of mast cell chemotaxis and with ways of how these studies profited from the results obtained in other cellular systems. PMID:22654878

  3. Intracellular Signaling Pathways Involved in Childhood Acute Lymphoblastic Leukemia; Molecular Targets.

    PubMed

    Layton Tovar, Cristian Fabián; Mendieta Zerón, Hugo

    2016-06-01

    Acute lymphoblastic leukemia (ALL) is a malignant disease characterized by an uncontrolled proliferation of immature lymphoid cells. ALL is the most common hematologic malignancy in early childhood, and it reaches peak incidence between the ages of 2 and 3 years. The prognosis of ALL is associated with aberrant gene expression, in addition to the presence of numerical or structural chromosomal alterations, age, race, and immunophenotype. The Relapse rate with regard to pharmacological treatment rises in childhood; thus, the expression of biomarkers associated with the activation of cell signaling pathways is crucial to establish the disease prognosis. Intracellular pathways involved in ALL are diverse, including Janus kinase/Signal transducers and transcription activators (JAK-STAT), Phosphoinositide-3-kinase-protein kinase B (PI3K-AKT), Ras mitogen-activated protein kinase (Ras-MAPK), Glycogen synthase kinase-3β (GSK-3β), Nuclear factor-kappa beta (NF-κB), and Hypoxia-inducible transcription factor 1α (HIF-1α), among others. In this review, we present several therapeutic targets, intracellular pathways, and molecular markers that are being studied extensively at present.

  4. Histone deacetylase 6 represents a novel drug target in the oncogenic Hedgehog signaling pathway.

    PubMed

    Dhanyamraju, Pavan Kumar; Holz, Philipp Simon; Finkernagel, Florian; Fendrich, Volker; Lauth, Matthias

    2015-03-01

    Uncontrolled Hedgehog (Hh) signaling is the cause of several malignancies, including the pediatric cancer medulloblastoma, a neuroectodermal tumor affecting the cerebellum. Despite the development of potent Hh pathway antagonists, medulloblastoma drug resistance is still an unresolved issue that requires the identification of novel drug targets. Following up on our observation that histone deacetylase 6 (HDAC6) expression was increased in Hh-driven medulloblastoma, we found that this enzyme is essential for full Hh pathway activation. Intriguingly, these stimulatory effects of HDAC6 are partly integrated downstream of primary cilia, a known HDAC6-regulated structure. In addition, HDAC6 is also required for the complete repression of basal Hh target gene expression. These contrasting effects are mediated by HDAC6's impact on Gli2 mRNA and GLI3 protein expression. As a result of this complex interaction with Hh signaling, global transcriptome analysis revealed that HDAC6 regulates only a subset of Smoothened- and Gli-driven genes, including all well-established Hh targets such as Ptch1 or Gli1. Importantly, medulloblastoma cell survival was severely compromised by HDAC6 inhibition in vitro and pharmacologic HDAC6 blockade strongly reduced tumor growth in an in vivo allograft model. In summary, our data describe an important role for HDAC6 in regulating the mammalian Hh pathway and encourage further studies focusing on HDAC6 as a novel drug target in medulloblastoma. PMID:25552369

  5. Dickkopf-Related Protein 1 Inhibits the WNT Signaling Pathway and Improves Pig Oocyte Maturation

    PubMed Central

    Spate, Lee D.; Brown, Alana N.; Redel, Bethany K.; Whitworth, Kristin M.; Murphy, Clifton N.; Prather, Randall S.

    2014-01-01

    The ability to mature oocytes in vitro provides a tool for creating embryos by parthenogenesis, fertilization, and cloning. Unfortunately the quality of oocytes matured in vitro falls behind that of in vivo matured oocytes. To address this difference, transcriptional profiling by deep sequencing was conducted on pig oocytes that were either matured in vitro or in vivo. Alignment of over 18 million reads identified 1,316 transcripts that were differentially represented. One pathway that was overrepresented in the oocytes matured in vitro was for Wingless-type MMTV integration site (WNT) signaling. In an attempt to inhibit the WNT pathway, Dickkopf-related protein 1 was added to the in vitro maturation medium. Addition of Dickkopf-related protein 1 improved the percentage of oocytes that matured to the metaphase II stage, increased the number of nuclei in the resulting blastocyst stage embryos, and reduced the amount of disheveled segment polarity protein 1 protein in oocytes. It is concluded that transcriptional profiling is a powerful method for detecting differences between in vitro and in vivo matured oocytes, and that the WNT signaling pathway is important for proper oocyte maturation. PMID:24739947

  6. Sitagliptin attenuates cardiomyopathy by modulating the JAK/STAT signaling pathway in experimental diabetic rats.

    PubMed

    Al-Rasheed, Nouf M; Al-Rasheed, Nawal M; Hasan, Iman H; Al-Amin, Maha A; Al-Ajmi, Hanaa N; Mahmoud, Ayman M

    2016-01-01

    Sitagliptin, a dipeptidyl peptidase-4 inhibitor, has been reported to promote cardioprotection in diabetic hearts by limiting hyperglycemia and hyperlipidemia. However, little is known about the involvement of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway modulation in the cardioprotective effects of sitagliptin. The current study aimed to investigate the protective effects of sitagliptin against diabetic cardiomyopathy (DCM), focusing on the modulation of the JAK/STAT pathway. Diabetes was induced by streptozotocin injection, and rats received sitagliptin orally and daily for 90 days. Diabetic rats exhibited hyperglycemia, hyperlipidemia, and a significant increase in heart-to-body weight (HW/BW) ratio. Serum troponin I and creatine kinase MB, cardiac interleukin-6 (IL-6), lipid peroxidation, and nitric oxide levels showed significant increase in diabetic rats. In contrast, both enzymatic and nonenzymatic antioxidant defenses were significantly declined in the heart of diabetic rats. Histopathological study revealed degenerations, increased collagen deposition in the heart of diabetic rats. Sitagliptin alleviated hyperglycemia, hyperlipidemia, HW/BW ratio, histological architecture, oxidative stress, and inflammation, and rejuvenated the antioxidant defenses. In addition, cardiac levels of pJAK2 and pSTAT3 were increased in diabetic rats, an effect which was remarkably decreased after sitagliptin treatment. In conclusion, these results confer an evidence that sitagliptin has great therapeutic potential on DCM through down-regulation of the JAK/STAT signaling pathway. PMID:27418808

  7. Sitagliptin attenuates cardiomyopathy by modulating the JAK/STAT signaling pathway in experimental diabetic rats

    PubMed Central

    Al-Rasheed, Nouf M; Al-Rasheed, Nawal M; Hasan, Iman H; Al-Amin, Maha A; Al-Ajmi, Hanaa N; Mahmoud, Ayman M

    2016-01-01

    Sitagliptin, a dipeptidyl peptidase-4 inhibitor, has been reported to promote cardioprotection in diabetic hearts by limiting hyperglycemia and hyperlipidemia. However, little is known about the involvement of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway modulation in the cardioprotective effects of sitagliptin. The current study aimed to investigate the protective effects of sitagliptin against diabetic cardiomyopathy (DCM), focusing on the modulation of the JAK/STAT pathway. Diabetes was induced by streptozotocin injection, and rats received sitagliptin orally and daily for 90 days. Diabetic rats exhibited hyperglycemia, hyperlipidemia, and a significant increase in heart-to-body weight (HW/BW) ratio. Serum troponin I and creatine kinase MB, cardiac interleukin-6 (IL-6), lipid peroxidation, and nitric oxide levels showed significant increase in diabetic rats. In contrast, both enzymatic and nonenzymatic antioxidant defenses were significantly declined in the heart of diabetic rats. Histopathological study revealed degenerations, increased collagen deposition in the heart of diabetic rats. Sitagliptin alleviated hyperglycemia, hyperlipidemia, HW/BW ratio, histological architecture, oxidative stress, and inflammation, and rejuvenated the antioxidant defenses. In addition, cardiac levels of pJAK2 and pSTAT3 were increased in diabetic rats, an effect which was remarkably decreased after sitagliptin treatment. In conclusion, these results confer an evidence that sitagliptin has great therapeutic potential on DCM through down-regulation of the JAK/STAT signaling pathway. PMID:27418808

  8. The emerging role of the Nrf2–Keap1 signaling pathway in cancer

    PubMed Central

    Jaramillo, Melba C.; Zhang, Donna D.

    2013-01-01

    The Nrf2 (nuclear factor erythroid 2 [NF-E2]-related factor 2 [Nrf2])–Keap1 (Kelch-like erythroid cell-derived protein with CNC homology [ECH]-associated protein 1) signaling pathway is one of the most important cell defense and survival pathways. Nrf2 can protect cells and tissues from a variety of toxicants and carcinogens by increasing the expression of a number of cytoprotective genes. As a result, several Nrf2 activators are currently being tested as chemopreventive compounds in clinical trials. Just as Nrf2 protects normal cells, studies have shown that Nrf2 may also protect cancer cells from chemotherapeutic agents and facilitate cancer progression. Nrf2 is aberrantly accumulated in many types of cancer, and its expression is associated with a poor prognosis in patients. In addition, Nrf2 expression is induced during the course of drug resistance. Collectively, these studies suggest that Nrf2 contributes to both intrinsic and acquired chemoresistance. This discovery has opened up a broad spectrum of research geared toward a better understanding of the role of Nrf2 in cancer. This review provides an overview of (1) the Nrf2–Keap1 signaling pathway, (2) the dual role of Nrf2 in cancer, (3) the molecular basis of Nrf2 activation in cancer cells, and (4) the challenges in the development of Nrf2-based drugs for chemoprevention and chemotherapy. PMID:24142871

  9. Epidermal growth factor promotes proliferation of dermal papilla cells via Notch signaling pathway.

    PubMed

    Zhang, Haihua; Nan, Weixiao; Wang, Shiyong; Zhang, Tietao; Si, Huazhe; Wang, Datao; Yang, Fuhe; Li, Guangyu

    2016-08-01

    The effect of epidermal growth factor (EGF) on the development and growth of hair follicle is controversial. In the present study, 2-20 ng/ml EGF promoted the growth of mink hair follicles in vitro, whereas 200 ng/ml EGF inhibited follicle growth. Further, dermal papilla (DP) cells, a group of mesenchymal cells that govern hair follicle development and growth, were isolated and cultured in vitro. Treatment with or forced expression of EGF accelerated proliferation and induced G1/S transition in DP cells. Moreover, EGF upregulated the expression of DP mesenchymal genes, such as alkaline phosphatase (ALP) and insulin-like growth factor (IGF-1), as well as the Notch pathway molecules including Notch1, Jagged1, Hes1 and Hes5. In addition, inhibition of Notch signaling pathway by DAPT significantly reduced the basal and EGF-enhanced proliferation rate, and also suppressed cell cycle progression. We also show that the expression of several follicle-regulatory genes, such as Survivin and Msx2, were upregulated by EGF, and was inhibited by DAPT. In summary, our study demonstrates that the concentration of EGF is critical for the switch between hair follicle growth and inhibition, and EGF promotes DP cell proliferation via Notch signaling pathway.

  10. Identification and function of an evolutionarily conserved signaling intermediate in Toll pathways (ECSIT) from Crassostrea hongkongensis.

    PubMed

    Qu, Fufa; Xiang, Zhiming; Wang, Fuxuan; Zhang, Yang; Li, Jun; Zhang, Yuehuan; Xiao, Shu; Yu, Ziniu

    2015-11-01

    Evolutionarily conserved signaling intermediate in Toll pathways (ECSIT) is a multifunctional adaptor protein that plays a key role in the regulation of the oxidative phosphorylation (OXPHOS) system, bone morphogenetic protein (BMP) pathway and Toll-like receptor (TLR) signaling pathway in mammals. However, the function of ECSIT homologs in mollusks, the second most diverse group of animals, is not well understood. In this study, we identified an ECSIT homolog in the Hong Kong oyster Crassostrea hongkongensis (ChECSIT) and investigated its biological functions. The full-length cDNA of ChECSIT is 1734 bp and includes an open reading frame (ORF) of 1074 bp that encodes a polypeptide of 451 amino acids. The predicted ChECSIT protein shares similar structural characteristics with other known ECSIT family proteins. Quantitative real-time PCR analysis revealed that ChECSIT mRNA is broadly expressed in all of the examined tissues and at different stages of embryonic development; its transcript level could be significantly up-regulated by challenge with microorganisms (Vibrio alginolyticus, Staphylococcus haemolyticus and Saccharomyces cerevisiae). In addition, ChECSIT was found to be located primarily in the cytoplasm, and its overexpression stimulated the transcriptional activity of an NF-κB reporter gene in HEK293T cells. These findings suggest that ChECSIT might be involved in embryogenesis processes and immune responses in C. hongkongensis.

  11. Novel lipid signaling pathways in Alzheimer's disease pathogenesis.

    PubMed

    Giannopoulos, Phillip F; Joshi, Yash B; Praticò, Domenico

    2014-04-15

    Alzheimer's disease (AD) is the most common cause of dementia in the elderly. With an increasing longevity and the absence of a cure, AD has become not only a major health problem but also a heavy social and economic burden worldwide. In addition to the presence of abundant intra- and extra-cellular neurotoxic amyloid β (Aβ) peptides, which form the amyloid plaques, and intracellular hyperphosphorylated tau protein, the main component of neurofibrillary tangles, consistent evidence indicates that the AD brain is characterized by extensive neuroinflammatory processes. The 5-lipoxygenase (5LO) is a pro-inflammatory enzymatic pathway widely distributed within the central nervous system and is up-regulated in AD. In the last five years our group has been involved in unraveling the neurobiology of this protein and investigating its relationship with cellular and molecular events of functional importance in AD pathogenesis. By using a combination of in vitro and in vivo experimental tools and implementing genetic as well as pharmacological approaches today we know that 5LO is likely an endogenous regulator of Aβ formation via the modulation of the γ-secretase complex, and tau metabolism by modulating its phosphorylation state at specific epitopes via the cyclin-dependent kinase-5 (cdk-5). In addition, 5LO influences synaptic function and integrity and by doing so significantly affects learning and memory in the Tg2576 and 3xTg AD transgenic mouse models. Taken together our data establish this protein as a pleiotropic contributor to the development of the full spectrum of the AD-like phenotype in these mouse models of the disease, making it a viable therapeutic target for the treatment of AD in humans.

  12. Novel lipid signaling pathways in Alzheimer’s disease pathogenesis

    PubMed Central

    Giannopoulos, Phillip F.; Joshi, Yash B.; Praticò, Domenico

    2013-01-01

    Alzheimer’s disease (AD) is the most common cause of dementia in the elderly. With an increasing longevity and the absence of a cure, AD has become not only a major health problem but also a heavy social and economic burden worldwide. In addition to the presence of abundant intra- and extracellular neurotoxic amyloid β (Aβ) peptides, which form the amyloid plaques, and intracellular hyperphosphorylated tau protein, the main component of neurofibrillary tangles, consistent evidence indicate that the AD brain is characterized by extensive neuroinflammatory processes. The 5-Lipoxygenase (5LO) is a pro-inflammatory enzymatic pathway widely distributed within the central nervous system and is up-regulated in AD. In the last five years our group has been involved in unraveling the neurobiology of this protein and investigating its relationship with cellular and molecular events of functional importance in AD pathogenesis. By using a combination of in vitro and in vivo experimental tools and implementing genetic as well as pharmacological approaches today we know that 5LO is likely an endogenous regulator of Aβ formation via the modulation of the γ-secretase complex, and tau metabolism by modulating its phosphorylation state at specific epitopes via the cyclin-dependent kinase-5 (cdk-5). In addition, 5LO influences synaptic function and integrity and by doing so significantly affects learning and memory in the Tg2576 and 3×Tg AD transgenic mouse models. Taken together our data establish this protein as a pleiotropic contributor to the development of the full spectrum of the AD-like phenotype in these mouse models of the disease, making it a viable therapeutic target for the treatment of AD in humans. PMID:24269629

  13. Nitric Oxide Regulation of H-NOX Signaling Pathways in Bacteria.

    PubMed

    Nisbett, Lisa-Marie; Boon, Elizabeth M

    2016-09-01

    Nitric oxide (NO) is a freely diffusible, radical gas that has now been established as an integral signaling molecule in eukaryotes and bacteria. It has been demonstrated that NO signaling is initiated upon ligation to the heme iron of an H-NOX domain in mammals and in some bacteria. Bacterial H-NOX proteins have been found to interact with enzymes that participate in signaling pathways and regulate bacterial processes such as quorum sensing, biofilm formation, and symbiosis. Here, we review the biochemical characterization of these signaling pathways and, where available, describe how ligation of NO to H-NOX specifically regulates the activity of these pathways and their associated bacterial phenotypes.

  14. Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

    SciTech Connect

    Beildeck, Marcy E.; Gelmann, Edward P.; Byers, Stephen W.

    2010-07-01

    Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

  15. Components of the Calcium-Calcineurin Signaling Pathway in Fungal Cells and Their Potential as Antifungal Targets

    PubMed Central

    Liu, Shuyuan; Hou, Yinglong; Liu, Weiguo; Lu, Chunyan; Wang, Weixin

    2015-01-01

    In recent years, the emergence of fungal resistance has become frequent, partly due to the widespread clinical use of fluconazole, which is minimally toxic and effective in the prevention and treatment of Candida albicans infections. The limited selection of antifungal drugs for clinical fungal infection therapy has prompted us to search for new antifungal drug targets. Calcium, which acts as the second messenger in both mammals and fungi, plays a direct role in controlling the expression patterns of its signaling systems and has important roles in cell survival. In addition, calcium and some of the components, mainly calcineurin, in the fungal calcium signaling pathway mediate fungal resistance to antifungal drugs. Therefore, an overview of the components of the fungal calcium-calcineurin signaling network and their potential roles as antifungal targets is urgently needed. The calcium-calcineurin signaling pathway consists of various channels, transporters, pumps, and other proteins or enzymes. Many transcriptional profiles have indicated that mutant strains that lack some of these components are sensitized to fluconazole or other antifungal drugs. In addition, many researchers have identified efficient compounds that exhibit antifungal activity by themselves or in combination with antifungal drugs by targeting some of the components in the fungal calcium-calcineurin signaling pathway. This targeting disrupts Ca2+ homeostasis, which suggests that this pathway contains potential targets for the development of new antifungal drugs. PMID:25636321

  16. Notch signalling pathway as an oncogenic factor involved in cancer development

    PubMed Central

    Piecuch, Adam; Dittfeld, Anna; Mielańczyk, Łukasz; Michalski, Marek; Wyrobiec, Grzegorz; Harabin-Słowińska, Marzena; Kurek, Józef; Wojnicz, Romuald

    2016-01-01

    Notch signalling is an evolutionarily conserved signalling pathway, which plays a significant role in a wide array of cellular processes including proliferation, differentiation, and apoptosis. Nevertheless, it must be noted that Notch is a binary cell fate determinant, and its overexpression has been described as oncogenic in a broad range of human malignancies. This finding led to interest in therapeutically targeting this pathway especially by the use of GSIs, which block the cleavage of Notch at the cell membrane and inhibit release of the transcriptionally active NotchIC subunit. Preclinical cancer models have clearly demonstrated that GSIs suppress the growth of such malignancies as pancreatic, breast, and lung cancer; however, GSI treatment in vivo is associated with side effects, especially those within the gastrointestinal tract. Although intensive studies are associated with the role of γ-secretase in pathological states, it should be pointed out that this complex impacts on proteolytic cleavages of around 55 membrane proteins. Therefore, it is clear that GSIs are highly non-specific and additional drugs must be designed, which will more specifically target components of the Notch signalling.

  17. Notch signalling pathway as an oncogenic factor involved in cancer development.

    PubMed

    Brzozowa-Zasada, Marlena; Piecuch, Adam; Dittfeld, Anna; Mielańczyk, Łukasz; Michalski, Marek; Wyrobiec, Grzegorz; Harabin-Słowińska, Marzena; Kurek, Józef; Wojnicz, Romuald

    2016-01-01

    Notch signalling is an evolutionarily conserved signalling pathway, which plays a significant role in a wide array of cellular processes including proliferation, differentiation, and apoptosis. Nevertheless, it must be noted that Notch is a binary cell fate determinant, and its overexpression has been described as oncogenic in a broad range of human malignancies. This finding led to interest in therapeutically targeting this pathway especially by the use of GSIs, which block the cleavage of Notch at the cell membrane and inhibit release of the transcriptionally active NotchIC subunit. Preclinical cancer models have clearly demonstrated that GSIs suppress the growth of such malignancies as pancreatic, breast, and lung cancer; however, GSI treatment in vivo is associated with side effects, especially those within the gastrointestinal tract. Although intensive studies are associated with the role of γ-secretase in pathological states, it should be pointed out that this complex impacts on proteolytic cleavages of around 55 membrane proteins. Therefore, it is clear that GSIs are highly non-specific and additional drugs must be designed, which will more specifically target components of the Notch signalling. PMID:27688721

  18. Notch signalling pathway as an oncogenic factor involved in cancer development

    PubMed Central

    Piecuch, Adam; Dittfeld, Anna; Mielańczyk, Łukasz; Michalski, Marek; Wyrobiec, Grzegorz; Harabin-Słowińska, Marzena; Kurek, Józef; Wojnicz, Romuald

    2016-01-01

    Notch signalling is an evolutionarily conserved signalling pathway, which plays a significant role in a wide array of cellular processes including proliferation, differentiation, and apoptosis. Nevertheless, it must be noted that Notch is a binary cell fate determinant, and its overexpression has been described as oncogenic in a broad range of human malignancies. This finding led to interest in therapeutically targeting this pathway especially by the use of GSIs, which block the cleavage of Notch at the cell membrane and inhibit release of the transcriptionally active NotchIC subunit. Preclinical cancer models have clearly demonstrated that GSIs suppress the growth of such malignancies as pancreatic, breast, and lung cancer; however, GSI treatment in vivo is associated with side effects, especially those within the gastrointestinal tract. Although intensive studies are associated with the role of γ-secretase in pathological states, it should be pointed out that this complex impacts on proteolytic cleavages of around 55 membrane proteins. Therefore, it is clear that GSIs are highly non-specific and additional drugs must be designed, which will more specifically target components of the Notch signalling. PMID:27688721

  19. Modulation of Wnt/β-catenin signaling pathway by bioactive food components

    PubMed Central

    Tarapore, Rohinton S.; Siddiqui, Imtiaz A.; Mukhtar, Hasan

    2012-01-01

    The Wnt/β-catenin signaling pathway, one of the most conserved intercellular signaling cascade, is a known regulator of cellular functions related to tumor initiation and progression, cell proliferation, differentiation, survival and adhesion. Because aberrant Wnt/β-catenin signaling has been observed in a variety of human cancers including a majority of colorectal cancers, about half of prostate cancers and a third of melanomas, inhibitors of its complex signaling pathways are being investigated for therapy as well as chemoprevention of these cancers. During the last decade, several naturally occurring dietary agents have been shown to target intermediates in the Wnt/β-catenin signaling pathway. In this review, we highlight the current understanding of the Wnt/β-catenin signaling pathway and present an analysis of the key findings from laboratory studies on the effects of a panel of dietary agents against a variety of cancers. Promise of these agents for treating and preventing human cancer is then discussed. PMID:22198211

  20. Combined blockade of signalling pathways shows marked anti-tumour potential in phaeochromocytoma cell lines

    PubMed Central

    Nölting, Svenja; Garcia, Edwin; Alusi, Ghassan; Giubellino, Alessio; Pacak, Karel; Korbonits, Márta; Grossman, Ashley B

    2016-01-01

    Currently, there is no completely effective therapy available for metastatic phaeochromocytomas (PCCs) and paragangliomas. In this study, we explore new molecular targeted therapies for these tumours, using one more benign (mouse phaeochromocytoma cell (MPC)) and one more malignant (mouse tumour tissue (MTT)) mouse PCC cell line –both generated from heterozygous neurofibromin 1 knockout mice. Several PCC-promoting gene mutations have been associated with aberrant activation of PI3K/AKT, mTORC1 and RAS/RAF/ERK signalling. We therefore investigated different agents that interfere specifically with these pathways, including antagonism of the IGF1 receptor by NVP-AEW541. We found that NVP-AEW541 significantly reduced MPC and MTT cell viability at relatively high doses but led to a compensatory up-regulation of ERK and mTORC1 signalling at suboptimal doses while PI3K/AKT inhibition remained stable. We subsequently investigated the effect of the dual PI3K/mTORC1/2 inhibitor NVP-BEZ235, which led to a significant decrease of MPC and MTT cell viability at doses down to 50 nM but again increased ERK signalling. Accordingly, we next examined the combination of NVP-BEZ235 with the established agent lovastatin, as this has been described to inhibit ERK signalling. Lovastatin alone significantly reduced MPC and MTT cell viability at therapeutically relevant doses and inhibited both ERK and AKT signalling, but increased mTORC1/p70S6K signalling. Combination treatment with NVP-BEZ235 and lovastatin showed a significant additive effect in MPC and MTT cells and resulted in inhibition of both AKT and mTORC1/p70S6K signalling without ERK up-regulation. Simultaneous inhibition of PI3K/AKT, mTORC1/2 and ERK signalling suggests a novel therapeutic approach for malignant PCCs. PMID:22715163

  1. Combined blockade of signalling pathways shows marked anti-tumour potential in phaeochromocytoma cell lines.

    PubMed

    Nölting, Svenja; Garcia, Edwin; Alusi, Ghassan; Giubellino, Alessio; Pacak, Karel; Korbonits, Márta; Grossman, Ashley B

    2012-10-01

    Currently, there is no completely effective therapy available for metastatic phaeochromocytomas (PCCs) and paragangliomas. In this study, we explore new molecular targeted therapies for these tumours, using one more benign (mouse phaeochromocytoma cell (MPC)) and one more malignant (mouse tumour tissue (MTT)) mouse PCC cell line - both generated from heterozygous neurofibromin 1 knockout mice. Several PCC-promoting gene mutations have been associated with aberrant activation of PI3K/AKT, mTORC1 and RAS/RAF/ERK signalling. We therefore investigated different agents that interfere specifically with these pathways, including antagonism of the IGF1 receptor by NVP-AEW541. We found that NVP-AEW541 significantly reduced MPC and MTT cell viability at relatively high doses but led to a compensatory up-regulation of ERK and mTORC1 signalling at suboptimal doses while PI3K/AKT inhibition remained stable. We subsequently investigated the effect of the dual PI3K/mTORC1/2 inhibitor NVP-BEZ235, which led to a significant decrease of MPC and MTT cell viability at doses below 50 nM but again increased ERK signalling. Accordingly, we next examined the combination of NVP-BEZ235 with the established agent lovastatin, as this has been described to inhibit ERK signalling. Lovastatin alone significantly reduced MPC and MTT cell viability at therapeutically relevant doses and inhibited both ERK and AKT signalling, but increased mTORC1/p70S6K signalling. Combination treatment with NVP-BEZ235 and lovastatin showed a significant additive effect in MPC and MTT cells and resulted in inhibition of both AKT and mTORC1/p70S6K signalling without ERK up-regulation. Simultaneous inhibition of PI3K/AKT, mTORC1/2 and ERK signalling suggests a novel therapeutic approach for malignant PCCs.

  2. Resveratrol inhibits the hedgehog signaling pathway and epithelial-mesenchymal transition and suppresses gastric cancer invasion and metastasis

    PubMed Central

    GAO, QIAN; YUAN, YUAN; GAN, HUI-ZHONG; PENG, QIONG

    2015-01-01

    The hedgehog (Hh) signaling pathway is vital to vertebrate development, the homeostatic process and tumorigenesis. Epithelial-mesenchymal transition (EMT) is a cellular process during which epithelial cells become mesenchymal-appearing cells, which in turn promotes cancer metastasis and invasion. Resveratrol is a natural polyphenolic compound found in grapes, a variety of berries, peanuts and other plants. Numerous studies have demonstrated that the Hh signaling pathway is able to regulate the EMT, and that resveratrol can suppress carcinoma invasion and metastasis. In addition, certain studies have indicated that resveratrol can inhibit the Hh signaling pathway and EMT in cancers other than gastric cancer. The purpose of the present study was to investigate the inhibitory effect of resveratrol on the Hh signaling pathway and EMT in gastric cancer in vitro. Gastric cancer SGC-7901 cells were treated with resveratrol or cyclopamine at different concentrations. The viability of the cells was assessed using an MTT assay. The expression of Gli-1, a key component of the Hh signaling pathway, and Snail, E-cadherin and N-cadherin, key components of EMT, was detected by reverse transcription polymerase chain reaction (RT-PCR) and western blotting. The invasion and metastasis of the cells were observed by performing a cell scratch test. The RT-PCR and western blotting showed a decrease in Gli-1, Snail and N-cadherin expression, and an increase in E-cadherin expression in the resveratrol and cyclopamine group compared with the control group, suggesting that resveratrol inhibited the Hh pathway and EMT, as did cyclopamine. The MTT assay indicated that the viability of the SGC-7901 cells was significantly decreased in a concentration-dependent manner following resveratrol and cyclopamine treatment. The cell scratch test showed slower cell invasion and metastasis in the resveratrol and cyclopamine groups. These findings indicated that resveratrol was able to inhibit the Hh

  3. The Interface between BCR-ABL-Dependent and -Independent Resistance Signaling Pathways in Chronic Myeloid Leukemia

    PubMed Central

    Nestal de Moraes, Gabriela; Souza, Paloma Silva; Costas, Fernanda Casal de Faria; Vasconcelos, Flavia Cunha; Reis, Flaviana Ruade Souza; Maia, Raquel Ciuvalschi

    2012-01-01

    Chronic myeloid leukemia (CML) is a clonal hematopoietic disorder characterized by the presence of the Philadelphia chromosome which resulted from the reciprocal translocation between chromosomes 9 and 22. The pathogenesis of CML involves the constitutive activation of the BCR-ABL tyrosine kinase, which governs malignant disease by activating multiple signal transduction pathways. The BCR-ABL kinase inhibitor, imatinib, is the front-line treatment for CML, but the emergence of imatinib resistance and other tyrosine kinase inhibitors (TKIs) has called attention for additional resistance mechanisms and has led to the search for alternative drug treatments. In this paper, we discuss our current understanding of mechanisms, related or unrelated to BCR-ABL, which have been shown to account for chemoresistance and treatment failure. We focus on the potential role of the influx and efflux transporters, the inhibitor of apoptosis proteins, and transcription factor-mediated signals as feasible molecular targets to overcome the development of TKIs resistance in CML. PMID:23259070

  4. Identification of a Novel Gnao-Mediated Alternate Olfactory Signaling Pathway in Murine OSNs

    PubMed Central

    Scholz, Paul; Mohrhardt, Julia; Jansen, Fabian; Kalbe, Benjamin; Haering, Claudia; Klasen, Katharina; Hatt, Hanns; Osterloh, Sabrina

    2016-01-01

    It is generally agreed that in olfactory sensory neurons (OSNs), the binding of odorant molecules to their specific olfactory receptor (OR) triggers a cAMP-dependent signaling cascade, activating cyclic-nucleotide gated (CNG) channels. However, considerable controversy dating back more than 20 years has surrounded the question of whether alternate signaling plays a role in mammalian olfactory transduction. In this study, we demonstrate a specific alternate signaling pathway in Olfr73-expressing OSNs. Methylisoeugenol (MIEG) and at least one other known weak Olfr73 agonist (Raspberry Ketone) trigger a signaling cascade independent from the canonical pathway, leading to the depolarization of the cell. Interestingly, this pathway is mediated by Gnao activation, leading to Cl− efflux; however, the activation of adenylyl cyclase III (ACIII), the recruitment of Ca2+ from extra-or intracellular stores, and phosphatidylinositol 3-kinase-dependent signaling (PI signaling) are not involved. Furthermore, we demonstrated that our newly identified pathway coexists with the canonical olfactory cAMP pathway in the same OSN and can be triggered by the same OR in a ligand-selective manner. We suggest that this pathway might reflect a mechanism for odor recognition predominantly used in early developmental stages before olfactory cAMP signaling is fully developed. Taken together, our findings support the existence of at least one odor-induced alternate signal transduction pathway in native OSNs mediated by Olfr73 in a ligand-selective manner. PMID:27065801

  5. Identification of a Novel Gnao-Mediated Alternate Olfactory Signaling Pathway in Murine OSNs.

    PubMed

    Scholz, Paul; Mohrhardt, Julia; Jansen, Fabian; Kalbe, Benjamin; Haering, Claudia; Klasen, Katharina; Hatt, Hanns; Osterloh, Sabrina

    2016-01-01

    It is generally agreed that in olfactory sensory neurons (OSNs), the binding of odorant molecules to their specific olfactory receptor (OR) triggers a cAMP-dependent signaling cascade, activating cyclic-nucleotide gated (CNG) channels. However, considerable controversy dating back more than 20 years has surrounded the question of whether alternate signaling plays a role in mammalian olfactory transduction. In this study, we demonstrate a specific alternate signaling pathway in Olfr73-expressing OSNs. Methylisoeugenol (MIEG) and at least one other known weak Olfr73 agonist (Raspberry Ketone) trigger a signaling cascade independent from the canonical pathway, leading to the depolarization of the cell. Interestingly, this pathway is mediated by Gnao activation, leading to Cl(-) efflux; however, the activation of adenylyl cyclase III (ACIII), the recruitment of Ca(2+) from extra-or intracellular stores, and phosphatidylinositol 3-kinase-dependent signaling (PI signaling) are not involved. Furthermore, we demonstrated that our newly identified pathway coexists with the canonical olfactory cAMP pathway in the same OSN and can be triggered by the same OR in a ligand-selective manner. We suggest that this pathway might reflect a mechanism for odor recognition predominantly used in early developmental stages before olfactory cAMP signaling is fully developed. Taken together, our findings support the existence of at least one odor-induced alternate signal transduction pathway in native OSNs mediated by Olfr73 in a ligand-selective manner.

  6. Identification of a Novel Gnao-Mediated Alternate Olfactory Signaling Pathway in Murine OSNs.

    PubMed

    Scholz, Paul; Mohrhardt, Julia; Jansen, Fabian; Kalbe, Benjamin; Haering, Claudia; Klasen, Katharina; Hatt, Hanns; Osterloh, Sabrina

    2016-01-01

    It is generally agreed that in olfactory sensory neurons (OSNs), the binding of odorant molecules to their specific olfactory receptor (OR) triggers a cAMP-dependent signaling cascade, activating cyclic-nucleotide gated (CNG) channels. However, considerable controversy dating back more than 20 years has surrounded the question of whether alternate signaling plays a role in mammalian olfactory transduction. In this study, we demonstrate a specific alternate signaling pathway in Olfr73-expressing OSNs. Methylisoeugenol (MIEG) and at least one other known weak Olfr73 agonist (Raspberry Ketone) trigger a signaling cascade independent from the canonical pathway, leading to the depolarization of the cell. Interestingly, this pathway is mediated by Gnao activation, leading to Cl(-) efflux; however, the activation of adenylyl cyclase III (ACIII), the recruitment of Ca(2+) from extra-or intracellular stores, and phosphatidylinositol 3-kinase-dependent signaling (PI signaling) are not involved. Furthermore, we demonstrated that our newly identified pathway coexists with the canonical olfactory cAMP pathway in the same OSN and can be triggered by the same OR in a ligand-selective manner. We suggest that this pathway might reflect a mechanism for odor recognition predominantly used in early developmental stages before olfactory cAMP signaling is fully developed. Taken together, our findings support the existence of at least one odor-induced alternate signal transduction pathway in native OSNs mediated by Olfr73 in a ligand-selective manner. PMID:27065801

  7. Dystroglycan is involved in skin morphogenesis downstream of the Notch signaling pathway.

    PubMed

    Sirour, Cathy; Hidalgo, Magdalena; Bello, Valérie; Buisson, Nicolas; Darribère, Thierry; Moreau, Nicole

    2011-08-15

    Dystroglycan (Dg) is a transmembrane protein involved both in the assembly and maintenance of basement membrane structures essential for tissue morphogenesis, and the transmission of signals across the plasma membrane. We used a morpholino knockdown approach to investigate the function of Dg during Xenopus laevis skin morphogenesis. The loss of Dg disrupts epidermal differentiation by affecting the intercalation of multiciliated cells, deposition of laminin, and organization of fibronectin in the extracellular matrix (ECM). Depletion of Dg also affects cell-cell adhesion, as shown by the reduction of E-cadherin expression at the intercellular contacts, without affecting the distribution of β(1) integrins. This was associated with a decrease of cell proliferation, a disruption of multiciliated-cell intercalation, and the down-regulation of the transcription factor P63, a marker of differentiated epidermis. In addition, we demonstrated that inhibition or activation of the Notch pathway prevents and promotes transcription of X-dg. Our study showed for the first time in vivo that Dg, in addition to organizing laminin in the ECM, also acts as a key signaling component in the Notch pathway. PMID:21680717

  8. Quantitative Site-Specific Phosphoproteomics of Trichoderma reesei Signaling Pathways upon Induction of Hydrolytic Enzyme Production.

    PubMed

    Nguyen, Elizabeth V; Imanishi, Susumu Y; Haapaniemi, Pekka; Yadav, Avinash; Saloheimo, Markku; Corthals, Garry L; Pakula, Tiina M

    2016-02-01

    The filamentous fungus Trichoderma reesei is used for industrial production of secreted enzymes including carbohydrate active enzymes, such as cellulases and hemicellulases. The production of many of these enzymes by T. reesei is influenced by the carbon source it grows on, where the regulation system controlling hydrolase genes involves various signaling pathways. T. reesei was cultivated in the presence of sorbitol, a carbon source that does not induce the production of cellulases and hemicellulases, and then exposed to either sophorose or spent-grain extract, which are efficient inducers of the enzyme production. Specific changes at phosphorylation sites were investigated in relation to the production of cellulases and hemicellulases using an MS-based framework. Proteome-wide phosphorylation following carbon source exchange was investigated in the early stages of induction: 0, 2, 5, and 10 min. The workflow involved sequential trypsin digestion, TiO2 enrichment, and MS analysis using a Q Exactive mass spectrometer. We report on the identification and quantitation of 1721 phosphorylation sites. Investigation of the data revealed a complex signaling network activated upon induction involving components related to light-mediated cellulase induction, osmoregulation, and carbon sensing. Changes in protein phosphorylation were detected in the glycolytic pathway, suggesting an inhibition of glucose catabolism at 10 min after the addition of sophorose and as early as 2 min after the addition of spent-grain extract. Differential phosphorylation of factors related to carbon storage, intracellular trafficking, cytoskeleton, and cellulase gene regulation were also observed.

  9. Functional signaling pathway analysis of lung adenocarcinomas identifies novel therapeutic targets for KRAS mutant tumors.

    PubMed

    Baldelli, Elisa; Bellezza, Guido; Haura, Eric B; Crinó, Lucio; Cress, W Douglas; Deng, Jianghong; Ludovini, Vienna; Sidoni, Angelo; Schabath, Matthew B; Puma, Francesco; Vannucci, Jacopo; Siggillino, Annamaria; Liotta, Lance A; Petricoin, Emanuel F; Pierobon, Mariaelena

    2015-10-20

    Little is known about the complex signaling architecture of KRAS and the interconnected RAS-driven protein-protein interactions, especially as it occurs in human clinical specimens. This study explored the activated and interconnected signaling network of KRAS mutant lung adenocarcinomas (AD) to identify novel therapeutic targets.Thirty-four KRAS mutant (MT) and twenty-four KRAS wild-type (WT) frozen biospecimens were obtained from surgically treated lung ADs. Samples were subjected to Laser Capture Microdissection and Reverse Phase Protein Microarray analysis to explore the expression/activation levels of 150 signaling proteins along with co-activation concordance mapping. An independent set of 90 non-small cell lung cancers (NSCLC) was used to validate selected findings by immunohistochemistry (IHC).Compared to KRAS WT tumors, the signaling architecture of KRAS MT ADs revealed significant interactions between KRAS downstream substrates, the AKT/mTOR pathway, and a number of Receptor Tyrosine Kinases (RTK). Approximately one-third of the KRAS MT tumors had ERK activation greater than the WT counterpart (p<0.01). Notably 18% of the KRAS MT tumors had elevated activation of the Estrogen Receptor alpha (ER-α) (p=0.02).This finding was verified in an independent population by IHC (p=0.03).KRAS MT lung ADs appear to have a more intricate RAS linked signaling network than WT tumors with linkage to many RTKs and to the AKT-mTOR pathway. Combination therapy targeting different nodes of this network may be necessary to treat this group of patients. In addition, for patients with KRAS MT tumors and activation of the ER-α, anti-estrogen therapy may have important clinical implications. PMID:26468985

  10. Mutations modulating the Argos-regulated signaling pathway in Drosophila eye development.

    PubMed

    Taguchi, A; Sawamoto, K; Okano, H

    2000-04-01

    Argos is a secreted protein that contains an EGF-like domain and acts as an inhibitor of Drosophila EGF receptor activation. To identify genes that function in the Argos-regulated signaling pathway, we performed a genetic screen for enhancers and suppressors of the eye phenotype caused by the overexpression of argos. As a result, new alleles of known genes encoding components of the EGF receptor pathway, such as Star, sprouty, bulge, and clown, were isolated. To study the role of clown in development, we examined the eye and wing phenotypes of the clown mutants in detail. In the eye discs of clown mutants, the pattern of neuronal differentiation was impaired, showing a phenotype similar to those caused by a gain-of-function EGF receptor mutation and overexpression of secreted Spitz, an activating ligand for the EGF receptor. There was also an increased number of pigment cells in the clown eyes. Epistatic analysis placed clown between argos and Ras1. In addition, we found that clown negatively regulated the development of wing veins. These results suggest that the clown gene product is important for the Argos-mediated inhibition of EGF receptor activation during the development of various tissues. In addition to the known genes, we identified six mutations of novel genes. Genetic characterization of these mutants suggested that they have distinct roles in cell differentiation and/or survival regulated by the EGF receptor pathway.

  11. Genetic variants in mammary development, prolactin signalling and involution pathways explain considerable variation in bovine milk production and milk composition

    PubMed Central

    2014-01-01

    Background The maintenance of lactation in mammals is the result of a balance between competing signals from mammary development, prolactin signalling and involution pathways. Dairy cattle are an interesting case study to investigate the effect of polymorphisms that affect the function of genes in these pathways. In dairy cattle, lactation yields and milk composition (for example protein percentage and fat percentage) are routinely recorded, and these vary greatly between individuals. In this study, we test 8058 single nucleotide polymorphisms in or close to genes in these pathways for association with milk production traits and determine the proportion of variance explained by each pathway, using data on 16 812 dairy cattle, including Holstein-Friesian and Jersey bulls and cows. Results Single nucleotide polymorphisms close to genes in the mammary development, prolactin signalling and involution pathways were significantly associated with milk production traits. The involution pathway explained the largest proportion of genetic variation for production traits. The mammary development pathway also explained additional genetic variation for milk volume, fat percentage and protein percentage. Conclusions Genetic variants in the involution pathway explained considerably more genetic variation in milk production traits than expected by chance. Many of the associations for single nucleotide polymorphisms in genes in this pathway have not been detected in conventional genome-wide association studies. The pathway approach used here allowed us to identify some novel candidates for further studies that will be aimed at refining the location of associated genomic regions and identifying polymorphisms contributing to variation in lactation volume and milk composition. PMID:24779965

  12. Targeting tissue-specific metabolic signaling pathways in aging: the promise and limitations.

    PubMed

    Hu, Fang; Liu, Feng

    2014-01-01

    It has been well established that most of the age-related diseases such as insulin resistance, type 2 diabetes, hypertension, cardiovascular disease, osteoporosis, and atherosclerosis are all closely related to metabolic dysfunction. On the other hand, interventions on metabolism such as calorie restriction or genetic manipulations of key metabolic signaling pathways such as the insulin and mTOR signaling pathways slow down the aging process and improve healthy aging. These findings raise an important question as to whether improving energy homeostasis by targeting certain metabolic signaling pathways in specific tissues could be an effective anti-aging strategy. With a more comprehensive understanding of the tissue-specific roles of distinct metabolic signaling pathways controlling energy homeostasis and the cross-talks between these pathways during aging may lead to the development of more effective therapeutic interventions not only for metabolic dysfunction but also for aging.

  13. [Cell signaling pathways interaction in cellular proliferation: Potential target for therapeutic interventionism].

    PubMed

    Valdespino-Gómez, Víctor Manuel; Valdespino-Castillo, Patricia Margarita; Valdespino-Castillo, Víctor Edmundo

    2015-01-01

    Nowadays, cellular physiology is best understood by analysing their interacting molecular components. Proteins are the major components of the cells. Different proteins are organised in the form of functional clusters, pathways or networks. These molecules are ordered in clusters of receptor molecules of extracellular signals, transducers, sensors and biological response effectors. The identification of these intracellular signaling pathways in different cellular types has required a long journey of experimental work. More than 300 intracellular signaling pathways have been identified in human cells. They participate in cell homeostasis processes for structural and functional maintenance. Some of them participate simultaneously or in a nearly-consecutive progression to generate a cellular phenotypic change. In this review, an analysis is performed on the main intracellular signaling pathways that take part in the cellular proliferation process, and the potential use of some components of these pathways as target for therapeutic interventionism are also underlined. PMID:25986976

  14. Modeling and analysis of early events in T-lymphocyte antigen-activated intracellular-signaling pathways

    NASA Astrophysics Data System (ADS)

    Zheng, Yanan; Balakrishnan, Venkataramanan; Buzzard, Greg; Geahlen, Robert; Harrison, Marietta; Rundell, Ann

    2005-12-01

    The T-cell antigen-activated signaling pathway is a highly regulated intracellular biochemical system that is crucial for initiating an appropriate adaptive immune response. To improve the understanding of the complex regulatory mechanisms controlling the early events in T-cell signaling, a detailed mathematical model was developed that utilizes ordinary differential equations to describe chemical reactions of the signaling pathway. The model parameter values were constrained by experimental data on the activation of a specific signaling intermediate and indicated an initial rapid cascade of phosphorylation events followed by a comparatively slow signal downregulation. Nonlinear analysis of the model suggested that thresholding and bistability occur as a result of the embedded positive and negative feedback loops within the model. These nonlinear system properties may enhance the T-cell receptor specificity and provide sub-threshold noise filtering with switch-like behavior to ensure proper cell response. Additional analysis using a reduced second-order model led to further understanding of the observed system behavior. Moreover, the interactions between the positive and negative feedback loops enabled the model to exhibit, among a variety of other feasible dynamics, a sustained oscillation that corresponds to a stable limit cycle in the two-dimensional phase plane. Quantitative analysis in this paper has helped identify potential regulatory mechanisms in the early T-cell signaling events. This integrated approach provides a framework to quantify and discover the ensemble of interconnected T-cell antigen-activated signaling pathways from limited experimental data.

  15. Humid heat exposure induced oxidative stress and apoptosis in cardiomyocytes through the angiotensin II signaling pathway.

    PubMed

    Wang, Xiaowu; Yuan, Binbin; Dong, Wenpeng; Yang, Bo; Yang, Yongchao; Lin, Xi; Gong, Gu

    2015-05-01

    Exposure to humid heat stress leads to the initiation of serious physiological dysfunction that may result in heat-related diseases, including heat stroke, heat cramp, heat exhaustion, and even death. Increasing evidences have shown that the humid heat stress-induced dysfunction of the cardiovascular system was accompanied with severe cardiomyocyte injury; however, the precise mechanism of heat stress-induced injury of cardiomyocyte remains unknown. In the present study, we hypothesized that humid heat stress promoted oxidative stress through the activation of angiotensin II (Ang II) in cardiomyocytes. To test our hypothesis, we established mouse models of humid heat stress. Using the animal models, we found that Ang II levels in serum were significantly up-regulated and that the Ang II receptor AT1 was increased in cardiomyocytes. The antioxidant ability in plasma and heart tissues which was detected by the ferric reducing/antioxidant power assay was also decreased with the increased ROS production under humid heat stress, as was the expression of antioxidant genes (SOD2, HO-1, GPx). Furthermore, we demonstrated that the Ang II receptor antagonist, valsartan, effectively relieved oxidative stress, blocked Ang II signaling pathway and suppressed cardiomyocyte apoptosis induced by humid heat stress. In addition, overexpression of antioxidant genes reversed cardiomyocyte apoptosis induced by Ang II. Overall, these results implied that humid heat stress increased oxidative stress and caused apoptosis of cardiomyocytes through the Ang II signaling pathway. Thus, targeting the Ang II signaling pathway may provide a promising approach for the prevention and treatment of cardiovascular diseases caused by humid heat stress.

  16. Signalling pathways involved in the synergistic effects of human growth differentiation factor 9 and bone morphogenetic protein 15.

    PubMed

    Reader, Karen L; Mottershead, David G; Martin, Georgia A; Gilchrist, Robert B; Heath, Derek A; McNatty, Kenneth P; Juengel, Jennifer L

    2016-03-01

    Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) act synergistically to regulate granulosa cell proliferation and steroid production in several species. Several non-Sma and mothers against decapentaplegic (SMAD) signalling pathways are involved in the action of murine and ovine GDF9 and BMP15 in combination, with the pathways utilised differing between the two species. The aims of this research were to determine if human GDF9 and BMP15 also act in a synergistic manner to stimulate granulosa cell proliferation and to identify which non-SMAD signalling pathways are activated. Human GDF9 with BMP15 (GDF9+BMP15) stimulated an increase in (3)H-thymidine incorporation (P<0.001), which was greater than the increase with BMP15 alone, while GDF9 alone had no effect. The stimulation of (3)H-thymidine incorporation by GDF9+BMP15 was reduced by the addition of inhibitors to the SMAD2/3, nuclear factor-KB (NF-KB) and c-Jun N-terminal kinase (JNK) signalling pathways. Inhibitors to the SMAD1/5/8, extracellular signal-regulated kinase mitogen-activated protein kinase (ERK-MAPK) or p38-MAPK pathways had no effect. The addition of the BMP receptor 2 (BMPR2) extracellular domain also inhibited stimulation of (3)H-thymidine incorporation by GDF9+BMP15. In conclusion, human GDF9 and BMP15 act synergistically to stimulate granulosa cell proliferation, a response that also involves species-specific non-SMAD signalling pathways.

  17. Crosstalk between Wnt/β-Catenin and NF-κB Signaling Pathway during Inflammation

    PubMed Central

    Ma, Bin; Hottiger, Michael O.

    2016-01-01

    Besides its important role in embryonic development and homeostatic self-renewal in adult tissues, Wnt/β-catenin signaling exerts both anti-inflammatory and proinflammatory functions. This is, at least partially, due to either repressing or enhancing the NF-κB pathway. Similarly, the NF-κB pathway either positively or negatively regulates Wnt/β-catenin signaling. Different components of the two pathways are involved in this crosstalk, forming a complex regulatory network. This review summarizes our current understanding of the molecular mechanisms underlying the cross-regulation between the two pathways and discusses their involvement in inflammation and inflammation-associated diseases such as cancer. PMID:27713747

  18. Notch and Wnt/β-catenin signaling pathway play important roles in activating liver cancer stem cells

    PubMed Central

    Wang, Ronghua; Sun, Qian; Wang, Peng; Liu, Man; Xiong, Si; Luo, Jing; Huang, Hai; Du, Qiang; Geller, David A.; Cheng, Bin

    2016-01-01

    Human hepatocellular carcinoma (HCC) is driven and maintained by liver cancer stem cells (LCSCs) that display stem cell properties. These LCSCs are promoted by the intersecting of Notch and Wnt/β-Catenin signaling pathways. In this study, we demonstrate that LCSCs with markers CD90, CD24, CD13, and CD133 possess stem properties of self-renewal and tumorigenicity in NOD/SCID mice. The increased expression of these markers was correlated with advanced disease stage, larger tumors, and worse overall survival in 61 HCC cases. We also found that both Notch and Wnt/β-catenin signaling pathways played important roles in increasing the stem-ness characteristics of LCSCs. Our data suggested that Notch1 was downstream of Wnt/β-catenin. The active form of Notch1 intracellular domain (NICD) expression depended on Wnt/β-catenin pathway activation. Moreover, Notch1 negatively contributed to Wnt/β-catenin signaling modulation. Knock down of Notch1 with lentivirus N1ShRNA up-regulated the active form of β-catenin. Ectopic expression of NICD with LV-Notch1 in LCSCs attenuated β-catenin/TCF dependent luciferase activity significantly. In addition, there was a non-proteasome mediated feedback loop between Notch1 and Wnt/β-catenin signaling in LCSCs. The central role of Notch and the Wnt/β-catenin signaling pathway in LCSCs may provide an attractive therapeutic strategy against HCC. PMID:26735577

  19. The Arabidopsis RGA gene encodes a transcriptional regulator repressing the gibberellin signal transduction pathway.

    PubMed

    Silverstone, A L; Ciampaglio, C N; Sun, T

    1998-02-01

    The recessive rga mutation is able to partially suppress phenotypic defects of the Arabidopsis gibberellin (GA) biosynthetic mutant ga1-3. Defects in stem elongation, flowering time, and leaf abaxial trichome initiation are suppressed by rga. This indicates that RGA is a negative regulator of the GA signal transduction pathway. We have identified 10 additional alleles of rga from a fast-neutron mutagenized ga1-3 population and used them to isolate the RGA gene by genomic subtraction. Our data suggest that RGA may be functioning as a transcriptional regulator. RGA was found to be a member of the VHIID regulatory family, which includes the radial root organizing gene SCARECROW and another GA signal transduction repressor, GAI. RGA and GAI proteins share a high degree of homology, but their N termini are more divergent. The presence of several structural features, including homopolymeric serine and threonine residues, a putative nuclear localization signal, leucine heptad repeats, and an LXXLL motif, indicates that the RGA protein may be a transcriptional regulator that represses the GA response. In support of the putative nuclear localization signal, we demonstrated that a transiently expressed green fluorescent protein-RGA fusion protein is localized to the nucleus in onion epidermal cells. Because the rga mutation abolished the high level of expression of the GA biosynthetic gene GA4 in the ga1-3 mutant background, we conclude that RGA may also play a role in controlling GA biosynthesis.

  20. Fn14, a Downstream Target of the TGF-β Signaling Pathway, Regulates Fibroblast Activation

    PubMed Central

    Yang, Min; Lai, Wen; Ye, Litong; Chen, Jing; Hou, Xinghua; Ding, Hong; Zhang, Wenwei; Wu, Yueheng; Liu, Xiaoying; Huang, Shufang; Yu, Xiyong; Xiao, Dingzhang

    2015-01-01

    Fibrosis, the hallmark of human injuries and diseases such as serious burns, is characterized by excessive collagen synthesis and myofibroblast accumulation. Transforming growth factor-β (TGF-β), a potent inducer of collagen synthesis, has been implicated in fibrosis in animals. In addition to TGF-β, fibroblast growth factor-inducible molecule 14 (Fn14) has been reported to play an important role in fibrotic diseases, such as cardiac fibrosis. However, the function and detailed regulatory mechanism of Fn14 in fibrosis are unclear. Here, we investigated the effect of Fn14 on the activation of human dermal fibroblasts. In normal dermal fibroblasts, TGF-β signaling increased collagen production and Fn14 expression. Furthermore, Fn14 siRNA blocked extracellular matrix gene expression; even when TGF-β signaling was activated by TGF-β1, fibroblast activation remained blocked in the presence of Fn14 siRNA. Overexpressing Fn14 increased extracellular matrix gene expression. In determining the molecular regulatory mechanism, we discovered that SMAD4, an important TGF-β signaling co-mediator, bound to the Fn14 promoter and activated Fn14 transcription. Taken together, these results indicate that the TGF-β signaling pathway activates Fn14 expression through the transcription factor SMAD4 and that activated Fn14 expression increases extracellular matrix synthesis and fibroblast activation. Therefore, Fn14 may represent a promising approach to preventing the excessive accumulation of collagen or ECM in skin fibrosis. PMID:26625141

  1. Quinomycin A targets Notch signaling pathway in pancreatic cancer stem cells

    PubMed Central

    Ponnurangam, Sivapriya; Dandawate, Prasad R.; Dhar, Animesh; Tawfik, Ossama W.; Parab, Rajashri R.; Mishra, Prabhu Dutt; Ranadive, Prafull; Sharma, Rajiv; Mahajan, Girish; Umar, Shahid; Weir, Scott J.; Sugumar, Aravind; Jensen, Roy A.; Padhye, Subhash B.; Balakrishnan, Arun; Anant, Shrikant; Subramaniam, Dharmalingam

    2016-01-01

    Cancer stem cells (CSCs) appear to explain many aspects of the neoplastic evolution of tumors and likely account for enhanced therapeutic resistance following treatment. Dysregulated Notch signaling, which affects CSCs plays an important role in pancreatic cancer progression. We have determined the ability of Quinomycin to inhibit CSCs and the Notch signaling pathway. Quinomycin treatment resulted in significant inhibition of proliferation and colony formation in pancreatic cancer cell lines, but not in normal pancreatic epithelial cells. Moreover, Quinomycin affected pancreatosphere formation. The compound also decreased the expression of CSC marker proteins DCLK1, CD44, CD24 and EPCAM. In addition, flow cytometry studies demonstrated that Quinomycin reduced the number of DCLK1+ cells. Furthermore, levels of Notch 1–4 receptors, their ligands Jagged1, Jagged2, DLL1, DLL3, DLL4 and the downstream target protein Hes-1 were reduced. The γ-secretase complex proteins, Presenilin 1, Nicastrin, Pen2, and APH-1, required for Notch activation also exhibited decreased expression. Ectopic expression of the Notch Intracellular Domain (NICD) partially rescued the cells from Quinomycin mediated growth suppression. To determine the effect of Quinomycin on tumor growth in vivo, nude mice carrying tumor xenografts were administered Quinomycin intraperitoneally every day for 21 days. Treatment with the compound significantly inhibited tumor xenograft growth, coupled with significant reduction in the expression of CSC markers and Notch signaling proteins. Together, these data suggest that Quinomycin is a potent inhibitor of pancreatic cancer that targets the stem cells by inhibiting Notch signaling proteins. PMID:26673007

  2. Toll-like receptors (TLRs) in aquatic animals: signaling pathways, expressions and immune responses.

    PubMed

    Rauta, Pradipta R; Samanta, Mrinal; Dash, Hirak R; Nayak, Bismita; Das, Surajit

    2014-01-01

    The innate system's recognition of non-self and danger signals is mediated by a limited number of germ-line encoded pattern recognition receptors (PRRs) that recognize pathogen associated molecular patterns (PAMPs). Toll-like receptors (TLRs) are single, non-catalytic, membrane-spanning PRRs present in invertebrates and vertebrates. They act by specifically recognizing PAMPs of a variety of microbes and activate signaling cascades to induce innate immunity. A large number of TLRs have been identified in various aquatic animals of phyla Cnidaria, Annelida, Mollusca, Arthropoda, Echinodermata and Chordata. TLRs of aquatic and warm-blooded higher animals exhibit some distinctive features due to their diverse evolutionary lineages. However, majority of them share conserve signaling pathways in pathogen recognition and innate immunity. Functional analysis of novel TLRs in aquatic animals is very important in understanding the comparative immunology between warm-blooded and aquatic animals. In additions to innate immunity, recent reports have highlighted the additional roles of TLRs in adaptive immunity. Therefore, vaccines against many critical diseases of aquatic animals may be made more effective by supplementing TLR activators which will stimulate dendritic cells. This article describes updated information of TLRs in aquatic animals and their structural and functional relationship with warm-blooded animals.

  3. Frequency of alcohol consumption in humans; the role of metabotropic glutamate receptors and downstream signaling pathways.

    PubMed

    Meyers, J L; Salling, M C; Almli, L M; Ratanatharathorn, A; Uddin, M; Galea, S; Wildman, D E; Aiello, A E; Bradley, B; Ressler, K; Koenen, K C

    2015-01-01

    Rodent models implicate metabotropic glutamate receptors (mGluRs) and downstream signaling pathways in addictive behaviors through metaplasticity. One way mGluRs can influence synaptic plasticity is by regulating the local translation of AMPA receptor trafficking proteins via eukaryotic elongation factor 2 (eEF2). However, genetic variation in this pathway has not been examined with human alcohol use phenotypes. Among a sample of adults living in Detroit, Michigan (Detroit Neighborhood Health Study; n = 788; 83% African American), 206 genetic variants across the mGluR-eEF2-AMPAR pathway (including GRM1, GRM5, HOMER1, HOMER2, EEF2K, MTOR, EIF4E, EEF2, CAMK2A, ARC, GRIA1 and GRIA4) were found to predict number of drinking days per month (corrected P-value < 0.01) when considered as a set (set-based linear regression conducted in PLINK). In addition, a CpG site located in the 3'-untranslated region on the north shore of EEF2 (cg12255298) was hypermethylated in those who drank more frequently (P < 0.05). Importantly, the association between several genetic variants within the mGluR-eEF2-AMPAR pathway and alcohol use behavior (i.e., consumption and alcohol-related problems) replicated in the Grady Trauma Project (GTP), an independent sample of adults living in Atlanta, Georgia (n = 1034; 95% African American), including individual variants in GRM1, GRM5, EEF2, MTOR, GRIA1, GRIA4 and HOMER2 (P < 0.05). Gene-based analyses conducted in the GTP indicated that GRM1 (empirical P < 0.05) and EEF2 (empirical P < 0.01) withstood multiple test corrections and predicted increased alcohol consumption and related problems. In conclusion, insights from rodent studies enabled the identification of novel human alcohol candidate genes within the mGluR-eEF2-AMPAR pathway. PMID:26101849

  4. Frequency of alcohol consumption in humans; the role of metabotropic glutamate receptors and downstream signaling pathways

    PubMed Central

    Meyers, J L; Salling, M C; Almli, L M; Ratanatharathorn, A; Uddin, M; Galea, S; Wildman, D E; Aiello, A E; Bradley, B; Ressler, K; Koenen, K C

    2015-01-01

    Rodent models implicate metabotropic glutamate receptors (mGluRs) and downstream signaling pathways in addictive behaviors through metaplasticity. One way mGluRs can influence synaptic plasticity is by regulating the local translation of AMPA receptor trafficking proteins via eukaryotic elongation factor 2 (eEF2). However, genetic variation in this pathway has not been examined with human alcohol use phenotypes. Among a sample of adults living in Detroit, Michigan (Detroit Neighborhood Health Study; n=788; 83% African American), 206 genetic variants across the mGluR–eEF2–AMPAR pathway (including GRM1, GRM5, HOMER1, HOMER2, EEF2K, MTOR, EIF4E, EEF2, CAMK2A, ARC, GRIA1 and GRIA4) were found to predict number of drinking days per month (corrected P-value <0.01) when considered as a set (set-based linear regression conducted in PLINK). In addition, a CpG site located in the 3′-untranslated region on the north shore of EEF2 (cg12255298) was hypermethylated in those who drank more frequently (P<0.05). Importantly, the association between several genetic variants within the mGluR–eEF2–AMPAR pathway and alcohol use behavior (i.e., consumption and alcohol-related problems) replicated in the Grady Trauma Project (GTP), an independent sample of adults living in Atlanta, Georgia (n=1034; 95% African American), including individual variants in GRM1, GRM5, EEF2, MTOR, GRIA1, GRIA4 and HOMER2 (P<0.05). Gene-based analyses conducted in the GTP indicated that GRM1 (empirical P<0.05) and EEF2 (empirical P<0.01) withstood multiple test corrections and predicted increased alcohol consumption and related problems. In conclusion, insights from rodent studies enabled the identification of novel human alcohol candidate genes within the mGluR–eEF2–AMPAR pathway. PMID:26101849

  5. The TOR signaling pathway regulates vegetative development and virulence in Fusarium graminearum.

    PubMed

    Yu, Fangwei; Gu, Qin; Yun, Yingzi; Yin, Yanni; Xu, Jin-Rong; Shim, Won-Bo; Ma, Zhonghua

    2014-07-01

    The target of rapamycin (TOR) signaling pathway plays critical roles in controlling cell growth in a variety of eukaryotes. However, the contribution of this pathway in regulating virulence of plant pathogenic fungi is unknown. We identified and characterized nine genes encoding components of the TOR pathway in Fusarium graminearum. Biological, genetic and biochemical functions of each component were investigated. The FgFkbp12-rapamycin complex binds to the FgTor kinase. The type 2A phosphatases FgPp2A, FgSit4 and FgPpg1 were found to interact with FgTap42, a downstream component of FgTor. Among these, we determined that FgPp2A is likely to be essential for F. graminearum survival, and FgSit4 and FgPpg1 play important roles in cell wall integrity by positively regulating the phosphorylation of FgMgv1, a key MAP kinase in the cell wall integrity pathway. In addition, the FgPpg1 interacting protein, FgTip41, is involved in regulating mycelial growth and virulence. Notably, FgTip41 does not interact with FgTap42 but with FgPpg1, suggesting the existence of FgTap42:FgPpg1:FgTip41 heterotrimer in F. graminearum, a complex not observed in the yeast model. Collectively, we defined a genetic regulatory framework that elucidates how the TOR pathway regulates virulence and vegetative development in F. graminearum.

  6. The Tumor Suppressor BCL7B Functions in the Wnt Signaling Pathway.

    PubMed

    Uehara, Tomoko; Kage-Nakadai, Eriko; Yoshina, Sawako; Imae, Rieko; Mitani, Shohei

    2015-01-01

    Human BCL7 gene family consists of BCL7A, BCL7B, and BCL7C. A number of clinical studies have reported that BCL7 family is involved in cancer incidence, progression, and development. Among them, BCL7B, located on chromosome 7q11.23, is one of the deleted genes in patients with Williams-Beuren syndrome. Although several studies have suggested that malignant diseases occurring in patients with Williams-Beuren syndrome are associated with aberrations in BCL7B, little is known regarding the function of this gene at the cellular level. In this study, we focused on bcl-7, which is the only homolog of BCL7 gene family in Caenorhabditis elegans, and analyzed bcl-7 deletion mutants. As a result, we found that bcl-7 is required for the asymmetric differentiation of epithelial seam cells, which have self-renewal properties as stem cells and divide asymmetrically through the WNT pathway. Distal tip cell development, which is regulated by the WNT pathway in Caenorhabditis elegans, was also affected in bcl-7-knockout mutants. Interestingly, bcl-7 mutants exhibited nuclear enlargement, reminiscent of the anaplastic features of malignant cells. Furthermore, in KATOIII human gastric cancer cells, BCL7B knockdown induced nuclear enlargement, promoted the multinuclei phenotype and suppressed cell death. In addition, this study showed that BCL7B negatively regulates the Wnt-signaling pathway and positively regulates the apoptotic pathway. Taken together, our data indicate that BCL7B/BCL-7 has some roles in maintaining the structure of nuclei and is involved in the modulation of multiple pathways, including Wnt and apoptosis. This study may implicate a risk of malignancies with BCL7B-deficiency, such as Williams-Beuren syndrome. PMID:25569233

  7. The Tumor Suppressor BCL7B Functions in the Wnt Signaling Pathway

    PubMed Central

    Uehara, Tomoko; Kage-Nakadai, Eriko; Yoshina, Sawako; Imae, Rieko; Mitani, Shohei

    2015-01-01

    Human BCL7 gene family consists of BCL7A, BCL7B, and BCL7C. A number of clinical studies have reported that BCL7 family is involved in cancer incidence, progression, and development. Among them, BCL7B, located on chromosome 7q11.23, is one of the deleted genes in patients with Williams-Beuren syndrome. Although several studies have suggested that malignant diseases occurring in patients with Williams-Beuren syndrome are associated with aberrations in BCL7B, little is known regarding the function of this gene at the cellular level. In this study, we focused on bcl-7, which is the only homolog of BCL7 gene family in Caenorhabditis elegans, and analyzed bcl-7 deletion mutants. As a result, we found that bcl-7 is required for the asymmetric differentiation of epithelial seam cells, which have self-renewal properties as stem cells and divide asymmetrically through the WNT pathway. Distal tip cell development, which is regulated by the WNT pathway in Caenorhabditis elegans, was also affected in bcl-7-knockout mutants. Interestingly, bcl-7 mutants exhibited nuclear enlargement, reminiscent of the anaplastic features of malignant cells. Furthermore, in KATOIII human gastric cancer cells, BCL7B knockdown induced nuclear enlargement, promoted the multinuclei phenotype and suppressed cell death. In addition, this study showed that BCL7B negatively regulates the Wnt-signaling pathway and positively regulates the apoptotic pathway. Taken together, our data indicate that BCL7B/BCL-7 has some roles in maintaining the structure of nuclei and is involved in the modulation of multiple pathways, including Wnt and apoptosis. This study may implicate a risk of malignancies with BCL7B-deficiency, such as Williams-Beuren syndrome. PMID:25569233

  8. Cross-talk between signalling pathways and the multidrug resistant protein MDR-1

    PubMed Central

    Ding, S; Chamberlain, M; McLaren, A; Goh, L-b; Duncan, I; Wolf, C R

    2001-01-01

    The multidrug resistant protein MDR-1 has been associated with the resistance to a wide range of anti-cancer drugs. Taxol is a substrate for this transporter system and is used in the treatment of a wide range of human malignancies including lung, breast and ovarian cancer. We have generated a series of ovarian cell lines resistant to this compound, all of which overexpress MDR-1 through gene amplification. We present novel evidence that a constitutive activation of the ERK1/2 MAP kinase pathway was also observed although the level of active JNK and p38 remained unchanged. Inhibition of the ERK1/2 MAP kinase pathway using UO126 or PD098059 re-sensitised the Taxol resistant cells at least 20-fold. Importantly, when Mdr-1 cDNA was stably expressed in the wild-type cell line to generate a highly Taxol-resistant sub-line, 1847/MDR5, ERK1/2 MAP kinases again became activated. This result demonstrated that the increased activity of the signalling pathway in the Taxol-resistant lines was directly attributable to MDR-1 overexpression and was not due to the effects of Taxol itself. Additionally, we demonstrated that inhibition of the P13K pathway with LY294002 sensitised the MDR-1-expressing 1847/TX0.5 cells and 1847/MDR5 cells at least 10-fold but had no effect in the wild-type cells. This finding suggests a possible role for this pathway, also, in the generation of resistance to Taxol. © 2001 Cancer Research Campaign  http://www.bjcancer.com PMID:11710832

  9. Cardioprotective actions of Notch1 against myocardial infarction via LKB1-dependent AMPK signaling pathway.

    PubMed

    Yang, Hui; Sun, Wanqing; Quan, Nanhu; Wang, Lin; Chu, Dongyang; Cates, Courtney; Liu, Quan; Zheng, Yang; Li, Ji

    2016-05-15

    AMP-activated protein kinase (AMPK) signaling pathway plays a pivotal role in intracellular adaptation to energy stress during myocardial ischemia. Notch1 signaling in the adult myocardium is also activated in response to ischemic stress. However, the relationship between Notch1 and AMPK signaling pathways during ischemia remains unclear. We hypothesize that Notch1 as an adaptive signaling pathway protects the heart from ischemic injury via modulating the cardioprotective AMPK signaling pathway. C57BL/6J mice were subjected to an in vivo ligation of left anterior descending coronary artery and the hearts from C57BL/6J mice were subjected to an ex vivo globe ischemia and reperfusion in the Langendorff perfusion system. The Notch1 signaling was activated during myocardial ischemia. A Notch1 γ-secretase inhibitor, dibenzazepine (DBZ), was intraperitoneally injected into mice to inhibit Notch1 signaling pathway by ischemia. The inhibition of Notch1 signaling by DBZ significantly augmented cardiac dysfunctions caused by myocardial infarction. Intriguingly, DBZ treatment also significantly blunted the activation of AMPK signaling pathway. The immunoprecipitation experiments demonstrated that an interaction between Notch1 and liver kinase beta1 (LKB1) modulated AMPK activation during myocardial ischemia. Furthermore, a ligand of Notch1 Jagged1 can significantly reduce cardiac damage caused by ischemia via activation of AMPK signaling pathway and modulation of glucose oxidation and fatty acid oxidation during ischemia and reperfusion. But Jagged1 did not have any cardioprotections on AMPK kinase dead transgenic hearts. Taken together, the results indicate that the cardioprotective effect of Notch1 against ischemic damage is mediated by AMPK signaling via an interaction with upstream LKB1.

  10. Signal Transduction Pathway Analysis in Desmoid-type Fibromatosis: TGFβ, COX2 and Sex Steroid Receptors

    PubMed Central

    Mignemi, Nicholas A.; Itani, Doha M.; Fasig, John H.; Keedy, Vicki L.; Hande, Kenneth R.; Whited, Brent W.; Homlar, Kelly C.; Correa, Hernan; Coffin, Cheryl M.; Black, Jennifer O.; Yi, Yajun; Halpern, Jennifer L.; Holt, Ginger E.; Schwartz, Herbert S.; Schoenecker, Jonathan G.; Cates, Justin M. M.

    2014-01-01

    Summary Despite reports of sex steroid receptor and COX2 expression in desmoid-type fibromatosis, responses to single agent therapy with anti-estrogens and nonsteroidal anti-inflammatory drugs are unpredictable. Perhaps combination pharmacotherapy might be more effective in desmoid tumors that co-express these targets. Clearly, a further understanding of the signaling pathways deregulated in desmoid tumors is essential for development of targeted molecular therapy. Transforming growth factor-β (TGFβ) and bone morphogenetic proteins (BMPs) are important regulators of fibroblast proliferation and matrix deposition, but little is known about the TGFβ superfamily in fibromatosis. A tissue microarray representing 27 desmoid tumors was constructed; 14 samples of healing scar and 6 samples of normal fibrous tissue were included for comparison. Expression of selected receptors and activated downstream transcription factors of TGFβ family signaling pathways, β-catenin, sex steroid hormone receptors and COX2 were assessed by immunohistochemistry; patterns of co-expression were explored via correlational statistical analyses. In addition to β-catenin, immunoreactivity for phosphorylated SMAD2/3 (indicative of active TGFβ signaling) and COX2 was significantly increased in desmoid tumors compared to healing scar and quiescent fibrous tissue. Low levels of phosphorylated SMAD1/5/8 were detected in only a minority of cases. TGFβ receptor type 1 and androgen receptor were expressed in both desmoid tumors and scar, but not in fibrous tissue. Estrogen receptor-β was present in all cases studied. TGFβ signaling appears to be activated in desmoid-type fibromatosis and phosphorylated SMAD2/3 and COX2 immunoreactivity may be of diagnostic utility in these tumors. Given the frequency of androgen receptor, estrogen receptor-β and COX2 co-expression in desmoid tumors, further assessment of the efficacy of combination pharmacotherapy using hormonal agonists/antagonists together

  11. Making memories of stressful events: a journey along epigenetic, gene transcription, and signaling pathways.

    PubMed

    Reul, Johannes M H M

    2014-01-01

    Strong psychologically stressful events are known to have a long-lasting impact on behavior. The consolidation of such, largely adaptive, behavioral responses to stressful events involves changes in gene expression in limbic brain regions such as the hippocampus and amygdala. However, the underlying molecular mechanisms were until recently unresolved. More than a decade ago, we started to investigate the role of these hormones in signaling and epigenetic mechanisms participating in the effects of stress on gene transcription in hippocampal neurons. We discovered a novel, rapid non-genomic mechanism in which glucocorticoids via glucocorticoid receptors facilitate signaling of the ERK-MAPK signaling pathway to the downstream nuclear kinases MSK1 and Elk-1 in dentate gyrus granule neurons. Activation of this signaling pathway results in serine10 (S10) phosphorylation and lysine14 (K14) acetylation at histone H3 (H3S10p-K14ac), leading to the induction of the immediate-early genes c-Fos and Egr-1. In addition, we found a role of the DNA methylation status of gene promoters. A series of studies showed that these molecular mechanisms play a critical role in the long-lasting consolidation of behavioral responses in the forced swim test and Morris water maze. Furthermore, an important role of GABA was found in controlling the epigenetic and gene transcriptional responses to psychological stress. Thus, psychologically stressful events evoke a long-term impact on behavior through changes in hippocampal function brought about by distinct glutamatergic and glucocorticoid-driven changes in epigenetic regulation of gene transcription, which are modulated by (local) GABAergic interneurons and limbic afferent inputs. These epigenetic processes may play an important role in the etiology of stress-related mental disorders such as major depressive and anxiety disorders like post-traumatic stress disorder. PMID:24478733

  12. Making Memories of Stressful Events: A Journey Along Epigenetic, Gene Transcription, and Signaling Pathways

    PubMed Central

    Reul, Johannes M. H. M.

    2014-01-01

    Strong psychologically stressful events are known to have a long-lasting impact on behavior. The consolidation of such, largely adaptive, behavioral responses to stressful events involves changes in gene expression in limbic brain regions such as the hippocampus and amygdala. However, the underlying molecular mechanisms were until recently unresolved. More than a decade ago, we started to investigate the role of glucocorticoid hormones in signaling and epigenetic mechanisms participating in the effects of stress on gene transcription in hippocampal neurons. We discovered a novel, rapid non-genomic mechanism in which glucocorticoids via glucocorticoid receptors facilitate signaling of the ERK-MAPK signaling pathway to the downstream nuclear kinases MSK1 and Elk-1 in dentate gyrus granule neurons. Activation of this signaling pathway results in serine10 (S10) phosphorylation and lysine14 (K14) acetylation at histone H3 (H3S10p-K14ac), leading to the induction of the immediate-early genes c-Fos and Egr-1. In addition, we found a role of the DNA methylation status of gene promoters. A series of studies showed that these molecular mechanisms play a critical role in the long-lasting consolidation of behavioral responses in the forced swim test and Morris water maze. Furthermore, an important role of GABA was found in controlling the epigenetic and gene transcriptional responses to psychological stress. Thus, psychologically stressful events evoke a long-term impact on behavior through changes in hippocampal function brought about by distinct glutamatergic and glucocorticoid-driven changes in epigenetic regulation of gene transcription, which are modulated by (local) GABAergic interneurons and limbic afferent inputs. These epigenetic processes may play an important role in the etiology of stress-related mental disorders such as major depressive and anxiety disorders like post-traumatic stress disorder. PMID:24478733

  13. Wnt Signaling Inhibits Osteoclast Differentiation by Activating Canonical and Noncanonical cAMP/PKA Pathways

    PubMed Central

    Weivoda, Megan M; Ruan, Ming; Hachfeld, Christine M; Pederson, Larry; Howe, Alan; Davey, Rachel A; Zajac, Jeffrey D; Kobayashi, Yasuhiro; Williams, Bart O; Westendorf, Jennifer J; Khosla, Sundeep; Oursler, Merry Jo

    2016-01-01

    Although there has been extensive characterization of the Wnt signaling pathway in the osteoblast lineage, the effects of Wnt proteins on the osteoclast lineage are less well studied. We found that osteoclast lineage cells express canonical Wnt receptors. Wnt3a reduced osteoclast formation when applied to early bone-marrow macrophage (BMM) osteoclast differentiation cultures, whereas late addition did not suppress osteoclast formation. Early Wnt3a treatment inactivated the crucial transcription factor NFATc1 in osteoclast progenitors. Wnt3a led to the accumulation of nuclear β-catenin, confirming activation of canonical Wnt signaling. Reducing low-density lipoprotein receptor-related proteins (Lrp) 5 and Lrp6 protein expression prevented Wnt3a-induced inactivation of NFATc1; however, deletion of β-catenin did not block Wnt3a inactivation of NFATc1, suggesting that this effect was mediated by a noncanonical pathway. Wnt3a rapidly activated the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway and pharmacological stimulation of cAMP/PKA signaling suppressed osteoclast differentiation; Wnt3a-induced NFATc1 phosphorylation was blocked by inhibiting interactions between PKA and A-kinase anchoring proteins (AKAPs). These data indicate that Wnt3a directly suppresses osteoclast differentiation through both canonical (β-catenin) and noncanonical (cAMP/PKA) pathways in osteoclast precursors. In vivo reduction of Lrp5 and Lrp6 expressions in the early osteoclast lineage via Rank promoter Cre recombination reduced trabecular bone mass, whereas disruption of Lrp5/6 expression in late osteoclast precursors via cathepsin K (Ctsk) promoter Cre recombination did not alter the skeletal phenotype. Surprisingly, reduction of Lrp5/6 in the early osteoclast lineage decreased osteoclast numbers, as well as osteoblast numbers. Published studies have previously noted that β-catenin signaling is required for osteoclast progenitor proliferation. Our in vivo data

  14. pathFinder: a static network analysis tool for pharmacological analysis of signal transduction pathways.

    PubMed

    Samal, Babru B; Eiden, Lee E

    2008-01-01

    The study of signal transduction is becoming a de facto part of the analysis of gene expression and protein profiling techniques. Many online tools are used to cluster genes in various ways or to assign gene products to signal transduction pathways. Among these, pathFinder is a unique tool that can find signal transduction pathways between first, second, or nth messengers and their targets within the cell. pathFinder can identify qualitatively all possible signal transduction pathways connecting any starting component and target within a database of two-component pathways (directional dyads). One or more intermediate pathway components can be excluded to simulate the use of pharmacological inhibitors or genetic deletion (knockout). Missing elements in a pathway connecting the activator or initiator and target can also be inferred from a null pathway result. The value of this static network analysis tool is illustrated by the predication from pathFinder analysis of a novel cyclic AMP-dependent, protein kinase A-independent signaling pathway in neuroendocrine cells, which has been experimentally confirmed.

  15. The inositol phosphate/diacylglycerol signalling pathway in Trypanosoma cruzi.

    PubMed Central

    Docampo, R; Pignataro, O P

    1991-01-01

    Using [32P]Pi and [3H]inositol as precursors, we have detected the presence of phosphatidylinositol, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, and their derivatives inositol phosphate, inositol 1,4-bisphosphate and inositol 1,4,5-trisphosphate respectively, in Trypanosoma cruzi epimastigotes. Using digitonin-permeabilized cells it was possible to detect a stimulation in the formation of inositol 1,4,5-trisphosphate and inositol 1,4-bisphosphate as well as an increased generation of diacylglycerol in the presence of 1 mM-CaCl2. These results are consistent with the operation of a functional inositol phosphate/diacylglycerol pathway in T. cruzi, and constitute the first demonstration of the presence and activation of this pathway in a parasitic protozoan. These results also indicate that this pathway is conserved during evolution from lower to higher eukaryotic organisms. Images Fig. 1. PMID:2025225

  16. Overexpression of LRIG1 regulates PTEN via MAPK/MEK signaling pathway in esophageal squamous cell carcinoma

    PubMed Central

    Jiang, Xiaofang; Li, Huiwu

    2016-01-01

    The present study aimed to evaluate the role of leucine-rich repeats and immunoglobulin-like domain protein 1 (LRIG1) in the regulation of phosphatase and tensin homolog (PTEN) expression in esophageal carcinogenesis. LRIG1 was overexpressed in esophageal squamous cell carcinoma (ESCC) cell lines, and the effect of LRIG1 overexpression on the mRNA and protein expression levels of PTEN was evaluated by reverse transcription-quantitative polymerase chain reaction and western blotting. Furthermore, the effects of LRIG1 overexpression on the cell cycle distribution and apoptosis of ESCC cells were examined by flow cytometry. Various cell signaling pathway inhibitors were used to assess the effects of LRIG1 on downstream signaling in ESCC cell lines. In addition, the association between LRIG1 and PTEN expression was examined in 48 samples from patients with ESCC. LRIG1 overexpression was demonstrated to downregulate PTEN expression in ESCC cell lines, and promote their proliferation and inhibit apoptosis. In addition, LRIG1-mediated suppression of PTEN expression was inhibited by the U0126 inhibitor, which suggests that LRIG1 may inhibit the activation of PTEN signaling molecules by triggering the mitogen-activated protein kinase (MAPK)/MAPK kinase 1 (MEK) signaling pathway. In conclusion, the present study demonstrated that overexpression of LRIG1 significantly and adversely affected the survival of ESCC cells, and that the MAPK/MEK signaling pathway may be responsible for the repression of PTEN expression and function. PMID:27698691

  17. Wnt/β-catenin signaling pathway activation is required for proliferation of chicken primordial germ cells in vitro

    PubMed Central

    Lee, Hyung Chul; Lim, Sumi; Han, Jae Yong

    2016-01-01

    Here, we investigated the role of the Wnt/β-catenin signaling pathway in chicken primordial germ cells (PGCs) in vitro. We confirmed the expression of Wnt signaling pathway-related genes and the localization of β-catenin in the nucleus, revealing that this pathway is potentially activated in chicken PGCs. Then, using the single-cell pick-up assay, we examined the proliferative capacity of cultured PGCs in response to Wnt ligands, a β-catenin-mediated Wnt signaling activator (6-bromoindirubin-3′-oxime [BIO]) or inhibitor (JW74), in the presence or absence of basic fibroblast growth factor (bFGF). WNT1, WNT3A, and BIO promoted the proliferation of chicken PGCs similarly to bFGF, whereas JW74 inhibited this proliferation. Meanwhile, such treatments in combination with bFGF did not show a synergistic effect. bFGF treatment could not rescue PGC proliferation in the presence of JW74. In addition, we confirmed the translocation of β-catenin into the nucleus by the addition of bFGF after JW74 treatment. These results indicate that there is signaling crosstalk between FGF and Wnt, and that β-catenin acts on PGC proliferation downstream of bFGF. In conclusion, our study suggests that Wnt signaling enhances the proliferation of chicken PGCs via the stabilization of β-catenin and activation of its downstream genes. PMID:27687983

  18. Overexpression of LRIG1 regulates PTEN via MAPK/MEK signaling pathway in esophageal squamous cell carcinoma

    PubMed Central

    Jiang, Xiaofang; Li, Huiwu

    2016-01-01

    The present study aimed to evaluate the role of leucine-rich repeats and immunoglobulin-like domain protein 1 (LRIG1) in the regulation of phosphatase and tensin homolog (PTEN) expression in esophageal carcinogenesis. LRIG1 was overexpressed in esophageal squamous cell carcinoma (ESCC) cell lines, and the effect of LRIG1 overexpression on the mRNA and protein expression levels of PTEN was evaluated by reverse transcription-quantitative polymerase chain reaction and western blotting. Furthermore, the effects of LRIG1 overexpression on the cell cycle distribution and apoptosis of ESCC cells were examined by flow cytometry. Various cell signaling pathway inhibitors were used to assess the effects of LRIG1 on downstream signaling in ESCC cell lines. In addition, the association between LRIG1 and PTEN expression was examined in 48 samples from patients with ESCC. LRIG1 overexpression was demonstrated to downregulate PTEN expression in ESCC cell lines, and promote their proliferation and inhibit apoptosis. In addition, LRIG1-mediated suppression of PTEN expression was inhibited by the U0126 inhibitor, which suggests that LRIG1 may inhibit the activation of PTEN signaling molecules by triggering the mitogen-activated protein kinase (MAPK)/MAPK kinase 1 (MEK) signaling pathway. In conclusion, the present study demonstrated that overexpression of LRIG1 significantly and adversely affected the survival of ESCC cells, and that the MAPK/MEK signaling pathway may be responsible for the repression of PTEN expression and function.

  19. Streptozotocin induced activation of oxidative stress responsive splenic cell signaling pathways: Protective role of arjunolic acid

    SciTech Connect

    Manna, Prasenjit; Ghosh, Jyotirmoy; Das, Joydeep

    2010-04-15

    Present study investigates the beneficial role of arjunolic acid (AA) against the alteration in the cytokine levels and simultaneous activation of oxidative stress responsive signaling pathways in spleen under hyperglycemic condition. Diabetes was induced by injection of streptozotocin (STZ) (at a dose of 70 mg/kg body weight, injected in the tail vain). STZ administration elevated the levels of IL-2 as well as IFN-gamma and attenuated the level of TNF-alpha in the sera of diabetic animals. In addition, hyperglycemia is also associated with the increased production of intracellular reactive intermediates resulting with the elevation in lipid peroxidation, protein carbonylation and reduction in intracellular antioxidant defense. Investigating the oxidative stress responsive cell signaling pathways, increased expressions (immunoreactive concentrations) of phosphorylated p65 as well as its inhibitor protein phospho IkappaBalpha and phosphorylated mitogen activated protein kinases (MAPKs) have been observed in diabetic spleen tissue. Studies on isolated splenocytes revealed that hyperglycemia caused disruption of mitochondrial membrane potential, elevation in the concentration of cytosolic cytochrome c as well as activation of caspase 3 leading to apoptotic cell death. Histological examination revealed that diabetic induction depleted the white pulp scoring which is in agreement with the reduced immunological response. Treatment with AA prevented the hyperglycemia and its associated pathogenesis in spleen tissue. Results suggest that AA might act as an anti-diabetic and immunomodulatory agent against hyperglycemia.

  20. NRSF/REST regulates the mTOR signaling pathway in oral cancer cells.

    PubMed

    Cho, Eugene; Moon, Sung-Min; Park, Bo Ram; Kim, Do Kyung; Lee, Byung-Kwon; Kim, Chun Sung

    2015-03-01

    The neuron-restrictive silencer factor/repressor element 1-silencing transcription factor (NRSF/REST) was originally discovered as a transcriptional repressor of neuronal genes in non-neuronal cells. However, it was recently reported to be abundantly expressed in several types of aggressive cancer cells, as well as in mature neurons. In the present study, the role of NRSF/REST in the human oral squamous cell carcinoma (SCC) KB cell line was evaluated. NRSF/REST was expressed at a higher level in KB cells when compared with that in normal human oral keratinocytes (NHOKs). Knockdown of NRSF/REST by siRNA reduced cell viability only in KB cells in a time-dependent manner, and this effect was due to the activation of apoptosis components and DNA fragmentation. In addition, knockdown of NRSF/REST disrupted the mTOR signaling pathway which is a key survival factor in many types of cancer cells. For example, the phosphorylation of elF4G, elF4E and 4E-BP1 was significantly reduced in the KΒ cells upon NRSF/REST knockdown. These results imply that NRSF/REST plays an important role in the survival of oral cancer cells by regulating the mTOR signaling pathway. PMID:25524378

  1. UV-B signaling pathways and fluence rate dependent transcriptional regulation of ARIADNE12.

    PubMed

    Lang-Mladek, Christina; Xie, Lisi; Nigam, Neha; Chumak, Nina; Binkert, Melanie; Neubert, Susanne; Hauser, Marie-Theres

    2012-08-01

    ARI12 belongs to a family of 'RING between RING fingers' (RBR) domain proteins with E3 ligase activity (Eisenhaber et al. 2007). The Arabidopsis genome codes for 14 ARI genes and two pseudogenes (Mladek et al. 2003). Under standard growth conditions ARI12 is predominantly expressed in roots. In addition, ARI12 is strongly induced in leaves following exposure to ultraviolet (UV)-B radiation at dosages similar to those in areas under a reduced ozone layer. With quantitative reverse transcription polymerase chain reaction analyses and promoter:reporter constructs we show that the expression of ARI12 peaks 2-4 h after UV-B radiation exposure. To test if ARI12's transcriptional activation depends on key players of the UV-B signaling pathway, ARI12 expression was quantified in mutants of the ELONGATED HYPOCOTYL5 (HY5), HY5 HOMOLOG (HYH) and the UV RESISTANCE LOCUS8 (UVR8) genes. ARI12 transcription was reduced by 50-70% in hy5, hyh and hy5/hyh double mutants, but not in uvr8 mutants. However, under low fluence rate UV-B conditions ARI12 is not induced in these mutants. Our results show that ARI12 represents a downstream target of the low fluence rate UVR8/HY5/HYH UV-B signaling pathway while under high fluence rates its expression is regulated by the two bZIP transcription factors HY5 and HYH in an UVR8-independent manner.

  2. Clinical Development of VEGF Signaling Pathway Inhibitors in Childhood Solid Tumors

    PubMed Central

    Yamashiro, Darrell J.; Fox, Elizabeth

    2011-01-01

    Angiogenesis is a target shared by both adult epithelial cancers and the mesenchymal or embryonal tumors of childhood. Development of antiangiogenic agents for the pediatric population has been complicated by largely theoretical concern for toxicities specific to the growing child and prioritization among the many antiangiogenic agents being developed for adults. This review summarizes the mechanism of action and preclinical data relevant to childhood cancers and early-phase clinical trials in childhood solid tumors. Single-agent adverse event profiles in adults and children are reviewed with emphasis on cardiovascular, bone health, and endocrine side effects. In addition, pharmacological factors that may be relevant for prioritizing clinical trials of these agents in children are reviewed. Considerations for further clinical evaluation should include preclinical data, relative potency, efficacy in adults, and the current U.S. Food and Drug Administration approval status. Toxicity profiles of vascular endothelial growth factor (VEGF) signaling pathway inhibitors may be age dependent and ultimately, their utility in the treatment of childhood cancer will require combination with standard cytotoxic drugs or other molecularly targeted agents. In combination studies, toxicity profiles, potential drug interactions, and late effects must be considered. Studies to assess the long-term impact of VEGF signaling pathway inhibitors on cardiovascular, endocrine, and bone health in children with cancer are imperative if these agents are to be administered to growing children and adolescents with newly diagnosed cancers. PMID:22042784

  3. Retinoids interfere with the AP1 signalling pathway in human breast cancer cells.

    PubMed

    Dedieu, Stephane; Lefebvre, Philippe

    2006-06-01

    Retinoic acid and its synthetic analogs exert major effects on many biological processes including cell proliferation and differentiation and are now considered as promising pharmacological agents for prevention and treatment of various cancers. The capacity of retinoids to inhibit AP1-responsive genes seems to be the basis for the chemopreventive and chemotherapeutic effects of these agents against hyperproliferative diseases. However, the molecular basis of retinoid antiproliferative properties remains to this day largely unknown. Here, we showed that retinoids inhibit phorbol ester-induced MMP-1 and MMP-3 expression in human breast cancer cells. Transcriptional interference was observed for both retinoid agonist and antagonist treatments, revealing separated transactivation and transrepression functions of retinoids. In addition, we examined MAP kinases as potential targets of retinoid signalling in human breast cancer cells and demonstrated that retinoids repress AP1-responsive gene expression by inhibiting MKK6/p38 and mainly MEK/ERK signalling pathways. On the contrary, the JNK-dependent pathway was not identified as a molecular relay for AP1 activity and was insensitive to retinoid treatments. Finally, we established that overexpressed c-fos and c-jun partially abolished the ability of retinoids to inhibit AP1 activity, suggesting that c-jun and/or c-fos containing dimers may constitute one target of retinoids for transrepression of AP1. All together, our data help to improve our understanding of how retinoids antagonize AP1 activity and may regulate tumoral cell proliferation.

  4. Identification of signal transduction pathways involved in the formation of platelet subpopulations upon activation.

    PubMed

    Topalov, Nikolai N; Kotova, Yana N; Vasil'ev, Sergey A; Panteleev, Mikhail A

    2012-04-01

    Platelets are formed elements of blood. Upon activation, they externalize phosphatidylserine, thus accelerating membrane-dependent reactions of blood coagulation. Activated platelets form two subpopulations, only one of which expresses phosphatidylserine. This study aimed to identify signalling pathways responsible for this segregation. Gel-filtered platelets, intact or loaded with calcium-sensitive dyes, were activated and labelled with annexin V and antibodies, followed by flow cytometric analysis. Calcium Green and Fura Red dyes were compared, and only the latter was able to detect calcium level differences in the platelet subpopulations. Phosphatidylserine-positive platelets produced by thrombin had stably high intracellular calcium level; addition of convulxin increased and stabilized calcium level in the phosphatidylserine-negative subpopulation. PAR1 agonist SFLLRN also induced calcium rise and subpopulation formation, but the resulting platelets were not coated with alpha-granule proteins. Adenylatecyclase activator forskolin inhibited phosphatidylserine-positive platelets formation several-fold, while its inhibitor SQ22536 had no effect. This suggests that adenylatecyclase inactivation is necessary, but not rate-limiting, for subpopulation segregation. Inhibition of mitogen-activated protein kinase kinase (U0126) and glycoprotein IIb-IIIa (Monafram(®)) was without effect, whereas inhibitors of phosphatidylinositol 3-kinase (wortmannin) and Src tyrosine kinase (PP2) decreased the procoagulant subpopulation threefold. These data identify the principal signalling pathways controlling platelet heterogeneity. PMID:23379894

  5. Cross talk of tyrosine kinases with the DNA damage signaling pathways

    PubMed Central

    Mahajan, Kiran; Mahajan, Nupam P.

    2015-01-01

    Tyrosine kinases respond to extracellular and intracellular cues by activating specific cellular signaling cascades to regulate cell cycle, growth, proliferation, differentiation and survival. Likewise, DNA damage response proteins (DDR) activated by DNA lesions or chromatin alterations recruit the DNA repair and cell cycle checkpoint machinery to restore genome integrity and cellular homeostasis. Several new examples have been uncovered in recent studies which reveal novel epigenetic and non-epigenetic mechanisms by which tyrosine kinases interact with DDR proteins to dictate cell fate, i.e. survival or apoptosis, following DNA damage. These studies reveal the ability of tyrosine kinases to directly regulate the activity of DNA repair and cell cycle check point proteins by tyrosine phosphorylation. In addition, tyrosine kinases epigenetically regulate DNA damage signaling pathways by modifying the core histones as well as chromatin modifiers at critical tyrosine residues. Thus, deregulated tyrosine kinase driven epigenomic alterations have profound implications in cancer, aging and genetic disorders. Consequently, targeting oncogenic tyrosine kinase induced epigenetic alterations has gained significant traction in overcoming cancer cell resistance to various therapies. This review discusses mechanisms by which tyrosine kinases interact with DDR pathways to regulate processes critical for maintaining genome integrity as well as clinical strategies for targeted cancer therapies. PMID:26546517

  6. Signaling pathway involved in the immunomodulatory effect of Ganoderma atrum polysaccharide in spleen lymphocytes.

    PubMed

    Yu, Qiang; Nie, Shao-Ping; Wang, Jun-Qiao; Huang, Dan-Fei; Li, Wen-Juan; Xie, Ming-Yong

    2015-03-18

    The aim of this study was to investigate the molecular mechanism underlying the immunomodulatory effect of Ganoderma atrum polysaccharide (PSG-1) in spleen lymphocytes. Our results showed that PSG-1 increased the intracellular Ca2+ concentration and calcineurin (CaN) activity. Moreover, PSG-1 was found to elevate nuclear factor of activated T cells (NFAT) activity, but this effect could be diminished by the treatment of CaN inhibitors (cyclosporin A and FK506). PSG-1-induced interleukin (IL)-2 production was also inhibited by cyclosporin A and FK506. In addition, PSG-1 was found to significantly enhance protein kinase C (PKC) activity. PKC was involved in induction of NFAT activity by PSG-1, as evidenced by abrogation of NFAT activity by PKC inhibitor calphostin C, which significantly decreased PSG-1-induced IL-2 production. On the basis of these results, we concluded that PSG-1 may induce activation of spleen lymphocytes at least in part via the Ca2+/CaN/NFAT/IL-2 signaling pathway and the PKC/NFAT/IL-2 signaling pathway cooperatively regulated PSG-1-induced activation of spleen lymphocytes.

  7. CLE peptides and their signaling pathways in plant development.

    PubMed

    Yamaguchi, Yasuka L; Ishida, Takashi; Sawa, Shinichiro

    2016-08-01

    Cell-to-cell communication is crucial for the coherent functioning of multicellular organisms, and they have evolved intricate molecular mechanisms to achieve such communication. Small, secreted peptide hormones participate in cell-to-cell communication to regulate various physiological processes. One such family of plant peptide hormones is the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION-related (CLE) family, whose members play crucial roles in the differentiation of shoot and root meristems. Recent biochemical and genetic studies have characterized various CLE signaling modules, which include CLE peptides, transmembrane receptors, and downstream intracellular signaling components. CLE signaling systems are conserved across the plant kingdom but have divergent modes of action in various developmental processes in different species. Moreover, several CLE peptides play roles in symbiosis, parasitism, and responses to abiotic cues. Here we review recent studies that have provided new insights into the mechanisms of CLE signaling. PMID:27229733

  8. Control of Proliferation and Cancer Growth by the Hippo Signaling Pathway.

    PubMed

    Ehmer, Ursula; Sage, Julien

    2016-02-01

    The control of cell division is essential for normal development and the maintenance of cellular homeostasis. Abnormal cell proliferation is associated with multiple pathological states, including cancer. Although the Hippo/YAP signaling pathway was initially thought to control organ size and growth, increasing evidence indicates that this pathway also plays a major role in the control of proliferation independent of organ size control. In particular, accumulating evidence indicates that the Hippo/YAP signaling pathway functionally interacts with multiple other cellular pathways and serves as a central node in the regulation of cell division, especially in cancer cells. Here, recent observations are highlighted that connect Hippo/YAP signaling to transcription, the basic cell-cycle machinery, and the control of cell division. Furthermore, the oncogenic and tumor-suppressive attributes of YAP/TAZ are reviewed, which emphasizes the relevance of the Hippo pathway in cancer.

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

    PubMed Central

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

    2015-01-01

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

  10. p53 and ATF4 mediate distinct and additive pathways to skeletal muscle atrophy during limb immobilization.

    PubMed

    Fox, Daniel K; Ebert, Scott M; Bongers, Kale S; Dyle, Michael C; Bullard, Steven A; Dierdorff, Jason M; Kunkel, Steven D; Adams, Christopher M

    2014-08-01

    Immobilization causes skeletal muscle atrophy via complex signaling pathways that are not well understood. To better understand these pathways, we investigated the roles of p53 and ATF4, two transcription factors that mediate adaptations to a variety of cellular stresses. Using mouse models, we demonstrate that 3 days of muscle immobilization induces muscle atrophy and increases expression of p53 and ATF4. Furthermore, muscle fibers lacking p53 or ATF4 are partially resistant to immobilization-induced muscle atrophy, and forced expression of p53 or ATF4 induces muscle fiber atrophy in the absence of immobilization. Importantly, however, p53 and ATF4 do not require each other to promote atrophy, and coexpression of p53 and ATF4 induces more atrophy than either transcription factor alone. Moreover, muscle fibers lacking both p53 and ATF4 are more resistant to immobilization-induced atrophy than fibers lacking only p53 or ATF4. Interestingly, the independent and additive nature of the p53 and ATF4 pathways allows for combinatorial control of at least one downstream effector, p21. Using genome-wide mRNA expression arrays, we identified p21 mRNA as a skeletal muscle transcript that is highly induced in immobilized muscle via the combined actions of p53 and ATF4. Additionally, in mouse muscle, p21 induces atrophy in a manner that does not require immobilization, p53 or ATF4, and p21 is required for atrophy induced by immobilization, p53, and ATF4. Collectively, these results identify p53 and ATF4 as essential and complementary mediators of immobilization-induced muscle atrophy and discover p21 as a critical downstream effector of the p53 and ATF4 pathways.

  11. Caenorhabditis elegans TRPV channels function in a modality-specific pathway to regulate response to aberrant sensory signaling.

    PubMed

    Ezak, Meredith J; Hong, Elizabeth; Chaparro-Garcia, Angela; Ferkey, Denise M

    2010-05-01

    Olfaction and some forms of taste (including bitter) are mediated by G protein-coupled signal transduction pathways. Olfactory and gustatory ligands bind to chemosensory G protein-coupled receptors (GPCRs) in specialized sensory cells to activate intracellular signal transduction cascades. G protein-coupled receptor kinases (GRKs) are negative regulators of signaling that specifically phosphorylate activated GPCRs to terminate signaling. Although loss of GRK function usually results in enhanced cellular signaling, Caenorhabditis elegans lacking GRK-2 function are not hypersensitive to chemosensory stimuli. Instead, grk-2 mutant animals do not chemotax toward attractive olfactory stimuli or avoid aversive tastes and smells. We show here that loss-of-function mutations in the transient receptor potential vanilloid (TRPV) channels OSM-9 and OCR-2 selectively restore grk-2 behavioral avoidance of bitter tastants, revealing modality-specific mechanisms for TRPV channel function in the regulation of C. elegans chemosensation. Additionally, a single amino acid point mutation in OCR-2 that disrupts TRPV channel-mediated gene expression, but does not decrease channel function in chemosensory primary signal transduction, also restores grk-2 bitter taste avoidance. Thus, loss of GRK-2 function may lead to changes in gene expression, via OSM-9/OCR-2, to selectively alter the levels of signaling components that transduce or regulate bitter taste responses. Our results suggest a novel mechanism and multiple modality-specific pathways that sensory cells employ in response to aberrant signal transduction. PMID:20176974

  12. Caenorhabditis elegans TRPV Channels Function in a Modality-Specific Pathway to Regulate Response to Aberrant Sensory Signaling

    PubMed Central

    Ezak , Meredith J.; Hong , Elizabeth; Chaparro-Garcia , Angela; Ferkey , Denise M.

    2010-01-01

    Olfaction and some forms of taste (including bitter) are mediated by G protein-coupled signal transduction pathways. Olfactory and gustatory ligands bind to chemosensory G protein-coupled receptors (GPCRs) in specialized sensory cells to activate intracellular signal transduction cascades. G protein-coupled receptor kinases (GRKs) are negative regulators of signaling that specifically phosphorylate activated GPCRs to terminate signaling. Although loss of GRK function usually results in enhanced cellular signaling, Caenorhabditis elegans lacking GRK-2 function are not hypersensitive to chemosensory stimuli. Instead, grk-2 mutant animals do not chemotax toward attractive olfactory stimuli or avoid aversive tastes and smells. We show here that loss-of-function mutations in the transient receptor potential vanilloid (TRPV) channels OSM-9 and OCR-2 selectively restore grk-2 behavioral avoidance of bitter tastants, revealing modality-specific mechanisms for TRPV channel function in the regulation of C. elegans chemosensation. Additionally, a single amino acid point mutation in OCR-2 that disrupts TRPV channel-mediated gene expression, but does not decrease channel function in chemosensory primary signal transduction, also restores grk-2 bitter taste avoidance. Thus, loss of GRK-2 function may lead to changes in gene expression, via OSM-9/OCR-2, to selectively alter the levels of signaling components that transduce or regulate bitter taste responses. Our results suggest a novel mechanism and multiple modality-specific pathways that sensory cells employ in response to aberrant signal transduction. PMID:20176974

  13. Behavioral Evidence for More than One Taste Signaling Pathway for Sugars in Rats

    PubMed Central

    Schier, Lindsey A.

    2016-01-01

    By conventional behavioral measures, rodents respond to natural sugars, such as glucose and fructose, as though they elicit an identical perceptual taste quality. Beyond that, the metabolic and sensory effects of these two sugars are quite different. Considering the capacity to immediately respond to the more metabolically expedient sugar, glucose, would seem advantageous for energy intake, the present experiment assessed whether experience consuming these two sugars would modify taste-guided ingestive responses to their yet unknown distinguishing orosensory properties. One group (GvF) had randomized access to three concentrations of glucose and fructose (0.316, 0.56, 1.1 m) in separate 30-min single access training sessions, whereas control groups received equivalent exposure to the three glucose or fructose concentrations only, or remained sugar naive. Comparison of the microstructural licking patterns for the two sugars revealed that GvF responded more positively to glucose (increased total intake, increased burst size, decreased number of pauses), relative to fructose, across training. As training progressed, GvF rats began to respond more positively to glucose in the first minute of the session when intake is principally taste-driven. During post-training brief-access taste tests, GvF rats licked more for glucose than for fructose, whereas the other training groups did not respond differentially to the two sugars. Additional brief access testing showed that this did not generalize to Na-saccharin or galactose. Thus, in addition to eliciting a common taste signal, glucose and fructose produce distinct signals that are apparently rendered behaviorally relevant and hedonically distinct through experience. The taste pathway(s) underlying this remain to be identified. SIGNIFICANCE STATEMENT The T1R2+T1R3 heterodimer is thought by many to be the only taste receptor for sugars. Although most sugars have been conventionally shown to correspondingly produce a unitary

  14. ASBESTOS-INDUCED ACTIVATION OF CELL SIGNALING PATHWAYS IN HUMAN BRONCHIAL EPITHELIAL CELLS

    EPA Science Inventory

    Using respiratory epithelial cells transfected with either superoxide dismutase (SOD) or catalase, the authors tested the hypothesis that the activation of the epidermal growth factor (EGF) receptor signal pathway after asbestos exposure involves an oxidative stress. Western blot...

  15. Mapping toll-like receptor signaling pathway genes of Zhikong scallop ( Chlamys farreri) with FISH

    NASA Astrophysics Data System (ADS)

    Zhao, Bosong; Zhao, Liang; Liao, Huan; Cheng, Jie; Lian, Shanshan; Li, Xuan; Huang, Xiaoting; Bao, Zhenmin

    2015-12-01

    Toll-like receptor (TLR) signaling pathway plays a pivotal role in the innate immune system. Studies on TLR signaling pathway genes in Zhikong scallop ( Chlamys farreri) have mainly focused on sequence analysis and expression profiling, no research has been carried out on their localization. The chromosomal position of TLR signaling pathway genes can be valuable for assemblying scallop genome and analysizing gene regulatory networks. In the present study, five key TLR signaling pathway genes ( CfTLR, CfMyd88, CfTRAF6, CfNFκB, and CfIκB) containing bacterial artificial chromosomes (BACs) were isolated and physically mapped through fluorescence in situ hybridization on five non-homologous chromosome pairs, showing a similar distribution to another five model species. The isolation and mapping of these key immune genes of C. farreri will aid to the research on innate immunity, assignment of interested genes to chromosomes, and integration of physical, linkage and cytogenetic maps of this species.

  16. IL-10/microRNA-155/SHIP-1 signaling pathway is crucial for commensal bacteria induced spontaneous colitis.

    PubMed

    Li, Yi; Tian, Yun; Zhu, Weiming; Gong, Jianfeng; Guo, Zhen; Guo, Feilong; Gu, Lili; Li, Jieshou

    2016-09-15

    Interleukin 10 (IL-10) microRNA-155 (miR-155)/Src homology 2 domain-containing inositol 5-phosphatase 1 (SHIP-1) signaling pathway plays an important role in maintaining immune homeostasis. We aimed to determine and characterize the changes induced by commensal bacteria on the IL-10/miR-155/SHIP-1 signaling pathway, as well as the potential therapeutic effects of anti-miR-155 on colitis in IL-10 deficient (IL-10(-)/(-)) mice. Age- and sex-matched C57BL/6 IL-10(-)/(-) and wild type mice were transferred from a germ-free environment to a specific pathogen free condition. Part of IL-10(-)/(-) mice were then treated with anti-miR-155. IL-10/miR-155/SHIP-1 signaling pathway was evaluated and the therapeutic effects of anti-miR-155 treatment on colitis in IL-10(-)/(-) mice was assessed. The expression and the relationship of IL-10, miR-155, and SHIP-1 were also measured in patients with active Crohn's colitis. IL-10/miR-155/SHIP-1 signaling pathway was activated in IL-10(-)/(-) mice transferring from a germ-free environment to a specific pathogen free condition. Anti-miR-155 treatment significantly ameliorated the severity of colitis in IL-10(-)/(-) mice. Additionally, administration of anti-miR-155 was associated with a restoration of SHIP-1 signaling pathway. The relationship of IL-10, miR-155, and SHIP-1 was confirmed in human study using samples from patients with active Crohn's colitis. IL-10/miR-155/SHIP-1 pathways play a critical role in commensal bacteria induced colitis and miR-155 may be a potential therapeutic target for human inflammatory bowel disease. PMID:27395764

  17. IL-10/microRNA-155/SHIP-1 signaling pathway is crucial for commensal bacteria induced spontaneous colitis.

    PubMed

    Li, Yi; Tian, Yun; Zhu, Weiming; Gong, Jianfeng; Guo, Zhen; Guo, Feilong; Gu, Lili; Li, Jieshou

    2016-09-15

    Interleukin 10 (IL-10) microRNA-155 (miR-155)/Src homology 2 domain-containing inositol 5-phosphatase 1 (SHIP-1) signaling pathway plays an important role in maintaining immune homeostasis. We aimed to determine and characterize the changes induced by commensal bacteria on the IL-10/miR-155/SHIP-1 signaling pathway, as well as the potential therapeutic effects of anti-miR-155 on colitis in IL-10 deficient (IL-10(-)/(-)) mice. Age- and sex-matched C57BL/6 IL-10(-)/(-) and wild type mice were transferred from a germ-free environment to a specific pathogen free condition. Part of IL-10(-)/(-) mice were then treated with anti-miR-155. IL-10/miR-155/SHIP-1 signaling pathway was evaluated and the therapeutic effects of anti-miR-155 treatment on colitis in IL-10(-)/(-) mice was assessed. The expression and the relationship of IL-10, miR-155, and SHIP-1 were also measured in patients with active Crohn's colitis. IL-10/miR-155/SHIP-1 signaling pathway was activated in IL-10(-)/(-) mice transferring from a germ-free environment to a specific pathogen free condition. Anti-miR-155 treatment significantly ameliorated the severity of colitis in IL-10(-)/(-) mice. Additionally, administration of anti-miR-155 was associated with a restoration of SHIP-1 signaling pathway. The relationship of IL-10, miR-155, and SHIP-1 was confirmed in human study using samples from patients with active Crohn's colitis. IL-10/miR-155/SHIP-1 pathways play a critical role in commensal bacteria induced colitis and miR-155 may be a potential therapeutic target for human inflammatory bowel disease.

  18. The Stress-Activated Signaling (SAS) Pathways of a Human Fungal Pathogen, Cryptococcus neoformans.

    PubMed

    Jung, Kwang-Woo; Bahn, Yong-Sun

    2009-09-01

    Cryptococcus neoformans is a basidiomycete human fungal pathogen that causes meningoencephalitis in both immunocompromised and immunocompetent individuals. The ability to sense and respond to diverse extracellular signals is essential for the pathogen to infect and cause disease in the host. Four major stress-activated signaling (SAS) pathways have been characterized in C. neoformans, including the HOG (high osmolarity glycerol response), PKC/Mpk1 MAPK (mitogen-activated protein kinase), calcium-dependent calcineurin, and RAS signaling pathways. The HOG pathway in C. neoformans not only controls responses to diverse environmental stresses, including osmotic shock, UV irradiation, oxidative stress, heavy metal stress, antifungal drugs, toxic metabolites, and high temperature, but also regulates ergosterol biosynthesis. The PKC (Protein kinase C)/Mpk1 pathway in C. neoformans is involved in a variety of stress responses, including osmotic, oxidative, and nitrosative stresses and breaches of cell wall integrity. The Ca(2+)/calmodulin- and Ras-signaling pathways also play critical roles in adaptation to certain environmental stresses, such as high temperature and sexual differentiation. Perturbation of the SAS pathways not only impairs the ability of C. neoformans to resist a variety of environmental stresses during host infection, but also affects production of virulence factors, such as capsule and melanin. A drug(s) capable of targeting signaling components of the SAS pathway will be effective for treatment of cryptococcosis.

  19. Regulation of the Hippo-YAP pathway by G-protein coupled receptor signaling

    PubMed Central

    Yu, Fa-Xing; Zhao, Bin; Panupinthu, Nattapon; Jewell, Jenna L.; Lian, Ian; Wang, Lloyd H.; Zhao, Jiagang; Yuan, Haixin; Tumaneng, Karen; Li, Hairi; Fu, Xiang-Dong; Mills, Gordon B.; Guan, Kun-Liang

    2012-01-01

    SUMMARY The Hippo pathway is crucial in organ size control and its dysregulation contributes to tumorigenesis. However, upstream signals that regulate the mammalian Hippo pathway have remained elusive. Here we report that the Hippo pathway is regulated by G-protein coupled receptor (GPCR) signaling. Serum-borne lysophosphatidic acid (LPA) and sphingosine 1-phosphophate (S1P) act through G12/13-coupled receptors to inhibit the Hippo pathway kinases Lats1/2 thereby activating YAP and TAZ transcription co-activators, which are oncoproteins repressed by Lats1/2. YAP and TAZ are involved in LPA-induced gene expression, cell migration, and proliferation. In contrast, stimulation of Gs-coupled receptors by glucagon or epinephrine activates Lats1/2 kinase activity, thereby inhibiting YAP function. Thus, GPCR signaling can either activate or inhibit the Hippo-YAP pathway depending on the coupled G-protein. Our study identifies extracellular diffusible signals that modulate the Hippo pathway and also establishes the Hippo-YAP pathway as a critical signaling branch downstream of GPCR. PMID:22863277

  20. Teaching the Toolkit: A Laboratory Series to Demonstrate the Evolutionary Conservation of Metazoan Cell Signaling Pathways

    ERIC Educational Resources Information Center

    LeClair, Elizabeth E.

    2008-01-01

    A major finding of comparative genomics and developmental genetics is that metazoans share certain conserved, embryonically deployed signaling pathways that instruct cells as to their ultimate fate. Because the DNA encoding these pathways predates the evolutionary split of most animal groups, it should in principle be possible to clone…

  1. Immune signaling pathways activated in response to different pathogenic micro-organisms in Bombyx mori.

    PubMed

    Liu, Wei; Liu, Jiabin; Lu, Yahong; Gong, Yongchang; Zhu, Min; Chen, Fei; Liang, Zi; Zhu, Liyuan; Kuang, Sulan; Hu, Xiaolong; Cao, Guangli; Xue, Renyu; Gong, Chengliang

    2015-06-01

    The JAK/STAT, Toll, Imd, and RNAi pathways are the major signaling pathways associated with insect innate immunity. To explore the different immune signaling pathways triggered in response to pathogenic micro-organism infections in the silkworm, Bombyx mori, the expression levels of the signal transducer and activator of transcription (BmSTAT), spatzle-1 (Bmspz-1), peptidoglycan-recognition protein LB (BmPGRP-LB), peptidoglycan-recognition protein LE (BmPGRP-LE), argonaute 2 (Bmago2), and dicer-2 (Bmdcr2) genes after challenge with Escherichia coli (E. coli), Serratiamarcescens (Sm), Bacillus bombyseptieus (Bab), Beauveriabassiana (Beb), nucleopolyhedrovirus (BmNPV), cypovirus (BmCPV), bidensovirus (BmBDV), or Nosemabombycis (Nb) were determined using real-time PCR. We found that the JAK/STAT pathway could be activated by challenge with BmNPV and BmBDV, the Toll pathway could be most robustly induced by challenge with Beb, the Imd pathway was mainly activated in response to infection by E. coli and Sm, and the RNAi pathway was not activated by viral infection, but could be triggered by some bacterial infections. These findings yield insights into the immune signaling pathways activated in response to different pathogenic micro-organisms in the silkworm.

  2. On an Additive Semigraphoid Model for Statistical Networks With Application to Pathway Analysis

    PubMed Central

    Li, Bing; Chun, Hyonho; Zhao, Hongyu

    2014-01-01

    We introduce a nonparametric method for estimating non-gaussian graphical models based on a new statistical relation called additive conditional independence, which is a three-way relation among random vectors that resembles the logical structure of conditional independence. Additive conditional independence allows us to use one-dimensional kernel regardless of the dimension of the graph, which not only avoids the curse of dimensionality but also simplifies computation. It also gives rise to a parallel structure to the gaussian graphical model that replaces the precision matrix by an additive precision operator. The estimators derived from additive conditional independence cover the recently introduced nonparanormal graphical model as a special case, but outperform it when the gaussian copula assumption is violated. We compare the new method with existing ones by simulations and in genetic pathway analysis. PMID:26401064

  3. cDNA microarray reveals signaling pathways involved in hormones expression of human pituitary.

    PubMed

    Ma, Yue-Yun; Qi, Xiao-Fei; Song, Shao-Jun; Zhao, Zhan-Yong; Zhu, Zhi-Dong; Qi, Jia; Zhang, Xin; Xiao, Hua-Sheng; Teng, Yun; Han, Ze-Guang

    2005-09-01

    Pituitary, a master gland of neuroendocrine system, secretes hormones that orchestrate many physiological processes, under the regulation of multiple signaling pathways. To investigate the genes involved in hormones expression of human pituitary, homemade cDNA microarray containing 14,800 human genes/ESTs were used to profile the gene expression in both fetal and adult pituitaries. Seven hundred and twelve known genes changed over 2-fold between the both tissues. Of which, 23 genes were changed with hormones expression in aging were confirmed by RT-PCR, not only the known regulators such as Pit1, GATA4, ESRRA, GABA-A, and EMK, but also LOC55884, DUSP3, PNN, and RCL, which had not been reported to be involved in the hormones expression. Correspondingly, the mRNAs of GH, PRL, POMC, TSH-beta, FSH-beta, and LH-beta, was increased as much as 6- to 20-fold in adult pituitary than those in fetal pituitary, by real-time quantitative RT-PCR assay. In addition, the mRNAs of signaling pathways, such as cAMP-PKA-CREB, PI3K-Akt, and PKA-ERK were further investigated. Of them, it was only cAMP-PKA-CREB pathway, but not PI3K-Akt and PKA-ERK have the same expressing pattern as hormones. It suggested that cDNA microarray is highly advantages to profile the differential expressed genes that were involved in hormones expression of human pituitary, but it might ignore some responding proteins regulated posttranscriptionally.

  4. Planarian Hh signaling regulates regeneration polarity and links Hh pathway evolution to cilia

    PubMed Central

    Rink, Jochen C.; Gurley, Kyle A.; Elliott, Sarah A.; Alvarado, Alejandro Sánchez

    2010-01-01

    The Hedgehog (Hh) signaling pathway plays multiple essential roles during metazoan development, homeostasis, and disease. Although core protein components are highly conserved, the variations in Hh signal transduction mechanisms exhibited by existing model systems (Drosophila, fish, and mammals) are difficult to understand. We characterize the Hh pathway in planarians. Hh signaling is essential for establishing the Anterior/Posterior axis during regeneration by modulating wnt expression. Moreover, RNAi methods to reduce signal transduction proteins Cos2/Kif27/Kif7, Fused, or Iguana do not result in detectable Hh signaling defects; however, these proteins are essential for planarian ciliogenesis. Our study expands the understanding of Hh signaling in the animal kingdom and suggests an ancestral mechanistic link between Hh signaling and the function of cilia. PMID:19933103

  5. Helicobacter pylori virulence factor CagA promotes tumorigenesis of gastric cancer via multiple signaling pathways.

    PubMed

    Yong, Xin; Tang, Bo; Li, Bo-Sheng; Xie, Rui; Hu, Chang-Jiang; Luo, Gang; Qin, Yong; Dong, Hui; Yang, Shi-Ming

    2015-01-01

    Helicobacter pylori (H. pylori) infection is strongly associated with the development of gastric diseases but also with several extragastric diseases. The clinical outcomes caused by H. pylori infection are considered to be associated with a complex combination of host susceptibility, environmental factors and bacterial isolates. Infections involving H. pylori strains that possess the virulence factor CagA have a worse clinical outcome than those involving CagA-negative strains. It is remarkable that CagA-positive H. pylori increase the risk for gastric cancer over the risk associated with H. pylori infection alone. CagA behaves as a bacterial oncoprotein playing a key role in H. pylori-induced gastric cancer. Activation of oncogenic signaling pathways and inactivation of tumor suppressor pathways are two crucial events in the development of gastric cancer. CagA shows the ability to affect the expression or function of vital protein in oncogenic or tumor suppressor signaling pathways via several molecular mechanisms, such as direct binding or interaction, phosphorylation of vital signaling proteins and methylation of tumor suppressor genes. As a result, CagA continuously dysregulates of these signaling pathways and promotes tumorigenesis. Recent research has enriched our understanding of how CagA effects on these signaling pathways. This review summarizes the results of the most relevant studies, discusses the complex molecular mechanism involved and attempts to delineate the entire signaling pathway.

  6. Dietary influence on MAPK-signaling pathways and risk of colon and rectal cancer

    PubMed Central

    Slattery, Martha L.; Lundgreen, Abbie; Wolff, Roger K.

    2014-01-01

    Mitogen-activated protein kinase (MAPK) pathways regulate cellular functions including cell proliferation, differentiation, migration, and apoptosis. Associations between genes in the DUSP, ERK1/2, JNK, and p38 MAPK-signaling pathways and dietary factors associated with growth factors, inflammation, and oxidative stress and risk of colon and rectal cancer were evaluated. Data include colon cases (n=1555) and controls (n=1956) and rectal cases (n=754) and controls (n=959). Statistically significant interactions were observed for the MAPK-signaling pathways after adjustment for multiple comparisons. DUSP genes interacted with carbohydrates, mutagen index, calories, calcium, vitamin D, lycopene, dietary fats, folic acid, and selenium. MAPK1, MAPK3, MAPK1 and RAF1 within the ERK1/2 MAPK-signaling pathway interacted with dietary fats and cruciferous vegetables. Within the JNK MAPK-signaling pathway, interactions between MAP3K7 and protein, vitamin C, iron, folic acid, carbohydrates, and cruciferous vegetables; MAP3K10 and folic acid; MAP3K9 and lutein/zeaxanthin; MAPK8 and calcium; MAP3K3 and calcium and lutein; MAP3K1 and cruciferous vegetables. Interaction within the p38-signaling pathway included: MAPK14 with calories, carbohydrates saturated fat, selenium, vitamin C; MAP3K2 and carbohydrates, and folic acid. These data suggest that dietary factors involved in inflammation and oxidative stress interact with MAPK-signaling genes to alter risk of colorectal cancer. PMID:23859041

  7. Activation of the yeast Hippo pathway by phosphorylation-dependent assembly of signaling complexes.

    PubMed

    Rock, Jeremy M; Lim, Daniel; Stach, Lasse; Ogrodowicz, Roksana W; Keck, Jamie M; Jones, Michele H; Wong, Catherine C L; Yates, John R; Winey, Mark; Smerdon, Stephen J; Yaffe, Michael B; Amon, Angelika

    2013-05-17

    Scaffold-assisted signaling cascades guide cellular decision-making. In budding yeast, one such signal transduction pathway called the mitotic exit network (MEN) governs the transition from mitosis to the G1 phase of the cell cycle. The MEN is conserved and in metazoans is known as the Hippo tumor-suppressor pathway. We found that signaling through the MEN kinase cascade was mediated by an unusual two-step process. The MEN kinase Cdc15 first phosphorylated the scaffold Nud1. This created a phospho-docking site on Nud1, to which the effector kinase complex Dbf2-Mob1 bound through a phosphoserine-threonine binding domain, in order to be activated by Cdc15. This mechanism of pathway activation has implications for signal transmission through other kinase cascades and might represent a general principle in scaffold-assisted signaling.

  8. Conformational change of Dishevelled plays a key regulatory role in the Wnt signaling pathways

    PubMed Central

    Lee, Ho-Jin; Shi, De-Li; Zheng, Jie J

    2015-01-01

    The intracellular signaling molecule Dishevelled (Dvl) mediates canonical and non-canonical Wnt signaling via its PDZ domain. Different pathways diverge at this point by a mechanism that remains unclear. Here we show that the peptide-binding pocket of the Dvl PDZ domain can be occupied by Dvl's own highly conserved C-terminus, inducing a closed conformation. In Xenopus, Wnt-regulated convergent extension (CE) is readily affected by Dvl mutants unable to form the closed conformation than by wild-type Dvl. We also demonstrate that while Dvl cooperates with other Wnt pathway elements to activate canonical Wnt signaling, the open conformation of Dvl more effectively activates Jun N-terminal kinase (JNK). These results suggest that together with other players in the Wnt signaling pathway, the conformational change of Dvl regulates Wnt stimulated JNK activity in the non-canonical Wnt signaling. DOI: http://dx.doi.org/10.7554/eLife.08142.001 PMID:26297804

  9. Foxc2 enhances proliferation and inhibits apoptosis through activating Akt/mTORC1 signaling pathway in mouse preadipocytes

    PubMed Central

    Gan, Lu; Liu, Zhenjiang; Jin, Wei; Zhou, Zhongjie; Sun, Chao

    2015-01-01

    Forkhead box C2 (Foxc2) protein is a transcription factor in regulation of development, metabolism, and immunology. However, the regulatory mechanisms of Foxc2 on proliferation and apoptosis of preadipocytes are unclear. In this study, we found that high-fat-diet-induced obesity elevated the expression of Foxc2 and cyclin E after 6 weeks. Additionally, Foxc2 suppressed preadipocyte differentiation, increased cell counts and augmented G1-S transition of preadipocytes, along with the elevation of cyclin E expression and the reduction levels of p27 and p53. Furthermore, Foxc2 knockdown reduced early apoptotic cells with accompanying reduction of mitochondrial membrane potential and increased fragmentation of genomic DNA. We show that Foxc2 reduces the expression of Bax, caspase-9, and caspase-3 in both serum-starved and palmitic acid-induced cell apoptotic models, which confirms the anti-apoptotic role of Foxc2. Moreover, the protein kinase B (Akt)/mammalian target of rapamycin (mTOR)C1 signaling pathway and the ERK/mTORC1 signaling pathway were activated along with preadipocyte proliferation in response to Foxc2 overexpression, whereas apoptosis marker genes were downregulated during this process. Those effects were blocked by the interference of Foxc2 or signal pathways specific inhibitors. These data collectively reveal that Foxc2 enhances proliferation of preadipocytes and inhibits apoptosis of preadipocytes by activating the Akt/mTORC1 and ERK/mTORC1 signaling pathways. PMID:26113535

  10. No-dependent signaling pathways in unloaded skeletal muscle

    PubMed Central

    Shenkman, Boris S.; Nemirovskaya, Tatiana L.; Lomonosova, Yulia N.

    2015-01-01

    The main focus of the current review is the nitric oxide (NO)-mediated signaling mechanism in unloaded skeletal. Review of the published data describing muscles during physical activity and inactivity demonstrates that NO is an essential trigger of signaling processes, which leads to structural and metabolic changes of the muscle fibers. The experiments with modulation of NO-synthase (NOS) activity during muscle unloading demonstrate the ability of an activated enzyme to stabilize degradation processes and prevent development of muscle atrophy. Various forms of muscle mechanical activity, i.e., plantar afferent stimulation, resistive exercise and passive chronic stretch increase the content of neural NOS (nNOS) and thus may facilitate an increase in NO production. Recent studies demonstrate that NO-synthase participates in the regulation of protein and energy metabolism in skeletal muscle by fine-tuning and stabilizing complex signaling systems which regulate protein synthesis and degradation in the fibers of inactive muscle. PMID:26582991

  11. Signalling pathways that control vertebrate haematopoietic stem cell specification

    PubMed Central

    Clements, Wilson K.; Traver, David

    2014-01-01

    Haematopoietic stem cells (HSCs) are tissue-specific stem cells that replenish all mature blood lineages during the lifetime of an individual. Clinically, HSCs form the foundation of transplantation-based therapies for leukaemias and congenital blood disorders. Researchers have long been interested in understanding the normal signalling mechanisms that specify HSCs in the embryo, in part because recapitulating these requirements in vitro might provide a means to generate immune-compatible HSCs for transplantation. Recent embryological work has demonstrated the existence of previously unknown signalling requirements. Moreover, it is now clear that gene expression in the nearby somite is integrally involved in regulating the transition of the embryonic endothelium to a haemogenic fate. Here, we review current knowledge of the intraembryonic signals required for the specification of HSCs in vertebrates. PMID:23618830

  12. Impact of Arachidonic Acid and the Leukotriene Signaling Pathway on Vasculogenesis of Mouse Embryonic Stem Cells.

    PubMed

    Huang, Yu-Han; Sharifpanah, Fatemeh; Becker, Sven; Wartenberg, Maria; Sauer, Heinrich

    2016-01-01

    Embryonic stem (ES) cells can differentiate into various kinds of cells, such as endothelial and hematopoietic cells. In addition, some evidence suggests that inflammatory mediators such as leukotrienes (LTs), which include the 5-lipoxygenase (LOX) family, can regulate endothelial cell differentiation. In the present study, the eicosanoid precursor arachidonic acid (AA) stimulated vasculogenesis of ES cells by increasing the number of fetal liver kinase-1+ vascular progenitor cells as well as vascular structures positive for platelet endothelial cell adhesion protein-1 and vascular endothelial cadherin. The stimulation of vasculogenesis and expression of the rate-limiting enzyme in the LT signaling pathway, 5-LOX-activating protein (FLAP), was blunted upon treatment with the FLAP inhibitors AM643 and REV5901. Vasculogenesis was significantly restored upon exogenous addition of LTs. Downstream of FLAP, the LTB4 receptor (BLT1) blocker U75302, the BLT2 receptor blocker LY255283 as well as the cysteinyl LT blocker BAY-u9773 inhibited vasculogenesis of ES cells. AA treatment of differentiating ES cells increased reactive oxygen species (ROS) generation, which was not affected upon either FLAP or cyclooxygenase-2 inhibition. Prevention of ROS generation by either the free radical scavengers vitamin E and N-(2-mercaptopropionyl)glycine or the NADPH oxidase inhibitor VAS2870 downregulated vasculogenesis of ES cells and blunted the provasculogenic effect of AA. In summary, our data demonstrate that proinflammatory AA stimulates vasculogenesis of ES cells via the LT pathway by mechanisms involving ROS generation. PMID:27198524

  13. An additional channel for FM signal transmission in standard fiber-optic AM communication lines

    NASA Astrophysics Data System (ADS)

    Lebedev, V. V.; Anufriev, K. M.; Toguzov, N. V.; Il'ichev, I. V.; Shamray, A. V.

    2015-11-01

    A paradigm has been developed according to which an additional FM signal transfer channel is formed in a standard optical fiber transmission line without violating the main AM channel operation. Using the proposed approach, an RS-232 interface signal has been experimentally transferred via a standard intraobject 100-Mbit Ethernet line based on an SMF-28 single-mode optical fiber.

  14. Regulation of PCP by the Fat signaling pathway

    PubMed Central

    Matis, Maja; Axelrod, Jeffrey D.

    2013-01-01

    Planar cell polarity (PCP) in epithelia, orthogonal to the apical–basal axis, is essential for numerous developmental events and physiological functions. Drosophila model systems have been at the forefront of studies revealing insights into mechanisms regulating PCP and have revealed distinct signaling modules. One of these, involving the atypical cadherins Fat and Dachsous and the ectokinase Four-jointed, appears to link the direction of cell polarization to the tissue axes. We discuss models for the function of this signaling module as well as several unanswered questions that may guide future investigations. PMID:24142873

  15. The role of APE/Ref-1 signaling pathway in hepatocellular carcinoma progression.

    PubMed

    Yang, Zhen; Yang, Sun; Misner, Bobbye J; Liu-Smith, Feng; Meyskens, Frank L

    2014-11-01

    Hepatocellular carcinoma (HCC) is responsible for a third of the estimated cancer-caused deaths worldwide. To deeply understand the mechanisms controlling HCC progression is of primary importance to develop new approaches for treatment. Apurinic/apyrimidinic endonuclease-1/redox effector factor 1 (APE/Ref-1) has been uncovered elevated in various types of cancer, including HCC. Additionally, HCC progression is always correlated with elevated copper (Cu). Our previous data demonstrated that Cu treatment initiated APE/Ref-1 expression and its downstream targets. Therefore, we hypothesized that APE/Ref-1 may be involved in HCC progression through mediating the effect of Cu to its signaling cascades. Following different treatments, human HCC cell line (Hep3B) and immortalized non-malignant hepatocyte cell line (THLE3) were analyzed to explore the role of APE/Ref-1 signaling pathway. Unstained human tissue microarrays (TMA) were subjected to IHC analysis to study the relationship between APE/Ref-1 expression and clinic features. APE/Ref-1 was upregulated in HCC cells consistent with the strong expression of APE/Ref-1 in HCC tissue microarray. Greater cytoplasmic accumulation of APE/Ref-1 was found in poorly differentiated and more aggressive tumors. Also we provide evidence to show that APE/Ref-1 signaling pathway stimulates cellular proliferation, enhances anti-apoptosis, and facilitates metastasis through experimental knockdown of APE/Ref-1 using siRNA in Hep3B cells or overexpressing APE/Ref-1 in THLE3 cells. These results define a novel role of APE/Ref-1 in HCC progression as being an important mediating and potentiating molecule, and also provide a basis for further investigations utilizing appropriate APE/Ref-1 inhibitors in combination with chemo-drugs for HCC treatment.

  16. ERK- and JNK-Dependent Signaling Pathways Contribute to Bombyx mori Nucleopolyhedrovirus Infection▿

    PubMed Central

    Katsuma, Susumu; Mita, Kazuei; Shimada, Toru

    2007-01-01

    Mitogen-activated protein kinases (MAPKs) often play important roles in virus infection. To explore intracellular signaling pathways induced by baculovirus infection, we examined the involvement of MAPKs in Bombyx mori nucleopolyhedrovirus (BmNPV) infection of BmN cells. We found that specific inhibitors of extracellular signal-regulated kinase (ERK) kinase and c-Jun NH2-terminal kinase (JNK) significantly reduced occlusion body (OB) formation and budded virus (BV) production. Next, we quantified OB and BV production after applying the inhibitors at different times postinfection (p.i.). The inhibitors significantly reduced OB and BV production to various extents when applied at 12 h p.i., indicating that the reduction of BmNPV infectivity by these inhibitors occurs at the late stage of infection. Also, we observed that these inhibitors markedly repressed or deregulated the expression of delayed early, late, and very late gene products. Western blot analysis using phospho-MAPK-specific antibodies showed that ERK and JNK were activated at the late stage of BmNPV infection. In addition, the magnitude and pattern of MAPK activation were dependent on the multiplicity of infection. To verify the effects of the inhibitors on BmNPV infection, we also attempted to knock down the B. mori genes BmErk and BmJnk, which encode ERK and JNK, respectively. Knockdown of BmErk and BmJnk resulted in the reduced production of OBs and BVs, confirming that BmERK and BmJNK are involved in the BmNPV infection process. Taken together, these results indicate that the activation of MAPK signaling pathways is required for efficient infection by BmNPV. PMID:17913811

  17. Titanium With Nanotopography Induces Osteoblast Differentiation by Regulating Endogenous Bone Morphogenetic Protein Expression and Signaling Pathway.

    PubMed

    M S Castro-Raucci, Larissa; S Francischini, Marcelo; N Teixeira, Lucas; P Ferraz, Emanuela; B Lopes, Helena; T de Oliveira, Paulo; Hassan, Mohammad Q; Losa, Adalberto L; Beloti, Marcio M

    2016-07-01

    We aimed at evaluating the effect of titanium (Ti) with nanotopography (Nano) on the endogenous expression of BMP-2 and BMP-4 and the relevance of this process to the nanotopography-induced osteoblast differentiation. MC3T3-E1 cells were grown on Nano and machined (Machined) Ti surfaces and the endogenous BMP-2/4 expression and the effect of BMP receptor BMPR1A silencing in both osteoblast differentiation and expression of genes related to TGF-β/BMP signaling were evaluated. Nano supported higher BMP-2 gene and protein expression and upregulated the osteoblast differentiation compared with Machined Ti surface. The BMPR1A silencing inhibited the osteogenic potential induced by Nano Ti surface as indicated by reduced alkaline phosphatase (ALP), osteocalcin and RUNX2 gene expression, RUNX2 protein expression and ALP activity. In addition, the expression of genes related to TGF-β/BMP signaling was deeply affected by BMPR1A-silenced cells grown on Nano Ti surface. In conclusion, we have demonstrated for the first time that nanotopography induces osteoblast differentiation, at least in part, by upregulating the endogenous production of BMP-2 and modulating BMP signaling pathway. J. Cell. Biochem. 117: 1718-1726, 2016. © 2015 Wiley Periodicals, Inc. PMID:26681207

  18. Computational discovery of Epstein-Barr virus targeted human genes and signalling pathways

    PubMed Central

    Mei, Suyu; Zhang, Kun

    2016-01-01

    Epstein-Barr virus (EBV) plays important roles in the origin and the progression of human carcinomas, e.g. diffuse large B cell tumors, T cell lymphomas, etc. Discovering EBV targeted human genes and signaling pathways is vital to understand EBV tumorigenesis. In this study we propose a noise-tolerant homolog knowledge transfer method to reconstruct functional protein-protein interactions (PPI) networks between Epstein-Barr virus and Homo sapiens. The training set is augmented via homolog instances and the homolog noise is counteracted by support vector machine (SVM). Additionally we propose two methods to define subcellular co-localization (i.e. stringent and relaxed), based on which to further derive physical PPI networks. Computational results show that the proposed method achieves sound performance of cross validation and independent test. In the space of 648,672 EBV-human protein pairs, we obtain 51,485 functional interactions (7.94%), 869 stringent physical PPIs and 46,050 relaxed physical PPIs. Fifty-eight evidences are found from the latest database and recent literature to validate the model. This study reveals that Epstein-Barr virus interferes with normal human cell life, such as cholesterol homeostasis, blood coagulation, EGFR binding, p53 binding, Notch signaling, Hedgehog signaling, etc. The proteome-wide predictions are provided in the supplementary file for further biomedical research. PMID:27470517

  19. hCLP46 regulates U937 cell proliferation via Notch signaling pathway

    SciTech Connect

    Ma, Wenzhan; Du, Jie; Chu, Qiaoyun; Wang, Youxin; Liu, Lixin; Song, Manshu; Wang, Wei

    2011-04-29

    Highlights: {yields} Knock down of hCLP46 by RNAi impairs mammalian Notch signaling. {yields} hCLP46 affects neither cell surface Notch1 expression nor ligand-receptor binding. {yields} Knock down of hCLP46 inhibits U937 cell-growth by up-regulation of CDKN1B. -- Abstract: Human CAP10-like protein 46 kDa (hCLP46) is the homolog of Rumi, which is the first identified protein O-glucosyltransferase that modifies Notch receptor in Drosophila. Dysregulation of hCLP46 occurs in many hematologic diseases, but the role of hCLP46 remains unclear. Knockdown of hCLP46 by RNA interference resulted in decreased protein levels of endogenous Notch1, Notch intracellular domain (NICD) and Notch target gene Hes-1, suggesting the impairment of the Notch signaling. However, neither cell surface Notch expression nor ligand binding activities were affected. In addition, down-regulated expression of hCLP46 inhibited the proliferation of U937 cells, which was correlated with increased cyclin-dependent kinase inhibitor (CDKI) CDKN1B (p27) and decreased phosphorylation of retinoblastoma (RB) protein. We showed that lack of hCLP46 results in impaired ligand induced Notch activation in mammalian cell, and hCLP46 regulates the proliferation of U937 cell through CDKI-RB signaling pathway, which may be important for the pathogenesis of leukemia.

  20. The mitochondrial Ca2+ uniporter: regulation by auxiliary subunits and signal transduction pathways.

    PubMed

    Jhun, Bong Sook; Mishra, Jyotsna; Monaco, Sarah; Fu, Deming; Jiang, Wenmin; Sheu, Shey-Shing; O-Uchi, Jin

    2016-07-01

    Mitochondrial Ca(2+) homeostasis, the Ca(2+) influx-efflux balance, is responsible for the control of numerous cellular functions, including energy metabolism, generation of reactive oxygen species, spatiotemporal dynamics of Ca(2+) signaling, and cell growth and death. Recent discovery of the molecular identity of the mitochondrial Ca(2+) uniporter (MCU) provides new possibilities for application of genetic approaches to study the mitochondrial Ca(2+) influx mechanism in various cell types and tissues. In addition, the subsequent discovery of various auxiliary subunits associated with MCU suggests that mitochondrial Ca(2+) uptake is not solely regulated by a single protein (MCU), but likely by a macromolecular protein complex, referred to as the MCU-protein complex (mtCUC). Moreover, recent reports have shown the potential role of MCU posttranslational modifications in the regulation of mitochondrial Ca(2+) uptake through mtCUC. These observations indicate that mtCUCs form a local signaling complex at the inner mitochondrial membrane that could significantly regulate mitochondrial Ca(2+) handling, as well as numerous mitochondrial and cellular functions. In this review we discuss the current literature on mitochondrial Ca(2+) uptake mechanisms, with a particular focus on the structure and function of mtCUC, as well as its regulation by signal transduction pathways, highlighting current controversies and discrepancies.

  1. The Gordon Wilson Lecture: Neurohormonal Signaling Pathways That Link Cardiac Growth and Death

    PubMed Central

    Dorn, Gerald W.

    2007-01-01

    Far from being a simple muscular pump, the heart senses changes in hemodynamic forces and neurohormonal signaling, and responds by elaborating autocrine and paracrine factors that self-regulate cardiomyocyte contraction, growth, and programmed death. Interference with the afferent or efferent arms of this stress-response mechanism, as with inhibition of the β-adrenergic or renin/angiotensin systems, is a mainstay of pharmacological therapy for heart failure. However, despite striking group-mean effects showing mortality benefits of neurohormonal antagonists, inter-individual variability in the therapeutic response to these agents suggests a pharmacogenomic interaction, where common sequence variations of genes that regulate neurohormonal signaling modify the individual response to treatment. Furthermore, there is increasing evidence that, depending upon physiological milieu, conventional neurohormone receptor-ligand pairs can activate non-traditional signaling pathways, with pathological consequences. Recently, studies that integrate the findings from human gene polymorphism discovery, recombinant gene variant expression in cell and animal models, and outcome or risk analysis of polymorphisms in human disease have provided additional understanding into adaptive and maladaptive events that are the consequence of the cardiac stress-response sequence. PMID:18528498

  2. Lhx9 gene expression during early limb development in mice requires the FGF signalling pathway.

    PubMed

    Yang, Yisheng; Wilson, Megan J

    2015-01-01

    Lhx9 is a member of the LIM-homeodomain gene family necessary for the correct development of many organs including gonads, limbs, heart and the nervous system. In the context of limb development, Lhx9 has been implicated as an integrator for Fibroblast growth factor (FGF) and Sonic hedgehog (Shh) signalling required for proximal-distal (PD) and anterior-posterior (AP) development of the limb. Three splice variants of the Lhx9 transcript are expressed during development, two of which are predicted to act in a dominant negative fashion, competing with the DNA binding version of Lhx9 for binding to cofactors via the LIM-domain. We examined the expression pattern for the three alternative splice forms of Lhx9; Lhx9α, Lhx9β and Lhx9c during early limb development. We have found that of the three Lhx9 isoforms, only Lhx9α and Lhx9c (intact homeodomain) are expressed during early limb development, each with their own distinct expression pattern. Additionally we determined that Lhx9 expression overlaps with FGF10 expression in the developing limb bud mesenchyme. Limb bud explant cultures, in the presence of signalling pathway inhibitors, also indicated that Lhx9 mRNA expression in the limb bud was dependent on FGF signalling. PMID:26220830

  3. Computational discovery of Epstein-Barr virus targeted human genes and signalling pathways.

    PubMed

    Mei, Suyu; Zhang, Kun

    2016-01-01

    Epstein-Barr virus (EBV) plays important roles in the origin and the progression of human carcinomas, e.g. diffuse large B cell tumors, T cell lymphomas, etc. Discovering EBV targeted human genes and signaling pathways is vital to understand EBV tumorigenesis. In this study we propose a noise-tolerant homolog knowledge transfer method to reconstruct functional protein-protein interactions (PPI) networks between Epstein-Barr virus and Homo sapiens. The training set is augmented via homolog instances and the homolog noise is counteracted by support vector machine (SVM). Additionally we propose two methods to define subcellular co-localization (i.e. stringent and relaxed), based on which to further derive physical PPI networks. Computational results show that the proposed method achieves sound performance of cross validation and independent test. In the space of 648,672 EBV-human protein pairs, we obtain 51,485 functional interactions (7.94%), 869 stringent physical PPIs and 46,050 relaxed physical PPIs. Fifty-eight evidences are found from the latest database and recent literature to validate the model. This study reveals that Epstein-Barr virus interferes with normal human cell life, such as cholesterol homeostasis, blood coagulation, EGFR binding, p53 binding, Notch signaling, Hedgehog signaling, etc. The proteome-wide predictions are provided in the supplementary file for further biomedical research. PMID:27470517

  4. Conservation, duplication, and loss of the Tor signaling pathway in the fungal kingdom

    PubMed Central

    2010-01-01

    Background The nutrient-sensing Tor pathway governs cell growth and is conserved in nearly all eukaryotic organisms from unicellular yeasts to multicellular organisms, including humans. Tor is the target of the immunosuppressive drug rapamycin, which in complex with the prolyl isomerase FKBP12 inhibits Tor functions. Rapamycin is a gold standard drug for organ transplant recipients that was approved by the FDA in 1999 and is finding additional clinical indications as a chemotherapeutic and antiproliferative agent. Capitalizing on the plethora of recently sequenced genomes we have conducted comparative genomic studies to annotate the Tor pathway throughout the fungal kingdom and related unicellular opisthokonts, including Monosiga brevicollis, Salpingoeca rosetta, and Capsaspora owczarzaki. Results Interestingly, the Tor signaling cascade is absent in three microsporidian species with available genome sequences, the only known instance of a eukaryotic group lacking this conserved pathway. The microsporidia are obligate intracellular pathogens with highly reduced genomes, and we hypothesize that they lost the Tor pathway as they adapted and streamlined their genomes for intracellular growth in a nutrient-rich environment. Two TOR paralogs are present in several fungal species as a result of either a whole genome duplication or independent gene/segmental duplication events. One such event was identified in the amphibian pathogen Batrachochytrium dendrobatidis, a chytrid responsible for worldwide global amphibian declines and extinctions. Conclusions The repeated independent duplications of the TOR gene in the fungal kingdom might reflect selective pressure acting upon this kinase that populates two proteinaceous complexes with different cellular roles. These comparative genomic analyses illustrate the evolutionary trajectory of a central nutrient-sensing cascade that enables diverse eukaryotic organisms to respond to their natural environments. PMID:20863387

  5. Phytohormones Signaling Pathways and ROS Involvement in Seed Germination.

    PubMed

    Oracz, Krystyna; Karpiński, Stanisław

    2016-01-01

    Phytohormones and reactive oxygen species (ROS) are major determinants of the regulation of development and stress responses in plants. During life cycle of these organisms, signaling networks of plant growth regulators and ROS interact in order to render an appropriate developmental and environmental response. In plant's photosynthetic (e.g., leaves) and non-photosynthetic (e.g., seeds) tissues, enhanced and suboptimal ROS production is usually associated with stress, which in extreme cases can be lethal to cells, a whole organ or even an organism. However, controlled production of ROS is appreciated for cellular signaling. Despite the current progress that has been made in plant biology and increasing number of findings that have revealed roles of ROS and hormonal signaling in germination, some questions still arise, e.g., what are the downstream protein targets modified by ROS enabling stimulus-specific cellular responses of the seed? Or which molecular regulators allow ROS/phytohormones interactions and what is their function in seed life? In this particular review the role of some transcription factors, kinases and phosphatases is discussed, especially those which usually known to be involved in ROS and hormonal signal transduction under stress in plants, may also play a role in the regulation of processes occurring in seeds. The summarized recent findings regarding particular ROS- and phytohormones-related regulatory proteins, as well as their integration, allowed to propose a novel, possible model of action of LESION SIMULATING DISEASE 1, ENHANCED DISEASE SUSCEPTIBILITY 1, and PHYTOALEXIN DEFICIENT 4 functioning during seeds life.

  6. Tyrosine-based signal mediates LRP6 receptor endocytosis and desensitization of Wnt/β-catenin pathway signaling.

    PubMed

    Liu, Chia-Chen; Kanekiyo, Takahisa; Roth, Barbara; Bu, Guojun

    2014-10-01

    Wnt/β-catenin signaling orchestrates a number of critical events including cell growth, differentiation, and cell survival during development. Misregulation of this pathway leads to various human diseases, specifically cancers. Endocytosis and phosphorylation of the LDL receptor-related protein 6 (LRP6), an essential co-receptor for Wnt/β-catenin signaling, play a vital role in mediating Wnt/β-catenin signal transduction. However, its regulatory mechanism is not fully understood. In this study, we define the mechanisms by which LRP6 endocytic trafficking regulates Wnt/β-catenin signaling activation. We show that LRP6 mutant with defective tyrosine-based signal in its cytoplasmic tail has an increased cell surface distribution and decreased endocytosis rate. These changes in LRP6 endocytosis coincide with an increased distribution to caveolae, increased phosphorylation, and enhanced Wnt/β-catenin signaling. We further demonstrate that treatment of Wnt3a ligands or blocking the clathrin-mediated endocytosis of LRP6 leads to a redistribution of wild-type receptor to lipid rafts. The LRP6 tyrosine mutant also exhibited an increase in signaling activation in response to Wnt3a stimulation when compared with wild-type LRP6, and this activation is suppressed when caveolae-mediated endocytosis is blocked. Our results reveal molecular mechanisms by which LRP6 endocytosis routes regulate its phosphorylation and the strength of Wnt/β-catenin signaling, and have implications on how this pathway can be modulated in human diseases.

  7. β-adrenergic receptor agonist, Compound 49b, inhibits TLR4 signaling pathway in diabetic retina

    PubMed Central

    Berger, Elizabeth A.; Carion, Thomas W.; Jiang, Youde; Liu, Li; Chahine, Adam; Walker, Robert Jason; Steinle, Jena J.

    2016-01-01

    Diabetic retinopathy has recently become associated with complications similar to chronic inflammatory diseases. While it is clear that tumor necrosis factor- alpha (TNF-α) is increased in diabetes, the role of innate immunity is only recently being investigated. As such, we hypothesized that diabetes would increase toll-like receptor 4 (TLR4) signaling, which could be inhibited by a β-adrenergic receptor agonist (Compound 49b) previously shown to have anti-inflammatory actions. In order to investigate β-adrenergic receptor signaling and TLR4 in the diabetic retina, streptozotocin-injected diabetic mice, as well as human primary retinal endothelial cells (REC) and rat retinal Müller cells (rMC-1) exposed to high glucose (25mM), were treated with a novel β-adrenergic receptor agonist, Compound 49b (50nM), or PBS (control). TLR4 and its downstream signaling partners (MyD88, IRAK1, TRAF6, total and phosphorylated NF-κB) were examined. In addition, we assessed high mobility box group 1 (HMGB1) protein levels. Our data showed that diabetes or high glucose culture conditions significantly increased TLR4 and downstream signaling partners. Compound 49b was able to significantly reduce TLR4 and related molecules in the diabetic animal and retinal cells. HMGB1 was significantly increased in REC and Müller cells grown in high glucose, which was subsequently reduced with Compound 49b treatment. Our findings suggest that high glucose may increase HMGB1 levels that lead to increased TLR4 signaling. Compound 49b significantly inhibited this pathway providing a potential mechanism for its protective actions. PMID:26888251

  8. MyD88-dependent Toll-like receptor 4 signal pathway in intervertebral disc degeneration

    PubMed Central

    Qin, Chuqiang; Zhang, Bo; Zhang, Liang; Zhang, Zhi; Wang, Le; Tang, Long; Li, Shuangqing; Yang, Yixi; Yang, Fuguo; Zhang, Ping; Yang, Bo

    2016-01-01

    Lower back pain (LBP) is a common and remitting problem. One of the primary causes of LBP is thought to be degeneration of the intervertebral disc (IVD). The aim of the present study was to investigate the role of the myeloid differentiation primary-response protein 88 (MyD88)-dependent Toll-like receptor 4 (TLR4) signal pathway in the mechanism of IVD degeneration. IVD nucleus pulposus cells isolated and cultured from the lumbar vertebrae of Wistar rats were stimulated by various doses of lipopolysaccharide (LPS; 0.1, 1, 10 and 100 µg/ml) to simulate IVD degeneration. Cells were rinsed and cultured in serum-free Dulbecco's modified Eagle's medium/F12. Reverse transcription-quantitative polymerase chain reaction was used to determine the levels of TLR4, MyD88, tumor necrosis factor α (TNFα), and interleukin-1β (IL-1β) mRNA expression after 1, 3, 6, 9 and 12 h of incubation. Additionally, western blot and enzyme-linked immunosorbent assay analyses were used to determine the levels of TLR4, MyD88, TNFα, and IL-1β protein expression after 24, 48 and 72 h of incubation. The levels of TLR4, MyD88, TNFα and IL-1β mRNA all increased in the cells stimulated by 10 µg/ml LPS at 3, 6 and 9 h (all P<0.001). Furthermore, the levels of TLR4, MyD88, TNFα and IL-1β protein all increased at 24, 48 and 72 h (all P<0.001). Additionally, the mRNA and protein levels of TLR4, MyD88, TNFα and IL-1β increased significantly in the cells stimulated by 1, 10 and 100 µg/ml LPS compared with the control group, and reached a peak in the 10 µg/ml LPS group (all P<0.001). These results suggest that the MyD88-dependent TLR4 signal pathway is a target pathway in IVD degeneration. This pathway is time phase- and dose-dependent, and when activated can lead to the release of inflammatory factors that participate in IVD degeneration. PMID:27446251

  9. Yeast as a tool to study signaling pathways in mitochondrial stress response and cytoprotection.

    PubMed

    Zdralević, Maša; Guaragnella, Nicoletta; Antonacci, Lucia; Marra, Ersilia; Giannattasio, Sergio

    2012-01-01

    Cell homeostasis results from the balance between cell capability to adapt or succumb to environmental stress. Mitochondria, in addition to supplying cellular energy, are involved in a range of processes deciding about cellular life or death. The crucial role of mitochondria in cell death is well recognized. Mitochondrial dysfunction has been associated with the death process and the onset of numerous diseases. Yet, mitochondrial involvement in cellular adaptation to stress is still largely unexplored. Strong interest exists in pharmacological manipulation of mitochondrial metabolism and signaling. The yeast Saccharomyces cerevisiae has proven a valuable model organism in which several intracellular processes have been characterized in great detail, including the retrograde response to mitochondrial dysfunction and, more recently, programmed cell death. In this paper we review experimental evidences of mitochondrial involvement in cytoprotection and propose yeast as a model system to investigate the role of mitochondria in the cross-talk between prosurvival and prodeath pathways. PMID:22454613

  10. Yeast as a Tool to Study Signaling Pathways in Mitochondrial Stress Response and Cytoprotection

    PubMed Central

    Ždralević, Maša; Guaragnella, Nicoletta; Antonacci, Lucia; Marra, Ersilia; Giannattasio, Sergio

    2012-01-01

    Cell homeostasis results from the balance between cell capability to adapt or succumb to environmental stress. Mitochondria, in addition to supplying cellular energy, are involved in a range of processes deciding about cellular life or death. The crucial role of mitochondria in cell death is well recognized. Mitochondrial dysfunction has been associated with the death process and the onset of numerous diseases. Yet, mitochondrial involvement in cellular adaptation to stress is still largely unexplored. Strong interest exists in pharmacological manipulation of mitochondrial metabolism and signaling. The yeast Saccharomyces cerevisiae has proven a valuable model organism in which several intracellular processes have been characterized in great detail, including the retrograde response to mitochondrial dysfunction and, more recently, programmed cell death. In this paper we review experimental evidences of mitochondrial involvement in cytoprotection and propose yeast as a model system to investigate the role of mitochondria in the cross-talk between prosurvival and prodeath pathways. PMID:22454613

  11. Hormone-Mediated Intercellular Calcium Signalling in an Insect Salivary Gland Pathways and Mechanisms

    NASA Astrophysics Data System (ADS)

    Zimmermann, Bernhard; Walz, Bernd

    The salivary glands of the blowfly Calliphora vicina are a favourable preparation for investigations into spatio-temporal Ca 2+ dynamics in an intact miniorgan by using Ca 2+-sensitive indicator dyes and digital imaging techniques, including confocal microscopy, in combination with pharmacological approaches. The review summarizes the available data on the spatio-temporal patterns of the hormone-induced and IP 3-mediated Ca 2+ dynamics at both the intracellular and the intercellular level (intra- and intercellular Ca 2+ waves). The underlying signaling mechanisms are addressed, as well as the pathways of intercellular communication responsible for the complex spatio-temporal Ca 2+ dynamics. In addition, we review evidence for the exchange of Ca 2+ between IP 3 sensitive intracellular Ca 2+ stores and mitochondria including a modulatory effect of mitochondrial Ca 2+ uptake on the frequency of IP 3-induced Ca 2+ spiking.

  12. Adapting the Stress Response: Viral Subversion of the mTOR Signaling Pathway.

    PubMed

    Le Sage, Valerie; Cinti, Alessandro; Amorim, Raquel; Mouland, Andrew J

    2016-01-01

    The mammalian target of rapamycin (mTOR) is a central regulator of gene expression, translation and various metabolic processes. Multiple extracellular (growth factors) and intracellular (energy status) molecular signals as well as a variety of stressors are integrated into the mTOR pathway. Viral infection is a significant stress that can activate, reduce or even suppress the mTOR signaling pathway. Consequently, viruses have evolved a plethora of different mechanisms to attack and co-opt the mTOR pathway in order to make the host cell a hospitable environment for replication. A more comprehensive knowledge of different viral interactions may provide fruitful targets for new antiviral drugs.

  13. Involvement of the PI3K and ERK signaling pathways in largemouth bass virus-induced apoptosis and viral replication.

    PubMed

    Huang, Xiaohong; Wang, Wei; Huang, Youhua; Xu, Liwen; Qin, Qiwei

    2014-12-01

    Increased reports demonstrated that largemouth Bass, Micropterus salmoides in natural and artificial environments were always suffered from an emerging iridovirus disease, largemouth Bass virus (LMBV). However, the underlying mechanism of LMBV pathogenesis remained largely unknown. Here, we investigated the cell signaling events involved in virus induced cell death and viral replication in vitro. We found that LMBV infection in epithelioma papulosum cyprini (EPC) cells induced typical apoptosis, evidenced by the appearance of apoptotic bodies, cytochrome c release, mitochondrial membrane permeabilization (MMP) destruction and reactive oxygen species (ROS) generation. Two initiators of apoptosis, caspase-8 and caspase-9, and the executioner of apoptosis, caspase-3, were all significantly activated with the infection time, suggested that not only mitochondrion-mediated, but also death receptor-mediated apoptosis were involved in LMBV infection. Reporter gene assay showed that the promoter activity of transcription factors including p53, NF-κB, AP-1 and cAMP response element-binding protein (CREB) were decreased during LMBV infection. After treatment with different signaling pathway inhibitors, virus production were significantly suppressed by the inhibition of phosphatidylinositol 3-kinase (PI3K) pathway and extracellular-signal-regulated kinases (ERK) signaling pathway. Furthermore, LMBV infection induced apoptosis was enhanced by PI3K inhibitor LY294002, but decreased by addition of ERK inhibitor UO126. Therefore, we speculated that apoptosis was sophisticatedly regulated by a series of cell signaling events for efficient virus propagation. Taken together, our results provided new insights into the molecular mechanism of ranavirus infection. PMID:25260912

  14. Pronounced Phenotypic Changes in Transgenic Tobacco Plants Overexpressing Sucrose Synthase May Reveal a Novel Sugar Signaling Pathway

    PubMed Central

    Nguyen, Quynh Anh; Luan, Sheng; Wi, Seung G.; Bae, Hanhong; Lee, Dae-Seok; Bae, Hyeun-Jong

    2016-01-01

    Soluble sugars not only serve as nutrients, but also act as signals for plant growth and development, but how sugar signals are perceived and translated into physiological responses in plants remains unclear. We manipulated sugar levels in transgenic plants by overexpressing sucrose synthase (SuSy), which is a key enzyme believed to have reversible sucrose synthesis and sucrose degradation functions. The ectopically expressed SuSy protein exhibited sucrose-degrading activity, which may change the flux of sucrose demand from photosynthetic to non-photosynthetic cells, and trigger an unknown sucrose signaling pathway that lead to increased sucrose content in the transgenic plants. An experiment on the transition from heterotrophic to autotrophic growth demonstrated the existence of a novel sucrose signaling pathway, which stimulated photosynthesis, and enhanced photosynthetic synthesis of sucrose, which was the direct cause or the sucrose increase. In addition, a light/dark time treatment experiment, using different day length ranges for photosynthesis/respiration showed the carbohydrate pattern within a 24-h day and consolidated the role of sucrose signaling pathway as a way to maintain sucrose demand, and indicated the relationships between increased sucrose and upregulation of genes controlling development of the shoot apical meristem (SAM). As a result, transgenic plants featured a higher biomass and a shorter time required to switch to reproduction compared to those of control plants, indicating altered phylotaxis and more rapid advancement of developmental stages in the transgenic plants. PMID:26793204

  15. Involvement of the PI3K and ERK signaling pathways in largemouth bass virus-induced apoptosis and viral replication.

    PubMed

    Huang, Xiaohong; Wang, Wei; Huang, Youhua; Xu, Liwen; Qin, Qiwei

    2014-12-01

    Increased reports demonstrated that largemouth Bass, Micropterus salmoides in natural and artificial environments were always suffered from an emerging iridovirus disease, largemouth Bass virus (LMBV). However, the underlying mechanism of LMBV pathogenesis remained largely unknown. Here, we investigated the cell signaling events involved in virus induced cell death and viral replication in vitro. We found that LMBV infection in epithelioma papulosum cyprini (EPC) cells induced typical apoptosis, evidenced by the appearance of apoptotic bodies, cytochrome c release, mitochondrial membrane permeabilization (MMP) destruction and reactive oxygen species (ROS) generation. Two initiators of apoptosis, caspase-8 and caspase-9, and the executioner of apoptosis, caspase-3, were all significantly activated with the infection time, suggested that not only mitochondrion-mediated, but also death receptor-mediated apoptosis were involved in LMBV infection. Reporter gene assay showed that the promoter activity of transcription factors including p53, NF-κB, AP-1 and cAMP response element-binding protein (CREB) were decreased during LMBV infection. After treatment with different signaling pathway inhibitors, virus production were significantly suppressed by the inhibition of phosphatidylinositol 3-kinase (PI3K) pathway and extracellular-signal-regulated kinases (ERK) signaling pathway. Furthermore, LMBV infection induced apoptosis was enhanced by PI3K inhibitor LY294002, but decreased by addition of ERK inhibitor UO126. Therefore, we speculated that apoptosis was sophisticatedly regulated by a series of cell signaling events for efficient virus propagation. Taken together, our results provided new insights into the molecular mechanism of ranavirus infection.

  16. Metallofullerene nanoparticles promote osteogenic differentiation of bone marrow stromal cells through BMP signaling pathway

    NASA Astrophysics Data System (ADS)

    Yang, Kangning; Cao, Weipeng; Hao, Xiaohong; Xue, Xue; Zhao, Jing; Liu, Juan; Zhao, Yuliang; Meng, Jie; Sun, Baoyun; Zhang, Jinchao; Liang, Xing-Jie

    2013-01-01

    Although endohedral metallofullerenol [Gd@C82(OH)22]n nanoparticles have anti-tumor efficiency and mostly deposit in the bones of mice, how these nanoparticles act in bone marrow stromal cells (MSCs) remains largely unknown. Herein, we observed that [Gd@C82(OH)22]n nanoparticles facilitated the differentiation of MSCs toward osteoblasts, as evidenced by the enhancement of alkaline phosphatase (ALP) activity and mineralized nodule formation upon [Gd@C82(OH)22]n nanoparticle treatment. Mechanistically, the effect of [Gd@C82(OH)22]n nanoparticles on ALP activity was inhibited by the addition of noggin as an inhibitor of the BMP signaling pathway. Moreover, the in vivo results of the ovariectomized rats further indicated that [Gd@C82(OH)22]n nanoparticles effectively improved bone density and prevented osteoporosis.Although endohedral metallofullerenol [Gd@C82(OH)22]n nanoparticles have anti-tumor efficiency and mostly deposit in the bones of mice, how these nanoparticles act in bone marrow stromal cells (MSCs) remains largely unknown. Herein, we observed that [Gd@C82(OH)22]n nanoparticles facilitated the differentiation of MSCs toward osteoblasts, as evidenced by the enhancement of alkaline phosphatase (ALP) activity and mineralized nodule formation upon [Gd@C82(OH)22]n nanoparticle treatment. Mechanistically, the effect of [Gd@C82(OH)22]n nanoparticles on ALP activity was inhibited by the addition of noggin as an inhibitor of the BMP signaling pathway. Moreover, the in vivo results of the ovariectomized rats further indicated that [Gd@C82(OH)22]n nanoparticles effectively improved bone density and prevented osteoporosis. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33575a

  17. Recursive ideal observer detection of known M-ary signals in multiplicative and additive Gaussian noise.

    NASA Technical Reports Server (NTRS)

    Painter, J. H.; Gupta, S. C.

    1973-01-01

    This paper presents the derivation of the recursive algorithms necessary for real-time digital detection of M-ary known signals that are subject to independent multiplicative and additive Gaussian noises. The motivating application is minimum probability of error detection of digital data-link messages aboard civil aircraft in the earth reflection multipath environment. For each known signal, the detector contains one Kalman filter and one probability computer. The filters estimate the multipath disturbance. The estimates and the received signal drive the probability computers. Outputs of all the computers are compared in amplitude to give the signal decision. The practicality and usefulness of the detector are extensively discussed.

  18. The non-canonical BMP and Wnt/β-catenin signaling pathways orchestrate early tooth development.

    PubMed

    Yuan, Guohua; Yang, Guobin; Zheng, Yuqian; Zhu, Xiaojing; Chen, Zhi; Zhang, Zunyi; Chen, YiPing

    2015-01-01

    BMP and Wnt signaling pathways play a crucial role in organogenesis, including tooth development. Despite extensive studies, the exact functions, as well as if and how these two pathways act coordinately in regulating early tooth development, remain elusive. In this study, we dissected regulatory functions of BMP and Wnt pathways in early tooth development using a transgenic noggin (Nog) overexpression model (K14Cre;pNog). It exhibits early arrested tooth development, accompanied by reduced cell proliferation and loss of odontogenic fate marker Pitx2 expression in the dental epithelium. We demonstrated that overexpression of Nog disrupted BMP non-canonical activity, which led to a dramatic reduction of cell proliferation rate but did not affect Pitx2 expression. We further identified a novel function of Nog by inhibiting Wnt/β-catenin signaling, causing loss of Pitx2 expression. Co-immunoprecipitation and TOPflash assays revealed direct binding of Nog to Wnts to functionally prevent Wnt/β-catenin signaling. In situ PLA and immunohistochemistry on Nog mutants confirmed in vivo interaction between endogenous Nog and Wnts and modulation of Wnt signaling by Nog in tooth germs. Genetic rescue experiments presented evidence that both BMP and Wnt signaling pathways contribute to cell proliferation regulation in the dental epithelium, with Wnt signaling also controlling the odontogenic fate. Reactivation of both BMP and Wnt signaling pathways, but not of only one of them, rescued tooth developmental defects in K14Cre;pNog mice, in which Wnt signaling can be substituted by transgenic activation of Pitx2. Our results reveal the orchestration of non-canonical BMP and Wnt/β-catenin signaling pathways in the regulation of early tooth development.

  19. Phosphoproteomic analyses reveal novel cross-modulation mechanisms between two signaling pathways in yeast

    PubMed Central

    Vaga, Stefania; Bernardo-Faura, Marti; Cokelaer, Thomas; Maiolica, Alessio; Barnes, Christopher A; Gillet, Ludovic C; Hegemann, Björn; van Drogen, Frank; Sharifian, Hoda; Klipp, Edda; Peter, Matthias; Saez-Rodriguez, Julio; Aebersold, Ruedi

    2014-01-01

    Cells respond to environmental stimuli via specialized signaling pathways. Concurrent stimuli trigger multiple pathways that integrate information, predominantly via protein phosphorylation. Budding yeast responds to NaCl and pheromone via two mitogen-activated protein kinase cascades, the high osmolarity, and the mating pathways, respectively. To investigate signal integration between these pathways, we quantified the time-resolved phosphorylation site dynamics after pathway co-stimulation. Using shotgun mass spectrometry, we quantified 2,536 phosphopeptides across 36 conditions. Our data indicate that NaCl and pheromone affect phosphorylation events within both pathways, which thus affect each other at more levels than anticipated, allowing for information exchange and signal integration. We observed a pheromone-induced down-regulation of Hog1 phosphorylation due to Gpd1, Ste20, Ptp2, Pbs2, and Ptc1. Distinct Ste20 and Pbs2 phosphosites responded differently to the two stimuli, suggesting these proteins as key mediators of the information exchange. A set of logic models was then used to assess the role of measured phosphopeptides in the crosstalk. Our results show that the integration of the response to different stimuli requires complex interconnections between signaling pathways. PMID:25492886

  20. Identification of Potential Drug Targets in Cancer Signaling Pathways using Stochastic Logical Models.

    PubMed

    Zhu, Peican; Aliabadi, Hamidreza Montazeri; Uludağ, Hasan; Han, Jie

    2016-03-18

    The investigation of vulnerable components in a signaling pathway can contribute to development of drug therapy addressing aberrations in that pathway. Here, an original signaling pathway is derived from the published literature on breast cancer models. New stochastic logical models are then developed to analyze the vulnerability of the components in multiple signalling sub-pathways involved in this signaling cascade. The computational results are consistent with the experimental results, where the selected proteins were silenced using specific siRNAs and the viability of the cells were analyzed 72 hours after silencing. The genes elF4E and NFkB are found to have nearly no effect on the relative cell viability and the genes JAK2, Stat3, S6K, JUN, FOS, Myc, and Mcl1 are effective candidates to influence the relative cell growth. The vulnerabilities of some targets such as Myc and S6K are found to vary significantly depending on the weights of the sub-pathways; this will be indicative of the chosen target to require customization for therapy. When these targets are utilized, the response of breast cancers from different patients will be highly variable because of the known heterogeneities in signaling pathways among the patients. The targets whose vulnerabilities are invariably high might be more universally acceptable targets.

  1. Non Linear Programming (NLP) formulation for quantitative modeling of protein signal transduction pathways.

    PubMed

    Mitsos, Alexander; Melas, Ioannis N; Morris, Melody K; Saez-Rodriguez, Julio; Lauffenburger, Douglas A; Alexopoulos, Leonidas G

    2012-01-01

    Modeling of signal transduction pathways plays a major role in understanding cells' function and predicting cellular response. Mathematical formalisms based on a logic formalism are relatively simple but can describe how signals propagate from one protein to the next and have led to the construction of models that simulate the cells response to environmental or other perturbations. Constrained fuzzy logic was recently introduced to train models to cell specific data to result in quantitative pathway models of the specific cellular behavior. There are two major issues in this pathway optimization: i) excessive CPU time requirements and ii) loosely constrained optimization problem due to lack of data with respect to large signaling pathways. Herein, we address both issues: the former by reformulating the pathway optimization as a regular nonlinear optimization problem; and the latter by enhanced algorithms to pre/post-process the signaling network to remove parts that cannot be identified given the experimental conditions. As a case study, we tackle the construction of cell type specific pathways in normal and transformed hepatocytes using medium and large-scale functional phosphoproteomic datasets. The proposed Non Linear Programming (NLP) formulation allows for fast optimization of signaling topologies by combining the versatile nature of logic modeling with state of the art optimization algorithms.

  2. Balancing act: matching growth with environment by the TOR signalling pathway.

    PubMed

    Henriques, Rossana; Bögre, László; Horváth, Beátrix; Magyar, Zoltán

    2014-06-01

    One of the most fundamental aspects of growth in plants is its plasticity in relation to fluctuating environmental conditions. Growth of meristematic cells relies predominantly on protein synthesis, one of the most energy-consuming activities in cells, and thus is tightly regulated in accordance with the available nutrient and energy supplies. The Target of Rapamycin (TOR) signalling pathway takes a central position in this regulation. The core of the TOR signalling pathway is conserved throughout evolution, and can be traced back to the last eukaryotic common ancestor. In plants, a single complex constitutes the TOR signalling pathway. Manipulating the components of the TOR complex in Arabidopsis highlighted its common role as a major regulator of protein synthesis and metabolism, that is also involved in other biological functions such as cell-wall integrity, regulation of cell proliferation, and cell size. TOR, as an integral part of the auxin signalling pathway, connects hormonal and nutrient pathways. Downstream of TOR, S6 kinase and the ribosomal S6 protein have been shown to mediate several of these responses, although there is evidence of other complex non-linear TOR signalling pathway structures.

  3. Identification of Potential Drug Targets in Cancer Signaling Pathways using Stochastic Logical Models

    PubMed Central

    Zhu, Peican; Aliabadi, Hamidreza Montazeri; Uludağ, Hasan; Han, Jie

    2016-01-01

    The investigation of vulnerable components in a signaling pathway can contribute to development of drug therapy addressing aberrations in that pathway. Here, an original signaling pathway is derived from the published literature on breast cancer models. New stochastic logical models are then developed to analyze the vulnerability of the components in multiple signalling sub-pathways involved in this signaling cascade. The computational results are consistent with the experimental results, where the selected proteins were silenced using specific siRNAs and the viability of the cells were analyzed 72 hours after silencing. The genes elF4E and NFkB are found to have nearly no effect on the relative cell viability and the genes JAK2, Stat3, S6K, JUN, FOS, Myc, and Mcl1 are effective candidates to influence the relative cell growth. The vulnerabilities of some targets such as Myc and S6K are found to vary significantly depending on the weights of the sub-pathways; this will be indicative of the chosen target to require customization for therapy. When these targets are utilized, the response of breast cancers from different patients will be highly variable because of the known heterogeneities in signaling pathways among the patients. The targets whose vulnerabilities are invariably high might be more universally acceptable targets. PMID:26988076

  4. The Wnt pathway: a key network in cell signalling dysregulated by viruses.

    PubMed

    van Zuylen, Wendy J; Rawlinson, William D; Ford, Caroline E

    2016-09-01

    Viruses are obligate parasites dependent on host cells for survival. Viral infection of a cell activates a panel of pattern recognition receptors that mediate antiviral host responses to inhibit viral replication and dissemination. Viruses have evolved mechanisms to evade and subvert this antiviral host response, including encoding proteins that hijack, mimic and/or manipulate cellular processes such as the cell cycle, DNA damage repair, cellular metabolism and the host immune response. Currently, there is an increasing interest whether viral modulation of these cellular processes, including the cell cycle, contributes to cancer development. One cellular pathway related to cell cycle signalling is the Wnt pathway. This review focuses on the modulation of this pathway by human viruses, known to cause (or associated with) cancer development. The main mechanisms where viruses interact with the Wnt pathway appear to be through (i) epigenetic modification of Wnt genes; (ii) cellular or viral miRNAs targeting Wnt genes; (iii) altering specific Wnt pathway members, often leading to (iv) nuclear translocation of β-catenin and activation of Wnt signalling. Given that diverse viruses affect this signalling pathway, modulating Wnt signalling could be a generalised critical process for the initiation or maintenance of viral pathogenesis, with resultant dysregulation contributing to virus-induced cancers. Further study of this virus-host interaction may identify options for targeted therapy against Wnt signalling molecules as a means to reduce virus-induced pathogenesis and the downstream consequences of infection. Copyright © 2016 John Wiley & Sons, Ltd.

  5. The Wnt pathway: a key network in cell signalling dysregulated by viruses.

    PubMed

    van Zuylen, Wendy J; Rawlinson, William D; Ford, Caroline E

    2016-09-01

    Viruses are obligate parasites dependent on host cells for survival. Viral infection of a cell activates a panel of pattern recognition receptors that mediate antiviral host responses to inhibit viral replication and dissemination. Viruses have evolved mechanisms to evade and subvert this antiviral host response, including encoding proteins that hijack, mimic and/or manipulate cellular processes such as the cell cycle, DNA damage repair, cellular metabolism and the host immune response. Currently, there is an increasing interest whether viral modulation of these cellular processes, including the cell cycle, contributes to cancer development. One cellular pathway related to cell cycle signalling is the Wnt pathway. This review focuses on the modulation of this pathway by human viruses, known to cause (or associated with) cancer development. The main mechanisms where viruses interact with the Wnt pathway appear to be through (i) epigenetic modification of Wnt genes; (ii) cellular or viral miRNAs targeting Wnt genes; (iii) altering specific Wnt pathway members, often leading to (iv) nuclear translocation of β-catenin and activation of Wnt signalling. Given that diverse viruses affect this signalling pathway, modulating Wnt signalling could be a generalised critical process for the initiation or maintenance of viral pathogenesis, with resultant dysregulation contributing to virus-induced cancers. Further study of this virus-host interaction may identify options for targeted therapy against Wnt signalling molecules as a means to reduce virus-induced pathogenesis and the downstream consequences of infection. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27273590

  6. Phytohormones Signaling Pathways and ROS Involvement in Seed Germination

    PubMed Central

    Oracz, Krystyna; Karpiński, Stanisław

    2016-01-01

    Phytohormones and reactive oxygen species (ROS) are major determinants of the regulation of development and stress responses in plants. During life cycle of these organisms, signaling networks of plant growth regulators and ROS interact in order to render an appropriate developmental and environmental response. In plant’s photosynthetic (e.g., leaves) and non-photosynthetic (e.g., seeds) tissues, enhanced and suboptimal ROS production is usually associated with stress, which in extreme cases can be lethal to cells, a whole organ or even an organism. However, controlled production of ROS is appreciated for cellular signaling. Despite the current progress that has been made in plant biology and increasing number of findings that have revealed roles of ROS and hormonal signaling in germination, some questions still arise, e.g., what are the downstream protein targets modified by ROS enabling stimulus-specific cellular responses of the seed? Or which molecular regulators allow ROS/phytohormones interactions and what is their function in seed life? In this particular review the role of some transcription factors, kinases and phosphatases is discussed, especially those which usually known to be involved in ROS and hormonal signal transduction under stress in plants, may also play a role in the regulation of processes occurring in seeds. The summarized recent findings regarding particular ROS- and phytohormones-related regulatory proteins, as well as their integration, allowed to propose a novel, possible model of action of LESION SIMULATING DISEASE 1, ENHANCED DISEASE SUSCEPTIBILITY 1, and PHYTOALEXIN DEFICIENT 4 functioning during seeds life. PMID:27379144

  7. Phytohormones Signaling Pathways and ROS Involvement in Seed Germination.

    PubMed

    Oracz, Krystyna; Karpiński, Stanisław

    2016-01-01

    Phytohormones and reactive oxygen species (ROS) are major determinants of the regulation of development and stress responses in plants. During life cycle of these organisms, signaling networks of plant growth regulators and ROS interact in order to render an appropriate developmental and environmental response. In plant's photosynthetic (e.g., leaves) and non-photosynthetic (e.g., seeds) tissues, enhanced and suboptimal ROS production is usually associated with stress, which in extreme cases can be lethal to cells, a whole organ or even an organism. However, controlled production of ROS is appreciated for cellular signaling. Despite the current progress that has been made in plant biology and increasing number of findings that have revealed roles of ROS and hormonal signaling in germination, some questions still arise, e.g., what are the downstream protein targets modified by ROS enabling stimulus-specific cellular responses of the seed? Or which molecular regulators allow ROS/phytohormones interactions and what is their function in seed life? In this particular review the role of some transcription factors, kinases and phosphatases is discussed, especially those which usually known to be involved in ROS and hormonal signal transduction under stress in plants, may also play a role in the regulation of processes occurring in seeds. The summarized recent findings regarding particular ROS- and phytohormones-related regulatory proteins, as well as their integration, allowed to propose a novel, possible model of action of LESION SIMULATING DISEASE 1, ENHANCED DISEASE SUSCEPTIBILITY 1, and PHYTOALEXIN DEFICIENT 4 functioning during seeds life. PMID:27379144

  8. Convergence and divergence of the signaling pathways for insulin and phosphoinositolglycans.

    PubMed Central

    Müller, G.; Wied, S.; Piossek, C.; Bauer, A.; Bauer, J.; Frick, W.

    1998-01-01

    ineffective. The desensitized adipocytes were reconstituted for stimulation of lipogenesis by PIG-P by addition of the concentrated trypsin/salt extract. The reconstituted adipocytes exhibited 65-75% of the maximal PIG-P response and similar EC50 values for PIG-P (2 to 5 microns) compared with control cells. A proteinaceous N-ethylmaleimide (NEM)-sensitive component contained in the trypsin/salt extract was demonstrated to bind in a functional manner to the adipocyte plasma membrane of desensitized adipocytes via bipolar interactions. An excess of trypsin/salt extract inhibited PIG-P action in untreated adipocytes in a competitive fashion compatible with a receptor function for PIG-P of this protein. The presence of the putative PIG-P receptor protein in detergent-insoluble complexes prepared from isolated rat adipocytes suggests that caveolae/detergent-insoluble complexes of the plasma membrane may play a role in insulin-mimetic signaling by PIG-P. Furthermore, treatment of isolated rat diaphragms and adipocytes with PIG-P as well as with other agents exerting partially insulin-mimetic activity, such as PI-specific phospholipase C (PLC) and the sulfonylurea glimepiride, triggered tyrosine phosphorylation of the caveolar marker protein caveolin, which was apparently correlated with stimulation of lipogenesis. Strikingly, in adipocytes subjected to combined trypsin/salt treatment, PIG-P, PI-specific PLC, and glimepiride failed completely to provoke insulin-mimetic effects. A working model is presented for a signaling pathway in insulin-sensitive cells used by PIG(-P) molecules which involves GPI structures, the trypsin/salt- and NEM-sensitive receptor protein for PIG-P, and additional proteins located in caveolae/detergent-insoluble complexes. Images Fig. 10 Fig. 13 Fig. 14 PMID:9642681

  9. INOH: ontology-based highly structured database of signal transduction pathways

    PubMed Central

    Sakai, Noriko; Nakamura, Hiromi; Fukagawa, Hiroshi; Fukuda, Ken; Takagi, Toshihisa

    2011-01-01

    The Integrating Network Objects with Hierarchies (INOH) database is a highly structured, manually curated database of signal transduction pathways including Mammalia, Xenopus laevis, Drosophila melanogaster, Caenorhabditis elegans and canonical. Since most pathway knowledge resides in scientific articles, the database focuses on curating and encoding textual knowledge into a machine-processable form. We use a hierarchical pathway representation model with a compound graph, and every pathway component in the INOH database is annotated by a set of uniquely developed ontologies. Finally, we developed the Similarity Search using the combination of a compound graph and hierarchical ontologies. The INOH database is to be a good resource for many users who want to analyze a large protein network. INOH ontologies and 73 signal transduction and 29 metabolic pathway diagrams (including over 6155 interactions and 3395 protein entities) are freely available in INOH XML and BioPAX formats. Database URL: http://www.inoh.org/ PMID:22120663

  10. Cell-Based Assay for Identifying the Modulators of Antioxidant Response Element Signaling Pathway.

    PubMed

    Zhao, Jinghua; Shukla, Sunita J; Xia, Menghang

    2016-01-01

    The antioxidant response element (ARE) signaling pathway plays an important role in the amelioration of cellular oxidative stress. Thus, assays that detect this pathway can be useful for identifying chemicals that induce or inhibit oxidative stress signaling. The focus of this chapter is to describe a cell-based ARE assay in a quantitative high-throughput screening (qHTS) format to test a large collection of compounds that induce nuclear factor erythroid 2-related factor (Nrf2)/ARE signaling. The assay is described through cell handling, assay preparation, and instrument usage. PMID:27518623

  11. Regulation of drug-induced liver injury by signal transduction pathways: critical role of mitochondria

    PubMed Central

    Han, Derick; Dara, Lily; Win, Sanda; Than, Tin Aung; Yuan, Liyun; Abbasi, Sadeea Q; Liu, Zhang-Xu; Kaplowitz, Neil

    2013-01-01

    Drugs that cause liver injury often “stress” mitochondria and activate signal transduction pathways important in determining cell survival or death. In most cases, hepatocytes adapt to the drug-induced stress by activating adaptive signaling pathways, such as mitochondrial adaptive responses and erythroid 2-related factor 2 (Nrf-2), a transcription factor that upregulates antioxidant defenses. Due to adaptation, drugs alone rarely cause liver injury, with acetaminophen being the notable exception. Drug-induced liver injury (DILI) usually involves other extrinsic factors, such as the adaptive immune system, that cause “stressed” hepatocytes to become injured; leading to idiosyncratic DILI, the rare and unpredictable adverse drug reaction in the liver. Hepatocyte injury, due to drug and extrinsic insult, causes a second wave of signaling changes associated with adaptation, cell death, and repair. If the stress and injury reach a critical threshold, then death signaling pathways such as JNK become dominant and hepatocytes enter a failsafe mode to undergo self-destruction. DILI can be seen as an active process involving recruitment of death signaling pathways that mediate cell death rather than a passive process due to overwhelming biochemical injury. In this review, we highlight the role of signal transduction pathways, which frequently involve mitochondria, in the development of DILI. PMID:23453390

  12. Regulation of drug-induced liver injury by signal transduction pathways: critical role of mitochondria.

    PubMed

    Han, Derick; Dara, Lily; Win, Sanda; Than, Tin Aung; Yuan, Liyun; Abbasi, Sadeea Q; Liu, Zhang-Xu; Kaplowitz, Neil

    2013-04-01

    Drugs that cause liver injury often 'stress' mitochondria and activate signal transduction pathways important in determining cell survival or death. In most cases, hepatocytes adapt to the drug-induced stress by activating adaptive signaling pathways, such as mitochondrial adaptive responses and nuclear factor erythroid 2-related factor 2 (Nrf-2), a transcription factor that upregulates antioxidant defenses. Owing to adaptation, drugs alone rarely cause liver injury, with acetaminophen (APAP) being the notable exception. Drug-induced liver injury (DILI) usually involves other extrinsic factors, such as the adaptive immune system, that cause 'stressed' hepatocytes to become injured, leading to idiosyncratic DILI, the rare and unpredictable adverse drug reaction in the liver. Hepatocyte injury, due to drug and extrinsic insult, causes a second wave of signaling changes associated with adaptation, cell death, and repair. If the stress and injury reach a critical threshold, then death signaling pathways such as c-Jun N-terminal kinase (JNK) become dominant and hepatocytes enter a failsafe mode to undergo self-destruction. DILI can be seen as an active process involving recruitment of death signaling pathways that mediate cell death rather than a passive process due to overwhelming biochemical injury. In this review, we highlight the role of signal transduction pathways, which frequently involve mitochondria, in the development of DILI. PMID:23453390

  13. Integrated QSAR study for inhibitors of hedgehog signal pathway against multiple cell lines:a collaborative filtering method

    PubMed Central

    2012-01-01

    proposed several possible chemical modifications to improve the inhibitor affinity towards multiple targets in the Hedgehog Signaling Pathway. Conclusions Our model with the feature selection strategy presented here is efficient, robust, and flexible, and can be easily extended to model large-scale multiple cell line/QSAR data. The data and scripts for collaborative QSAR modeling are available in the Additional file 1. PMID:22849868

  14. miR-30c regulates proliferation, apoptosis and differentiation via the Shh signaling pathway in P19 cells.

    PubMed

    Liu, Xuehua; Li, Mengmeng; Peng, Yuzhu; Hu, Xiaoshan; Xu, Jing; Zhu, Shasha; Yu, Zhangbin; Han, Shuping

    2016-01-01

    MicroRNAs (miRNAs) are small, non-coding single-stranded RNAs that suppress protein expression by binding to the 3' untranslated regions of their target genes. Many studies have shown that miRNAs have important roles in congenital heart diseases (CHDs) by regulating gene expression and signaling pathways. We previously found that miR-30c was highly expressed in the heart tissues of aborted embryos with ventricular septal defects. Therefore, this study aimed to explore the effects of miR-30c in CHDs. miR-30c was overexpressed or knocked down in P19 cells, a myocardial cell model that is widely used to study cardiogenesis. We found that miR-30c overexpression not only increased cell proliferation by promoting cell entry into S phase but also suppressed cell apoptosis. In addition, we found that miR-30c inhibited dimethyl sulfoxide-induced differentiation of P19 cells. miR-30c knockdown, in contrast, inhibited cell proliferation and increased apoptosis and differentiation. The Sonic hedgehog (Shh) signaling pathway is essential for normal embryonic development. Western blotting and luciferase assays revealed that Gli2, a transcriptional factor that has essential roles in the Shh signaling pathway, was a potential target gene of miR-30c. Ptch1, another important player in the Shh signaling pathway and a transcriptional target of Gli2, was downregulated by miR-30c overexpression and upregulated by miR-30c knockdown. Collectively, our study revealed that miR-30c suppressed P19 cell differentiation by inhibiting the Shh signaling pathway and altered the balance between cell proliferation and apoptosis, which may result in embryonic cardiac malfunctions. PMID:27469029

  15. miR-30c regulates proliferation, apoptosis and differentiation via the Shh signaling pathway in P19 cells

    PubMed Central

    Liu, Xuehua; Li, Mengmeng; Peng, Yuzhu; Hu, Xiaoshan; Xu, Jing; Zhu, Shasha; Yu, Zhangbin; Han, Shuping

    2016-01-01

    MicroRNAs (miRNAs) are small, non-coding single-stranded RNAs that suppress protein expression by binding to the 3′ untranslated regions of their target genes. Many studies have shown that miRNAs have important roles in congenital heart diseases (CHDs) by regulating gene expression and signaling pathways. We previously found that miR-30c was highly expressed in the heart tissues of aborted embryos with ventricular septal defects. Therefore, this study aimed to explore the effects of miR-30c in CHDs. miR-30c was overexpressed or knocked down in P19 cells, a myocardial cell model that is widely used to study cardiogenesis. We found that miR-30c overexpression not only increased cell proliferation by promoting cell entry into S phase but also suppressed cell apoptosis. In addition, we found that miR-30c inhibited dimethyl sulfoxide-induced differentiation of P19 cells. miR-30c knockdown, in contrast, inhibited cell proliferation and increased apoptosis and differentiation. The Sonic hedgehog (Shh) signaling pathway is essential for normal embryonic development. Western blotting and luciferase assays revealed that Gli2, a transcriptional factor that has essential roles in the Shh signaling pathway, was a potential target gene of miR-30c. Ptch1, another important player in the Shh signaling pathway and a transcriptional target of Gli2, was downregulated by miR-30c overexpression and upregulated by miR-30c knockdown. Collectively, our study revealed that miR-30c suppressed P19 cell differentiation by inhibiting the Shh signaling pathway and altered the balance between cell proliferation and apoptosis, which may result in embryonic cardiac malfunctions. PMID:27469029

  16. Metastasis-associated lung adenocarcinoma transcript 1 promotes the proliferation of chondrosarcoma cell via activating Notch-1 signaling pathway

    PubMed Central

    Xu, Fengqin; Zhang, Zhi-qiang; Fang, Yong-chao; Li, Xiao-lei; Sun, Yu; Xiong, Chuan-zhi; Yan, Lian-qi; Wang, Qiang

    2016-01-01

    Background Metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) is identified to be overexpressed in several cancers. However, the role of MALAT-1 in chondrosarcoma is poorly understood. Methods The expression of MALAT-1 and Notch-1 signaling pathway was detected in chondrosarcoma tissues and chondrosarcoma cells by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was performed to examine the cell viability of chondrosarcoma cells transfected with si-MALAT-1 or pcDNA-MALAT-1. Then the expression of Notch-1 signaling pathway was detected when MALAT-1 was upregulated or downregulated in chondrosarcoma cells. A subcutaneous chondrosarcoma cells xenograft model was used to confirm the effect of MALAT-1 on tumor growth in vivo. Results We found the increased expression of MALAT-1 and Notch-1 signaling pathway in chondrosarcoma tissue and cells. MALAT-1 promoted the proliferation of chondrosarcoma cells. In addition, MALAT-1 activated the Notch-1 signaling pathway at posttranscriptional level in chondrosarcoma cells. Meanwhile, overexpression of Notch-1 reversed the effect of si-MALAT-1 on the proliferation of chondrosarcoma cells. Finally, we found that MALAT-1 promoted the tumor growth in a subcutaneous chondrosarcoma cells xenograft model, which confirmed the promoted effect of MALAT-1 on the tumor growth in vivo. Conclusion Taken together, our study demonstrated that MALAT-1 promoted the proliferation of chondrosarcoma cell via activating Notch-1 signaling pathway. PMID:27110130

  17. Broccoli Consumption Interacts with GSTM1 to Perturb Oncogenic Signalling Pathways in the Prostate

    PubMed Central

    Traka, Maria; Gasper, Amy V.; Melchini, Antonietta; Bacon, James R.; Needs, Paul W.; Frost, Victoria; Chantry, Andrew; Jones, Alexandra M. E.; Ortori, Catharine A.; Barrett, David A.; Ball, Richard Y.; Mills, Robert D.; Mithen, Richard F.

    2008-01-01

    Background Epidemiological studies suggest that people who consume more than one portion of cruciferous vegetables per week are at lower risk of both the incidence of prostate cancer and of developing aggressive prostate cancer but there is little understanding of the underlying mechanisms. In this study, we quantify and interpret changes in global gene expression patterns in the human prostate gland before, during and after a 12 month broccoli-rich diet. Methods and Findings Volunteers were randomly assigned to either a broccoli-rich or a pea-rich diet. After six months there were no differences in gene expression between glutathione S-transferase mu 1 (GSTM1) positive and null individuals on the pea-rich diet but significant differences between GSTM1 genotypes on the broccoli-rich diet, associated with transforming growth factor beta 1 (TGFβ1) and epidermal growth factor (EGF) signalling pathways. Comparison of biopsies obtained pre and post intervention revealed more changes in gene expression occurred in individuals on a broccoli-rich diet than in those on a pea-rich diet. While there were changes in androgen signalling, regardless of diet, men on the broccoli diet had additional changes to mRNA processing, and TGFβ1, EGF and insulin signalling. We also provide evidence that sulforaphane (the isothiocyanate derived from 4-methylsuphinylbutyl glucosinolate that accumulates in broccoli) chemically interacts with TGFβ1, EGF and insulin peptides to form thioureas, and enhances TGFβ1/Smad-mediated transcription. Conclusions These findings suggest that consuming broccoli interacts with GSTM1 genotype to result in complex changes to signalling pathways associated with inflammation and carcinogenesis in the prostate. We propose that these changes may be mediated through the chemical interaction of isothiocyanates with signalling peptides in the plasma. This study provides, for the first time, experimental evidence obtained in humans to support observational studies

  18. Peptide Ligand Structure and I-Aq Binding Avidity Influence T Cell Signaling Pathway Utilization

    PubMed Central

    Myers, Linda K; Cullins, David L; Park, Jeoung-Eun; Yi, Ae-Kyung; Brand, David D; Rosloniec, Edward F; Stuart, John M; Kang, Andrew H

    2015-01-01

    Factors that drive T cells to signal through differing pathways remain unclear. We have shown that an altered peptide ligand (A9) activates T cells to utilize an alternate signaling pathway which is dependent upon FcRγ and Syk. However, it remains unknown whether the affinity of peptide binding to MHC drives this selection. To answer this question we developed a panel of peptides designed so that amino acids interacting with the p6 and p9 predicted MHC binding pockets were altered. Analogs were tested for binding to I-Aq using a competitive binding assay and selected analogs were administered to arthritic mice. Using the collagen-induced arthritis (CIA) model, arthritis severity was correlated with T cell cytokine production and molecular T cell signaling responses. We establish that reduced affinity of interaction with the MHC correlates with T cell signaling through the alternative pathway, leading ultimately to secretion of suppressive cytokine and attenuation of arthritis. PMID:25982319

  19. The ubiquitin–proteasome system and signal transduction pathways regulating Epithelial Mesenchymal transition of cancer

    PubMed Central

    2012-01-01

    Epithelial to Mesenchymal transition (EMT) in cancer, a process permitting cancer cells to become mobile and metastatic, has a signaling hardwire forged from development. Multiple signaling pathways that regulate carcinogenesis enabling characteristics in neoplastic cells such as proliferation, resistance to apoptosis and angiogenesis are also the main players in EMT. These pathways, as almost all cellular processes, are in their turn regulated by ubiquitination and the Ubiquitin-Proteasome System (UPS). Ubiquitination is the covalent link of target proteins with the small protein ubiquitin and serves as a signal to target protein degradation by the proteasome or to other outcomes such as endocytosis, degradation by the lysosome or specification of cellular localization. This paper reviews signal transduction pathways regulating EMT and being regulated by ubiquitination. PMID:22827778

  20. siRNA screen of the human signaling proteome identifies the PtdIns(3,4,5)P3-mTOR signaling pathway as a primary regulator of transferrin uptake

    PubMed Central

    Galvez, Thierry; Teruel, Mary N; Heo, Won Do; Jones, Joshua T; Kim, Man Lyang; Liou, Jen; Myers, Jason W; Meyer, Tobias

    2007-01-01

    Background Iron uptake via endocytosis of iron-transferrin-transferrin receptor complexes is a rate-limiting step for cell growth, viability and proliferation in tumor cells as well as non-transformed cells such as activated lymphocytes. Signaling pathways that regulate transferrin uptake have not yet been identified. Results We surveyed the human signaling proteome for regulators that increase or decrease transferrin uptake by screening 1,804 dicer-generated signaling small interfering RNAs using automated quantitative imaging. In addition to known transport proteins, we identified 11 signaling proteins that included a striking signature set for the phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3)-target of rapamycin (mTOR) signaling pathway. We show that the PI3K-mTOR signaling pathway is a positive regulator of transferrin uptake that increases the number of transferrin receptors per endocytic vesicle without affecting endocytosis or recycling rates. Conclusion Our study identifies the PtdIns(3,4,5)P3-mTOR signaling pathway as a new regulator of iron-transferrin uptake and serves as a proof-of-concept that targeted RNA interference screens of the signaling proteome provide a powerful and unbiased approach to discover or rank signaling pathways that regulate a particular cell function. PMID:17640392

  1. Phosphatase specificity and pathway insulation in signaling networks.

    PubMed

    Rowland, Michael A; Harrison, Brian; Deeds, Eric J

    2015-02-17

    Phosphatases play an important role in cellular signaling networks by regulating the phosphorylation state of proteins. Phosphatases are classically considered to be promiscuous, acting on tens to hundreds of different substrates. We recently demonstrated that a shared phosphatase can couple the responses of two proteins to incoming signals, even if those two substrates are from otherwise isolated areas of the network. This finding raises a potential paradox: if phosphatases are indeed highly promiscuous, how do cells insulate themselves against unwanted crosstalk? Here, we use mathematical models to explore three possible insulation mechanisms. One approach involves evolving phosphatase KM values that are large enough to prevent saturation by the phosphatase's substrates. Although this is an effective method for generating isolation, the phosphatase becomes a highly inefficient enzyme, which prevents the system from achieving switch-like responses and can result in slow response kinetics. We also explore the idea that substrate degradation can serve as an effective phosphatase. Assuming that degradation is unsaturatable, this mechanism could insulate substrates from crosstalk, but it would also preclude ultrasensitive responses and would require very high substrate turnover to achieve rapid dephosphorylation kinetics. Finally, we show that adaptor subunits, such as those found on phosphatases like PP2A, can provide effective insulation against phosphatase crosstalk, but only if their binding to substrates is uncoupled from their binding to the catalytic core. Analysis of the interaction network of PP2A's adaptor domains reveals that although its adaptors may isolate subsets of targets from one another, there is still a strong potential for phosphatase crosstalk within those subsets. Understanding how phosphatase crosstalk and the insulation mechanisms described here impact the function and evolution of signaling networks represents a major challenge for

  2. Phosphatase Specificity and Pathway Insulation in Signaling Networks

    PubMed Central

    Rowland, Michael A.; Harrison, Brian; Deeds, Eric J.

    2015-01-01

    Phosphatases play an important role in cellular signaling networks by regulating the phosphorylation state of proteins. Phosphatases are classically considered to be promiscuous, acting on tens to hundreds of different substrates. We recently demonstrated that a shared phosphatase can couple the responses of two proteins to incoming signals, even if those two substrates are from otherwise isolated areas of the network. This finding raises a potential paradox: if phosphatases are indeed highly promiscuous, how do cells insulate themselves against unwanted crosstalk? Here, we use mathematical models to explore three possible insulation mechanisms. One approach involves evolving phosphatase KM values that are large enough to prevent saturation by the phosphatase’s substrates. Although this is an effective method for generating isolation, the phosphatase becomes a highly inefficient enzyme, which prevents the system from achieving switch-like responses and can result in slow response kinetics. We also explore the idea that substrate degradation can serve as an effective phosphatase. Assuming that degradation is unsaturatable, this mechanism could insulate substrates from crosstalk, but it would also preclude ultrasensitive responses and would require very high substrate turnover to achieve rapid dephosphorylation kinetics. Finally, we show that adaptor subunits, such as those found on phosphatases like PP2A, can provide effective insulation against phosphatase crosstalk, but only if their binding to substrates is uncoupled from their binding to the catalytic core. Analysis of the interaction network of PP2A’s adaptor domains reveals that although its adaptors may isolate subsets of targets from one another, there is still a strong potential for phosphatase crosstalk within those subsets. Understanding how phosphatase crosstalk and the insulation mechanisms described here impact the function and evolution of signaling networks represents a major challenge for

  3. Hypoxia signaling pathways: modulators of oxygen-related organelles

    PubMed Central

    Schönenberger, Miriam J.; Kovacs, Werner J.

    2015-01-01

    Oxygen (O2) is an essential substrate in cellular metabolism, bioenergetics, and signaling and as such linked to the survival and normal function of all metazoans. Low O2 tension (hypoxia) is a fundamental feature of physiological processes as well as pathophysiological conditions such as cancer and ischemic diseases. Central to the molecular mechanisms underlying O2 homeostasis are the hypoxia-inducible factors-1 and -2 alpha (HIF-1α and EPAS1/HIF-2α) that function as master regulators of the adaptive response to hypoxia. HIF-induced genes promote characteristic tumor behaviors, including angiogenesis and metabolic reprogramming. The aim of this review is to critically explore current knowledge of how HIF-α signaling regulates the abundance and function of major O2-consuming organelles. Abundant evidence suggests key roles for HIF-1α in the regulation of mitochondrial homeostasis. An essential adaptation to sustained hypoxia is repression of mitochondrial respiration and induction of glycolysis. HIF-1α activates several genes that trigger mitophagy and represses regulators of mitochondrial biogenesis. Several lines of evidence point to a strong relationship between hypoxia, the accumulation of misfolded proteins in the endoplasmic reticulum, and activation of the unfolded protein response. Surprisingly, although peroxisomes depend highly on molecular O2 for their function, there has been no evidence linking HIF signaling to peroxisomes. We discuss our recent findings that establish HIF-2α as a negative regulator of peroxisome abundance and suggest a mechanism by which cells attune peroxisomal function with O2 availability. HIF-2α activation augments peroxisome turnover by pexophagy and thereby changes lipid composition reminiscent of peroxisomal disorders. We discuss potential mechanisms by which HIF-2α might trigger pexophagy and place special emphasis on the potential pathological implications of HIF-2α-mediated pexophagy for human health. PMID:26258123

  4. Protein kinase A activity and Hedgehog signaling pathway.

    PubMed

    Kotani, Tomoya

    2012-01-01

    Protein kinase A (PKA) is a well-known kinase that plays fundamental roles in a variety of biological processes. In Hedgehog-responsive cells, PKA plays key roles in proliferation and fate specification by modulating the transduction of Hedgehog signaling. In the absence of Hedgehog, a basal level of PKA activity represses the transcription of Hedgehog target genes. The main substrates of PKA in this process are the Ci/Gli family of bipotential transcription factors, which activate and repress Hedgehog target gene expression. PKA phosphorylates Ci/Gli, promoting the production of the repressor forms of Ci/Gli and thus repressing Hedgehog target gene expression. In contrast, the activation of Hedgehog signaling in response to Hedgehog increases the active forms of Ci/Gli, resulting in Hedgehog target gene expression. Because both decreased and increased levels of PKA activity cause abnormal cell proliferation and alter cell fate specification, the basal level of PKA activity in Hedgehog-responsive cells should be precisely regulated. However, the mechanism by which PKA activity is regulated remains obscure and appears to vary between cell types, tissues, and organisms. To date, two mechanisms have been proposed. One is a classical mechanism in which PKA activity is regulated by a small second messenger, cAMP; the other is a novel mechanism in which PKA activity is regulated by a protein, Misty somites. PMID:22391308

  5. TRANSDUCING BIOELECTRIC SIGNALS INTO EPIGENETIC PATHWAYS DURING TADPOLE TAIL REGENERATION

    PubMed Central

    Tseng, Ai-Sun; Levin, Michael

    2012-01-01

    One important component of the cell-cell communication that occurs during regenerative patterning is bioelectrical signaling. In particular, the regeneration of the tail in Xenopus laevis tadpoles both requires, and can be initiated at non-regenerative stages by, specific regulation of bioelectrical signaling (alteration in resting membrane potential and a subsequent change in sodium content of blastemal cells). While standing gradients of transmembrane voltage and ion concentration can provide positional guidance and other morphogenetic cues, these biophysical parameters must be transduced into transcriptional responses within cells. A number of mechanisms have been described for linking slow voltage changes to gene expression, but recent data on the importance of epigenetic marks for regeneration suggest a novel hypothesis: that sodium/butyrate transporters link ion flows to influx of small molecules needed to modify chromatin state. Here, we briefly review the data on bioelectricity in tadpole tail regeneration, present a technique for convenient alteration of transmembrane potential in vivo that does not require transgenes, show augmentation of regeneration in vivo by manipulation of voltage, and present new data in the Xenopus tail consistent with the hypothesis that the monocarboxlyate transporter SLC5A8 may link regeneration-relevant epigenetic modification with upstream changes in ion content. PMID:22933452

  6. Determinants of contrast in the signal-key procedure: Evidence against additivity theory.

    PubMed

    Williams, B A; Heyneman, N

    1981-03-01

    Two experiments are reported that challenge the interpretation of previous results with the signal-key procedure, in which the discriminative stimuli are located on a response key different from the key associated with the operant response requirement. Experiment 1 replicated the procedure of Keller (1974), and found that contrast effects on the operant key occurred reliably for only one of four subjects. High rates to the signal key initially occurred for only one subject, but modifications of the procedure produced substantial rates to the signal key for all subjects. In all cases, however, signal-key behavior was greatly reduced by the addition of a changeover delay which prevented reinforcement within 2 seconds of the last peck to the signal key, suggesting that signal-key pecking was maintained primarily by adventitious reinforcement. Experiment 2 modified the signal-key procedure by using three response keys, so that the discriminative stimuli on the signal key controlled different responses during all phases of training. With this modification, reliable contrast effects on the operant key occurred for all subjects, suggesting that the failure to find contrast in previous studies has been due to the confounding of changes in the discrimination requirements with changes in relative rate of reinforcement. The results challenge the additivity theory of contrast, and suggest that "elicited" behavior plays a minor role, if any, in the determination of contrast effects in multiple schedules.

  7. Hydrogen peroxide induces activation of insulin signaling pathway via AMP-dependent kinase in podocytes

    SciTech Connect

    Piwkowska, Agnieszka; Rogacka, Dorota; Angielski, Stefan; Jankowski, Maciej

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer H{sub 2}O{sub 2} activates the insulin signaling pathway and glucose uptake in podocytes. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} induces time-dependent changes in AMPK phosphorylation. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} enhances insulin signaling pathways via AMPK activation. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} stimulation of glucose uptake is AMPK-dependent. -- Abstract: Podocytes are cells that form the glomerular filtration barrier in the kidney. Insulin signaling in podocytes is critical for normal kidney function. Insulin signaling is regulated by oxidative stress and intracellular energy levels. We cultured rat podocytes to investigate the effects of hydrogen peroxide (H{sub 2}O{sub 2}) on the phosphorylation of proximal and distal elements of insulin signaling. We also investigated H{sub 2}O{sub 2}-induced intracellular changes in the distribution of protein kinase B (Akt). Western blots showed that H{sub 2}O{sub 2} (100 {mu}M) induced rapid, transient phosphorylation of the insulin receptor (IR), the IR substrate-1 (IRS1), and Akt with peak activities at 5 min ({Delta} 183%, P < 0.05), 3 min ({Delta} 414%, P < 0.05), and 10 min ({Delta} 35%, P < 0.05), respectively. Immunostaining cells with an Akt-specific antibody showed increased intensity at the plasma membrane after treatment with H{sub 2}O{sub 2}>. Furthermore, H{sub 2}O{sub 2} inhibited phosphorylation of the phosphatase and tensin homologue (PTEN; peak activity at 10 min; {Delta} -32%, P < 0.05) and stimulated phosphorylation of the AMP-dependent kinase alpha subunit (AMPK{alpha}; 78% at 3 min and 244% at 10 min). The stimulation of AMPK was abolished with an AMPK inhibitor, Compound C (100 {mu}M, 2 h). Moreover, Compound C significantly reduced the effect of H{sub 2}O{sub 2} on IR phosphorylation by about 40% (from 2.07 {+-} 0.28 to 1.28 {+-} 0.12, P < 0.05). In addition, H{sub 2}O{sub 2} increased glucose uptake in podocytes

  8. Capsaicin inhibits the Wnt/β-catenin signaling pathway by down-regulating PP2A.

    PubMed

    Park, Dong-Seok; Yoon, Gang-Ho; Lee, Hyun-Shik; Choi, Sun-Cheol

    2016-09-01

    Xenopus embryo serves as an ideal model for teratogenesis assays to examine the effects of any substances on the cellular processes critical for early development and adult tissue homeostasis. In our chemical library screening with frog embryo, capsaicin was found to repress the Wnt/β-catenin signaling. Depending on the stages at which embryos became exposed to capsaicin, it could disrupt formation of dorsal or posterior body axis of embryo, which is associated with inhibition of maternal or zygotic Wnt signal in early development. In agreement with these phenotypes, capsaicin suppressed the expression of Wnt target genes such as Siamois and Chordin in the organizer region of embryo and in Wnt signals-stimulated tissue explants. In addition, the cellular level of β-catenin, a key component of Wnt pathway, was down-regulated in capsaicin-treated embryonic cells. Unlike wild-type β-catenin, its non-phosphorylatable mutant in which serine and threonine residues phosphorylated by GSK3 are substituted with alanine was not destabilized by capsaicin, indicative of the effect of this chemical on the phosphorylation status of β-catenin. In support of this, capsaicin up-regulated the level of GSK3- or CK1-phosphorylated β-catenin, concomitantly lowering that of its de-phosphorylated version. Notably, capsaicin augmented the phosphorylation of a phosphatase, PP2A at tyrosine 307, suggesting its repression of the enzymatic activity of the phosphatase. Furthermore, capsaicin still enhanced β-catenin phosphorylation in cells treated with a GSK3 inhibitor, LiCl but not in those treated with a phosphatase inhibitor, okadaic acid. Together, these results indicate that capsaicin inhibits the patterning of the dorso-ventral and anterior-posterior body axes of embryo by repressing PP2A and thereby down-regulating the Wnt/β-catenin signaling. PMID:27318088

  9. IL-16 activates the SAPK signaling pathway in CD4+ macrophages.

    PubMed

    Krautwald, S

    1998-06-15

    IL-16 has been reported as a modulator of T cell activation and was shown to function as chemoattractant factor. The chemotactic activity of IL-16 depends on the expression of CD4 on the surface of target cells, but the intracellular signaling pathways are only now being deciphered. This report describes IL-16 as an additional activator of the stress-activated protein kinase (SAPK) pathway in CD4+ macrophages. Treatment of these cells with recombinant expressed IL-16 leads to the phosphorylation of SEK-1, resulting in activation of the SAPKs p46 and p54. IL-16 stimulation also leads to the phosphorylation of c-Jun and p38 MAPK (mitogen-activated protein kinase), without inducing MAPK-family members ERK-1 and ERK-2. Interestingly, the IL-16-mediated activation of SAPKs and p38 MAPK in macrophages alone induces no detectable apoptotic cell death. These observations suggest specific regulatory functions of IL-16 distinct from the proinflammatory cytokines TNF-alpha and IL-1beta. PMID:9637499

  10. Epidermal stem cells (ESCs) accelerate diabetic wound healing via the Notch signalling pathway

    PubMed Central

    Yang, Rong-Hua; Qi, Shao-Hai; Shu, Bin; Ruan, Shu-Bin; Lin, Ze-Peng; Lin, Yan; Shen, Rui; Zhang, Feng-Gang; Chen, Xiao-Dong; Xie, Ju-Lin

    2016-01-01

    Chronic, non-healing wounds are a major complication of diabetes. Recently, various cell therapies have been reported for promotion of diabetic wound healing. Epidermal stem cells (ESCs) are considered a powerful tool for tissue therapy. However, the effect and the mechanism of the therapeutic properties of ESCs in the diabetic wound healing are unclear. Herein, to determine the ability of ESCs to diabetic wound healing, a dorsal skin defect in a streptozotocin (STZ)-induced diabetes mellitus (DM) mouse model was used. ESCs were isolated from mouse skin. We found that both the mRNA and protein levels of a Notch ligand Jagged1 (Jag1), Notch1 and Notch target gene Hairy Enhancer of Split-1 (Hes1) were significantly increased at the wound margins. In addition, we observed that Jag1 was high expressed in ESCs. Overexpression of Jag1 promotes ESCs migration, whereas knockdown Jag1 resulted in a significant reduction in ESCs migration in vitro. Importantly, Jag1 overexpression improves diabetic wound healing in vivo. These results provide evidence that ESCs accelerate diabetic wound healing via the Notch signalling pathway, and provide a promising potential for activation of the Notch pathway for the treatment of diabetic wound. PMID:27129289

  11. Wwox suppresses breast cancer cell growth through modulation of the hedgehog–GLI1 signaling pathway

    SciTech Connect

    Xiong, Anwen; Wei, Li; Ying, Mingzhen; Wu, Hongmei; Hua, Jin; Wang, Yajie

    2014-01-24

    Highlights: • We investigated Gli1 as a novel partner of Wwox. • We observed a physical association between Wwox and the Gli1. • Wwox–Gli1 interaction affects Gli1 intracellular localization. • Gli1 Blocks Wwox-induced growth inhibition and apoptosis in T47D cells. - Abstract: Wwox is a tumor suppressor that is frequently deleted or altered in several cancer types, including breast cancer. Previous studies have shown that ectopic expression of Wwox inhibits proliferation of breast cancer cells. However, the underlying mechanism remains unclear. To better understand the molecular mechanisms of Wwox function, we investigated novel partners of this protein. Utilizing the coimmunoprecipitation assay, we observed a physical association between Wwox and the Gli1 zinc-finger transcription factor involved in the hedgehog pathway. Our results further demonstrated that Wwox expression triggered redistribution of nuclear Gli1 to the cytoplasm. Additionally, ectopic expression of Wwox reduced Gli1 expression in vitro. Furthermore, Gli1 Blocks Wwox-induced breast cancer cell growth inhibition. These findings suggest a functional crosstalk between Wwox and hedgehog–GLI1 signaling pathway in tumorigenesis.

  12. ALA-PDT inhibits proliferation and promotes apoptosis of SCC cells through STAT3 signal pathway.

    PubMed

    Qiao, Li; Mei, Zhusong; Yang, Zhiyong; Li, Xinji; Cai, Hong; Liu, Wei

    2016-06-01

    Previous studies suggest that apoptosis of carcinoma cells led by photodynamics is mainly intrinsic apoptosis, but whether the extrinsic pathway is involved in the treatment of carcinoma by photodynamic therapy is not confirmed. This research investigated the effect of ALA-PDT on the proliferation and apoptosis of SCC cell A431 and COLO-16, and discussed the role played by JAK/STAT3 signal pathway in this process. Our data showed that the expression levels STAT3 and p-STAT3 protein in the cancer tissue are higher than the corresponding adjacent tissue to carcinoma. The expression level of p-STAT3 in cancerous tissue has a correlation with the tumor size and tissue histopathological differentiation. ALA-PDT could inhibit proliferation of A431 and COLO-16 cells, STAT3 knock down could enhance ALA-PDT's inhibition of cell proliferation, and promote apoptosis induced by ALA-PDT. On the other hand, overexpression of STAT3 has the opposite effect. In addition, ALA-PDT can weaken the protein expression of STAT3 and its target gene Bcl-2 mRNA, and ALA-PDT can strengthen the protein expression of STAT3's target gene Bax mRNA. Overexpression of STAT3 can offset the effect on Bcl-2 and Bax by ALA-PDT; on the other hand, STAT3 knocking down can strengthen ALA-PDT's effect on Bcl-2 and Bax. PMID:26805005

  13. Epidermal stem cells (ESCs) accelerate diabetic wound healing via the Notch signalling pathway.

    PubMed

    Yang, Rong-Hua; Qi, Shao-Hai; Shu, Bin; Ruan, Shu-Bin; Lin, Ze-Peng; Lin, Yan; Shen, Rui; Zhang, Feng-Gang; Chen, Xiao-Dong; Xie, Ju-Lin

    2016-08-01

    Chronic, non-healing wounds are a major complication of diabetes. Recently, various cell therapies have been reported for promotion of diabetic wound healing. Epidermal stem cells (ESCs) are considered a powerful tool for tissue therapy. However, the effect and the mechanism of the therapeutic properties of ESCs in the diabetic wound healing are unclear. Herein, to determine the ability of ESCs to diabetic wound healing, a dorsal skin defect in a streptozotocin (STZ)-induced diabetes mellitus (DM) mouse model was used. ESCs were isolated from mouse skin. We found that both the mRNA and protein levels of a Notch ligand Jagged1 (Jag1), Notch1 and Notch target gene Hairy Enhancer of Split-1 (Hes1) were significantly increased at the wound margins. In addition, we observed that Jag1 was high expressed in ESCs. Overexpression of Jag1 promotes ESCs migration, whereas knockdown Jag1 resulted in a significant reduction in ESCs migration in vitro Importantly, Jag1 overexpression improves diabetic wound healing in vivo These results provide evidence that ESCs accelerate diabetic wound healing via the Notch signalling pathway, and provide a promising potential for activation of the Notch pathway for the treatment of diabetic wound. PMID:27129289

  14. Weaning Induced Hepatic Oxidative Stress, Apoptosis, and Aminotransferases through MAPK Signaling Pathways in Piglets

    PubMed Central

    Luo, Zhen; Zhu, Wei; Guo, Qi; Luo, Wenli; Zhang, Jing; Xu, Weina

    2016-01-01

    This study investigated the effects of weaning on the hepatic redox status, apoptosis, function, and the mitogen-activated protein kinase (MAPK) signaling pathways during the first week after weaning in piglets. A total of 12 litters of piglets were weaned at d 21 and divided into the weaning group (WG) and the control group (CG). Six piglets from each group were slaughtered at d 0 (d 20, referred to weaning), d 1, d 4, and d 7 after weaning. Results showed that weaning significantly increased the concentrations of hepatic free radicals H2O2 and NO, malondialdehyde (MDA), and 8-hydroxy-2′-deoxyguanosine (8-OHdG), while significantly decreasing the inhibitory hydroxyl ability (IHA) and glutathione peroxidase (GSH-Px), and altered the level of superoxide dismutase (SOD). The apoptosis results showed that weaning increased the concentrations of caspase-3, caspase-8, caspase-9 and the ratio of Bax/Bcl-2. In addition, aspartate aminotransferase transaminase (AST) and alanine aminotransferase (ALT) in liver homogenates increased after weaning. The phosphorylated JNK and ERK1/2 increased, while the activated p38 initially decreased and then increased. Our results suggested that weaning increased the hepatic oxidative stress and aminotransferases and initiated apoptosis, which may be related to the activated MAPK pathways in postweaning piglets. PMID:27807471

  15. Prognostic value of hedgehog signaling pathway in patients with colon cancer.

    PubMed

    Xu, Meihua; Li, Xinhua; Liu, Ting; Leng, Aimin; Zhang, Guiying

    2012-06-01

    Hedgehog signaling pathway plays an important role in normal mammalian gastrointestinal development and is implicated in the oncogenesis of various tumors. However, its correlation with progression and prognosis of colon cancer has not been well documented. This study was designed to investigate expression patterns of related proteins in hedgehog signaling pathway in colon cancer to elucidate its prognostic value in this tumor. Using human colon cancer and their corresponding non-diseased colon from 228 patients' biopsies, the expression of sonic hedgehog, its receptor Patched, and downstream transcription factor Gli1 was investigated by immunohistochemical staining to assess their association with the clinicopathological characteristics of colon cancer. Disease-free survival and overall survival were examined by Kaplan-Meier estimates and the log-rank test. Prognostic factors were determined by multivariate Cox analysis. One hundred and thirty-eight patients (59.6%) had sonic hedgehog-positive tumors and that the disease-free survival (43.5 vs. 73.3%, P < 0.001), and overall survival rates (50.7 vs. 88.9%, P < 0.001) of patients with sonic hedgehog-positive tumors were much lower than those of patients with sonic hedgehog-negative tumors. In addition, 163 patients (71.5%) had Patched-positive tumors, and the disease-free survival (41.7 vs. 76.9%, P < 0.001) and overall survival rates (55.2 vs. 80.0%, P = 0.002) of patients with Patched-positive tumors were also lower than those of patients with Patched-negative tumors. Moreover, positive Gli1 expression had a bad effect on the disease-free survival (41.9 vs. 73.2%, P < 0.001) and overall survival rate of patients with colon cancer (50.0 vs. 89.3%, P < 0.001). In a multivariate analysis, sonic hedgehog, Patched, and Gli1 status were indicators for poor disease-free survival and overall survival. These results have shown that the increasing expression of sonic hedgehog, Patched, and Gli1 are indicators for a poor

  16. Modular and Stochastic Approaches to Molecular Pathway Models of ATM, TGF beta, and WNT Signaling

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; O'Neill, Peter; Ponomarev, Artem; Carra, Claudio; Whalen, Mary; Pluth, Janice M.

    2009-01-01

    Deterministic pathway models that describe the biochemical interactions of a group of related proteins, their complexes, activation through kinase, etc. are often the basis for many systems biology models. Low dose radiation effects present a unique set of challenges to these models including the importance of stochastic effects due to the nature of radiation tracks and small number of molecules activated, and the search for infrequent events that contribute to cancer risks. We have been studying models of the ATM, TGF -Smad and WNT signaling pathways with the goal of applying pathway models to the investigation of low dose radiation cancer risks. Modeling challenges include introduction of stochastic models of radiation tracks, their relationships to more than one substrate species that perturb pathways, and the identification of a representative set of enzymes that act on the dominant substrates. Because several pathways are activated concurrently by radiation the development of modular pathway approach is of interest.

  17. Rho kinase signaling pathways during stretch in primary alveolar epithelia.

    PubMed

    DiPaolo, Brian C; Margulies, Susan S

    2012-05-15

    Alveolar epithelial cells (AECs) maintain integrity of the blood-gas barrier with actin-anchored intercellular tight junctions. Stretched type I-like AECs undergo magnitude- and frequency-dependent actin cytoskeletal remodeling into perijunctional actin rings. On the basis of published studies in human pulmonary artery endothelial cells (HPAECs), we hypothesize that RhoA activity, Rho kinase (ROCK) activity, and phosphorylation of myosin light chain II (MLC2) increase in stretched type I-like AECs in a manner that is dependent on stretch magnitude, and that RhoA, ROCK, or MLC2 activity inhibition will attenuate stretch-induced actin remodeling and preserve barrier properties. Primary type I-like AEC monolayers were stretched biaxially to create a change in surface area (ΔSA) of 12%, 25%, or 37% in a cyclic manner at 0.25 Hz for up to 60 min or left unstretched. Type I-like AECs were also treated with Rho pathway inhibitors (ML-7, Y-27632, or blebbistatin) and stained for F-actin or treated with the myosin phosphatase inhibitor calyculin-A and quantified for monolayer permeability. Counter to our hypothesis, ROCK activity and MLC2 phosphorylation decreased in type I-like AECs stretched to 25% and 37% ΔSA and did not change in monolayers stretched to 12% ΔSA. Furthermore, RhoA activity decreased in type I-like AECs stretched to 37% ΔSA. In contrast, MLC2 phosphorylation in HPAECs increased when HPAECs were stretched to 12% ΔSA but then decreased when they were stretched to 37% ΔSA, similar to type I-like AECs. Perijunctional actin rings were observed in unstretched type I-like AECs treated with the Rho pathway inhibitor blebbistatin. Myosin phosphatase inhibition increased MLC2 phosphorylation in stretched type I-like AECs but had no effect on monolayer permeability. In summary, stretch alters RhoA activity, ROCK activity, and MLC2 phosphorylation in a manner dependent on stretch magnitude and cell type. PMID:22287611

  18. Transplantation of prokaryotic two-component signaling pathways into mammalian cells.

    PubMed

    Hansen, Jonathan; Mailand, Erik; Swaminathan, Krishna Kumar; Schreiber, Joerg; Angelici, Bartolomeo; Benenson, Yaakov

    2014-11-01

    Signaling pathway engineering is a promising route toward synthetic biological circuits. Histidine-aspartate phosphorelays are thought to have evolved in prokaryotes where they form the basis for two-component signaling. Tyrosine-serine-threonine phosphorelays, exemplified by MAP kinase cascades, are predominant in eukaryotes. Recently, a prokaryotic two-component pathway was implemented in a plant species to sense environmental trinitrotoluene. We reasoned that "transplantation" of two-component pathways into mammalian host could provide an orthogonal and diverse toolkit for a variety of signal processing tasks. Here we report that two-component pathways could be partially reconstituted in mammalian cell culture and used for programmable control of gene expression. To enable this reconstitution, coding sequences of histidine kinase (HK) and response regulator (RR) components were codon-optimized for human cells, whereas the RRs were fused with a transactivation domain. Responsive promoters were furnished by fusing DNA binding sites in front of a minimal promoter. We found that coexpression of HKs and their cognate RRs in cultured mammalian cells is necessary and sufficient to strongly induce gene expression even in the absence of pathways' chemical triggers in the medium. Both loss-of-function and constitutive mutants behaved as expected. We further used the two-component signaling pathways to implement two-input logical AND, NOR, and OR gene regulation. Thus, two-component systems can be applied in different capacities in mammalian cells and their components can be used for large-scale synthetic gene circuits.

  19. Targeting the Hippo Signaling Pathway for Tissue Regeneration and Cancer Therapy.

    PubMed

    Juan, Wen Chun; Hong, Wanjin

    2016-01-01

    The Hippo signaling pathway is a highly-conserved developmental pathway that plays an essential role in organ size control, tumor suppression, tissue regeneration and stem cell self-renewal. The YES-associated protein (YAP) and the transcriptional co-activator with PDZ-binding motif (TAZ) are two important transcriptional co-activators that are negatively regulated by the Hippo signaling pathway. By binding to transcription factors, especially the TEA domain transcription factors (TEADs), YAP and TAZ induce the expression of growth-promoting genes, which can promote organ regeneration after injury. Therefore, controlled activation of YAP and TAZ can be useful for regenerative medicine. However, aberrant activation of YAP and TAZ due to deregulation of the Hippo pathway or overexpression of YAP/TAZ and TEADs can promote cancer development. Hence, pharmacological inhibition of YAP and TAZ may be a useful approach to treat tumors with high YAP and/or TAZ activity. In this review, we present the mechanisms regulating the Hippo pathway, the role of the Hippo pathway in tissue repair and cancer, as well as a detailed analysis of the different strategies to target the Hippo signaling pathway and the genes regulated by YAP and TAZ for regenerative medicine and cancer therapy. PMID:27589805

  20. Targeting the Hippo Signaling Pathway for Tissue Regeneration and Cancer Therapy

    PubMed Central

    Juan, Wen Chun; Hong, Wanjin

    2016-01-01

    The Hippo signaling pathway is a highly-conserved developmental pathway that plays an essential role in organ size control, tumor suppression, tissue regeneration and stem cell self-renewal. The YES-associated protein (YAP) and the transcriptional co-activator with PDZ-binding motif (TAZ) are two important transcriptional co-activators that are negatively regulated by the Hippo signaling pathway. By binding to transcription factors, especially the TEA domain transcription factors (TEADs), YAP and TAZ induce the expression of growth-promoting genes, which can promote organ regeneration after injury. Therefore, controlled activation of YAP and TAZ can be useful for regenerative medicine. However, aberrant activation of YAP and TAZ due to deregulation of the Hippo pathway or overexpression of YAP/TAZ and TEADs can promote cancer development. Hence, pharmacological inhibition of YAP and TAZ may be a useful approach to treat tumors with high YAP and/or TAZ activity. In this review, we present the mechanisms regulating the Hippo pathway, the role of the Hippo pathway in tissue repair and cancer, as well as a detailed analysis of the different strategies to target the Hippo signaling pathway and the genes regulated by YAP and TAZ for regenerative medicine and cancer therapy. PMID:27589805