On determining firing delay time of transitions for petri net based signaling pathways by introducing stochastic decision rules.

PubMed

Miwa, Yoshimasa; Li, Chen; Ge, Qi-Wei; Matsuno, Hiroshi; Miyano, Satoru

2011-01-01

Parameter determination is important in modeling and simulating biological pathways including signaling pathways. Parameters are determined according to biological facts obtained from biological experiments and scientific publications. However, such reliable data describing detailed reactions are not reported in most cases. This prompted us to develop a general methodology of determining the parameters of a model in the case of that no information of the underlying biological facts is provided. In this study, we use the Petri net approach for modeling signaling pathways, and propose a method to determine firing delay times of transitions for Petri net models of signaling pathways by introducing stochastic decision rules. Petri net technology provides a powerful approach to modeling and simulating various concurrent systems, and recently have been widely accepted as a description method for biological pathways. Our method enables to determine the range of firing delay time which realizes smooth token flows in the Petri net model of a signaling pathway. The availability of this method has been confirmed by the results of an application to the interleukin-1 induced signaling pathway.

Branches of the NF-κB signaling pathway regulate proliferation of oval cells in rat liver regeneration.

PubMed

Zhao, W M; Qin, Y L; Niu, Z P; Chang, C F; Yang, J; Li, M H; Zhou, Y; Xu, C S

2016-03-24

The NF-kB (nuclear factor kB) pathway is involved in the proliferation of many cell types. To explore the mechanism of the NF-kB signaling pathway underlying the oval cell proliferation during rat liver regeneration, the Rat Genome 230 2.0 Array was used to detect expression changes of NF-kB signaling pathway-related genes in oval cells. The results revealed that the expression levels of many genes in the NF-kB pathway were significantly changed. This included 48 known genes and 16 homologous genes, as well as 370 genes and 85 homologous genes related to cell proliferation. To further understand the biological significance of these changes, an expression profile function was used to analyze the potential biological processes. The results showed that the NF-kB pathway promoted oval cell proliferation mainly through three signaling branches; the tumor necrosis factor alpha branch (TNF-a pathway), the growth factor branch, and the chemokine branch. An integrated statistics method was used to define the key genes in the NF-kB pathway. Seven genes were identified to play vital roles in the NF-kB pathway. To confirm these results, the protein content, including two key genes (TNF and FGF11) and two non-key genes (CCL2 and TNFRSF12A), were analyzed using two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry. The results were generally consistent with those of the array data. To conclude, three branches and seven key genes were involved in the NF-kB signaling pathway that regulates oval cell proliferation during rat liver regeneration.

miR-958 inhibits Toll signaling and Drosomycin expression via direct targeting of Toll and Dif in Drosophila melanogaster.

PubMed

Li, Shengjie; Li, Yao; Shen, Li; Jin, Ping; Chen, Liming; Ma, Fei

2017-02-01

Drosophila melanogaster is widely used as a model system to study innate immunity and signaling pathways related to innate immunity, including the Toll signaling pathway. Although this pathway is well studied, the precise mechanisms of posttranscriptional regulation of key components of the Toll signaling pathway by microRNAs (miRNAs) remain obscure. In this study, we used an in silico strategy in combination with the Gal80 ts -Gal4 driver system to identify microRNA-958 (miR-958) as a candidate Toll pathway regulating miRNA in Drosophila We report that overexpression of miR-958 significantly reduces the expression of Drosomycin, a key antimicrobial peptide involved in Toll signaling and the innate immune response. We further demonstrate in vitro and in vivo that miR-958 targets the Toll and Dif genes, key components of the Toll signaling pathway, to negatively regulate Drosomycin expression. In addition, a miR-958 sponge rescued the expression of Toll and Dif, resulting in increased expression of Drosomycin. These results, not only revealed a novel function and modulation pattern of miR-958, but also provided a new insight into the underlying molecular mechanisms of Toll signaling in regulation of innate immunity. Copyright © 2017 the American Physiological Society.

[Pharmacodynamic evaluation and molecular mechanism research of Huanshao capsule on irregular menstruation].

PubMed

Sun, Jian-Hui; Huo, Hai-Ru; Li, Xiao-Qin; Li, Hong-Mei; Qin, De-Huai; Wu, Chun

2018-04-01

Huanshao capsule is widely used in irregular menstruation and has achieved a good effect. Huanshao capsule can promote gonad development in mice, significantly improve the ovarian index in mice, increase estrogen level and reduce FSH level in rats, inhibit the pain response induced by oxytocin and estrogen, inhibit writhing reaction induced by acetic acid pain in mice. Due to the complexity of traditional Chinese medical formula, the pharmacological mechanism of the treatment on the irregular menstruation of the Huanshao capsule is unclear. In this study, the internet-based computation platform (www.tcmip.cn）was used to explore the molecular mechanism of Huanshao capsule on the menstrual. The aim of this study was to find the molecular mechanism of Huanshao capsule in treating menstrual. In the study of the molecular mechanism of Huanshao capsule in the treatment of menstrual by using the internet-based computation platform, Huanshao capsule maybe treat the menstrual by the pathway of endocrine system, GnRH signal transduction pathway, estrogen signal transduction pathway, oxytocin signaling pathway, thyroid hormone signaling pathway, VEGF signaling pathway, FCεRI signaling pathway and purine metabolism and nucleotide metabolism. The early pharmacological study confirmed Huanshao capsule could increase the serum estradiol level and decrease follicle stimulating hormone level and the traditional Chinese medicine pharmacology coincide with the prediction result of internet-based computation platform which roles as the pathway of GnRH signaling pathway and estrogen signal transduction pathway. Other pathway needs further experimental verification. Copyright© by the Chinese Pharmaceutical Association.

Valproic acid exposure sequentially activates Wnt and mTOR pathways in rats.

PubMed

Qin, Liyan; Dai, Xufang; Yin, Yunhou

2016-09-01

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction, limited verbal communication and repetitive behaviors. Recent studies have demonstrated that Wnt signaling and mTOR signaling play important roles in the pathogenesis of ASD. However, the relationship of these two signaling pathways in ASD remains unclear. We assessed this question using the valproic acid (VPA) rat model of autism. Our results demonstrated that VPA exposure activated mTOR signaling and suppressed autophagy in the prefrontal cortex, hippocampus and cerebellum of autistic model rats, characterized by enhanced phospho-mTOR and phospho-S6 and decreased Beclin1, Atg5, Atg10, LC3-II and autophagosome formation. Rapamycin treatment suppressed the effect of VPA on mTOR signaling and ameliorated the autistic-like behaviors of rats in our autism model. The administration of VPA also activated Wnt signaling through up-regulating beta-catenin and phospho-GSK3beta. Suppression of the Wnt pathway by sulindac relieved autistic-like behaviors and attenuated VPA-induced mTOR signaling activation in autistic model rats. Our results demonstrate that VPA exposure sequentially activates Wnt signaling and mTOR signaling in rats. Suppression of the Wnt signaling pathway relieves autistic-like behaviors partially by deactivating the mTOR signaling pathway in VPA-exposed rats. Copyright © 2016 Elsevier Inc. All rights reserved.

The Hedgehog Signal Transduction Network

PubMed Central

Robbins, David J.; Fei, Dennis Liang; Riobo, Natalia A.

2013-01-01

Hedgehog (Hh) proteins regulate the development of a wide range of metazoan embryonic and adult structures, and disruption of Hh signaling pathways results in various human diseases. Here, we provide a comprehensive review of the signaling pathways regulated by Hh, consolidating data from a diverse array of organisms in a variety of scientific disciplines. Similar to the elucidation of many other signaling pathways, our knowledge of Hh signaling developed in a sequential manner centered on its earliest discoveries. Thus, our knowledge of Hh signaling has for the most part focused on elucidating the mechanism by which Hh regulates the Gli family of transcription factors, the so-called “canonical” Hh signaling pathway. However, in the past few years, numerous studies have shown that Hh proteins can also signal through Gli-independent mechanisms collectively referred to as “noncanonical” signaling pathways. Noncanonical Hh signaling is itself subdivided into two distinct signaling modules: (i) those not requiring Smoothened (Smo) and (ii) those downstream of Smo that do not require Gli transcription factors. Thus, Hh signaling is now proposed to occur through a variety of distinct context-dependent signaling modules that have the ability to crosstalk with one another to form an interacting, dynamic Hh signaling network. PMID:23074268

Three branches of phospholipase C signaling pathway promote hepatocyte growth in rat liver regeneration.

PubMed

Xu, G G; Geng, Z; Zhou, X C; He, Y G; He, T T; Mei, J X; Yang, Y J; Liu, Y Q; Xu, C S

2015-05-29

In general, the phospholipase C (PLC) signaling pathway is involved in many physiological activities, including cell growth. However, little is known regarding how the PLC signaling pathway participates in regulating hepatocyte (HC) growth during liver regeneration (LR). To further explore the influence of the PLC signaling pathway on HCs at the cellular level, HCs of high purity and vitality were isolated using Percoll density-gradient centrifugation after partial hepatectomy. The genes of the PLC signaling pathway and target genes of transcription factors in the pathway were obtained by searching the pathways and transcription factor databases, and changes in gene expression of isolated HCs were examined using the Rat Genome 230 2.0 Microarray. The results suggested that various genes involved in the pathway (including 151 known genes and 39 homologous genes) and cell growth (including 262 known genes and 37 homologous genes) were associated with LR. Subsequently, the synergetic effect of these genes in LR was analyzed using a mathematical model (Et) according to their expression profiles. The results showed that the Et values of G protein-coupled receptor/PLC, integrin/PLC, and growth factor receptor/PLC branches of the PLC pathway were all significantly strengthened during the progression and termination phases of LR. The synergetic effect of target genes, in parallel with target gene-related cell growth, was also enhanced during whole rat LR, suggesting the potential positive effect of PLC on HC growth. The present data indicate that the PLC signaling pathway may promote HC growth through 3 mechanisms during rat LR after partial hepatectomy.

Evolution and Design Governing Signal Precision and Amplification in a Bacterial Chemosensory Pathway

PubMed Central

Espinosa, Leon; Baronian, Grégory; Molle, Virginie; Mauriello, Emilia M. F.; Brochier-Armanet, Céline; Mignot, Tâm

2015-01-01

Understanding the principles underlying the plasticity of signal transduction networks is fundamental to decipher the functioning of living cells. In Myxococcus xanthus, a particular chemosensory system (Frz) coordinates the activity of two separate motility systems (the A- and S-motility systems), promoting multicellular development. This unusual structure asks how signal is transduced in a branched signal transduction pathway. Using combined evolution-guided and single cell approaches, we successfully uncoupled the regulations and showed that the A-motility regulation system branched-off an existing signaling system that initially only controlled S-motility. Pathway branching emerged in part following a gene duplication event and changes in the circuit structure increasing the signaling efficiency. In the evolved pathway, the Frz histidine kinase generates a steep biphasic response to increasing external stimulations, which is essential for signal partitioning to the motility systems. We further show that this behavior results from the action of two accessory response regulator proteins that act independently to filter and amplify signals from the upstream kinase. Thus, signal amplification loops may underlie the emergence of new connectivity in signal transduction pathways. PMID:26291327

Estradiol targets T cell signaling pathways in human systemic lupus.

PubMed

Walters, Emily; Rider, Virginia; Abdou, Nabih I; Greenwell, Cindy; Svojanovsky, Stan; Smith, Peter; Kimler, Bruce F

2009-12-01

The major risk factor for developing systemic lupus erythematosus (SLE) is being female. The present study utilized gene profiles of activated T cells from females with SLE and healthy controls to identify signaling pathways uniquely regulated by estradiol that could contribute to SLE pathogenesis. Selected downstream pathway genes (+/- estradiol) were measured by real time polymerase chain amplification. Estradiol uniquely upregulated six pathways in SLE T cells that control T cell function including interferon-alpha signaling. Measurement of interferon-alpha pathway target gene expression revealed significant differences (p= 0.043) in DRIP150 (+/- estradiol) in SLE T cell samples while IFIT1 expression was bimodal and correlated moderately (r= 0.55) with disease activity. The results indicate that estradiol alters signaling pathways in activated SLE T cells that control T cell function. Differential expression of transcriptional coactivators could influence estrogen-dependent gene regulation in T cell signaling and contribute to SLE onset and disease pathogenesis.

Signal-transducing protein phosphorylation cascades mediated by Ras/Rho proteins in the mammalian cell: the potential for multiplex signalling.

PubMed Central

Denhardt, D T

1996-01-01

The features of three distinct protein phosphorylation cascades in mammalian cells are becoming clear. These signalling pathways link receptor-mediated events at the cell surface or intracellular perturbations such as DNA damage to changes in cytoskeletal structure, vesicle transport and altered transcription factor activity. The best known pathway, the Ras-->Raf-->MEK-->ERK cascade [where ERK is extracellular-signal-regulated kinase and MEK is mitogen-activated protein (MAP) kinase/ERK kinase], is typically stimulated strongly by mitogens and growth factors. The other two pathways, stimulated primarily by assorted cytokines, hormones and various forms of stress, predominantly utilize p21 proteins of the Rho family (Rho, Rac and CDC42), although Ras can also participate. Diagnostic of each pathway is the MAP kinase component, which is phosphorylated by a unique dual-specificity kinase on both tyrosine and threonine in one of three motifs (Thr-Glu-Tyr, Thr-Phe-Tyr or Thr-Gly-Tyr), depending upon the pathway. In addition to activating one or more protein phosphorylation cascades, the initiating stimulus may also mobilize a variety of other signalling molecules (e.g. protein kinase C isoforms, phospholipid kinases, G-protein alpha and beta gamma subunits, phospholipases, intracellular Ca2+). These various signals impact to a greater or lesser extent on multiple downstream effectors. Important concepts are that signal transmission often entails the targeted relocation of specific proteins in the cell, and the reversible formation of protein complexes by means of regulated protein phosphorylation. The signalling circuits may be completed by the phosphorylation of upstream effectors by downstream kinases, resulting in a modulation of the signal. Signalling is terminated and the components returned to the ground state largely by dephosphorylation. There is an indeterminant amount of cross-talk among the pathways, and many of the proteins in the pathways belong to families of closely related proteins. The potential for more than one signal to be conveyed down a pathway simultaneously (multiplex signalling) is discussed. The net effect of a given stimulus on the cell is the result of a complex intracellular integration of the intensity and duration of activation of the individual pathways. The specific outcome depends on the particular signalling molecules expressed by the target cells and on the dynamic balance among the pathways. PMID:8836113

A network model of genomic hormone interactions underlying dementia and its translational validation through serendipitous off-target effect

PubMed Central

2013-01-01

Background While the majority of studies have focused on the association between sex hormones and dementia, emerging evidence supports the role of other hormone signals in increasing dementia risk. However, due to the lack of an integrated view on mechanistic interactions of hormone signaling pathways associated with dementia, molecular mechanisms through which hormones contribute to the increased risk of dementia has remained unclear and capacity of translating hormone signals to potential therapeutic and diagnostic applications in relation to dementia has been undervalued. Methods Using an integrative knowledge- and data-driven approach, a global hormone interaction network in the context of dementia was constructed, which was further filtered down to a model of convergent hormone signaling pathways. This model was evaluated for its biological and clinical relevance through pathway recovery test, evidence-based analysis, and biomarker-guided analysis. Translational validation of the model was performed using the proposed novel mechanism discovery approach based on ‘serendipitous off-target effects’. Results Our results reveal the existence of a well-connected hormone interaction network underlying dementia. Seven hormone signaling pathways converge at the core of the hormone interaction network, which are shown to be mechanistically linked to the risk of dementia. Amongst these pathways, estrogen signaling pathway takes the major part in the model and insulin signaling pathway is analyzed for its association to learning and memory functions. Validation of the model through serendipitous off-target effects suggests that hormone signaling pathways substantially contribute to the pathogenesis of dementia. Conclusions The integrated network model of hormone interactions underlying dementia may serve as an initial translational platform for identifying potential therapeutic targets and candidate biomarkers for dementia-spectrum disorders such as Alzheimer’s disease. PMID:23885764

Identification of signaling components required for the prediction of cytokine release in RAW 264.7 macrophages

PubMed Central

Pradervand, Sylvain; Maurya, Mano R; Subramaniam, Shankar

2006-01-01

Background Release of immuno-regulatory cytokines and chemokines during inflammatory response is mediated by a complex signaling network. Multiple stimuli produce different signals that generate different cytokine responses. Current knowledge does not provide a complete picture of these signaling pathways. However, using specific markers of signaling pathways, such as signaling proteins, it is possible to develop a 'coarse-grained network' map that can help understand common regulatory modules for various cytokine responses and help differentiate between the causes of their release. Results Using a systematic profiling of signaling responses and cytokine release in RAW 264.7 macrophages made available by the Alliance for Cellular Signaling, an analysis strategy is presented that integrates principal component regression and exhaustive search-based model reduction to identify required signaling factors necessary and sufficient to predict the release of seven cytokines (G-CSF, IL-1α, IL-6, IL-10, MIP-1α, RANTES, and TNFα) in response to selected ligands. This study provides a model-based quantitative estimate of cytokine release and identifies ten signaling components involved in cytokine production. The models identified capture many of the known signaling pathways involved in cytokine release and predict potentially important novel signaling components, like p38 MAPK for G-CSF release, IFNγ- and IL-4-specific pathways for IL-1a release, and an M-CSF-specific pathway for TNFα release. Conclusion Using an integrative approach, we have identified the pathways responsible for the differential regulation of cytokine release in RAW 264.7 macrophages. Our results demonstrate the power of using heterogeneous cellular data to qualitatively and quantitatively map intermediate cellular phenotypes. PMID:16507166

Quantification of growth factor signaling and pathway cross talk by live-cell imaging.

PubMed

Gross, Sean M; Rotwein, Peter

2017-03-01

Peptide growth factors stimulate cellular responses through activation of their transmembrane receptors. Multiple intracellular signaling cascades are engaged following growth factor-receptor binding, leading to short- and long-term biological effects. Each receptor-activated signaling pathway does not act in isolation but rather interacts at different levels with other pathways to shape signaling networks that are distinctive for each growth factor. To gain insights into the specifics of growth factor-regulated interactions among different signaling cascades, we developed a HeLa cell line stably expressing fluorescent live-cell imaging reporters that are readouts for two major growth factor-stimulated pathways, Ras-Raf-Mek-ERK and phosphatidylinositol (PI) 3-kinase-Akt. Incubation of cells with epidermal growth factor (EGF) resulted in rapid, robust, and sustained ERK signaling but shorter-term activation of Akt. In contrast, hepatocyte growth factor induced sustained Akt signaling but weak and short-lived ERK activity, and insulin-like growth factor-I stimulated strong long-term Akt responses but negligible ERK signaling. To address potential interactions between signaling pathways, we employed specific small-molecule inhibitors. In cells incubated with EGF or platelet-derived growth factor-AA, Raf activation and the subsequent stimulation of ERK reduced Akt signaling, whereas Mek inhibition, which blocked ERK activation, enhanced Akt and turned transient effects into sustained responses. Our results reveal that individual growth factors initiate signaling cascades that vary markedly in strength and duration and demonstrate in living cells the dramatic effects of cross talk from Raf and Mek to PI 3-kinase and Akt. Our data further indicate how specific growth factors can encode distinct cellular behaviors by promoting complex interactions among signaling pathways. Copyright © 2017 the American Physiological Society.

Quantification of growth factor signaling and pathway cross talk by live-cell imaging

PubMed Central

Gross, Sean M.

2017-01-01

Peptide growth factors stimulate cellular responses through activation of their transmembrane receptors. Multiple intracellular signaling cascades are engaged following growth factor–receptor binding, leading to short- and long-term biological effects. Each receptor-activated signaling pathway does not act in isolation but rather interacts at different levels with other pathways to shape signaling networks that are distinctive for each growth factor. To gain insights into the specifics of growth factor-regulated interactions among different signaling cascades, we developed a HeLa cell line stably expressing fluorescent live-cell imaging reporters that are readouts for two major growth factor-stimulated pathways, Ras–Raf–Mek–ERK and phosphatidylinositol (PI) 3-kinase–Akt. Incubation of cells with epidermal growth factor (EGF) resulted in rapid, robust, and sustained ERK signaling but shorter-term activation of Akt. In contrast, hepatocyte growth factor induced sustained Akt signaling but weak and short-lived ERK activity, and insulin-like growth factor-I stimulated strong long-term Akt responses but negligible ERK signaling. To address potential interactions between signaling pathways, we employed specific small-molecule inhibitors. In cells incubated with EGF or platelet-derived growth factor-AA, Raf activation and the subsequent stimulation of ERK reduced Akt signaling, whereas Mek inhibition, which blocked ERK activation, enhanced Akt and turned transient effects into sustained responses. Our results reveal that individual growth factors initiate signaling cascades that vary markedly in strength and duration and demonstrate in living cells the dramatic effects of cross talk from Raf and Mek to PI 3-kinase and Akt. Our data further indicate how specific growth factors can encode distinct cellular behaviors by promoting complex interactions among signaling pathways. PMID:28100485

Berberine inhibits enterovirus 71 replication by downregulating the MEK/ERK signaling pathway and autophagy.

PubMed

Wang, Huiqiang; Li, Ke; Ma, Linlin; Wu, Shuo; Hu, Jin; Yan, Haiyan; Jiang, Jiandong; Li, Yuhuan

2017-01-11

The MEK-ERK signaling pathway and autophagy play an important role for enterovirus71(EV71) replication. Inhibition of MEK-ERK signaling pathway and autophagy is shown to impair EV71 replication. Berberine (BBR), an isoquinoline alkaloid isolated from Berberis vulgaris L., has been reported to have ability to regulate this signaling pathway and autophagy. Herein, we want to determine whether berberine can inhibit EV71 infection by downregulating the MEK/ERK signaling pathway and autophagy. The antiviral effect of berberine was determined by cytopathic effect (CPE) assay, western blotting assay and qRT-PCR assay. The mechanism of BBR anti-virus was determined by western blotting assay and immunofluorescence assay. We showed that berberine does-dependently reduced EV71 RNA and protein synthesis, which was, at least in part, the result of inhibition of activation of MEK/ERK signaling pathway. Furthermore, we found that berberine suppressed the EV71-induced autophagy by activating AKT protein and inhibiting the phosphorylation of JNK and PI3KIII. BBR inhibited EV71 replication by downregulating autophagy and MEK/ERK signaling pathway. These findings suggest that BBR may be a potential agent or supplement against EV71 infection.

CD147 regulates extrinsic apoptosis in spermatocytes by modulating NFκB signaling pathways

PubMed Central

Wang, Chaoqun; Fok, Kin Lam; Cai, Zhiming; Chen, Hao; Chan, Hsiao Chang

2017-01-01

CD147 null mutant male mice are infertile with arrested spermatogenesis and increased apoptotic germ cells. Our previous studies have shown that CD147 prevents apoptosis in mouse spermatocytes but not spermatogonia. However, the underlying mechanism remains elusive. In the present study, we aim to determine the CD147-regulated apoptotic pathway in mouse spermatocytes. Our results showed that immunodepletion of CD147 triggered apoptosis through extrinsic apoptotic pathway in mouse testis and spermatocyte cell line (GC-2 cells), accompanied by activation of non-canonical NFκB signaling and suppression of canonical NFκB signaling. Furthermore, CD147 was found to interact with TRAF2, a factor known to regulate NFκB and extrinsic apoptotic signaling, and interfering CD147 led to the decrease of TRAF2. Consistently, depletion of CD147 by CRISPR/Cas9 technique in GC-2 cells down-regulated TRAF2 and resulted in cell death with suppressed canonical NFκB and activated non-canonical NFκB signaling. On the contrary, interfering of CD147 had no effect on NFκB signaling pathways as well as TRAF2 protein level in mouse spermatogonia cell line (GC-1 cells). Taken together, these results suggested that CD147 plays a key role in reducing extrinsic apoptosis in spermatocytes, but not spermatogonia, through modulating NFκB signaling pathway. PMID:27902973

CD147 regulates extrinsic apoptosis in spermatocytes by modulating NFκB signaling pathways.

PubMed

Wang, Chaoqun; Fok, Kin Lam; Cai, Zhiming; Chen, Hao; Chan, Hsiao Chang

2017-01-10

CD147 null mutant male mice are infertile with arrested spermatogenesis and increased apoptotic germ cells. Our previous studies have shown that CD147 prevents apoptosis in mouse spermatocytes but not spermatogonia. However, the underlying mechanism remains elusive. In the present study, we aim to determine the CD147-regulated apoptotic pathway in mouse spermatocytes. Our results showed that immunodepletion of CD147 triggered apoptosis through extrinsic apoptotic pathway in mouse testis and spermatocyte cell line (GC-2 cells), accompanied by activation of non-canonical NFκB signaling and suppression of canonical NFκB signaling. Furthermore, CD147 was found to interact with TRAF2, a factor known to regulate NFκB and extrinsic apoptotic signaling, and interfering CD147 led to the decrease of TRAF2. Consistently, depletion of CD147 by CRISPR/Cas9 technique in GC-2 cells down-regulated TRAF2 and resulted in cell death with suppressed canonical NFκB and activated non-canonical NFκB signaling. On the contrary, interfering of CD147 had no effect on NFκB signaling pathways as well as TRAF2 protein level in mouse spermatogonia cell line (GC-1 cells). Taken together, these results suggested that CD147 plays a key role in reducing extrinsic apoptosis in spermatocytes, but not spermatogonia, through modulating NFκB signaling pathway.

NAViGaTing the Micronome – Using Multiple MicroRNA Prediction Databases to Identify Signalling Pathway-Associated MicroRNAs

PubMed Central

Shirdel, Elize A.; Xie, Wing; Mak, Tak W.; Jurisica, Igor

2011-01-01

Background MicroRNAs are a class of small RNAs known to regulate gene expression at the transcript level, the protein level, or both. Since microRNA binding is sequence-based but possibly structure-specific, work in this area has resulted in multiple databases storing predicted microRNA:target relationships computed using diverse algorithms. We integrate prediction databases, compare predictions to in vitro data, and use cross-database predictions to model the microRNA:transcript interactome – referred to as the micronome – to study microRNA involvement in well-known signalling pathways as well as associations with disease. We make this data freely available with a flexible user interface as our microRNA Data Integration Portal — mirDIP (http://ophid.utoronto.ca/mirDIP). Results mirDIP integrates prediction databases to elucidate accurate microRNA:target relationships. Using NAViGaTOR to produce interaction networks implicating microRNAs in literature-based, KEGG-based and Reactome-based pathways, we find these signalling pathway networks have significantly more microRNA involvement compared to chance (p<0.05), suggesting microRNAs co-target many genes in a given pathway. Further examination of the micronome shows two distinct classes of microRNAs; universe microRNAs, which are involved in many signalling pathways; and intra-pathway microRNAs, which target multiple genes within one signalling pathway. We find universe microRNAs to have more targets (p<0.0001), to be more studied (p<0.0002), and to have higher degree in the KEGG cancer pathway (p<0.0001), compared to intra-pathway microRNAs. Conclusions Our pathway-based analysis of mirDIP data suggests microRNAs are involved in intra-pathway signalling. We identify two distinct classes of microRNAs, suggesting a hierarchical organization of microRNAs co-targeting genes both within and between pathways, and implying differential involvement of universe and intra-pathway microRNAs at the disease level. PMID:21364759

Spatial separation of two different pathways accounting for the generation of calcium signals in astrocytes.

PubMed

Oschmann, Franziska; Mergenthaler, Konstantin; Jungnickel, Evelyn; Obermayer, Klaus

2017-02-01

Astrocytes integrate and process synaptic information and exhibit calcium (Ca2+) signals in response to incoming information from neighboring synapses. The generation of Ca2+ signals is mostly attributed to Ca2+ release from internal Ca2+ stores evoked by an elevated metabotropic glutamate receptor (mGluR) activity. Different experimental results associated the generation of Ca2+ signals to the activity of the glutamate transporter (GluT). The GluT itself does not influence the intracellular Ca2+ concentration, but it indirectly activates Ca2+ entry over the membrane. A closer look into Ca2+ signaling in different astrocytic compartments revealed a spatial separation of those two pathways. Ca2+ signals in the soma are mainly generated by Ca2+ release from internal Ca2+ stores (mGluR-dependent pathway). In astrocytic compartments close to the synapse most Ca2+ signals are evoked by Ca2+ entry over the plasma membrane (GluT-dependent pathway). This assumption is supported by the finding, that the volume ratio between the internal Ca2+ store and the intracellular space decreases from the soma towards the synapse. We extended a model for mGluR-dependent Ca2+ signals in astrocytes with the GluT-dependent pathway. Additionally, we included the volume ratio between the internal Ca2+ store and the intracellular compartment into the model in order to analyze Ca2+ signals either in the soma or close to the synapse. Our model results confirm the spatial separation of the mGluR- and GluT-dependent pathways along the astrocytic process. The model allows to study the binary Ca2+ response during a block of either of both pathways. Moreover, the model contributes to a better understanding of the impact of channel densities on the interaction of both pathways and on the Ca2+ signal.

The Hippo-YAP signaling pathway and contact inhibition of growth

PubMed Central

Gumbiner, Barry M.; Kim, Nam-Gyun

2014-01-01

ABSTRACT The Hippo-YAP pathway mediates the control of cell proliferation by contact inhibition as well as other attributes of the physical state of cells in tissues. Several mechanisms sense the spatial and physical organization of cells, and function through distinct upstream modules to stimulate Hippo-YAP signaling: adherens junction or cadherin–catenin complexes, epithelial polarity and tight junction complexes, the FAT-Dachsous morphogen pathway, as well as cell shape, actomyosin or mechanotransduction. Soluble extracellular factors also regulate Hippo pathway signaling, often inhibiting its activity. Indeed, the Hippo pathway mediates a reciprocal relationship between contact inhibition and mitogenic signaling. As a result, cells at the edges of a colony, a wound in a tissue or a tumor are more sensitive to ambient levels of growth factors and more likely to proliferate, migrate or differentiate through a YAP and/or TAZ-dependent process. Thus, the Hippo-YAP pathway senses and responds to the physical organization of cells in tissues and coordinates these physical cues with classic growth-factor-mediated signaling pathways. This Commentary is focused on the biological significance of Hippo-YAP signaling and how upstream regulatory modules of the pathway interact to produce biological outcomes. PMID:24532814

Cellular Notch responsiveness is defined by phosphoinositide 3-kinase-dependent signals

PubMed Central

Mckenzie, Grahame; Ward, George; Stallwood, Yvette; Briend, Emmanuel; Papadia, Sofia; Lennard, Andrew; Turner, Martin; Champion, Brian; Hardingham, Giles E

2006-01-01

Background Notch plays a wide-ranging role in controlling cell fate, differentiation and development. The PI3K-Akt pathway is a similarly conserved signalling pathway which regulates processes such as differentiation, proliferation and survival. Mice with disrupted Notch and PI3K signalling show phenotypic similarities during haematopoietic cell development, suggesting functional interaction between these pathways. Results We show that cellular responsiveness to Notch signals depends on the activity of the PI3K-Akt pathway in cells as diverse as CHO cells, primary T-cells and hippocampal neurons. Induction of the endogenous PI3K-Akt pathway in CHO cells (by the insulin pathway), in T-cells (via TCR activation) or in neurons (via TrKB activation) potentiates Notch-dependent responses. We propose that the PI3K-Akt pathway exerts its influence on Notch primarily via inhibition of GSK3-beta, a kinase known to phosphorylate and regulate Notch signals. Conclusion The PI3K-Akt pathway acts as a "gain control" for Notch signal responses. Since physiological levels of intracellular Notch are often low, coincidence with PI3K-activation may be crucial for induction of Notch-dependent responses. PMID:16507111

Molecular mechanisms of the mammalian Hippo signaling pathway.

PubMed

Ji, Xin-yan; Zhong, Guoxuan; Zhao, Bin

2017-07-20

The Hippo pathway plays an evolutionarily conserved fundamental role in controlling organ size in multicellular organisms. Importantly, evidence from studies of patient samples and mouse models clearly indicates that deregulation of the Hippo signaling pathway plays a crucial role in the initiation and progression of many different types of human cancers. The Hippo signaling pathway is regulated by various stimuli, such as mechanical stress, G-protein coupled receptor signaling, and cellular energy status. When activated, the Hippo kinase cascade phosphorylates and inhibits the transcription co-activator YAP (Yes-associated protein), and its paralog TAZ (transcriptional coactivator with PDZ-binding motif), resulting in their cytoplasmic retention and degradation. When the Hippo signaling pathway is inactive, dephosphorylated YAP/TAZ translocate into the nucleus and activate gene transcription through binding to TEAD (TEA domain) family and other transcription factors. Such changes in gene expression promote cell proliferation and stem cell/progenitor cell self-renewal but inhibit apoptosis, thereby coordinately promote increase in organ size, tissue regeneration, and tumorigenesis. In this review, we summarize the molecular mechanisms of the mammalian Hippo signaling pathway with special emphasis on the Hippo kinase cascade and its upstream signals, the Hippo signaling pathway regulation of YAP and the mechanisms of YAP in regulation of gene transcription.

YAP and the Hippo pathway in pediatric cancer

PubMed Central

Mohamed, Abdalla D.; Gener, Melissa; Li, Weijie; Taboada, Eugenio

2017-01-01

ABSTRACT The Hippo pathway is an important signaling pathway that controls cell proliferation and apoptosis. It is evolutionarily conserved in mammals and is stimulated by cell–cell contact, inhibiting cell proliferation in response to increased cell density. During early embryonic development, the Hippo signaling pathway regulates organ development and size, and its functions result in the coordinated balance between proliferation, apoptosis, and differentiation. Its principal effectors, YAP and TAZ, regulate signaling by the embryonic stem cells and determine cell fate and histogenesis. Dysfunction of this pathway contributes to cancer development in adults and children. Emerging studies have shed light on the upregulation of Hippo pathway members in several pediatric cancers and may offer prognostic information on rhabdomyosarcoma, osteosarcoma, Wilms tumor, neuroblastoma, medulloblastoma, and other brain gliomas. We review the results of such published studies and highlight the potential clinical application of this pathway in pediatric oncologic and pathologic studies. These studies support targeting this pathway as a novel treatment strategy. PMID:28616573

RBP-Jκ-Dependent Notch Signaling Is Dispensable for Mouse Early Embryonic Development

PubMed Central

Souilhol, Céline; Cormier, Sarah; Tanigaki, Kenji; Babinet, Charles; Cohen-Tannoudji, Michel

2006-01-01

The Notch signaling pathway is an evolutionarily conserved signaling system which has been shown to be essential in cell fate specification and in numerous aspects of embryonic development in all metazoans thus far studied. We recently demonstrated that several components of the Notch signaling pathway, including the four Notch receptors and their five ligands known in mammals, are expressed in mouse oocytes, in mouse preimplantation embryos, or both. This suggested a possible implication of the Notch pathway in the first cell fate specification of the dividing mouse embryo, which results in the formation of the blastocyst. To address this issue directly, we generated zygotes in which both the maternal and the zygotic expression of Rbpsuh, a key element of the core Notch signaling pathway, were abrogated. We find that such zygotes give rise to blastocysts which implant and develop normally. Nevertheless, after gastrulation, these embryos die around midgestation, similarly to Rbpsuh-null mutants. This demonstrates that the RBP-Jκ-dependent pathway, otherwise called the canonical Notch pathway, is dispensable for blastocyst morphogenesis and the establishment of the three germ layers, ectoderm, endoderm, and mesoderm. These results are discussed in the light of recent observations which have challenged this conclusion. PMID:16782866

RBP-Jkappa-dependent notch signaling is dispensable for mouse early embryonic development.

PubMed

Souilhol, Céline; Cormier, Sarah; Tanigaki, Kenji; Babinet, Charles; Cohen-Tannoudji, Michel

2006-07-01

The Notch signaling pathway is an evolutionarily conserved signaling system which has been shown to be essential in cell fate specification and in numerous aspects of embryonic development in all metazoans thus far studied. We recently demonstrated that several components of the Notch signaling pathway, including the four Notch receptors and their five ligands known in mammals, are expressed in mouse oocytes, in mouse preimplantation embryos, or both. This suggested a possible implication of the Notch pathway in the first cell fate specification of the dividing mouse embryo, which results in the formation of the blastocyst. To address this issue directly, we generated zygotes in which both the maternal and the zygotic expression of Rbpsuh, a key element of the core Notch signaling pathway, were abrogated. We find that such zygotes give rise to blastocysts which implant and develop normally. Nevertheless, after gastrulation, these embryos die around midgestation, similarly to Rbpsuh-null mutants. This demonstrates that the RBP-Jkappa-dependent pathway, otherwise called the canonical Notch pathway, is dispensable for blastocyst morphogenesis and the establishment of the three germ layers, ectoderm, endoderm, and mesoderm. These results are discussed in the light of recent observations which have challenged this conclusion.

Inhibition of glycogen phosphorylation induces changes in cellular proteome and signaling pathways in MIA pancreatic cancer cells

PubMed Central

Ma, Danjun; Wang, Jiarui; Zhao, Yingchun; Lee, Wai-Nang Paul; Xiao, Jing; Go, Vay Liang W.; Wang, Qi; Recker, Robert; Xiao, Gary Guishan

2011-01-01

Objectives Novel quantitative proteomic approaches were used to study the effects of inhibition of glycogen phosphorylase on proteome and signaling pathways in MIA PaCa-2 pancreatic cancer cells. Methods We performed quantitative proteomic analysis in MIA PaCa-2 cancer cells treated with a stratified dose of CP-320626 (25 μM, 50 μM and 100 μM). The effect of metabolic inhibition on cellular protein turnover dynamics was also studied using the modified SILAC method (mSILAC). Results A total of twenty-two protein spots and four phosphoprotein spots were quantitatively analyzed. We found that dynamic expression of total proteins and phosphoproteins was significantly changed in MIA PaCa-2 cells treated with an incremental dose of CP-320626. Functional analyses suggested that most of the proteins differentially expressed were in the pathways of MAPK/ERK and TNF-α/NF-κB. Conclusions Signaling pathways and metabolic pathways share many common cofactors and substrates forming an extended metabolic network. The restriction of substrate through one pathway such as inhibition of glycogen phosphorylation induces pervasive metabolomic and proteomic changes manifested in protein synthesis, breakdown and post-translational modification of signaling molecules. Our results suggest that quantitative proteomic is an important approach to understand the interaction between metabolism and signaling pathways. PMID:22158071

AT1 receptor signaling pathways in the cardiovascular system.

PubMed

Kawai, Tatsuo; Forrester, Steven J; O'Brien, Shannon; Baggett, Ariele; Rizzo, Victor; Eguchi, Satoru

2017-11-01

The importance of the renin angiotensin aldosterone system in cardiovascular physiology and pathophysiology has been well described whereas the detailed molecular mechanisms remain elusive. The angiotensin II type 1 receptor (AT1 receptor) is one of the key players in the renin angiotensin aldosterone system. The AT1 receptor promotes various intracellular signaling pathways resulting in hypertension, endothelial dysfunction, vascular remodeling and end organ damage. Accumulating evidence shows the complex picture of AT1 receptor-mediated signaling; AT1 receptor-mediated heterotrimeric G protein-dependent signaling, transactivation of growth factor receptors, NADPH oxidase and ROS signaling, G protein-independent signaling, including the β-arrestin signals and interaction with several AT1 receptor interacting proteins. In addition, there is functional cross-talk between the AT1 receptor signaling pathway and other signaling pathways. In this review, we will summarize an up to date overview of essential AT1 receptor signaling events and their functional significances in the cardiovascular system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of tumor related signaling pathways with known compounds to determine potential agents for lung adenocarcinoma.

PubMed

Xu, Song; Liu, Renwang; Da, Yurong

2018-06-05

This study compared tumor-related signaling pathways with known compounds to determine potential agents for lung adenocarcinoma (LUAD) treatment. Kyoto Encyclopedia of Genes and Genomes signaling pathway analyses were performed based on LUAD differentially expressed genes from The Cancer Genome Atlas (TCGA) project and genotype-tissue expression controls. These results were compared to various known compounds using the Connectivity Mapping dataset. The clinical significance of the hub genes identified by overlapping pathway enrichment analysis was further investigated using data mining from multiple sources. A drug-pathway network for LUAD was constructed, and molecular docking was carried out. After the integration of 57 LUAD-related pathways and 35 pathways affected by small molecules, five overlapping pathways were revealed. Among these five pathways, the p53 signaling pathway was the most significant, with CCNB1, CCNB2, CDK1, CDKN2A, and CHEK1 being identified as hub genes. The p53 signaling pathway is implicated as a risk factor for LUAD tumorigenesis and survival. A total of 88 molecules significantly inhibiting the five LUAD-related oncogenic pathways were involved in the LUAD drug-pathway network. Daunorubicin, mycophenolic acid, and pyrvinium could potentially target the hub gene CHEK1 directly. Our study highlights the critical pathways that should be targeted in the search for potential LUAD treatments, most importantly, the p53 signaling pathway. Some compounds, such as ciclopirox and AG-028671, may have potential roles for LUAD treatment but require further experimental verification. © 2018 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

Bone morphogenetic protein and activin membrane-bound inhibitor overexpression inhibits gastric tumor cell invasion via the transforming growth factor-β/epithelial-mesenchymal transition signaling pathway.

PubMed

Yuan, Chun-Ling; Liang, Rong; Liu, Zhi-Hui; Li, Yong-Qiang; Luo, Xiao-Ling; Ye, Jia-Zhou; Lin, Yan

2018-06-01

Gastric carcinoma is one of the most common human malignancies and remains the second leading cause of cancer-associated mortality worldwide. Gastric carcinoma is characterized by early-stage metastasis and is typically diagnosed in the advanced stage. Previous results have indicated that bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) overexpression has been demonstrated to inhibit growth and metastasis of gastric cancer cells. However, the molecular mechanisms of the BAMBI-mediated signaling pathway in the progression of gastric cancer are poorly understood. In the present study, to assess whether BAMBI overexpression inhibited the growth and aggressiveness of gastric carcinoma cells through regulation of transforming growth factor (TGF)-β/epithelial-mesenchymal transition (EMT) signaling pathway, the growth and metastasis of gastric carcinoma cells were analyzed following BAMBI overexpression and knockdown in vitro and in vivo . Molecular changes in the TGF-β/EMT signaling pathway were studied in gastric carcinoma cells following BAMBI overexpression and knockdown. DNA methylation of the gene regions encoding the TGF-β/EMT signaling pathway was investigated in gastric carcinoma cells. Tumor growth in tumor-bearing mice was analyzed after mice were subjected to endogenous overexpression of BAMBI. Results indicated that BAMBI overexpression significantly inhibited gastric carcinoma cell growth and aggressiveness, whereas knockdown of BAMBI significantly promoted its growth and metastasis compared with the control (P<0.01). The TGF-β/EMT signaling pathway was downregulated in BAMBI-overexpressed gastric carcinoma cells; however, signaling was promoted following BAMBI knockdown. In addition, it was observed that BAMBI overexpression significantly downregulated the DNA methylation of the gene regions encoding the TGF-β/EMT signaling pathway (P<0.01). Furthermore, RNA interference-mediated BAMBI overexpression also promoted apoptosis in gastric cancer cells and significantly inhibited growth of gastric tumors in murine xenografts (P<0.01). In conclusion, the present findings suggest that BAMBI overexpression inhibited the TGF-β/EMT signaling pathway and suppressed the invasiveness of gastric tumors, suggesting BAMBI may be a potential target for the treatment of gastric carcinoma via regulation of the TGF-β/EMT signaling pathway.

Modeling of cell signaling pathways in macrophages by semantic networks

PubMed Central

Hsing, Michael; Bellenson, Joel L; Shankey, Conor; Cherkasov, Artem

2004-01-01

Background Substantial amounts of data on cell signaling, metabolic, gene regulatory and other biological pathways have been accumulated in literature and electronic databases. Conventionally, this information is stored in the form of pathway diagrams and can be characterized as highly "compartmental" (i.e. individual pathways are not connected into more general networks). Current approaches for representing pathways are limited in their capacity to model molecular interactions in their spatial and temporal context. Moreover, the critical knowledge of cause-effect relationships among signaling events is not reflected by most conventional approaches for manipulating pathways. Results We have applied a semantic network (SN) approach to develop and implement a model for cell signaling pathways. The semantic model has mapped biological concepts to a set of semantic agents and relationships, and characterized cell signaling events and their participants in the hierarchical and spatial context. In particular, the available information on the behaviors and interactions of the PI3K enzyme family has been integrated into the SN environment and a cell signaling network in human macrophages has been constructed. A SN-application has been developed to manipulate the locations and the states of molecules and to observe their actions under different biological scenarios. The approach allowed qualitative simulation of cell signaling events involving PI3Ks and identified pathways of molecular interactions that led to known cellular responses as well as other potential responses during bacterial invasions in macrophages. Conclusions We concluded from our results that the semantic network is an effective method to model cell signaling pathways. The semantic model allows proper representation and integration of information on biological structures and their interactions at different levels. The reconstruction of the cell signaling network in the macrophage allowed detailed investigation of connections among various essential molecules and reflected the cause-effect relationships among signaling events. The simulation demonstrated the dynamics of the semantic network, where a change of states on a molecule can alter its function and potentially cause a chain-reaction effect in the system. PMID:15494071

Next Generation Sequencing Analysis of Gene Regulation in the Rat Model of Retinopathy of Prematurity

PubMed Central

Griffith, Rachel M.; Li, Hu; Zhang, Nan; Favazza, Tara L.; Fulton, Anne B.; Hansen, Ronald M.; Akula, James D.

2013-01-01

Purpose To identify the genes, biochemical signaling pathways and biological themes involved in the pathogenesis of retinopathy of prematurity (ROP). Methods Next-generation sequencing (NGS) was performed on the RNA transcriptome of rats with the Penn et al. (1994) oxygen-induced retinopathy (OIR) model of ROP at the height of vascular abnormality, postnatal day (P) 19, and normalized to age-matched, room-air-reared littermate controls. Eight custom developed pathways with potential relevance to known ROP sequelae were evaluated for significant regulation in ROP: The three major Wnt signaling pathways, canonical, planar cell polarity (PCP), and Wnt/Ca2+, two signaling pathways mediated by the Rho GTPases RhoA and Cdc42, which are respectively thought to intersect with canonical and noncanonical Wnt signaling, nitric oxide signaling pathways mediated by two nitrox oxide synthase (NOS) enzymes, neuronal (nNOS) and endothelial (eNOS), and the retinoic acid (RA) signaling pathway. Regulation of other biological pathways and themes were detected by gene ontology using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the NIH's Database for Annotation, Visualization and Integrated Discovery (DAVID)'s GO terms databases. Results Canonical Wnt signaling was found to be regulated, but the non-canonical PCP and Wnt/Ca2+ pathways were not. Nitric oxide (NO) signaling, as measured by the activation of nNOS eNOS, was also regulated, as was RA signaling. Biological themes related to protein translation (ribosomes), neural signaling, inflammation and immunity, cell cycle and cell death, were (among others) highly regulated in ROP rats. Conclusions These several genes and pathways identified by NGS might provide novel targets for intervention in ROP. PMID:23775346

Insulin-like growth factor-1 suppresses the Myostatin signaling pathway during myogenic differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Retamales, A.; Zuloaga, R.; Valenzuela, C.A.

Myogenic differentiation is a complex and well-coordinated process for generating mature skeletal muscle fibers. This event is autocrine/paracrine regulated by growth factors, principally Myostatin (MSTN) and Insulin-like Growth Factor-1 (IGF-1). Myostatin, a member of the transforming growth factor-β superfamily, is a negative regulator of skeletal muscle growth in vertebrates that exerts its inhibitory function by activating Smad transcription factors. In contrast, IGF-1 promotes the differentiation of skeletal myoblasts by activating the PI3K/Akt signaling pathway. This study reports on a novel functional crosstalk between the IGF-1 and MSTN signaling pathways, as mediated through interaction between PI3K/Akt and Smad3. Stimulation of skeletalmore » myoblasts with MSTN resulted in a transient increase in the pSmad3:Smad3 ratio and Smad-dependent transcription. Moreover, MSTN inhibited myod gene expression and myoblast fusion in an Activin receptor-like kinase/Smad3-dependent manner. Preincubation of skeletal myoblasts with IGF-1 blocked MSTN-induced Smad3 activation, promoting myod expression and myoblast differentiation. This inhibitory effect of IGF-1 on the MSTN signaling pathway was dependent on IGF-1 receptor, PI3K, and Akt activities. Finally, immunoprecipitation assay analysis determined that IGF-1 pretreatment increased Akt and Smad3 interaction. These results demonstrate that the IGF-1/PI3K/Akt pathway may inhibit MSTN signaling during myoblast differentiation, providing new insight to existing knowledge on the complex crosstalk between both growth factors. - Highlights: • IGF-1 inhibits Myostatin canonical signaling pathway through IGF-1R/PI3K/Akt pathway. • IGF-1 promotes myoblast differentiation through a direct blocking of Myostatin signaling pathway. • IGF-1 induces the interaction of Akt with Smad3 in skeletal myoblast.« less

Not so Fast: Co-Requirements for Sonic Hedgehog Induced Brain Tumorigenesis.

PubMed

Ward, Stacey A; Rubin, Joshua B

2015-08-06

The Sonic hedgehog (Shh) pathway plays an integral role in cellular proliferation during normal brain development and also drives growth in a variety of cancers including brain cancer. Clinical trials of Shh pathway inhibitors for brain tumors have yielded disappointing results, indicating a more nuanced role for Shh signaling. We postulate that Shh signaling does not work alone but requires co-activation of other signaling pathways for tumorigenesis and stem cell maintenance. This review will focus on the interplay between the Shh pathway and these pathways to promote tumor growth in brain tumors, presenting opportunities for the study of combinatorial therapies.

SPSB1, a Novel Negative Regulator of the Transforming Growth Factor-β Signaling Pathway Targeting the Type II Receptor.

PubMed

Liu, Sheng; Nheu, Thao; Luwor, Rodney; Nicholson, Sandra E; Zhu, Hong-Jian

2015-07-17

Appropriate cellular signaling is essential to control cell proliferation, differentiation, and cell death. Aberrant signaling can have devastating consequences and lead to disease states, including cancer. The transforming growth factor-β (TGF-β) signaling pathway is a prominent signaling pathway that has been tightly regulated in normal cells, whereas its deregulation strongly correlates with the progression of human cancers. The regulation of the TGF-β signaling pathway involves a variety of physiological regulators. Many of these molecules act to alter the activity of Smad proteins. In contrast, the number of molecules known to affect the TGF-β signaling pathway at the receptor level is relatively low, and there are no known direct modulators for the TGF-β type II receptor (TβRII). Here we identify SPSB1 (a Spry domain-containing Socs box protein) as a novel regulator of the TGF-β signaling pathway. SPSB1 negatively regulates the TGF-β signaling pathway through its interaction with both endogenous and overexpressed TβRII (and not TβRI) via its Spry domain. As such, TβRII and SPSB1 co-localize on the cell membrane. SPSB1 maintains TβRII at a low level by enhancing the ubiquitination levels and degradation rates of TβRII through its Socs box. More importantly, silencing SPSB1 by siRNA results in enhanced TGF-β signaling and migration and invasion of tumor cells. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Signal Transduction in the Chronic Leukemias: Implications for Targeted Therapies

PubMed Central

Ahmed, Wesam; Van Etten, Richard A.

2013-01-01

The chronic leukemias, including chronic myeloid leukemia (CML), the Philadelphia-negative myeloproliferative neoplasms (MPNs), and chronic lymphocytic leukemia (CLL), have been characterized extensively for abnormalities of cellular signaling pathways. This effort has led to the elucidation of the central role of dysregulated tyrosine kinase signaling in the chronic myeloid neoplasms and of constitutive B-cell receptor signaling in CLL. This, in turn, has stimulated the development of small molecule inhibitors of these signaling pathways for therapy of chronic leukemia. Although the field is still in its infancy, the clinical results with these agents have ranged from encouraging (CLL) to spectacular (CML). In this review, we summarize recent studies that have helped to define the signaling pathways critical to the pathogenesis of the chronic leukemias. We also discuss correlative studies emerging from clinical trials of drugs targeting these pathways. PMID:23307472

[Notch signaling pathway participates in the differentiation of hepatic progenitor cells into bile duct epithelial cells and progression of hepatic fibrosis in cholestatic liver fibrosis rat].

PubMed

Mu, Y P; Zhang, X; Xu, Y; Fan, W W; Li, X W; Chen, J M; Chen, G F; Liu, P

2017-06-08

Objective: To investigate differentiation direction of hepatic progenitor cells (HPCs) in cholestatic liver fibrosis (CLF), and the role of Notch signaling pathway in the differentiation of HPCs. Methods: A CLF rat model was established by bile duct ligation (BDL) followed by monitoring changes of Notch signal pathway and the cellular origin of proliferating cholangiocytes. After intraperitoneal injection of DAPT (a Notch signaling inhibitor) after bile duct ligation, the progress of liver fibrosis and the proliferation of cholangiocytes after inhibition of the Notch pathway were analyzed. Results: Data showed that bile duct proliferation gradually increased along with inflammatory cell infiltration and proliferating bile duct cells surrounded by abundant collagen in the BDL group. Immunostaining confirmed markedly increased expression of CK19, OV6, Sox9 and EpCAM. In addition, RT-PCR results showed that Notch signaling pathway was activated significantly. Once the Notch signaling pathway was inhibited by DAPT, bile duct proliferation markedly suppressed along with significantly decreased the mRNA expression of CK19, OV6, Sox9 and EpCAM, compared with BDL group [(10.2±0.7) vs . (22.3±0.8), (7.6±1.5) vs . (18.1±3.7), (1.4±0.4) vs . (4.1±1.1), (1.3±0.3) vs . (5.0±1.4), respectively, P <0.01]. Moreover, liver fibrosis was also reduced significantly. Conclusion: Notch signaling activation is required for HPCs differentiation into cholangiocytes in CLF and inhibition of the Notch signaling pathway may offer a therapeutic option for treating CLF.

Chordin and dickkopf-1b are essential for the formation of head structures through activation of the FGF signaling pathway in zebrafish.

PubMed

Tanaka, Shingo; Hosokawa, Hiroshi; Weinberg, Eric S; Maegawa, Shingo

2017-04-15

The ability of the Spemann organizer to induce dorsal axis formation is dependent on downstream factors of the maternal Wnt/β-catenin signaling pathway. The fibroblast growth factor (FGF) signaling pathway has been identified as one of the downstream components of the maternal Wnt/β-catenin signaling pathway. The ability of the FGF signaling pathway to induce the formation of a dorsal axis with a complete head structure requires chordin (chd) expression; however, the molecular mechanisms involved in this developmental process, due to activation of FGF signaling, remain unclear. In this study, we showed that activation of the FGF signaling pathway induced the formation of complete head structures through the expression of chd and dickkopf-1b (dkk1b). Using the organizer-deficient maternal mutant, ichabod, we identified dkk1b as a novel downstream factor in the FGF signaling pathway. We also demonstrate that dkk1b expression is necessary, after activation of the FGF signaling pathway, to induce neuroectoderm patterning along the anteroposterior (AP) axis and for formation of complete head structures. Co-injection of chd and dkk1b mRNA resulted in the formation of a dorsal axis with a complete head structure in ichabod embryos, confirming the role of these factors in this developmental process. Unexpectedly, we found that chd induced dkk1b expression in ichabod embryos at the shield stage. However, chd failed to maintain dkk1b expression levels in cells of the shield and, subsequently, in the cells of the prechordal plate after mid-gastrula stage. In contrast, activation of the FGF signaling pathway maintained the dkk1b expression from the beginning of gastrulation to early somitogenesis. In conclusion, activation of the FGF signaling pathway induces the formation of a dorsal axis with a complete head structure through the expression of chd and subsequent maintenance of dkk1b expression levels. Copyright © 2017 Elsevier Inc. All rights reserved.

Bayesian model of signal rewiring reveals mechanisms of gene dysregulation in acquired drug resistance in breast cancer

PubMed Central

Azad, A. K. M.; Keith, Jonathan M.

2017-01-01

Small molecule inhibitors, such as lapatinib, are effective against breast cancer in clinical trials, but tumor cells ultimately acquire resistance to the drug. Maintaining sensitization to drug action is essential for durable growth inhibition. Recently, adaptive reprogramming of signaling circuitry has been identified as a major cause of acquired resistance. We developed a computational framework using a Bayesian statistical approach to model signal rewiring in acquired resistance. We used the p1-model to infer potential aberrant gene-pairs with differential posterior probabilities of appearing in resistant-vs-parental networks. Results were obtained using matched gene expression profiles under resistant and parental conditions. Using two lapatinib-treated ErbB2-positive breast cancer cell-lines: SKBR3 and BT474, our method identified similar dysregulated signaling pathways including EGFR-related pathways as well as other receptor-related pathways, many of which were reported previously as compensatory pathways of EGFR-inhibition via signaling cross-talk. A manual literature survey provided strong evidence that aberrant signaling activities in dysregulated pathways are closely related to acquired resistance in EGFR tyrosine kinase inhibitors. Our approach predicted literature-supported dysregulated pathways complementary to both node-centric (SPIA, DAVID, and GATHER) and edge-centric (ESEA and PAGI) methods. Moreover, by proposing a novel pattern of aberrant signaling called V-structures, we observed that genes were dysregulated in resistant-vs-sensitive conditions when they were involved in the switch of dependencies from targeted to bypass signaling events. A literature survey of some important V-structures suggested they play a role in breast cancer metastasis and/or acquired resistance to EGFR-TKIs, where the mRNA changes of TGFBR2, LEF1 and TP53 in resistant-vs-sensitive conditions were related to the dependency switch from targeted to bypass signaling links. Our results suggest many signaling pathway structures are compromised in acquired resistance, and V-structures of aberrant signaling within/among those pathways may provide further insights into the bypass mechanism of targeted inhibition. PMID:28288164

Loss of Pancreas upon Activated Wnt Signaling Is Concomitant with Emergence of Gastrointestinal Identity

PubMed Central

Herrero-Martin, Griselda; Puri, Sapna; Taketo, Makoto Mark; Rojas, Anabel; Hebrok, Matthias; Cano, David A.

2016-01-01

Organ formation is achieved through the complex interplay between signaling pathways and transcriptional cascades. The canonical Wnt signaling pathway plays multiple roles during embryonic development including patterning, proliferation and differentiation in distinct tissues. Previous studies have established the importance of this pathway at multiple stages of pancreas formation as well as in postnatal organ function and homeostasis. In mice, gain-of-function experiments have demonstrated that activation of the canonical Wnt pathway results in pancreatic hypoplasia, a phenomenon whose underlying mechanisms remains to be elucidated. Here, we show that ectopic activation of epithelial canonical Wnt signaling causes aberrant induction of gastric and intestinal markers both in the pancreatic epithelium and mesenchyme, leading to the development of gut-like features. Furthermore, we provide evidence that β -catenin-induced impairment of pancreas formation depends on Hedgehog signaling. Together, our data emphasize the developmental plasticity of pancreatic progenitors and further underscore the key role of precise regulation of signaling pathways to maintain appropriate organ boundaries. PMID:27736991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Endele, Max; Etzrodt, Martin; Schroeder, Timm, E-mail: timm.schroeder@bsse.ethz.ch

Hematopoiesis is the cumulative consequence of finely tuned signaling pathways activated through extrinsic factors, such as local niche signals and systemic hematopoietic cytokines. Whether extrinsic factors actively instruct the lineage choice of hematopoietic stem and progenitor cells or are only selectively allowing survival and proliferation of already intrinsically lineage-committed cells has been debated over decades. Recent results demonstrated that cytokines can instruct lineage choice. However, the precise function of individual cytokine-triggered signaling molecules in inducing cellular events like proliferation, lineage choice, and differentiation remains largely elusive. Signal transduction pathways activated by different cytokine receptors are highly overlapping, but support themore » production of distinct hematopoietic lineages. Cellular context, signaling dynamics, and the crosstalk of different signaling pathways determine the cellular response of a given extrinsic signal. New tools to manipulate and continuously quantify signaling events at the single cell level are therefore required to thoroughly interrogate how dynamic signaling networks yield a specific cellular response. - Highlights: • Recent studies provided definite proof for lineage-instructive action of cytokines. • Signaling pathways involved in hematopoietic lineage instruction remain elusive. • New tools are emerging to quantitatively study dynamic signaling networks over time.« less

Encoding of temporal signals by the TGF-β pathway and implications for embryonic patterning

PubMed Central

Sorre, Benoit; Warmflash, Aryeh; Brivanlou, Ali H.; Siggia, Eric D.

2014-01-01

Summary Genetics and biochemistry have defined the components and wiring of the signaling pathways that pattern the embryo. Among them, the TGF-β pathway has the potential to behave as a morphogen: invitro experiments have clearly established that it can dictate cell fate in a concentration dependent manner. How morphogens convey positional information in a developing embryo, where signal levels are changing with time, is less understood. Using integrated microfluidic cell culture and time-lapse microscopy, we demonstrate here that the speed of ligand presentation has a key and previously unexpected influence on TGF-β signaling outcomes. The response to a TGF-β concentration step is transient and adaptive, slowly increasing the ligand concentration diminishes the response and well-spaced pulses of ligand combine additively resulting in greater pathway output than with constant stimulation. Our results suggest that in an embryonic context, the speed of change of ligand concentration is an instructive signal for patterning. PMID:25065773

Cross-talk between estradiol receptor and EGFR/IGF-IR signaling pathways in estrogen-responsive breast cancers: focus on the role and impact of proteoglycans.

PubMed

Skandalis, Spyros S; Afratis, Nikolaos; Smirlaki, Gianna; Nikitovic, Dragana; Theocharis, Achilleas D; Tzanakakis, George N; Karamanos, Nikos K

2014-04-01

In hormone-dependent breast cancer, estrogen receptors are the principal signaling molecules that regulate several cell functions either by the genomic pathway acting directly as transcription factors in the nucleus or by the non-genomic pathway interacting with other receptors and their adjacent pathways like EGFR/IGFR. It is well established in literature that EGFR and IGFR signaling pathways promote cell proliferation and differentiation. Moreover, recent data indicate the cross-talk between ERs and EGFR/IGFR signaling pathways causing a transformation of cell functions as well as deregulation on normal expression pattern of matrix molecules. Specifically, proteoglycans, a major category of extracellular matrix (ECM) and cell surface macromolecules, are modified during malignancy and cause alterations in cancer cell signaling, affecting eventually functional cell properties such as proliferation, adhesion and migration. The on-going strategies to block only one of the above signaling effectors result cancer cells to overcome such inactivation using alternative signaling pathways. In this article, we therefore review the underlying mechanisms in respect to the role of ERs and the involvement of cross-talk between ERs, IGFR and EGFR in breast cancer cell properties and expression of extracellular secreted and cell bound proteoglycans involved in cancer progression. Understanding such signaling pathways may help to establish new potential pharmacological targets in terms of using ECM molecules to design novel anticancer therapies. © 2013. Published by Elsevier B.V. All rights reserved.

A respiratory chain controlled signal transduction cascade in the mitochondrial intermembrane space mediates hydrogen peroxide signaling

PubMed Central

Patterson, Heide Christine; Gerbeth, Carolin; Thiru, Prathapan; Vögtle, Nora F.; Knoll, Marko; Shahsafaei, Aliakbar; Samocha, Kaitlin E.; Huang, Cher X.; Harden, Mark Michael; Song, Rui; Chen, Cynthia; Kao, Jennifer; Shi, Jiahai; Salmon, Wendy; Shaul, Yoav D.; Stokes, Matthew P.; Silva, Jeffrey C.; Bell, George W.; MacArthur, Daniel G.; Ruland, Jürgen; Meisinger, Chris; Lodish, Harvey F.

2015-01-01

Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) govern cellular homeostasis by inducing signaling. H2O2 modulates the activity of phosphatases and many other signaling molecules through oxidation of critical cysteine residues, which led to the notion that initiation of ROS signaling is broad and nonspecific, and thus fundamentally distinct from other signaling pathways. Here, we report that H2O2 signaling bears hallmarks of a regular signal transduction cascade. It is controlled by hierarchical signaling events resulting in a focused response as the results place the mitochondrial respiratory chain upstream of tyrosine-protein kinase Lyn, Lyn upstream of tyrosine-protein kinase SYK (Syk), and Syk upstream of numerous targets involved in signaling, transcription, translation, metabolism, and cell cycle regulation. The active mediators of H2O2 signaling colocalize as H2O2 induces mitochondria-associated Lyn and Syk phosphorylation, and a pool of Lyn and Syk reside in the mitochondrial intermembrane space. Finally, the same intermediaries control the signaling response in tissues and species responsive to H2O2 as the respiratory chain, Lyn, and Syk were similarly required for H2O2 signaling in mouse B cells, fibroblasts, and chicken DT40 B cells. Consistent with a broad role, the Syk pathway is coexpressed across tissues, is of early metazoan origin, and displays evidence of evolutionary constraint in the human. These results suggest that H2O2 signaling is under control of a signal transduction pathway that links the respiratory chain to the mitochondrial intermembrane space-localized, ubiquitous, and ancient Syk pathway in hematopoietic and nonhematopoietic cells. PMID:26438848

A respiratory chain controlled signal transduction cascade in the mitochondrial intermembrane space mediates hydrogen peroxide signaling.

PubMed

Patterson, Heide Christine; Gerbeth, Carolin; Thiru, Prathapan; Vögtle, Nora F; Knoll, Marko; Shahsafaei, Aliakbar; Samocha, Kaitlin E; Huang, Cher X; Harden, Mark Michael; Song, Rui; Chen, Cynthia; Kao, Jennifer; Shi, Jiahai; Salmon, Wendy; Shaul, Yoav D; Stokes, Matthew P; Silva, Jeffrey C; Bell, George W; MacArthur, Daniel G; Ruland, Jürgen; Meisinger, Chris; Lodish, Harvey F

2015-10-20

Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) govern cellular homeostasis by inducing signaling. H2O2 modulates the activity of phosphatases and many other signaling molecules through oxidation of critical cysteine residues, which led to the notion that initiation of ROS signaling is broad and nonspecific, and thus fundamentally distinct from other signaling pathways. Here, we report that H2O2 signaling bears hallmarks of a regular signal transduction cascade. It is controlled by hierarchical signaling events resulting in a focused response as the results place the mitochondrial respiratory chain upstream of tyrosine-protein kinase Lyn, Lyn upstream of tyrosine-protein kinase SYK (Syk), and Syk upstream of numerous targets involved in signaling, transcription, translation, metabolism, and cell cycle regulation. The active mediators of H2O2 signaling colocalize as H2O2 induces mitochondria-associated Lyn and Syk phosphorylation, and a pool of Lyn and Syk reside in the mitochondrial intermembrane space. Finally, the same intermediaries control the signaling response in tissues and species responsive to H2O2 as the respiratory chain, Lyn, and Syk were similarly required for H2O2 signaling in mouse B cells, fibroblasts, and chicken DT40 B cells. Consistent with a broad role, the Syk pathway is coexpressed across tissues, is of early metazoan origin, and displays evidence of evolutionary constraint in the human. These results suggest that H2O2 signaling is under control of a signal transduction pathway that links the respiratory chain to the mitochondrial intermembrane space-localized, ubiquitous, and ancient Syk pathway in hematopoietic and nonhematopoietic cells.

The SAL-PAP Chloroplast Retrograde Pathway Contributes to Plant Immunity by Regulating Glucosinolate Pathway and Phytohormone Signaling.

PubMed

Ishiga, Yasuhiro; Watanabe, Mutsumi; Ishiga, Takako; Tohge, Takayuki; Matsuura, Takakazu; Ikeda, Yoko; Hoefgen, Rainer; Fernie, Alisdair R; Mysore, Kirankumar S

2017-10-01

Chloroplasts have a crucial role in plant immunity against pathogens. Increasing evidence suggests that phytopathogens target chloroplast homeostasis as a pathogenicity mechanism. In order to regulate the performance of chloroplasts under stress conditions, chloroplasts produce retrograde signals to alter nuclear gene expression. Many signals for the chloroplast retrograde pathway have been identified, including chlorophyll intermediates, reactive oxygen species, and metabolic retrograde signals. Although there is a reasonably good understanding of chloroplast retrograde signaling in plant immunity, some signals are not well-understood. In order to understand the role of chloroplast retrograde signaling in plant immunity, we investigated Arabidopsis chloroplast retrograde signaling mutants in response to pathogen inoculation. sal1 mutants (fry1-2 and alx8) responsible for the SAL1-PAP retrograde signaling pathway showed enhanced disease symptoms not only to the hemibiotrophic pathogen Pseudomonas syringae pv. tomato DC3000 but, also, to the necrotrophic pathogen Pectobacterium carotovorum subsp. carotovorum EC1. Glucosinolate profiles demonstrated the reduced accumulation of aliphatic glucosinolates in the fry1-2 and alx8 mutants compared with the wild-type Col-0 in response to DC3000 infection. In addition, quantification of multiple phytohormones and analyses of their gene expression profiles revealed that both the salicylic acid (SA)- and jasmonic acid (JA)-mediated signaling pathways were down-regulated in the fry1-2 and alx8 mutants. These results suggest that the SAL1-PAP chloroplast retrograde pathway is involved in plant immunity by regulating the SA- and JA-mediated signaling pathways.

c-Met and its ligand hepatocyte growth factor/scatter factor regulate mature B cell survival in a pathway induced by CD74.

PubMed

Gordin, Maya; Tesio, Melania; Cohen, Sivan; Gore, Yael; Lantner, Frida; Leng, Lin; Bucala, Richard; Shachar, Idit

2010-08-15

The signals regulating the survival of mature splenic B cells have become a major focus in recent studies of B cell immunology. Durable B cell persistence in the periphery is dependent on survival signals that are transduced by cell surface receptors. In this study, we describe a novel biological mechanism involved in mature B cell homeostasis, the hepatocyte growth factor/scatter factor (HGF)/c-Met pathway. We demonstrate that c-Met activation by HGF leads to a survival cascade, whereas its blockade results in induction of mature B cell death. Our results emphasize a unique and critical function for c-Met signaling in the previously described macrophage migration inhibitory factor/CD74-induced survival pathway. Macrophage migration inhibitory factor recruits c-Met to the CD74/CD44 complex and thereby enables the induction of a signaling cascade within the cell. This signal results in HGF secretion, which stimulates the survival of the mature B cell population in an autocrine manner. Thus, the CD74-HGF/c-Met axis defines a novel physiologic survival pathway in mature B cells, resulting in the control of the humoral immune response.

The Hippo/YAP pathway interacts with EGFR signaling and HPV oncoproteins to regulate cervical cancer progression

PubMed Central

He, Chunbo; Mao, Dagan; Hua, Guohua; Lv, Xiangmin; Chen, Xingcheng; Angeletti, Peter C; Dong, Jixin; Remmenga, Steven W; Rodabaugh, Kerry J; Zhou, Jin; Lambert, Paul F; Yang, Peixin; Davis, John S; Wang, Cheng

2015-01-01

The Hippo signaling pathway controls organ size and tumorigenesis through a kinase cascade that inactivates Yes-associated protein (YAP). Here, we show that YAP plays a central role in controlling the progression of cervical cancer. Our results suggest that YAP expression is associated with a poor prognosis for cervical cancer. TGF-α and amphiregulin (AREG), via EGFR, inhibit the Hippo signaling pathway and activate YAP to induce cervical cancer cell proliferation and migration. Activated YAP allows for up-regulation of TGF-α, AREG, and EGFR, forming a positive signaling loop to drive cervical cancer cell proliferation. HPV E6 protein, a major etiological molecule of cervical cancer, maintains high YAP protein levels in cervical cancer cells by preventing proteasome-dependent YAP degradation to drive cervical cancer cell proliferation. Results from human cervical cancer genomic databases and an accepted transgenic mouse model strongly support the clinical relevance of the discovered feed-forward signaling loop. Our study indicates that combined targeting of the Hippo and the ERBB signaling pathways represents a novel therapeutic strategy for prevention and treatment of cervical cancer. PMID:26417066

Intracellular signal modulation by nanomaterials.

PubMed

Hussain, Salik; Garantziotis, Stavros; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Baeza-Squiban, Armelle; Boland, Sonja

2014-01-01

A thorough understanding of the interactions of nanomaterials with biological systems and the resulting activation of signal transduction pathways is essential for the development of safe and consumer friendly nanotechnology. Here we present an overview of signaling pathways induced by nanomaterial exposures and describe the possible correlation of their physicochemical characteristics with biological outcomes. In addition to the hierarchical oxidative stress model and a review of the intrinsic and cell-mediated mechanisms of reactive oxygen species (ROS) generating capacities of nanomaterials, we also discuss other oxidative stress dependent and independent cellular signaling pathways. Induction of the inflammasome, calcium signaling, and endoplasmic reticulum stress are reviewed. Furthermore, the uptake mechanisms can be of crucial importance for the cytotoxicity of nanomaterials and membrane-dependent signaling pathways have also been shown to be responsible for cellular effects of nanomaterials. Epigenetic regulation by nanomaterials, effects of nanoparticle-protein interactions on cell signaling pathways, and the induction of various cell death modalities by nanomaterials are described. We describe the common trigger mechanisms shared by various nanomaterials to induce cell death pathways and describe the interplay of different modalities in orchestrating the final outcome after nanomaterial exposures. A better understanding of signal modulations induced by nanomaterials is not only essential for the synthesis and design of safer nanomaterials but will also help to discover potential nanomedical applications of these materials. Several biomedical applications based on the different signaling pathways induced by nanomaterials are already proposed and will certainly gain a great deal of attraction in the near future.

Intracellular Signal Modulation by Nanomaterials

PubMed Central

Hussain, Salik; Garantziotis, Stavros; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Baeza-Squiban, Armelle; Boland, Sonja

2016-01-01

A thorough understanding of the interactions of nanomaterials with biological systems and the resulting activation of signal transduction pathways is essential for the development of safe and consumer friendly nanotechnology. Here we present an overview of signaling pathways induced by nanomaterial exposures and describe the possible correlation of their physicochemical characteristics with biological outcomes. In addition to the hierarchical oxidative stress model and a review of the intrinsic and cell-mediated mechanisms of reactive Oxygen species (ROS) generating capacities of nanomaterials, we also discuss other oxidative stress dependent and independent cellular signaling pathways. Induction of the inflammasome, calcium signaling, and endoplasmic reticulum stress are reviewed. Furthermore, the uptake mechanisms can crucially affect the cytotoxicity of nanomaterials and membrane-dependent signaling pathways can be responsible for cellular effects of nanomaterials. Epigenetic regulation by nanomaterials effects of nanoparticle-protein interactions on cell signaling pathways, and the induction of various cell death modalities by nanomaterials are described. We describe the common trigger mechanisms shared by various nanomaterials to induce cell death pathways and describe the interplay of different modalities in orchestrating the final outcome after nanomaterial exposures. A better understanding of signal modulations induced by nanomaterials is not only essential for the synthesis and design of safer nanomaterials but will also help to discover potential nanomedical applications of these materials. Several biomedical applications based on the different signaling pathways induced by nanomaterials are already proposed and will certainly gain a great deal of attraction in the near future. PMID:24683030

Dendrosomatic Sonic Hedgehog Signaling in Hippocampal Neurons Regulates Axon Elongation

PubMed Central

Petralia, Ronald S.; Ott, Carolyn; Wang, Ya-Xian; Lippincott-Schwartz, Jennifer; Mattson, Mark P.

2015-01-01

The presence of Sonic Hedgehog (Shh) and its signaling components in the neurons of the hippocampus raises a question about what role the Shh signaling pathway may play in these neurons. We show here that activation of the Shh signaling pathway stimulates axon elongation in rat hippocampal neurons. This Shh-induced effect depends on the pathway transducer Smoothened (Smo) and the transcription factor Gli1. The axon itself does not respond directly to Shh; instead, the Shh signal transduction originates from the somatodendritic region of the neurons and occurs in neurons with and without detectable primary cilia. Upon Shh stimulation, Smo localization to dendrites increases significantly. Shh pathway activation results in increased levels of profilin1 (Pfn1), an actin-binding protein. Mutations in Pfn1's actin-binding sites or reduction of Pfn1 eliminate the Shh-induced axon elongation. These findings indicate that Shh can regulate axon growth, which may be critical for development of hippocampal neurons. SIGNIFICANCE STATEMENT Although numerous signaling mechanisms have been identified that act directly on axons to regulate their outgrowth, it is not known whether signals transduced in dendrites may also affect axon outgrowth. We describe here a transcellular signaling pathway in embryonic hippocampal neurons in which activation of Sonic Hedgehog (Shh) receptors in dendrites stimulates axon growth. The pathway involves the dendritic-membrane-associated Shh signal transducer Smoothened (Smo) and the transcription factor Gli, which induces the expression of the gene encoding the actin-binding protein profilin 1. Our findings suggest scenarios in which stimulation of Shh in dendrites results in accelerated outgrowth of the axon, which therefore reaches its presumptive postsynaptic target cell more quickly. By this mechanism, Shh may play critical roles in the development of hippocampal neuronal circuits. PMID:26658865

Defocused low-energy shock wave activates adipose tissue-derived stem cells in vitro via multiple signaling pathways.

PubMed

Xu, Lina; Zhao, Yong; Wang, Muwen; Song, Wei; Li, Bo; Liu, Wei; Jin, Xunbo; Zhang, Haiyang

2016-12-01

We found defocused low-energy shock wave (DLSW) could be applied in regenerative medicine by activating mesenchymal stromal cells. However, the possible signaling pathways that participated in this process remain unknown. In the present study, DLSW was applied in cultured rat adipose tissue-derived stem cells (ADSCs) to explore its effect on ADSCs and the activated signaling pathways. After treating with DLSW, the cellular morphology and cytoskeleton of ADSCs were observed. The secretions of ADSCs were detected. The expressions of ADSC surface antigens were analyzed using flow cytometry. The expressions of proliferating cell nuclear antigen and Ki67 were analyzed using western blot. The expression of CXCR2 and the migrations of ADSCs in vitro and in vivo were detected. The phosphorylation of selected signaling pathways with or without inhibitors was also detected. DLSW did not change the morphology and phenotype of ADSCs, and could promote the secretion, proliferation and migration of ADSCs. The phosphorylation levels were significantly higher in mitogen-activated protein kinases (MAPK) pathway, phosphoinositide 3-kinase (PI-3K)/AKT pathway and nuclear factor-kappa B (NF-κB) signaling pathway but not in Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Furthermore, ADSCs were not activated by DLSW after adding the inhibitors of these pathways simultaneously. Our results demonstrated for the first time that DLSW could activate ADSCs through MAPK, PI-3K/AKT and NF-κB signaling pathways. Combination of DLSW and agonists targeting these pathways might improve the efficacy of ADSCs in regenerative medicine in the future. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

New Insights from Drosophila into the Regulation of EGFR Signaling.

PubMed

Harden, Nicholas

2017-01-01

Genetic analysis of Egfr signaling in Drosophila has a long-standing track record of making important contributions to our understanding of the Egfr pathway. While the central Ras/MAPK pathway has long been well defined, there is much to learn with regard to its cross talk with other pathways and how it is regulated. A better understanding of the regulation of Egfr signaling is of particular interest with regard to the participation of misregulated Egfr signaling in tumorigenesis. Recent studies in the fly have led to some surprising results, identifying regulators of Egfr acting in unexpected ways.

Analysis of Differentially Expressed Genes and Signaling Pathways Related to Intramuscular Fat Deposition in Skeletal Muscle of Sex-Linked Dwarf Chickens

PubMed Central

Ye, Yaqiong; Lin, Shumao; Mu, Heping; Tang, Xiaohong; Ou, Yangdan; Chen, Jian; Ma, Yongjiang; Li, Yugu

2014-01-01

Intramuscular fat (IMF) plays an important role in meat quality. However, the molecular mechanisms underlying IMF deposition in skeletal muscle have not been addressed for the sex-linked dwarf (SLD) chicken. In this study, potential candidate genes and signaling pathways related to IMF deposition in chicken leg muscle tissue were characterized using gene expression profiling of both 7-week-old SLD and normal chickens. A total of 173 differentially expressed genes (DEGs) were identified between the two breeds. Subsequently, 6 DEGs related to lipid metabolism or muscle development were verified in each breed based on gene ontology (GO) analysis. In addition, KEGG pathway analysis of DEGs indicated that some of them (GHR, SOCS3, and IGF2BP3) participate in adipocytokine and insulin signaling pathways. To investigate the role of the above signaling pathways in IMF deposition, the gene expression of pathway factors and other downstream genes were measured by using qRT-PCR and Western blot analyses. Collectively, the results identified potential candidate genes related to IMF deposition and suggested that IMF deposition in skeletal muscle of SLD chicken is regulated partially by pathways of adipocytokine and insulin and other downstream signaling pathways (TGF-β/SMAD3 and Wnt/catenin-β pathway). PMID:24757673

In silico study of protein to protein interaction analysis of AMP-activated protein kinase and mitochondrial activity in three different farm animal species

NASA Astrophysics Data System (ADS)

Prastowo, S.; Widyas, N.

2018-03-01

AMP-activated protein kinase (AMPK) is cellular energy censor which works based on ATP and AMP concentration. This protein interacts with mitochondria in determine its activity to generate energy for cell metabolism purposes. For that, this paper aims to compare the protein to protein interaction of AMPK and mitochondrial activity genes in the metabolism of known animal farm (domesticated) that are cattle (Bos taurus), pig (Sus scrofa) and chicken (Gallus gallus). In silico study was done using STRING V.10 as prominent protein interaction database, followed with biological function comparison in KEGG PATHWAY database. Set of genes (12 in total) were used as input analysis that are PRKAA1, PRKAA2, PRKAB1, PRKAB2, PRKAG1, PRKAG2, PRKAG3, PPARGC1, ACC, CPT1B, NRF2 and SOD. The first 7 genes belong to gene in AMPK family, while the last 5 belong to mitochondrial activity genes. The protein interaction result shows 11, 8 and 5 metabolism pathways in Bos taurus, Sus scrofa and Gallus gallus, respectively. The top pathway in Bos taurus is AMPK signaling pathway (10 genes), Sus scrofa is Adipocytokine signaling pathway (8 genes) and Gallus gallus is FoxO signaling pathway (5 genes). Moreover, the common pathways found in those 3 species are Adipocytokine signaling pathway, Insulin signaling pathway and FoxO signaling pathway. Genes clustered in Adipocytokine and Insulin signaling pathway are PRKAA2, PPARGC1A, PRKAB1 and PRKAG2. While, in FoxO signaling pathway are PRKAA2, PRKAB1, PRKAG2. According to that, we found PRKAA2, PRKAB1 and PRKAG2 are the common genes. Based on the bioinformatics analysis, we can demonstrate that protein to protein interaction shows distinct different of metabolism in different species. However, further validation is needed to give a clear explanation.

Intrinsic noise analysis and stochastic simulation on transforming growth factor beta signal pathway

NASA Astrophysics Data System (ADS)

Wang, Lu; Ouyang, Qi

2010-10-01

A typical biological cell lives in a small volume at room temperature; the noise effect on the cell signal transduction pathway may play an important role in its dynamics. Here, using the transforming growth factor-β signal transduction pathway as an example, we report our stochastic simulations of the dynamics of the pathway and introduce a linear noise approximation method to calculate the transient intrinsic noise of pathway components. We compare the numerical solutions of the linear noise approximation with the statistic results of chemical Langevin equations, and find that they are quantitatively in agreement with the other. When transforming growth factor-β dose decreases to a low level, the time evolution of noise fluctuation of nuclear Smad2—Smad4 complex indicates the abnormal enhancement in the transient signal activation process.

Coordinate Activation of Redox-Dependent ASK1/TGF-β Signaling by a Multiprotein Complex (MPK38, ASK1, SMADs, ZPR9, and TRX) Improves Glucose and Lipid Metabolism in Mice.

PubMed

Seong, Hyun-A; Manoharan, Ravi; Ha, Hyunjung

2016-03-10

To explore the molecular connections between redox-dependent apoptosis signal-regulating kinase 1 (ASK1) and transforming growth factor-β (TGF-β) signaling pathways and to examine the physiological processes in which coordinated regulation of these two signaling pathways plays a critical role. We provide evidence that the ASK1 and TGF-β signaling pathways are interconnected by a multiprotein complex harboring murine protein serine-threonine kinase 38 (MPK38), ASK1, Sma- and Mad-related proteins (SMADs), zinc-finger-like protein 9 (ZPR9), and thioredoxin (TRX) and demonstrate that the activation of either ASK1 or TGF-β activity is sufficient to activate both the redox-dependent ASK1 and TGF-β signaling pathways. Physiologically, the restoration of the downregulated activation levels of ASK1 and TGF-β signaling in genetically and diet-induced obese mice by adenoviral delivery of SMAD3 or ZPR9 results in the amelioration of adiposity, hyperglycemia, hyperlipidemia, and impaired ketogenesis. Our data suggest that the multiprotein complex linking ASK1 and TGF-β signaling pathways may be a potential target for redox-mediated metabolic complications.

Integrated QSAR study for inhibitors of hedgehog signal pathway against multiple cell lines:a collaborative filtering method

PubMed Central

2012-01-01

Background The Hedgehog Signaling Pathway is one of signaling pathways that are very important to embryonic development. The participation of inhibitors in the Hedgehog Signal Pathway can control cell growth and death, and searching novel inhibitors to the functioning of the pathway are in a great demand. As the matter of fact, effective inhibitors could provide efficient therapies for a wide range of malignancies, and targeting such pathway in cells represents a promising new paradigm for cell growth and death control. Current research mainly focuses on the syntheses of the inhibitors of cyclopamine derivatives, which bind specifically to the Smo protein, and can be used for cancer therapy. While quantitatively structure-activity relationship (QSAR) studies have been performed for these compounds among different cell lines, none of them have achieved acceptable results in the prediction of activity values of new compounds. In this study, we proposed a novel collaborative QSAR model for inhibitors of the Hedgehog Signaling Pathway by integration the information from multiple cell lines. Such a model is expected to substantially improve the QSAR ability from single cell lines, and provide useful clues in developing clinically effective inhibitors and modifications of parent lead compounds for target on the Hedgehog Signaling Pathway. Results In this study, we have presented: (1) a collaborative QSAR model, which is used to integrate information among multiple cell lines to boost the QSAR results, rather than only a single cell line QSAR modeling. Our experiments have shown that the performance of our model is significantly better than single cell line QSAR methods; and (2) an efficient feature selection strategy under such collaborative environment, which can derive the commonly important features related to the entire given cell lines, while simultaneously showing their specific contributions to a specific cell-line. Based on feature selection results, we have 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

The fast track to canonical Wnt signaling in MC3T3-E1 cells protected by substance P against serum deprivation-induced apoptosis.

PubMed

Yang, Jianguo; Nie, Jiping; Fu, Su; Liu, Song; Wu, Jianqun; Cui, Liang; Zhang, Yongtao; Yu, Bin

2017-01-01

The canonical Wnt pathway is vital to bone physiology by increasing bone mass through elevated osteoblast survival. Although investigated extensively in stem cells, its role in osteoblastic MC3T3-E1 cells has not been completely determined. To explore how this pathway is regulated by different conditions, we assessed the anti-apoptotic effects of substance P on the canonical Wnt pathway in MC3T3-E1 cells by treating cells with serum deprivation or serum starving with "substance P," a neuropeptide demonstrated to promote bone growth and stimulate Wnt signaling. The results showed that serum deprivation both induced apoptosis and activated Wnt signal transduction while substance P further stimulated the Wnt pathway via the NK-1 receptor but protected the cells from apoptotic death. Fast-tracking of Wnt signaling by substance P was also noted. These results indicate that nutritional deprivation and substance P synergistically activated the canonical Wnt pathway, a finding that helps to reveal the role of Wnt signaling in bone physiology affected by nutritional deprivation and neuropeptide substance P. © 2016 International Federation for Cell Biology.

Similarities and differences between the Wnt and reelin pathways in the forming brain.

PubMed

Reiner, Orly; Sapir, Tamar

2005-01-01

One of the key features in development is the reutilization of successful signaling pathways. Here, we emphasize the involvement of the Wnt pathway, one of the five kinds of signal transduction pathway predominating early embryonic development of all animals, in regulating the formation of brain structure. We discuss the interrelationships between the Wnt and reelin pathways in the regulation of cortical layering. We summarize data emphasizing key molecules, which, when mutated, result in abnormal brain development. This integrated view, which is based on conservation of pathways, reveals the relative position of participants in the pathway, points to control mechanisms, and allows raising testable working hypotheses. Nevertheless, although signaling pathways are highly conserved from flies to humans, the overall morphology is not. We propose that future studies directed at understanding of diversification will provide fruitful insights on mammalian brain formation.

Signal persistence and amplification in cancer development and possible, related opportunities for novel therapies.

PubMed

Ford, Shea A; Blanck, George

2015-01-01

Research in cancer biology has been largely driven by experimental approaches whereby discreet inputs are used to assess discreet outputs, for example, gene-knockouts to assess cancer occurrence. However, cancer hallmarks are only rarely, if ever, exclusively dependent on discreet regulatory processes. Rather, cancer-related regulatory factors affect multiple cancer hallmarks. Thus, novel approaches and paradigms are needed for further advances. Signal pathway persistence and amplification, rather than signal pathway activation resulting from an on/off switch, represent emerging paradigms for cancer research, closely related to developmental regulatory paradigms. In this review, we address both mechanisms and effects of signal pathway persistence and amplification in cancer settings; and address the possibility that hyper-activation of pro-proliferative signal pathways in certain cancer settings could be exploited for therapy. Copyright © 2014. Published by Elsevier B.V.

[Down-regulatory effect of Nucleostemin expression on signal molecule of PI3K/AKT/mTOR pathway in HL-60 cells].

PubMed

Jia, Yu; Wei, Yuan-Yu; Zhang, Fan; Li, Zhao-Bo; Liu, Shuai; Yue, Bao-Hong

2014-02-01

This study was purpose to explore the down-regulatory effect of nucleostemin (NS) expression on signal molecules of PI3K/AKT/mTOR pathway belonged to candidate ways of p53-independent signal pathway in the leukemia cells. The expression of NS was interfered by using recombinant lentivirus expression vector NS-RNAi-GV248 to transfect HL-60 cells of p53 deficiency. The expression of NS and signal molecules of PI3K/AKT/mTOR pathway were detected by using Real-time PCR. The results of showed that the HL-60 cells were transfected by recombinant lentivirus vector NS-RNAi-GV248 successfully and with transfection rate up to 80%. According to results of Real-time PCR detection, the inhibition rate of NS gene was 56.5% in HL-60 cells. And the expression levels of PI3K,AKT and GβL mRNA (0.491 ± 0.084,0.398 ± 0.164, 0.472 ± 0.097 respectively) were obviously down-regulated by silencing NS, and showed statistical difference (P < 0.05) in comparison with control (1.002 ± 0.171, 1.000 ± 0.411, 1.001 ± 0.206 respectively) . It is concluded that the changes of signal molecules of PI3K/AKT/mTOR pathway positively correlate with NS down-regulation, which provides evidence for confirming PI3K/AKT/mTOR signal pathway possible as a type of NS p53-independent pathway.

Activation of the miR-34a/SIRT1/p53 Signaling Pathway Contributes to the Progress of Liver Fibrosis via Inducing Apoptosis in Hepatocytes but Not in HSCs.

PubMed

Tian, Xiao-Feng; Ji, Fu-Jian; Zang, Hong-Liang; Cao, Hong

2016-01-01

Liver fibrosis results from a sustained wound healing response to chronic liver injury, and the activation of nonparenchymal hepatic stellate cells (HSCs) is the pivotal process. MicroRNA-34a (miR-34a) is the direct target gene of p53 and activates p53 through sirtuin 1 (SIRT1) simultaneously. The miR-34a/SIRT1/p53 signaling pathway thus forms a positive feedback loop wherein p53 induces miR-34a and miR-34a activates p53 by inhibiting SIRT1, playing an important role in cell proliferation and apoptosis. miR-34a expression has been found to be increased in animal models or in human patients with different liver diseases, including liver fibrosis. However, the exact role of this classical miR-34a/SIRT1/p53 signaling pathway in liver fibrosis remains unclear. In the present study, using a CCl4-induced rat liver fibrosis model, we found that the miR-34a/SIRT1/p53 signaling pathway was activated and could be inhibited by SIRT1 activator SRT1720. Further studies showed that the miR-34a/SIRT1/p53 signaling pathway was activated in hepatocytes but not in HSCs. The activation of this pathway in hepatocytes resulted in the apoptosis of hepatocytes and thus activated HSCs. Our data indicate that the miR-34a/SIRT1/p53 signaling pathway might be a promising therapeutic target for liver fibrosis.

Non Linear Programming (NLP) Formulation for Quantitative Modeling of Protein Signal Transduction Pathways

PubMed Central

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. PMID:23226239

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.

De Novo Characterization of the Spleen Transcriptome of the Large Yellow Croaker (Pseudosciaena crocea) and Analysis of the Immune Relevant Genes and Pathways Involved in the Antiviral Response

PubMed Central

Ding, Yang; Ao, Jingqun; Hu, Songnian; Chen, Xinhua

2014-01-01

The large yellow croaker (Pseudosciaena crocea) is an economically important marine fish in China. To understand the molecular basis for antiviral defense in this species, we used Illumia paired-end sequencing to characterize the spleen transcriptome of polyriboinosinic:polyribocytidylic acid [poly(I:C)]-induced large yellow croakers. The library produced 56,355,728 reads and assembled into 108,237 contigs. As a result, 15,192 unigenes were found from this transcriptome. Gene ontology analysis showed that 4,759 genes were involved in three major functional categories: biological process, cellular component, and molecular function. We further ascertained that numerous consensus sequences were homologous to known immune-relevant genes. Kyoto Encyclopedia of Genes and Genomes orthology mapping annotated 5,389 unigenes and identified numerous immune-relevant pathways. These immune-relevant genes and pathways revealed major antiviral immunity effectors, including but not limited to: pattern recognition receptors, adaptors and signal transducers, the interferons and interferon-stimulated genes, inflammatory cytokines and receptors, complement components, and B-cell and T-cell antigen activation molecules. Moreover, the partial genes of Toll-like receptor signaling pathway, RIG-I-like receptors signaling pathway, Janus kinase-Signal Transducer and Activator of Transcription (JAK-STAT) signaling pathway, and T-cell receptor (TCR) signaling pathway were found to be changed after poly(I:C) induction by real-time polymerase chain reaction (PCR) analysis, suggesting that these signaling pathways may be regulated by poly(I:C), a viral mimic. Overall, the antivirus-related genes and signaling pathways that were identified in response to poly(I:C) challenge provide valuable leads for further investigation of the antiviral defense mechanism in the large yellow croaker. PMID:24820969

The JAK-STAT signaling pathway: input and output integration.

PubMed

Murray, Peter J

2007-03-01

Universal and essential to cytokine receptor signaling, the JAK-STAT pathway is one of the best understood signal transduction cascades. Almost 40 cytokine receptors signal through combinations of four JAK and seven STAT family members, suggesting commonality across the JAK-STAT signaling system. Despite intense study, there remain substantial gaps in understanding how the cascades are activated and regulated. Using the examples of the IL-6 and IL-10 receptors, I will discuss how diverse outcomes in gene expression result from regulatory events that effect the JAK1-STAT3 pathway, common to both receptors. I also consider receptor preferences by different STATs and interpretive problems in the use of STAT-deficient cells and mice. Finally, I consider how the suppressor of cytokine signaling (SOCS) proteins regulate the quality and quantity of STAT signals from cytokine receptors. New data suggests that SOCS proteins introduce additional diversity into the JAK-STAT pathway by adjusting the output of activated STATs that alters downstream gene activation.

Proapoptotic signaling induced by RIG-I and MDA-5 results in type I interferon–independent apoptosis in human melanoma cells

PubMed Central

Besch, Robert; Poeck, Hendrik; Hohenauer, Tobias; Senft, Daniela; Häcker, Georg; Berking, Carola; Hornung, Veit; Endres, Stefan; Ruzicka, Thomas; Rothenfusser, Simon; Hartmann, Gunther

2009-01-01

The retinoic acid–inducible gene I (RIG-I) and melanoma differentiation–associated antigen 5 (MDA-5) helicases sense viral RNA in infected cells and initiate antiviral responses such as the production of type I IFNs. Here we have shown that RIG-I and MDA-5 also initiate a proapoptotic signaling pathway that is independent of type I IFNs. In human melanoma cells, this signaling pathway required the mitochondrial adapter Cardif (also known as IPS-1) and induced the proapoptotic BH3-only proteins Puma and Noxa. RIG-I– and MDA-5–initiated apoptosis required Noxa but was independent of the tumor suppressor p53. Triggering this pathway led to efficient activation of mitochondrial apoptosis, requiring caspase-9 and Apaf-1. Surprisingly, this proapoptotic signaling pathway was also active in nonmalignant cells, but these cells were much less sensitive to apoptosis than melanoma cells. Endogenous Bcl-xL rescued nonmalignant, but not melanoma, cells from RIG-I– and MDA-5–mediated apoptosis. In addition, we confirmed the results of the in vitro studies, demonstrating that RIG-I and MDA-5 ligands both reduced human tumor lung metastasis in immunodeficient NOD/SCID mice. These results identify an IFN-independent antiviral signaling pathway initiated by RIG-I and MDA-5 that activates proapoptotic signaling and, unless blocked by Bcl-xL, results in apoptosis. Due to their immunostimulatory and proapoptotic activity, RIG-I and MDA-5 ligands have therapeutic potential due to their ability to overcome the characteristic resistance of melanoma cells to apoptosis. PMID:19620789

Wnt signaling during tooth replacement in zebrafish (Danio rerio): pitfalls and perspectives

PubMed Central

Huysseune, Ann; Soenens, Mieke; Elderweirdt, Fien

2014-01-01

The canonical (β-catenin dependent) Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1) in developing zebrafish (Danio rerio) tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl) mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement. The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i) potential technical pitfalls related to dose- or time-dependency, (ii) the complexity of the canonical Wnt pathway, and (iii) species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts. PMID:25339911

Multiple Signaling Pathways Are Involved in the Interleukine-4 Regulated Expression of DC-SIGN in THP-1 Cell Line

PubMed Central

Jin, Changzhong; Wu, Lijuan; Li, Jie; Fang, Meixin; Cheng, Linfang; Wu, Nanping

2012-01-01

Dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) is an important pattern recognition receptor on dendritic cells (DCs), and its expression shows significant cytological and histological specificity, being interleukine-4 (IL-4) dependent. The signaling pathways through which IL-4 regulates expression of DC-SIGN are still unclear. We used phorbol 12-myristate 13-acetate- (PMA-) differentiated THP-1 cells as the in vitro model of monocyte/macrophage cells to study the signaling pathways involved in IL-4-regulated expression of DC-SIGN. We found that a high expression of DC-SIGN could be induced by IL-4 at the levels of mRNA and cell surface protein. Upregulated expression of DC-SIGN was almost completely blocked by the specific inhibitor of ERK pathway, and partly reduced by the specific inhibitors of JAK-STAT and NF-κB pathways. The activation of the three signaling pathways was directly confirmed by testing the phosphorylation of protein kinase within the cytoplasm and nucleus over time. The analysis of cis-acting elements of DC-SIGN promoter showed that the activity of DC-SIGN promoter without Ets-1 transcription factors binding site almost completely disappeared. Our results demonstrated that multiple signaling pathways are involved in IL-4 induced high expression of DC-SIGN on THP-1 cells, in which ERK pathway is the main signaling pathway and mediated by the Ets-1 transcription factors binding site. PMID:22675249

Stem cell signaling as a target for novel drug discovery: recent progress in the WNT and Hedgehog pathways.

PubMed

An, Songzhu Michael; Ding, Qiang Peter; Li, Ling-song

2013-06-01

One of the most exciting fields in biomedical research over the past few years is stem cell biology, and therapeutic application of stem cells to replace the diseased or damaged tissues is also an active area in development. Although stem cell therapy has a number of technical challenges and regulatory hurdles to overcome, the use of stem cells as tools in drug discovery supported by mature technologies and established regulatory paths is expected to generate more immediate returns. In particular, the targeting of stem cell signaling pathways is opening up a new avenue for drug discovery. Aberrations in these pathways result in various diseases, including cancer, fibrosis and degenerative diseases. A number of drug targets in stem cell signaling pathways have been identified. Among them, WNT and Hedgehog are two most important signaling pathways, which are the focus of this review. A hedgehog pathway inhibitor, vismodegib (Erivedge), has recently been approved by the US FDA for the treatment of skin cancer, while several drug candidates for the WNT pathway are entering clinical trials. We have discovered that the stem cell signaling pathways respond to traditional Chinese medicines. Substances isolated from herbal medicine may act specifically on components of stem cell signaling pathways with high affinities. As many of these events can be explained through molecular interactions, these phenomena suggest that discovery of stem cell-targeting drugs from natural products may prove to be highly successful.

Application of Monte Carlo cross-validation to identify pathway cross-talk in neonatal sepsis.

PubMed

Zhang, Yuxia; Liu, Cui; Wang, Jingna; Li, Xingxia

2018-03-01

To explore genetic pathway cross-talk in neonates with sepsis, an integrated approach was used in this paper. To explore the potential relationships between differently expressed genes between normal uninfected neonates and neonates with sepsis and pathways, genetic profiling and biologic signaling pathway were first integrated. For different pathways, the score was obtained based upon the genetic expression by quantitatively analyzing the pathway cross-talk. The paired pathways with high cross-talk were identified by random forest classification. The purpose of the work was to find the best pairs of pathways able to discriminate sepsis samples versus normal samples. The results found 10 pairs of pathways, which were probably able to discriminate neonates with sepsis versus normal uninfected neonates. Among them, the best two paired pathways were identified according to analysis of extensive literature. Impact statement To find the best pairs of pathways able to discriminate sepsis samples versus normal samples, an RF classifier, the DS obtained by DEGs of paired pathways significantly associated, and Monte Carlo cross-validation were applied in this paper. Ten pairs of pathways were probably able to discriminate neonates with sepsis versus normal uninfected neonates. Among them, the best two paired pathways ((7) IL-6 Signaling and Phospholipase C Signaling (PLC); (8) Glucocorticoid Receptor (GR) Signaling and Dendritic Cell Maturation) were identified according to analysis of extensive literature.

The Hippo pathway: regulators and regulations

PubMed Central

Yu, Fa-Xing; Guan, Kun-Liang

2013-01-01

Control of cell number is crucial in animal development and tissue homeostasis, and its dysregulation may result in tumor formation or organ degeneration. The Hippo pathway in both Drosophila and mammals regulates cell number by modulating cell proliferation, cell death, and cell differentiation. Recently, numerous upstream components involved in the Hippo pathway have been identified, such as cell polarity, mechanotransduction, and G-protein-coupled receptor (GPCR) signaling. Actin cytoskeleton or cellular tension appears to be the master mediator that integrates and transmits upstream signals to the core Hippo signaling cascade. Here, we review regulatory mechanisms of the Hippo pathway and discuss potential implications involved in different physiological and pathological conditions. PMID:23431053

BMP signaling restricts hemato-vascular development from lateral mesoderm during somitogenesis.

PubMed

Gupta, Sunny; Zhu, Hao; Zon, Leonard I; Evans, Todd

2006-06-01

The bone morphogenetic protein (BMP) signaling pathway is essential during gastrulation for the generation of ventral mesoderm, which makes it a challenge to define functions for this pathway at later stages of development. We have established an approach to disrupt BMP signaling specifically in lateral mesoderm during somitogenesis, by targeting a dominant-negative BMP receptor to Lmo2+ cells in developing zebrafish embryos. This results in expansion of hematopoietic and endothelial cells, while restricting the expression domain of the pronephric marker pax2.1. Expression of a constitutively active receptor and transplantation experiments were used to confirm that BMP signaling in lateral mesoderm restricts subsequent hemato-vascular development. The results show that the BMP signaling pathway continues to function after cells are committed to a lateral mesoderm fate, and influences subsequent lineage decisions by restricting hemato-vascular fate in favor of pronephric development.

Could an endoneurial endothelial crosstalk between Wnt/β-catenin and Sonic Hedgehog pathways underlie the early disruption of the infra-orbital blood-nerve barrier following chronic constriction injury?

PubMed

Moreau, Nathan; Mauborgne, Annie; Couraud, Pierre-Olivier; Romero, Ignacio A; Weksler, Babette B; Villanueva, Luis; Pohl, Michel; Boucher, Yves

2017-01-01

Blood–nerve barrier disruption is pivotal in the development of neuroinflammation, peripheral sensitization, and neuropathic pain after peripheral nerve injury. Activation of toll-like receptor 4 and inactivation of Sonic Hedgehog signaling pathways within the endoneurial endothelial cells are key events, resulting in the infiltration of harmful molecules and immunocytes within the nerve parenchyma. However, we showed in a previous study that preemptive inactivation of toll-like receptor 4 signaling or sustained activation of Sonic Hedgehog signaling did not prevent the local alterations observed following peripheral nerve injury, suggesting the implication of another signaling pathway. Using a classical neuropathic pain model, the infraorbital nerve chronic constriction injury (IoN-CCI), we investigated the role of the Wnt/β-catenin pathway in chronic constriction injury-mediated blood–nerve barrier disruption and in its interactions with the toll-like receptor 4 and Sonic Hedgehog pathways. In the IoN-CCI model versus control, mRNA expression levels and/or immunochemical detection of major Wnt/Sonic Hedgehog pathway (Frizzled-7, vascular endothelial-cadherin, Patched-1 and Gli-1) and/or tight junction proteins (Claudin-1, Claudin-5, and Occludin) readouts were assessed. Vascular permeability was assessed by sodium fluorescein extravasation. IoN-CCI induced early alterations in the vascular endothelial-cadherin/β-catenin/Frizzled-7 complex, shown to participate in local blood–nerve barrier disruption via a β-catenin-dependent tight junction protein downregulation. Wnt pathway also mediated a crosstalk between toll-like receptor 4 and Sonic Hedgehog signaling within endoneurial endothelial cells. Nevertheless, preemptive inhibition of Wnt/β-catenin signaling before IoN-CCI could not prevent the downregulation of key Sonic Hedgehog pathway readouts or the disruption of the infraorbital blood–nerve barrier, suggesting that Sonic Hedgehog pathway inhibition observed following IoN-CCI is an independent event responsible for blood–nerve barrier disruption. A crosstalk between Wnt/β-catenin- and Sonic Hedgehog-mediated signaling pathways within endoneurial endothelial cells could mediate the chronic disruption of the blood–nerve barrier following IoN-CCI, resulting in increased irreversible endoneurial vascular permeability and neuropathic pain development.

Biphasic effects of FGF2 on odontoblast differentiation involve changes in the BMP and Wnt signaling pathways.

PubMed

Sagomonyants, Karen; Mina, Mina

2014-08-01

Odontoblast differentiation during physiological and reparative dentinogenesis is dependent upon multiple signaling molecules, including fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs) and Wingless/Integrated (Wnt) ligands. Recent studies in our laboratory showed that continuous exposure of primary dental pulp cultures to FGF2 exerted biphasic effects on the expression of markers of dentinogenesis. In the present study, we examined the possible involvement of the BMP and Wnt signaling pathways in mediating the effects of FGF2 on dental pulp cells. Our results showed that stimulatory effects of FGF2 on dentinogenesis during the proliferation phase of growth were associated with increased expression of the components of the BMP (Bmp2, Dlx5, Msx2, Osx) and Wnt (Wnt10a, Wisp2) pathways, and decreased expression of an inhibitor of the Wnt signaling, Nkd2. Further addition of FGF2 during the differentiation/mineralization phase of growth resulted in decreased expression of components of the BMP signaling (Bmp2, Runx2, Osx) and increased expression of inhibitors of the Wnt signaling (Nkd2, Dkk3). This suggests that both BMP and Wnt pathways may be involved in mediating the effects of FGF2 on dental pulp cells.

The Hippo/YAP pathway interacts with EGFR signaling and HPV oncoproteins to regulate cervical cancer progression.

PubMed

He, Chunbo; Mao, Dagan; Hua, Guohua; Lv, Xiangmin; Chen, Xingcheng; Angeletti, Peter C; Dong, Jixin; Remmenga, Steven W; Rodabaugh, Kerry J; Zhou, Jin; Lambert, Paul F; Yang, Peixin; Davis, John S; Wang, Cheng

2015-11-01

The Hippo signaling pathway controls organ size and tumorigenesis through a kinase cascade that inactivates Yes-associated protein (YAP). Here, we show that YAP plays a central role in controlling the progression of cervical cancer. Our results suggest that YAP expression is associated with a poor prognosis for cervical cancer. TGF-α and amphiregulin (AREG), via EGFR, inhibit the Hippo signaling pathway and activate YAP to induce cervical cancer cell proliferation and migration. Activated YAP allows for up-regulation of TGF-α, AREG, and EGFR, forming a positive signaling loop to drive cervical cancer cell proliferation. HPV E6 protein, a major etiological molecule of cervical cancer, maintains high YAP protein levels in cervical cancer cells by preventing proteasome-dependent YAP degradation to drive cervical cancer cell proliferation. Results from human cervical cancer genomic databases and an accepted transgenic mouse model strongly support the clinical relevance of the discovered feed-forward signaling loop. Our study indicates that combined targeting of the Hippo and the ERBB signaling pathways represents a novel therapeutic strategy for prevention and treatment of cervical cancer. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.

CXCR7/CXCR4 heterodimer constitutively recruits beta-arrestin to enhance cell migration.

PubMed

Décaillot, Fabien M; Kazmi, Manija A; Lin, Ying; Ray-Saha, Sarmistha; Sakmar, Thomas P; Sachdev, Pallavi

2011-09-16

G protein-coupled receptor hetero-oligomerization is emerging as an important regulator of ligand-dependent transmembrane signaling, but precisely how receptor heteromers affect receptor pharmacology remains largely unknown. In this study, we have attempted to identify the functional significance of the heteromeric complex between CXCR4 and CXCR7 chemokine receptors. We demonstrate that co-expression of CXCR7 with CXCR4 results in constitutive recruitment of β-arrestin to the CXCR4·CXCR7 complex and simultaneous impairment of G(i)-mediated signaling. CXCR7/CXCR4 co-expression also results in potentiation of CXCL12 (SDF-1)-mediated downstream β-arrestin-dependent cell signaling pathways, including ERK1/2, p38 MAPK, and SAPK as judged from the results of experiments using siRNA knockdown to deplete β-arrestin. Interestingly, CXCR7/CXCR4 co-expression enhances cell migration in response to CXCL12 stimulation. Again, inhibition of β-arrestin using either siRNA knockdown or a dominant negative mutant abrogates the enhanced CXCL12-dependent migration of CXCR4/CXCR7-expressing cells. These results show how CXCR7, which cannot signal directly through G protein-linked pathways, can nevertheless affect cellular signaling networks by forming a heteromeric complex with CXCR4. The CXCR4·CXCR7 heterodimer complex recruits β-arrestin, resulting in preferential activation of β-arrestin-linked signaling pathways over canonical G protein pathways. CXCL12-dependent signaling of CXCR4 and its role in cellular physiology, including cancer metastasis, should be evaluated in the context of potential functional hetero-oligomerization with CXCR7.

CXCR7/CXCR4 Heterodimer Constitutively Recruits β-Arrestin to Enhance Cell Migration*

PubMed Central

Décaillot, Fabien M.; Kazmi, Manija A.; Lin, Ying; Ray-Saha, Sarmistha; Sakmar, Thomas P.; Sachdev, Pallavi

2011-01-01

G protein-coupled receptor hetero-oligomerization is emerging as an important regulator of ligand-dependent transmembrane signaling, but precisely how receptor heteromers affect receptor pharmacology remains largely unknown. In this study, we have attempted to identify the functional significance of the heteromeric complex between CXCR4 and CXCR7 chemokine receptors. We demonstrate that co-expression of CXCR7 with CXCR4 results in constitutive recruitment of β-arrestin to the CXCR4·CXCR7 complex and simultaneous impairment of Gi-mediated signaling. CXCR7/CXCR4 co-expression also results in potentiation of CXCL12 (SDF-1)-mediated downstream β-arrestin-dependent cell signaling pathways, including ERK1/2, p38 MAPK, and SAPK as judged from the results of experiments using siRNA knockdown to deplete β-arrestin. Interestingly, CXCR7/CXCR4 co-expression enhances cell migration in response to CXCL12 stimulation. Again, inhibition of β-arrestin using either siRNA knockdown or a dominant negative mutant abrogates the enhanced CXCL12-dependent migration of CXCR4/CXCR7-expressing cells. These results show how CXCR7, which cannot signal directly through G protein-linked pathways, can nevertheless affect cellular signaling networks by forming a heteromeric complex with CXCR4. The CXCR4·CXCR7 heterodimer complex recruits β-arrestin, resulting in preferential activation of β-arrestin-linked signaling pathways over canonical G protein pathways. CXCL12-dependent signaling of CXCR4 and its role in cellular physiology, including cancer metastasis, should be evaluated in the context of potential functional hetero-oligomerization with CXCR7. PMID:21730065

Atypical Diabetic Foot Ulcer Keratinocyte Protein Signaling Correlates with Impaired Wound Healing.

PubMed

Hoke, Glenn D; Ramos, Corrine; Hoke, Nicholas N; Crossland, Mary C; Shawler, Lisa G; Boykin, Joseph V

2016-01-01

Diabetes mellitus is associated with chronic diabetic foot ulcers (DFUs) and wound infections often resulting in lower extremity amputations. The protein signaling architecture of the mechanisms responsible for impaired DFU healing has not been characterized. In this preliminary clinical study, the intracellular levels of proteins involved in signal transduction networks relevant to wound healing were non-biasedly measured using reverse-phase protein arrays (RPPA) in keratinocytes isolated from DFU wound biopsies. RPPA allows for the simultaneous documentation and assessment of the signaling pathways active in each DFU. Thus, RPPA provides for the accurate mapping of wound healing pathways associated with apoptosis, proliferation, senescence, survival, and angiogenesis. From the study data, we have identified potential diagnostic, or predictive, biomarkers for DFU wound healing derived from the ratios of quantified signaling protein expressions within interconnected pathways. These biomarkers may allow physicians to personalize therapeutic strategies for DFU management on an individual basis based upon the signaling architecture present in each wound. Additionally, we have identified altered, interconnected signaling pathways within DFU keratinocytes that may help guide the development of therapeutics to modulate these dysregulated pathways, many of which parallel the therapeutic targets which are the hallmarks of molecular therapies for treating cancer.

Atypical Diabetic Foot Ulcer Keratinocyte Protein Signaling Correlates with Impaired Wound Healing

PubMed Central

Hoke, Glenn D.; Ramos, Corrine; Hoke, Nicholas N.; Crossland, Mary C.; Shawler, Lisa G.

2016-01-01

Diabetes mellitus is associated with chronic diabetic foot ulcers (DFUs) and wound infections often resulting in lower extremity amputations. The protein signaling architecture of the mechanisms responsible for impaired DFU healing has not been characterized. In this preliminary clinical study, the intracellular levels of proteins involved in signal transduction networks relevant to wound healing were non-biasedly measured using reverse-phase protein arrays (RPPA) in keratinocytes isolated from DFU wound biopsies. RPPA allows for the simultaneous documentation and assessment of the signaling pathways active in each DFU. Thus, RPPA provides for the accurate mapping of wound healing pathways associated with apoptosis, proliferation, senescence, survival, and angiogenesis. From the study data, we have identified potential diagnostic, or predictive, biomarkers for DFU wound healing derived from the ratios of quantified signaling protein expressions within interconnected pathways. These biomarkers may allow physicians to personalize therapeutic strategies for DFU management on an individual basis based upon the signaling architecture present in each wound. Additionally, we have identified altered, interconnected signaling pathways within DFU keratinocytes that may help guide the development of therapeutics to modulate these dysregulated pathways, many of which parallel the therapeutic targets which are the hallmarks of molecular therapies for treating cancer. PMID:27840833

Contributions of Rod and Cone Pathways to Retinal Direction Selectivity Through Development

PubMed Central

Rosa, Juliana M.; Morrie, Ryan D.; Baertsch, Hans C.

2016-01-01

Direction selectivity is a robust computation across a broad stimulus space that is mediated by activity of both rod and cone photoreceptors through the ON and OFF pathways. However, rods, S-cones, and M-cones activate the ON and OFF circuits via distinct pathways and the relative contribution of each to direction selectivity is unknown. Using a variety of stimulation paradigms, pharmacological agents, and knockout mice that lack rod transduction, we found that inputs from the ON pathway were critical for strong direction-selective (DS) tuning in the OFF pathway. For UV light stimulation, the ON pathway inputs to the OFF pathway originated with rod signaling, whereas for visible stimulation, the ON pathway inputs to the OFF pathway originated with both rod and M-cone signaling. Whole-cell voltage-clamp recordings revealed that blocking the ON pathway reduced directional tuning in the OFF pathway via a reduction in null-side inhibition, which is provided by OFF starburst amacrine cells (SACs). Consistent with this, our recordings from OFF SACs confirmed that signals originating in the ON pathway contribute to their excitation. Finally, we observed that, for UV stimulation, ON contributions to OFF DS tuning matured earlier than direct signaling via the OFF pathway. These data indicate that the retina uses multiple strategies for computing DS responses across different colors and stages of development. SIGNIFICANCE STATEMENT The retina uses parallel pathways to encode different features of the visual scene. In some cases, these distinct pathways converge on circuits that mediate a distinct computation. For example, rod and cone pathways enable direction-selective (DS) ganglion cells to encode motion over a wide range of light intensities. Here, we show that although direction selectivity is robust across light intensities, motion discrimination for OFF signals is dependent upon ON signaling. At eye opening, ON directional tuning is mature, whereas OFF DS tuning is significantly reduced due to a delayed maturation of S-cone to OFF cone bipolar signaling. These results provide evidence that the retina uses multiple strategies for computing DS responses across different stimulus conditions. PMID:27629718

A high-throughput study on endothelial cell adhesion and growth mediated by adsorbed serum protein via signaling pathway PCR array

PubMed Central

Qu, Yayun; Hong, Ying; Huang, Yan; Zhang, Yiwen; Yang, Dayun; Zhang, Fudan; Xi, Tingfei; Zhang, Deyuan

2018-01-01

Abstract The purpose of this paper is to utilize the signaling pathway polymerase chain reaction (PCR) arrays to investigate the activation of two important biological signaling pathways in endothelial cell adhesion and growth mediated by adsorbed serum protein on the surface of bare and titanium nitride (TiN)-coated nickel titanium (NiTi) alloys. First, the endothelial cells were cultured on the bare and TiN-coated NiTi alloys and chitosan films as control for 4 h and 24 h, respectively. Then, the total RNA of the cells was collected and the PCR arrays were performed. After that, the differentially expressed genes in the transforming growth factor beta (TGF-β) signaling pathway and the regulation of actin cytoskeleton pathway were screened out; and the further bioinformatics analyses were performed. The results showed that both TGF-β signaling pathway and regulation of actin cytoskeleton pathway were activated in the cells after 4 h and 24 h culturing on the surface of bare and TiN-coated NiTi alloys compared to the chitosan group. The activated TGF-β signaling pathway promoted cell adhesion; the activated regulation of actin cytoskeleton pathway promoted cell adhesion, spreading, growth and motility. In addition, the activation of both pathways was much stronger in the cells cultured for 24 h versus 4 h, which indicated that cell adhesion and growth became more favorable with longer time on the surface of two NiTi alloy materials. PMID:29423265

The non-canonical BMP and Wnt/β-catenin signaling pathways orchestrate early tooth development

PubMed Central

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. PMID:25428587

Ties that bind: the integration of plastid signalling pathways in plant cell metabolism.

PubMed

Brunkard, Jacob O; Burch-Smith, Tessa M

2018-04-13

Plastids are critical organelles in plant cells that perform diverse functions and are central to many metabolic pathways. Beyond their major roles in primary metabolism, of which their role in photosynthesis is perhaps best known, plastids contribute to the biosynthesis of phytohormones and other secondary metabolites, store critical biomolecules, and sense a range of environmental stresses. Accordingly, plastid-derived signals coordinate a host of physiological and developmental processes, often by emitting signalling molecules that regulate the expression of nuclear genes. Several excellent recent reviews have provided broad perspectives on plastid signalling pathways. In this review, we will highlight recent advances in our understanding of chloroplast signalling pathways. Our discussion focuses on new discoveries illuminating how chloroplasts determine life and death decisions in cells and on studies elucidating tetrapyrrole biosynthesis signal transduction networks. We will also examine the role of a plastid RNA helicase, ISE2, in chloroplast signalling, and scrutinize intriguing results investigating the potential role of stromules in conducting signals from the chloroplast to other cellular locations. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Direct induction of T lymphocyte-specific gene expression by the mammalian Notch signaling pathway

PubMed Central

Reizis, Boris; Leder, Philip

2002-01-01

The Notch signaling pathway regulates the commitment and early development of T lymphocytes. We studied Notch-mediated induction of the pre-T cell receptor α (pTa) gene, a T-cell-specific transcriptional target of Notch. The pTa enhancer was activated by Notch signaling and contained binding sites for its nuclear effector, CSL. Mutation of the CSL-binding sites abolished enhancer induction by Notch and delayed the up-regulation of pTa transgene expression during T cell lineage commitment. These results show a direct mechanism of stage- and tissue-specific gene induction by the mammalian Notch/CSL signaling pathway. PMID:11825871

Impact of constitutional copy number variants on biological pathway evolution

PubMed Central

2013-01-01

Background Inherited Copy Number Variants (CNVs) can modulate the expression levels of individual genes. However, little is known about how CNVs alter biological pathways and how this varies across different populations. To trace potential evolutionary changes of well-described biological pathways, we jointly queried the genomes and the transcriptomes of a collection of individuals with Caucasian, Asian or Yoruban descent combining high-resolution array and sequencing data. Results We implemented an enrichment analysis of pathways accounting for CNVs and genes sizes and detected significant enrichment not only in signal transduction and extracellular biological processes, but also in metabolism pathways. Upon the estimation of CNV population differentiation (CNVs with different polymorphism frequencies across populations), we evaluated that 22% of the pathways contain at least one gene that is proximal to a CNV (CNV-gene pair) that shows significant population differentiation. The majority of these CNV-gene pairs belong to signal transduction pathways and 6% of the CNV-gene pairs show statistical association between the copy number states and the transcript levels. Conclusions The analysis suggested possible examples of positive selection within individual populations including NF-kB, MAPK signaling pathways, and Alu/L1 retrotransposition factors. Altogether, our results suggest that constitutional CNVs may modulate subtle pathway changes through specific pathway enzymes, which may become fixed in some populations. PMID:23342974

Comparative analysis of gene expression profiles of OPN signaling pathway in four kinds of liver diseases.

PubMed

Wang, Gaiping; Chen, Shasha; Zhao, Congcong; Li, Xiaofang; Zhao, Weiming; Yang, Jing; Chang, Cuifang; Xu, Cunshuan

2016-09-01

To explore the relevance of OPN signalling pathway to the occurrence and development of nonalcoholic fatty liver disease (NAFLD), liver cirrhosis (LC), hepatic cancer (HC) and acute hepatic failure (AHF) at transcriptional level, Rat Genome 230 2.0 Array was used to detect expression profiles of OPN signalling pathway-related genes in four kinds of liver diseases. The results showed that 23, 33, 59 and 74 genes were significantly changed in the above four kinds of liver diseases, respectively. H-clustering analysis showed that the expression profiles of OPN signalling-related genes were notably different in four kinds of liver diseases. Subsequently, a total of above-mentioned 147 genes were categorized into four clusters by k-means according to the similarity of gene expression, and expression analysis systematic explorer (EASE) functional enrichment analysis revealed that OPN signalling pathway-related genes were involved in cell adhesion and migration, cell proliferation, apoptosis, stress and inflammatory reaction, etc. Finally, ingenuity pathway analysis (IPA) software was used to predict the functions of OPN signalling-related genes, and the results indicated that the activities of ROS production, cell adhesion and migration, cell proliferation were remarkably increased, while that of apoptosis, stress and inflammatory reaction were reduced in four kinds of liver diseases. In summary, the above physiological activities changed more obviously in LC, HC and AHF than in NAFLD.

Bipolar cell gap junctions serve major signaling pathways in the human retina.

PubMed

Kántor, Orsolya; Varga, Alexandra; Nitschke, Roland; Naumann, Angela; Énzsöly, Anna; Lukáts, Ákos; Szabó, Arnold; Németh, János; Völgyi, Béla

2017-08-01

Connexin36 (Cx36) constituent gap junctions (GJ) throughout the brain connect neurons into functional syncytia. In the retina they underlie the transmission, averaging and correlation of signals prior conveying visual information to the brain. This is the first study that describes retinal bipolar cell (BC) GJs in the human inner retina, whose function is enigmatic even in the examined animal models. Furthermore, a number of unique features (e.g. fovea, trichromacy, midget system) necessitate a reexamination of the animal model results in the human retina. Well-preserved postmortem human samples of this study are allowed to identify Cx36 expressing BCs neurochemically. Results reveal that both rod and cone pathway interneurons display strong Cx36 expression. Rod BC inputs to AII amacrine cells (AC) appear in juxtaposition to AII GJs, thus suggesting a strategic AII cell targeting by rod BCs. Cone BCs serving midget, parasol or koniocellular signaling pathways display a wealth of Cx36 expression to form homologously coupled arrays. In addition, they also establish heterologous GJ contacts to serve an exchange of information between parallel signaling streams. Interestingly, a prominent Cx36 expression was exhibited by midget system BCs that appear to maintain intimate contacts with bistratified BCs serving other pathways. These findings suggest that BC GJs in parallel signaling streams serve both an intra- and inter-pathway exchange of signals in the human retina.

Induction of Canonical Wnt Signaling by the Alarmins S100A8/A9 in Murine Knee Joints: Implications for Osteoarthritis.

PubMed

van den Bosch, Martijn H; Blom, Arjen B; Schelbergen, Rik F P; Vogl, Thomas; Roth, Johannes P; Slöetjes, Annet W; van den Berg, Wim B; van der Kraan, Peter M; van Lent, Peter L E M

2016-01-01

Both alarmins S100A8/A9 and canonical Wnt signaling have been found to play active roles in the development of experimental osteoarthritis (OA). However, what activates canonical Wnt signaling remains unknown. This study was undertaken to investigate whether S100A8 induces canonical Wnt signaling and whether S100 proteins exert their effects via activation of Wnt signaling. Expression of the genes for S100A8/A9 and Wnt signaling pathway members was measured in an experimental OA model. Selected Wnt signaling pathway members were overexpressed, and levels of S100A8/A9 were measured. Activation of canonical Wnt signaling was determined after injection of S100A8 into naive joints and induction of collagenase-induced OA in S100A9-deficient mice. Expression of Wnt signaling pathway members was tested in macrophages and fibroblasts after S100A8 stimulation. Canonical Wnt signaling was inhibited in vivo to determine if the effects of S100A8 injections were dependent on Wnt signaling. The alarmins S100A8/A9 and members of the Wnt signaling pathway showed coinciding expression in synovial tissue in an experimental OA model. Synovial overexpression of selected Wnt signaling pathway members did not result in increased expression of S100 proteins. In contrast, intraarticular injection of S100A8 increased canonical Wnt signaling, whereas canonical Wnt signaling was decreased after induction of experimental OA in S100A9-deficient mice. S100A8 stimulation of macrophages, but not fibroblasts, resulted in increased expression of canonical Wnt signaling members. Overexpression of Dkk-1 to inhibit canonical Wnt signaling decreased the induction of matrix metalloproteinase 3, interleukin-6, and macrophage inflammatory protein 1α after injection of S100A8. Our findings indicate that the alarmin S100A8 induces canonical Wnt signaling in macrophages and murine knee joints. The effects of S100A8 are partially dependent on activation of canonical Wnt signaling. © 2016, American College of Rheumatology.

A high throughput screening for TLR3-IRF3 signaling pathway modulators identifies several antipsychotic drugs as TLR inhibitors1

PubMed Central

Zhu, Jianzhong; Smith, Kevin; Hsieh, Paishiun N.; Mburu, Yvonne K.; Chattopadhyay, Saurabh; Sen, Ganes C.; Sarkar, Saumendra N.

2010-01-01

Toll-like Receptor 3 (TLR3) is one of the major innate immune sensors of double stranded RNA (dsRNA). The signal transduction pathway activated by TLR3, upon binding to dsRNA, leads to the activation of two major transcription factors: NF-κB and IRF3. In an effort to identify specific chemical modulators of TLR3-IRF3 signal transduction pathway we developed a cell-based read out system. Using the interferon stimulated gene 56 (ISG56) promoter driven firefly luciferase gene stably integrated in a TLR3 expressing HEK293 cell line, we were able to generate a cell line where treatment with dsRNA resulted in a dose dependent induction of luciferase activity. A screen of two pharmacologically active compound libraries using this system, identified a number of TLR3-IRF3 signaling pathway modulators. Among them we focused on a subset of inhibitors and characterized their mode of action. Several antipsychotic drugs, such as Sertraline, Trifluoperazine and Fluphenazine were found to be direct inhibitors of the innate immune signaling pathway. These inhibitors also showed the ability to inhibit ISG56 induction mediated by TLR4 and TLR7/8 pathways. Interestingly, they did not show significant effect on TLR3, TLR7 and TLR8 mediated NF-κB activation. Detailed analysis of the signaling pathway indicated that these drugs may be exerting their inhibitory effects on IRF3 via PI3K signaling pathway. The data presented here provides mechanistic explanation of possible anti-inflammatory roles of some antipsychotic drugs. PMID:20382888

A MAP4 kinase related to Ste20 is a nutrient-sensitive regulator of mTOR signalling

PubMed Central

Findlay, Greg M.; Yan, Lijun; Procter, Julia; Mieulet, Virginie; Lamb, Richard F.

2007-01-01

The mTOR (mammalian target of rapamycin) signalling pathway is a key regulator of cell growth and is controlled by growth factors and nutrients such as amino acids. Although signalling pathways from growth factor receptors to mTOR have been elucidated, the pathways mediating signalling by nutrients are poorly characterized. Through a screen for protein kinases active in the mTOR signalling pathway in Drosophila we have identified a Ste20 family member (MAP4K3) that is required for maximal S6K (S6 kinase)/4E-BP1 [eIF4E (eukaryotic initiation factor 4E)-binding protein 1] phosphorylation and regulates cell growth. Importantly, MAP4K3 activity is regulated by amino acids, but not the growth factor insulin and is not regulated by the mTORC1 inhibitor rapamycin. Our results therefore suggest a model whereby nutrients signal to mTORC1 via activation of MAP4K3. PMID:17253963

A Phenotype-Based RNAi Screening for Ras-ERK/MAPK Signaling-Associated Stem Cell Regulators in C. elegans.

PubMed

Lee, Myon-Hee; Yoon, Dong Suk

2017-01-01

Stem cells have the ability to self-renew and to generate differentiated cell types. A regulatory network that controls this balance is critical for stem cell homeostasis and normal animal development. Particularly, Ras-ERK/MAPK signaling pathway is critical for stem cell self-renewal and differentiation in mammals, including humans. Aberrant regulation of Ras-ERK/MAPK signaling pathway results in either stem cell or overproliferation. Therefore, the identification of Ras-ERK/MAPK signaling pathway-associated regulators is critical to understand the mechanism of stem cell (possibly cancer stem cell) control. In this report, using the nematode C. elegans mutants, we developed a methodology for a phenotype-based RNAi screening that identifies stem cell regulator genes associated with Ras-ERK/MAPK signaling within the context of a whole organism. Importantly, this phenotype-based RNAi screening can be applied for other stem cell-associated signaling pathways such as Wnt/β-catenin and Notch using the C. elegans.

Integrated QSAR study for inhibitors of Hedgehog Signal Pathway against multiple cell lines:a collaborative filtering method.

PubMed

Gao, Jun; Che, Dongsheng; Zheng, Vincent W; Zhu, Ruixin; Liu, Qi

2012-07-31

The Hedgehog Signaling Pathway is one of signaling pathways that are very important to embryonic development. The participation of inhibitors in the Hedgehog Signal Pathway can control cell growth and death, and searching novel inhibitors to the functioning of the pathway are in a great demand. As the matter of fact, effective inhibitors could provide efficient therapies for a wide range of malignancies, and targeting such pathway in cells represents a promising new paradigm for cell growth and death control. Current research mainly focuses on the syntheses of the inhibitors of cyclopamine derivatives, which bind specifically to the Smo protein, and can be used for cancer therapy. While quantitatively structure-activity relationship (QSAR) studies have been performed for these compounds among different cell lines, none of them have achieved acceptable results in the prediction of activity values of new compounds. In this study, we proposed a novel collaborative QSAR model for inhibitors of the Hedgehog Signaling Pathway by integration the information from multiple cell lines. Such a model is expected to substantially improve the QSAR ability from single cell lines, and provide useful clues in developing clinically effective inhibitors and modifications of parent lead compounds for target on the Hedgehog Signaling Pathway. In this study, we have presented: (1) a collaborative QSAR model, which is used to integrate information among multiple cell lines to boost the QSAR results, rather than only a single cell line QSAR modeling. Our experiments have shown that the performance of our model is significantly better than single cell line QSAR methods; and (2) an efficient feature selection strategy under such collaborative environment, which can derive the commonly important features related to the entire given cell lines, while simultaneously showing their specific contributions to a specific cell-line. Based on feature selection results, we have proposed several possible chemical modifications to improve the inhibitor affinity towards multiple targets in the Hedgehog Signaling Pathway. 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.

Melatonin Inhibits Neural Cell Apoptosis and Promotes Locomotor Recovery via Activation of the Wnt/β-Catenin Signaling Pathway After Spinal Cord Injury.

PubMed

Shen, Zhaoliang; Zhou, Zipeng; Gao, Shuang; Guo, Yue; Gao, Kai; Wang, Haoyu; Dang, Xiaoqian

2017-08-01

The spinal cord is highly sensitive to spinal cord injury (SCI) by external mechanical damage, resulting in irreversible neurological damage. Activation of the Wnt/β-catenin signaling pathway can effectively reduce apoptosis and protect against SCI. Melatonin, an indoleamine originally isolated from bovine pineal tissue, exerts neuroprotective effects after SCI through activation of the Wnt/β-catenin signaling pathway. In this study, we demonstrated that melatonin exhibited neuroprotective effects on neuronal apoptosis and supported functional recovery in a rat SCI model by activating the Wnt/β-catenin signaling pathway. We found that melatonin administration after SCI significantly upregulated the expression of low-density lipoprotein receptor related protein 6 phosphorylation (p-LRP-6), lymphoid enhancer factor-1 (LEF-1) and β-catenin protein in the spinal cord. Melatonin enhanced motor neuronal survival in the spinal cord ventral horn and improved the locomotor functions of rats after SCI. Melatonin administration after SCI also reduced the expression levels of Bax and cleaved caspase-3 in the spinal cord and the proportion of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) positive cells, but increased the expression level of Bcl-2. These results suggest that melatonin attenuated SCI by activating the Wnt/β-catenin signaling pathway.

Detection of Pathways Affected by Positive Selection in Primate Lineages Ancestral to Humans

PubMed Central

Moretti, S.; Davydov, I.I.; Excoffier, L.

2017-01-01

Abstract Gene set enrichment approaches have been increasingly successful in finding signals of recent polygenic selection in the human genome. In this study, we aim at detecting biological pathways affected by positive selection in more ancient human evolutionary history. Focusing on four branches of the primate tree that lead to modern humans, we tested all available protein coding gene trees of the Primates clade for signals of adaptation in these branches, using the likelihood-based branch site test of positive selection. The results of these locus-specific tests were then used as input for a gene set enrichment test, where whole pathways are globally scored for a signal of positive selection, instead of focusing only on outlier “significant” genes. We identified signals of positive selection in several pathways that are mainly involved in immune response, sensory perception, metabolism, and energy production. These pathway-level results are highly significant, even though there is no functional enrichment when only focusing on top scoring genes. Interestingly, several gene sets are found significant at multiple levels in the phylogeny, but different genes are responsible for the selection signal in the different branches. This suggests that the same function has been optimized in different ways at different times in primate evolution. PMID:28333345

Primary cilia maintain corneal epithelial homeostasis by regulation of the Notch signaling pathway

PubMed Central

Grisanti, Laura; Revenkova, Ekaterina; Gordon, Ronald E.

2016-01-01

Primary cilia have been linked to signaling pathways involved in cell proliferation, cell motility and cell polarity. Defects in ciliary function result in developmental abnormalities and multiple ciliopathies. Patients affected by severe ciliopathies, such as Meckel syndrome, present several ocular surface disease conditions of unclear pathogenesis. Here, we show that primary cilia are predominantly present on basal cells of the mouse corneal epithelium (CE) throughout development and in the adult. Conditional ablation of cilia in the CE leads to an increase in proliferation and vertical migration of basal corneal epithelial cells (CECs). A consequent increase in cell density of suprabasal layers results in a thicker than normal CE. Surprisingly, in cilia-deficient CE, cilia-mediated signaling pathways, including Hh and Wnt pathways, were not affected but the intensity of Notch signaling was severely diminished. Although Notch1 and Notch2 receptors were expressed normally, nuclear Notch1 intracellular domain (N1ICD) expression was severely reduced. Postnatal development analysis revealed that in cilia-deficient CECs downregulation of the Notch pathway precedes cell proliferation defects. Thus, we have uncovered a function of the primary cilium in maintaining homeostasis of the CE by balancing proliferation and vertical migration of basal CECs through modulation of Notch signaling. PMID:27122169

The Bmp signaling pathway regulates development of left-right asymmetry in amphioxus.

PubMed

Soukup, Vladimir; Kozmik, Zbynek

2018-02-01

Establishment of asymmetry along the left-right (LR) body axis in vertebrates requires interplay between Nodal and Bmp signaling pathways. In the basal chordate amphioxus, the left-sided activity of the Nodal signaling has been attributed to the asymmetric morphogenesis of paraxial structures and pharyngeal organs, however the role of Bmp signaling in LR asymmetry establishment has not been addressed to date. Here, we show that Bmp signaling is necessary for the development of LR asymmetric morphogenesis of amphioxus larvae through regulation of Nodal signaling. Loss of Bmp signaling results in loss of the left-sided expression of Nodal, Gdf1/3, Lefty and Pitx and in gain of ectopic expression of Cerberus on the left side. As a consequence, the larvae display loss of the offset arrangement of axial structures, loss of the left-sided pharyngeal organs including the mouth, and ectopic development of the right-sided organs on the left side. Bmp inhibition thus phenocopies inhibition of Nodal signaling and results in the right isomerism. We conclude that Bmp and Nodal pathways act in concert to specify the left side and that Bmp signaling plays a fundamental role during LR development in amphioxus. Copyright © 2017 Elsevier Inc. All rights reserved.

Assigning Quantitative Function to Post-Translational Modifications Reveals Multiple Sites of Phosphorylation That Tune Yeast Pheromone Signaling Output

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pincus, David; Ryan, Christopher J.; Smith, Richard D.

2013-03-12

Cell signaling systems transmit information by post-­translationally modifying signaling proteins, often via phosphorylation. While thousands of sites of phosphorylation have been identified in proteomic studies, the vast majority of sites have no known function. Assigning functional roles to the catalog of uncharacterized phosphorylation sites is a key research challenge. Here we present a general approach to address this challenge and apply it to a prototypical signaling pathway, the pheromone response pathway in Saccharomyces cerevisiae. The pheromone pathway includes a mitogen activated protein kinase (MAPK) cascade activated by a G-­protein coupled receptor (GPCR). We used mass spectrometry-based proteomics to identify sitesmore » whose phosphorylation changed when the system was active, and evolutionary conservation to assign priority to a list of candidate MAPK regulatory sites. We made targeted alterations in those sites, and measured the effects of the mutations on pheromone pathway output in single cells. Our work identified six new sites that quantitatively tuned system output. We developed simple computational models to find system architectures that recapitulated the quantitative phenotypes of the mutants. Our results identify a number of regulated phosphorylation events that contribute to adjust the input-­output relationship of this model eukaryotic signaling system. We believe this combined approach constitutes a general means not only to reveal modification sites required to turn a pathway on and off, but also those required for more subtle quantitative effects that tune pathway output. Our results further suggest that relatively small quantitative influences from individual regulatory phosphorylation events endow signaling systems with plasticity that evolution may exploit to quantitatively tailor signaling outcomes.« less

A Novel Role for the BMP Antagonist Noggin in Sensitizing Cells to Non-canonical Wnt-5a/Ror2/Disheveled Pathway Activation

PubMed Central

Bernatik, Ondrej; Radaszkiewicz, Tomasz; Behal, Martin; Dave, Zankruti; Witte, Florian; Mahl, Annika; Cernohorsky, Nicole H.; Krejci, Pavel; Stricker, Sigmar; Bryja, Vitezslav

2017-01-01

Mammalian limb development is driven by the integrative input from several signaling pathways; a failure to receive or a misinterpretation of these signals results in skeletal defects. The brachydactylies, a group of overlapping inherited human hand malformation syndromes, are mainly caused by mutations in BMP signaling pathway components. Two closely related forms, Brachydactyly type B2 (BDB2) and BDB1 are caused by mutations in the BMP antagonist Noggin (NOG) and the atypical receptor tyrosine kinase ROR2 that acts as a receptor in the non-canonical Wnt pathway. Genetic analysis of Nog and Ror2 functional interaction via crossing Noggin and Ror2 mutant mice revealed a widening of skeletal elements in compound but not in any of the single mutants, thus indicating genetic interaction. Since ROR2 is a non-canonical Wnt co-receptor specific for Wnt-5a we speculated that this phenotype might be a result of deregulated Wnt-5a signaling activation, which is known to be essential for limb skeletal elements growth and patterning. We show that Noggin potentiates activation of the Wnt-5a-Ror2-Disheveled (Dvl) pathway in mouse embryonic fibroblast (MEF) cells in a Ror2-dependent fashion. Rat chondrosarcoma chondrocytes (RCS), however, are not able to respond to Noggin in this fashion unless growth arrest is induced by FGF2. In summary, our data demonstrate genetic interaction between Noggin and Ror2 and show that Noggin can sensitize cells to Wnt-5a/Ror2-mediated non-canonical Wnt signaling, a feature that in cartilage may depend on the presence of active FGF signaling. These findings indicate an unappreciated function of Noggin that will help to understand BMP and Wnt/PCP signaling pathway interactions. PMID:28523267

MULTI-SENSOR REPORTER CELL TECHNOLOGY TO ASSESS HAZARD INVOLVING ENDOCRINE SIGNALING PATHWAYS

EPA Science Inventory

Results will define an experimental approach that can be used in a high-throughput format to evaluate the response of hormone signaling pathways and networks to individual chemicals or mixtures. The assay also will have application across species and would significantly reduce...

Effects of the Transforming Growth Factor Beta Signaling Pathway on the Differentiation of Chicken Embryonic Stem Cells into Male Germ Cells

PubMed Central

Zhang, Yani; Wang, Yingjie; Zuo, Qisheng; Li, Dong; Zhang, Wenhui; Lian, Chao; Tang, Beibei; Xiao, Tianrong; Wang, Man; Wang, Kehua

2016-01-01

Abstract The objectives of the present study were to screen for key gene and signaling pathways involved in the production of male germ cells in poultry and to investigate the effects of the transforming growth factor beta (TGF-β) signaling pathway on the differentiation of chicken embryonic stem cells (ESCs) into male germ cells. The ESCs, primordial germ cells, and spermatogonial stem cells (SSCs) were sorted using flow cytometry for RNA sequencing (RNA-seq) technology. Male chicken ESCs were induced using 40 ng/mL of bone morphogenetic protein 4 (BMP4). The effects of the TGF-β signaling pathway on the production of chicken SSCs were confirmed by morphology, quantitative real-time polymerase chain reaction, and immunocytochemistry. One hundred seventy-three key genes relevant to development, differentiation, and metabolism and 20 signaling pathways involved in cell reproduction, differentiation, and signal transduction were identified by RNA-seq. The germ cells formed agglomerates and increased in number 14 days after induction by BMP4. During the induction process, the ESCs, Nanog, and Sox2 marker gene expression levels decreased, whereas expression of the germ cell-specific genes Stra8, Dazl, integrin-α6, and c-kit increased. The results indicated that the TGF-β signaling pathway participated in the differentiation of chicken ESCs into male germ cells. PMID:27906584

Interactions of Notch1 and TLR4 signaling pathways in DRG neurons of in vivo and in vitro models of diabetic neuropathy.

PubMed

Chen, Tianhua; Li, Hao; Yin, Yiting; Zhang, Yuanpin; Liu, Zhen; Liu, Huaxiang

2017-11-02

Understanding the interactions between Notch1 and toll-like receptor 4 (TLR4) signaling pathways in the development of diabetic peripheral neuropathy may lead to interpretation of the mechanisms and novel approaches for preventing diabetic neuropathic pain. In the present study, the interactions between Notch1 and TLR4 signaling pathways were investigated by using dorsal root ganglion (DRG) from diabetic neuropathic pain rats and cultured DRG neurons under high glucose challenge. The results showed that high glucose induced not only Notch1 mRNA, HES1 mRNA, and TLR4 mRNA expression, but also Notch1 intracellular domain (NICD1) and TLR4 protein expression in DRG neurons. The proportion of NICD1-immunoreactive (IR) and TLR4-IR neurons in DRG cultures was also increased after high glucose challenge. The above alterations could be partially reversed by inhibition of either Notch1 or TLR4 signaling pathway. Inhibition of either Notch1 or TLR4 signaling pathway could improve mechanical allodynia and thermal hyperalgesia thresholds. Inhibition of Notch1 or TLR4 signaling also decreased tumor necrosis factor-α (TNF-α) levels in DRG from diabetic neuropathic rats. These data imply that the interaction between Notch1 and TLR4 signaling pathways is one of the important mechanisms in the development or progression of diabetic neuropathy.

Chronic administration of aripiprazole activates GSK3β-dependent signalling pathways, and up-regulates GABAA receptor expression and CREB1 activity in rats.

PubMed

Pan, Bo; Huang, Xu-Feng; Deng, Chao

2016-07-20

Aripiprazole is a D2-like receptor (D2R) partial agonist with a favourable clinical profile. Previous investigations indicated that acute and short-term administration of aripiprazole had effects on PKA activity, GSK3β-dependent pathways, GABAA receptors, NMDA receptor and CREB1 in the brain. Since antipsychotics are used chronically in clinics, the present study investigated the long-term effects of chronic oral aripiprazole treatment on these cellular signalling pathways, in comparison with haloperidol (a D2R antagonist) and bifeprunox (a potent D2R partial agonist). We found that the Akt-GSK3β pathway was activated by aripiprazole and bifeprunox in the prefrontal cortex; NMDA NR2A levels were reduced by aripiprazole and haloperidol. In the nucleus accumbens, all three drugs increased Akt-GSK3β signalling; in addition, both aripiprazole and haloperidol, but not bifeprunox, increased the expression of Dvl-3, β-catenin and GABAA receptors, NMDA receptor subunits, as well as CREB1 phosphorylation levels. The results suggest that chronic oral administration of aripiprazole affects schizophrenia-related cellular signalling pathways and markers (including Akt-GSK3β signalling, Dvl-GSK3β-β-catenin signalling, GABAA receptor, NMDA receptor and CREB1) in a brain-region-dependent manner; the selective effects of aripiprazole on these signalling pathways might be associated with its unique clinical effects.

Wnt and Notch signaling pathway involved in wound healing by targeting c-Myc and Hes1 separately.

PubMed

Shi, Yan; Shu, Bin; Yang, Ronghua; Xu, Yingbin; Xing, Bangrong; Liu, Jian; Chen, Lei; Qi, Shaohai; Liu, Xusheng; Wang, Peng; Tang, Jinming; Xie, Julin

2015-06-16

Wnt and Notch signaling pathways are critically involved in relative cell fate decisions within the development of cutaneous tissues. Moreover, several studies identified the above two pathways as having a significant role during wound healing. However, their biological effects during cutaneous tissues repair are unclear. We employed a self-controlled model (Sprague-Dawley rats with full-thickness skin wounds) to observe the action and effect of Wnt/β-catenin and Notch signalings in vivo. The quality of wound repair relevant to the gain/loss-of-function Wnt/β-catenin and Notch activation was estimated by hematoxylin-and-eosin and Masson staining. Immunofluorescence analysis and Western blot analysis were used to elucidate the underlying mechanism of the regulation of Wnt and Notch signaling pathways in wound healing. Meanwhile, epidermal stem cells (ESCs) were cultured in keratinocyte serum-free medium with Jaggedl or in DAPT (N-[(3,5-difluorophenyl)acetyl]-L-alanyl-2-phenyl]glycine-1,1-dimethylethyl) to investigate whether the interruption of Notch signaling contributes to the expression of Wnt/β-catenin signaling. The results showed that in vivo the gain-of-function Wnt/β-catenin and Notch activation extended the ability to promote wound closure. We further determined that activation or inhibition of Wnt signaling and Notch signaling can affect the proliferation of ESCs, the differentiation and migration of keratinocytes, and follicle regeneration by targeting c-Myc and Hes1, which ultimately lead to enhanced or delayed wound healing. Furthermore, Western blot analysis suggested that the two pathways might interact in vivo and in vitro. These results suggest that Wnt and Notch signalings play important roles in cutaneous repair by targeting c-Myc and Hes1 separately. What's more, interaction between the above two pathways might act as a vital role in regulation of wound healing.

Whole-genome sequencing revealed novel prognostic biomarkers and promising targets for therapy of ovarian clear cell carcinoma.

PubMed

Itamochi, Hiroaki; Oishi, Tetsuro; Oumi, Nao; Takeuchi, Satoshi; Yoshihara, Kosuke; Mikami, Mikio; Yaegashi, Nobuo; Terao, Yasuhisa; Takehara, Kazuhiro; Ushijima, Kimio; Watari, Hidemichi; Aoki, Daisuke; Kimura, Tadashi; Nakamura, Toshiaki; Yokoyama, Yoshihito; Kigawa, Junzo; Sugiyama, Toru

2017-08-22

Ovarian clear cell carcinoma (OCCC) is mostly resistant to standard chemotherapy that results in poor patient survival. To understand the genetic background of these tumours, we performed whole-genome sequencing of OCCC tumours. Tumour tissue samples and matched blood samples were obtained from 55 Japanese women diagnosed with OCCC. Whole-genome sequencing was performed using the Illumina HiSeq platform according to standard protocols. Alterations to the switch/sucrose non-fermentable (SWI/SNF) subunit, the phosphatidylinositol-3-kinase (PI3K)/Akt signalling pathway, and the receptor tyrosine kinase (RTK)/Ras signalling pathway were found in 51%, 42%, and 29% of OCCC tumours, respectively. The 3-year overall survival (OS) rate for patients with an activated PI3K/Akt signalling pathway was significantly higher than that for those with inactive pathway (91 vs 40%, hazard ratio 0.24 (95% confidence interval (CI) 0.10-0.56), P=0.0010). Similarly, the OS was significantly higher in patients with the activated RTK/Ras signalling pathway than in those with the inactive pathway (91 vs 53%, hazard ratio 0.35 (95% CI 0.13-0.94), P=0.0373). Multivariable analysis revealed that activation of the PI3K/Akt and RTK/Ras signalling pathways was an independent prognostic factor for patients with OCCC. The PI3K/Akt and RTK/Ras signalling pathways may be potential prognostic biomarkers for OCCC patients. Furthermore, our whole-genome sequencing data highlight important pathways for molecular and biological characterisations and potential therapeutic targeting in OCCC.

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

Genomic Analysis of ATP Efflux in Saccharomyces cerevisiae

PubMed Central

Peters, Theodore W.; Miller, Aaron W.; Tourette, Cendrine; Agren, Hannah; Hubbard, Alan; Hughes, Robert E.

2015-01-01

Adenosine triphosphate (ATP) plays an important role as a primary molecule for the transfer of chemical energy to drive biological processes. ATP also functions as an extracellular signaling molecule in a diverse array of eukaryotic taxa in a conserved process known as purinergic signaling. Given the important roles of extracellular ATP in cell signaling, we sought to comprehensively elucidate the pathways and mechanisms governing ATP efflux from eukaryotic cells. Here, we present results of a genomic analysis of ATP efflux from Saccharomyces cerevisiae by measuring extracellular ATP levels in cultures of 4609 deletion mutants. This screen revealed key cellular processes that regulate extracellular ATP levels, including mitochondrial translation and vesicle sorting in the late endosome, indicating that ATP production and transport through vesicles are required for efflux. We also observed evidence for altered ATP efflux in strains deleted for genes involved in amino acid signaling, and mitochondrial retrograde signaling. Based on these results, we propose a model in which the retrograde signaling pathway potentiates amino acid signaling to promote mitochondrial respiration. This study advances our understanding of the mechanism of ATP secretion in eukaryotes and implicates TOR complex 1 (TORC1) and nutrient signaling pathways in the regulation of ATP efflux. These results will facilitate analysis of ATP efflux mechanisms in higher eukaryotes. PMID:26585826

The cold response of CBF genes in barley is regulated by distinct signaling mechanisms.

PubMed

Marozsán-Tóth, Zsuzsa; Vashegyi, Ildikó; Galiba, Gábor; Tóth, Balázs

2015-06-01

Cold acclimation ability is crucial in the winter survival of cereals. In this process CBF transcription factors play key role, therefore understanding the regulation of these genes might provide useful knowledge for molecular breeding. In the present study the signal transduction pathways leading to the cold induction of different CBF genes were investigated in barley cv. Nure using pharmacological approach. Our results showed that the cold induced expression of CBF9 and CBF14 transcription factors is regulated by phospholipase C, phospholipase D pathways and calcium. On the contrary, these pathways have negative effect on the cold induction of CBF12 that is regulated by a different, as yet unidentified pathway. The diversity in the regulation of these transcription factors corresponds to their sequence based phylogenetic relationships suggesting that their evolutionary separation happened on structural, functional and regulational levels as well. On the CBF effector gene level, the signaling regulation is more complex, resultant effect of multiple pathways. Copyright © 2015 Elsevier GmbH. All rights reserved.

c-Met must translocate to the nucleus to initiate calcium signals.

PubMed

Gomes, Dawidson A; Rodrigues, Michele A; Leite, M Fatima; Gomez, Marcus V; Varnai, Peter; Balla, Tamas; Bennett, Anton M; Nathanson, Michael H

2008-02-15

Hepatocyte growth factor (HGF) is important for cell proliferation, differentiation, and related activities. HGF acts through its receptor c-Met, which activates downstream signaling pathways. HGF binds to c-Met at the plasma membrane, where it is generally believed that c-Met signaling is initiated. Here we report that c-Met rapidly translocates to the nucleus upon stimulation with HGF. Ca(2+) signals that are induced by HGF result from phosphatidylinositol 4,5-bisphosphate hydrolysis and inositol 1,4,5-trisphosphate formation within the nucleus rather than within the cytoplasm. Translocation of c-Met to the nucleus depends upon the adaptor protein Gab1 and importin beta1, and formation of Ca(2+) signals in turn depends upon this translocation. HGF may exert its particular effects on cells because it bypasses signaling pathways in the cytoplasm to directly activate signaling pathways in the nucleus.

Social power, conflict policing, and the role of subordination signals in rhesus macaque society

PubMed Central

Beisner, Brianne A.; Hannibal, Darcy L.; Finn, Kelly R.; Fushing, Hsieh; McCowan, Brenda

2017-01-01

Objectives Policing is a conflict-limiting mechanism observed in many primate species. It is thought to require a skewed distribution of social power for some individuals to have sufficiently high social power to stop others’ fights, yet social power has not been examined in most species with policing behavior. We examined networks of subordination signals as a source of social power that permits policing behavior in rhesus macaques. Materials and Methods For each of seven captive groups of rhesus macaques, we (a) examined the structure of subordination signal networks and used GLMs to examine the relationship between (b) pairwise dominance certainty and subordination network pathways and (c) policing frequency and social power (group-level convergence in subordination signaling pathways). Results Networks of subordination signals had perfect linear transitivity, and pairs connected by both direct and indirect pathways of signals had more certain dominance relationships than pairs with no such network connection. Social power calculated using both direct and indirect network pathways showed a heavy-tailed distribution and positively predicted conflict policing. Conclusions Our results empirically substantiate that subordination signaling is associated with greater dominance relationship certainty and further show that pairs who signal rarely (or not at all) may use information from others’ signaling interactions to infer or reaffirm the relative certainty of their own relationships. We argue that the network of formal dominance relationships is central to societal stability because it is important for relationship stability and also supports the additional stabilizing mechanism of policing. PMID:26801956

A hidden oncogenic positive feedback loop caused by crosstalk between Wnt and ERK pathways.

PubMed

Kim, D; Rath, O; Kolch, W; Cho, K-H

2007-07-05

The Wnt and the extracellular signal regulated-kinase (ERK) pathways are both involved in the pathogenesis of various kinds of cancers. Recently, the existence of crosstalk between Wnt and ERK pathways was reported. Gathering all reported results, we have discovered a positive feedback loop embedded in the crosstalk between the Wnt and ERK pathways. We have developed a plausible model that represents the role of this hidden positive feedback loop in the Wnt/ERK pathway crosstalk based on the integration of experimental reports and employing established basic mathematical models of each pathway. Our analysis shows that the positive feedback loop can generate bistability in both the Wnt and ERK signaling pathways, and this prediction was further validated by experiments. In particular, using the commonly accepted assumption that mutations in signaling proteins contribute to cancerogenesis, we have found two conditions through which mutations could evoke an irreversible response leading to a sustained activation of both pathways. One condition is enhanced production of beta-catenin, the other is a reduction of the velocity of MAP kinase phosphatase(s). This enables that high activities of Wnt and ERK pathways are maintained even without a persistent extracellular signal. Thus, our study adds a novel aspect to the molecular mechanisms of carcinogenesis by showing that mutational changes in individual proteins can cause fundamental functional changes well beyond the pathway they function in by a positive feedback loop embedded in crosstalk. Thus, crosstalk between signaling pathways provides a vehicle through which mutations of individual components can affect properties of the system at a larger scale.

Update on Staphylococcal Superantigen-Induced Signaling Pathways and Therapeutic Interventions

PubMed Central

Krakauer, Teresa

2013-01-01

Staphylococcal enterotoxin B (SEB) and related bacterial toxins cause diseases in humans and laboratory animals ranging from food poisoning, acute lung injury to toxic shock. These superantigens bind directly to the major histocompatibility complex class II molecules on antigen-presenting cells and specific Vβ regions of T-cell receptors (TCR), resulting in rapid hyper-activation of the host immune system. In addition to TCR and co-stimulatory signals, proinflammatory mediators activate signaling pathways culminating in cell-stress response, activation of NFκB and mammalian target of rapamycin (mTOR). This article presents a concise review of superantigen-activated signaling pathways and focuses on the therapeutic challenges against bacterial superantigens. PMID:24064719

Exploring differentially expressed genes related to metabolism by RNA-Seq in goat liver after dexamethasone treatment.

PubMed

Chen, Qu; Hua, Canfeng; Niu, Liqiong; Geng, Yali; Cai, Liuping; Tao, Shiyu; Ni, Yingdong; Zhao, Ruqian

2018-06-15

Chronic stress severely threatens the welfare and health of animals and humans. In order to study the effects of chronic stress on metabolism, de novo transcriptome sequencing was used to generate the expressed sequence tag dataset for the goat, using nextgeneration sequencing technology. For this study, consecutive dexamethasone (Dex) injection was used in 10 healthy male goats (body weight 25 ± 1.0 kg) to mimic chronic stress. Ten male goats were randomly assigned into two groups, one group was injected intramuscularly with the same volume of saline as control (Con) group, and another (Dex) group was injected intramuscularly with 0.2 mg/kg Dex for 21 days. To elucidate the resulting changes in genes, transcriptome profiling of liver was conducted by analysing samples from three goats of each group using RNA-Seq. A total of 137 differentially expressed genes (DEGs) were identified between Con group and Dex group. GO classification showed rhythmic process and hormone secretion in term cellular, and chemoattractant activity in term molecular function had noticeable differences in the proportion between DEGs and all genes. By mapping the DEGs to the COG database, we found that general function prediction only, energy production and conversion, and amino acid transport and metabolism were the most frequently represented functional clusters. We mapped the unigenes to the KEGG pathway database and found most annotated genes were involved in the AMPK signalling pathway as well as pathways in cancer and insulin signalling pathway. Via KEGG enrichment analysis, we found the DEGs were significantly enriched in insulin signalling pathway, AMPK signalling pathway and adipocytokine signalling pathway. In addition, these pathways have close relationship with metabolism, which resulted in metabolic changes in which the identified DEGs may play important roles. These results provide valuable information for further research on the complex molecular mechanisms of dexamethasone in goats and will provide a foundation for future studies. Copyright © 2018 Elsevier B.V. All rights reserved.

A MicroRNA-Mediated Insulin Signaling Pathway Regulates the Toxicity of Multi-Walled Carbon Nanotubes in Nematode Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Zhao, Yunli; Yang, Junnian; Wang, Dayong

2016-03-01

The underlying mechanisms for functions of microRNAs (miRNAs) in regulating toxicity of nanomaterials are largely unclear. Using Illumina HiSeqTM 2000 sequencing technique, we obtained the dysregulated mRNA profiling in multi-walled carbon nanotubes (MWCNTs) exposed nematodes. Some dysregulated genes encode insulin signaling pathway. Genetic experiments confirmed the functions of these dysregulated genes in regulating MWCNTs toxicity. In the insulin signaling pathway, DAF-2/insulin receptor regulated MWCNTs toxicity by suppressing function of DAF-16/FOXO transcription factor. Moreover, we raised a miRNAs-mRNAs network involved in the control of MWCNTs toxicity. In this network, mir-355 might regulate MWCNTs toxicity by inhibiting functions of its targeted gene of daf-2, suggesting that mir-355 may regulate functions of the entire insulin signaling pathway by acting as an upregulator of DAF-2, the initiator of insulin signaling pathway, in MWCNTs exposed nematodes. Our results provides highlight on understanding the crucial role of miRNAs in regulating toxicity of nanomaterials in organisms.

A MicroRNA-Mediated Insulin Signaling Pathway Regulates the Toxicity of Multi-Walled Carbon Nanotubes in Nematode Caenorhabditis elegans

PubMed Central

Zhao, Yunli; Yang, Junnian; Wang, Dayong

2016-01-01

The underlying mechanisms for functions of microRNAs (miRNAs) in regulating toxicity of nanomaterials are largely unclear. Using Illumina HiSeqTM 2000 sequencing technique, we obtained the dysregulated mRNA profiling in multi-walled carbon nanotubes (MWCNTs) exposed nematodes. Some dysregulated genes encode insulin signaling pathway. Genetic experiments confirmed the functions of these dysregulated genes in regulating MWCNTs toxicity. In the insulin signaling pathway, DAF-2/insulin receptor regulated MWCNTs toxicity by suppressing function of DAF-16/FOXO transcription factor. Moreover, we raised a miRNAs-mRNAs network involved in the control of MWCNTs toxicity. In this network, mir-355 might regulate MWCNTs toxicity by inhibiting functions of its targeted gene of daf-2, suggesting that mir-355 may regulate functions of the entire insulin signaling pathway by acting as an upregulator of DAF-2, the initiator of insulin signaling pathway, in MWCNTs exposed nematodes. Our results provides highlight on understanding the crucial role of miRNAs in regulating toxicity of nanomaterials in organisms. PMID:26984256

Bmp signaling mediates endoderm pouch morphogenesis by regulating Fgf signaling in zebrafish.

PubMed

Lovely, C Ben; Swartz, Mary E; McCarthy, Neil; Norrie, Jacqueline L; Eberhart, Johann K

2016-06-01

The endodermal pouches are a series of reiterated structures that segment the pharyngeal arches and help pattern the vertebrate face. Multiple pathways regulate the complex process of endodermal development, including the Bone morphogenetic protein (Bmp) pathway. However, the role of Bmp signaling in pouch morphogenesis is poorly understood. Using genetic and chemical inhibitor approaches, we show that pouch morphogenesis requires Bmp signaling from 10-18 h post-fertilization, immediately following gastrulation. Blocking Bmp signaling during this window results in morphological defects to the pouches and craniofacial skeleton. Using genetic chimeras we show that Bmp signals directly to the endoderm for proper morphogenesis. Time-lapse imaging and analysis of reporter transgenics show that Bmp signaling is necessary for pouch outpocketing via the Fibroblast growth factor (Fgf) pathway. Double loss-of-function analyses demonstrate that Bmp and Fgf signaling interact synergistically in craniofacial development. Collectively, our analyses shed light on the tissue and signaling interactions that regulate development of the vertebrate face. © 2016. Published by The Company of Biologists Ltd.

Bmp signaling mediates endoderm pouch morphogenesis by regulating Fgf signaling in zebrafish

PubMed Central

Swartz, Mary E.; McCarthy, Neil; Norrie, Jacqueline L.; Eberhart, Johann K.

2016-01-01

The endodermal pouches are a series of reiterated structures that segment the pharyngeal arches and help pattern the vertebrate face. Multiple pathways regulate the complex process of endodermal development, including the Bone morphogenetic protein (Bmp) pathway. However, the role of Bmp signaling in pouch morphogenesis is poorly understood. Using genetic and chemical inhibitor approaches, we show that pouch morphogenesis requires Bmp signaling from 10-18 h post-fertilization, immediately following gastrulation. Blocking Bmp signaling during this window results in morphological defects to the pouches and craniofacial skeleton. Using genetic chimeras we show that Bmp signals directly to the endoderm for proper morphogenesis. Time-lapse imaging and analysis of reporter transgenics show that Bmp signaling is necessary for pouch outpocketing via the Fibroblast growth factor (Fgf) pathway. Double loss-of-function analyses demonstrate that Bmp and Fgf signaling interact synergistically in craniofacial development. Collectively, our analyses shed light on the tissue and signaling interactions that regulate development of the vertebrate face. PMID:27122171

E3 ubiquitin ligase Mule targets β-catenin under conditions of hyperactive Wnt signaling

PubMed Central

Dominguez-Brauer, Carmen; Khatun, Rahima; Elia, Andrew J.; Thu, Kelsie L.; Ramachandran, Parameswaran; Baniasadi, Shakiba P.; Hao, Zhenyue; Jones, Lisa D.; Haight, Jillian; Sheng, Yi; Mak, Tak W.

2017-01-01

Wnt signaling, named after the secreted proteins that bind to cell surface receptors to activate the pathway, plays critical roles both in embryonic development and the maintenance of homeostasis in many adult tissues. Two particularly important cellular programs orchestrated by Wnt signaling are proliferation and stem cell self-renewal. Constitutive activation of the Wnt pathway resulting from mutation or improper modulation of pathway components contributes to cancer development in various tissues. Colon cancers frequently bear inactivating mutations of the adenomatous polyposis coli (APC) gene, whose product is an important component of the destruction complex that regulates β-catenin levels. Stabilization and nuclear localization of β-catenin result in the expression of a panel of Wnt target genes. We previously showed that Mule/Huwe1/Arf-BP1 (Mule) controls murine intestinal stem and progenitor cell proliferation by modulating the Wnt pathway via c-Myc. Here we extend our investigation of Mule’s influence on oncogenesis by showing that Mule interacts directly with β-catenin and targets it for degradation under conditions of hyperactive Wnt signaling. Our findings suggest that Mule uses various mechanisms to fine-tune the Wnt pathway and provides multiple safeguards against tumorigenesis. PMID:28137882

E3 ubiquitin ligase Mule targets β-catenin under conditions of hyperactive Wnt signaling.

PubMed

Dominguez-Brauer, Carmen; Khatun, Rahima; Elia, Andrew J; Thu, Kelsie L; Ramachandran, Parameswaran; Baniasadi, Shakiba P; Hao, Zhenyue; Jones, Lisa D; Haight, Jillian; Sheng, Yi; Mak, Tak W

2017-02-14

Wnt signaling, named after the secreted proteins that bind to cell surface receptors to activate the pathway, plays critical roles both in embryonic development and the maintenance of homeostasis in many adult tissues. Two particularly important cellular programs orchestrated by Wnt signaling are proliferation and stem cell self-renewal. Constitutive activation of the Wnt pathway resulting from mutation or improper modulation of pathway components contributes to cancer development in various tissues. Colon cancers frequently bear inactivating mutations of the adenomatous polyposis coli ( APC ) gene, whose product is an important component of the destruction complex that regulates β-catenin levels. Stabilization and nuclear localization of β-catenin result in the expression of a panel of Wnt target genes. We previously showed that Mule/Huwe1/Arf-BP1 (Mule) controls murine intestinal stem and progenitor cell proliferation by modulating the Wnt pathway via c-Myc. Here we extend our investigation of Mule's influence on oncogenesis by showing that Mule interacts directly with β-catenin and targets it for degradation under conditions of hyperactive Wnt signaling. Our findings suggest that Mule uses various mechanisms to fine-tune the Wnt pathway and provides multiple safeguards against tumorigenesis.

Differential and directional estrogenic signaling pathways induced by enterolignans and their precursors

PubMed Central

Zhu, Yun; Kawaguchi, Kayoko; Kiyama, Ryoiti

2017-01-01

Mammalian lignans or enterolignans are metabolites of plant lignans, an important category of phytochemicals. Although they are known to be associated with estrogenic activity, cell signaling pathways leading to specific cell functions, and especially the differences among lignans, have not been explored. We examined the estrogenic activity of enterolignans and their precursor plant lignans and cell signaling pathways for some cell functions, cell cycle and chemokine secretion. We used DNA microarray-based gene expression profiling in human breast cancer MCF-7 cells to examine the similarities, as well as the differences, among enterolignans, enterolactone and enterodiol, and their precursors, matairesinol, pinoresinol and sesamin. The profiles showed moderate to high levels of correlation (R values: 0.44 to 0.81) with that of estrogen (17β-estradiol or E2). Significant correlations were observed among lignans (R values: 0.77 to 0.97), and the correlations were higher for cell functions related to enzymes, signaling, proliferation and transport. All the enterolignans/precursors examined showed activation of the Erk1/2 and PI3K/Akt pathways, indicating the involvement of rapid signaling through the non-genomic estrogen signaling pathway. However, when their effects on specific cell functions, cell cycle progression and chemokine (MCP-1) secretion were examined, positive effects were observed only for enterolactone, suggesting that signals are given in certain directions at a position closer to cell functions. We hypothesized that, while estrogen signaling is initiated by the enterolignans/precursors examined, their signals are differentially and directionally modulated later in the pathways, resulting in the differences at the cell function level. PMID:28152041

Assessing the relevance of light for fungi: Implications and insights into the network of signal transmission.

PubMed

Schmoll, Monika

2011-01-01

Light represents an important environmental cue, which provides information enabling fungi to prepare and react to the different ambient conditions between day and night. This adaptation requires both anticipation of the changing conditions, which is accomplished by daily rhythmicity of gene expression brought about by the circadian clock, and reaction to sudden illumination. Besides perception of the light signal, also integration of this signal with other environmental cues, most importantly nutrient availability, necessitates light-dependent regulation of signal transduction pathways and metabolic pathways. An influence of light and/or the circadian clock is known for the cAMP pathway, heterotrimeric G-protein signaling, mitogen-activated protein kinases, two-component phosphorelays, and Ca(2+) signaling. Moreover, also the target of rapamycin signaling pathway and reactive oxygen species as signal transducing elements are assumed to be connected to the light-response pathway. The interplay of the light-response pathway with signaling cascades results in light-dependent regulation of primary and secondary metabolism, morphology, development, biocontrol activity, and virulence. The frequent use of fungi in biotechnology as well as analysis of fungi in the artificial environment of a laboratory therefore requires careful consideration of still operative evolutionary heritage of these organisms. This review summarizes the diverse effects of light on fungi and the mechanisms they apply to deal both with the information content and with the harmful properties of light. Additionally, the implications of the reaction of fungi to light in a laboratory environment for experimental work and industrial applications are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

PI3K-AKT signaling pathway is involved in hypoxia/thermal-induced immunosuppression of small abalone Haliotis diversicolor.

PubMed

Sun, Yulong; Zhang, Xin; Wang, Guodong; Lin, Shi; Zeng, Xinyang; Wang, Yilei; Zhang, Ziping

2016-12-01

The PI3K-AKT signal pathway has been found to be involved in many important physiological and pathological processes of the innate immune system of vertebrates and invertebrates. In this study, the AKT (HdAKT) and PI3K (HdPI3K) gene of small abalone Haliotis diversicolor were cloned and characterized for the important status of PI3K and AKT protein in PI3K-AKT signaling pathway. The full length cDNAs of HdAKT and HdPI3K are 2126 bp and 6052 bp respectively, encoding proteins of 479 amino acids and 1097 amino acids, respectively. The mRNA expression level of fourteen genes in the PI3K-AKT signaling pathway were detected by quantitative real-time PCR. The results showed that all these fourteen genes were ubiquitously expressed in seven selected tissues. Meanwhile, HdAKT was expressed in haemocytes with the highest expression level (p < 0.05) next in hepatopancreas (p < 0.05). On the other hand, the expression level of HdPI3K in haemocytes was higher than other tissues. Under normal condition, the gene expression level of HdAKT, HdPI3K, and other PI3K-AKT signaling pathway members were significantly up-regulated by Vibrio parahaemolyticus infection which demonstrated that HdAKT, HdPI3K, and other PI3K-AKT signaling pathway members play a role in the innate immune system of abalone. The mRNA expression of these genes in gills, haemocytes and hepatopancreas was significantly down-regulated after the Vibrio parahaemolyticus stimulation with environment stimulation (thermal, hypoxia and thermal & hypoxia). These results indicate that the dual/multiple stresses defeat the immune system and lead to immunosuppression in abalone. PI3K-AKT signaling pathway may be involved in hypoxia/thermal-induced immunosuppression of small abalone Haliotis diversicolor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Floral pathway integrator gene expression mediates gradual transmission of environmental and endogenous cues to flowering time.

PubMed

van Dijk, Aalt D J; Molenaar, Jaap

2017-01-01

The appropriate timing of flowering is crucial for the reproductive success of plants. Hence, intricate genetic networks integrate various environmental and endogenous cues such as temperature or hormonal statues. These signals integrate into a network of floral pathway integrator genes. At a quantitative level, it is currently unclear how the impact of genetic variation in signaling pathways on flowering time is mediated by floral pathway integrator genes. Here, using datasets available from literature, we connect Arabidopsis thaliana flowering time in genetic backgrounds varying in upstream signalling components with the expression levels of floral pathway integrator genes in these genetic backgrounds. Our modelling results indicate that flowering time depends in a quite linear way on expression levels of floral pathway integrator genes. This gradual, proportional response of flowering time to upstream changes enables a gradual adaptation to changing environmental factors such as temperature and light.

Signaling Pathways Involved in the Regulation of mRNA Translation

PubMed Central

2018-01-01

ABSTRACT Translation is a key step in the regulation of gene expression and one of the most energy-consuming processes in the cell. In response to various stimuli, multiple signaling pathways converge on the translational machinery to regulate its function. To date, the roles of phosphoinositide 3-kinase (PI3K)/AKT and the mitogen-activated protein kinase (MAPK) pathways in the regulation of translation are among the best understood. Both pathways engage the mechanistic target of rapamycin (mTOR) to regulate a variety of components of the translational machinery. While these pathways regulate protein synthesis in homeostasis, their dysregulation results in aberrant translation leading to human diseases, including diabetes, neurological disorders, and cancer. Here we review the roles of the PI3K/AKT and MAPK pathways in the regulation of mRNA translation. We also highlight additional signaling mechanisms that have recently emerged as regulators of the translational apparatus. PMID:29610153

Tuning of major signaling networks (TGF-β, Wnt, Notch and Hedgehog) by miRNAs in human stem cells commitment to different lineages: Possible clinical application.

PubMed

Aval, Sedigheh Fekri; Lotfi, Hajie; Sheervalilou, Roghayeh; Zarghami, Nosratollah

2017-07-01

Two distinguishing characteristics of stem cells, their continuous division in the undifferentiated state and growth into any cell types, are orchestrated by a number of cell signaling pathways. These pathways act as a niche factor in controlling variety of stem cells. The core stem cell signaling pathways include Wingless-type (Wnt), Hedgehog (HH), and Notch. Additionally, they critically regulate the self-renewal and survival of cancer stem cells. Conversely, stem cells' main properties, lineage commitment and stemness, are tightly controlled by epigenetic mechanisms such as DNA methylation, histone modifications and non-coding RNA-mediated regulatory events. MicroRNAs (miRNAs) are cellular switches that modulate stem cells outcomes in response to diverse extracellular signals. Numerous scientific evidences implicating miRNAs in major signal transduction pathways highlight new crosstalks of cellular processes. Aberrant signaling pathways and miRNAs levels result in developmental defects and diverse human pathologies. This review discusses the crosstalk between the components of main signaling networks and the miRNA machinery, which plays a role in the context of stem cells development and provides a set of examples to illustrate the extensive relevance of potential novel therapeutic targets. Copyright © 2017. Published by Elsevier Masson SAS.

Knowledge-guided fuzzy logic modeling to infer cellular signaling networks from proteomic data

PubMed Central

Liu, Hui; Zhang, Fan; Mishra, Shital Kumar; Zhou, Shuigeng; Zheng, Jie

2016-01-01

Modeling of signaling pathways is crucial for understanding and predicting cellular responses to drug treatments. However, canonical signaling pathways curated from literature are seldom context-specific and thus can hardly predict cell type-specific response to external perturbations; purely data-driven methods also have drawbacks such as limited biological interpretability. Therefore, hybrid methods that can integrate prior knowledge and real data for network inference are highly desirable. In this paper, we propose a knowledge-guided fuzzy logic network model to infer signaling pathways by exploiting both prior knowledge and time-series data. In particular, the dynamic time warping algorithm is employed to measure the goodness of fit between experimental and predicted data, so that our method can model temporally-ordered experimental observations. We evaluated the proposed method on a synthetic dataset and two real phosphoproteomic datasets. The experimental results demonstrate that our model can uncover drug-induced alterations in signaling pathways in cancer cells. Compared with existing hybrid models, our method can model feedback loops so that the dynamical mechanisms of signaling networks can be uncovered from time-series data. By calibrating generic models of signaling pathways against real data, our method supports precise predictions of context-specific anticancer drug effects, which is an important step towards precision medicine. PMID:27774993

Cyclic Nucleotide Phosphodiesterases: important signaling modulators and therapeutic targets

PubMed Central

Ahmad, Faiyaz; Murata, Taku; Simizu, Kasumi; Degerman, Eva; Maurice, Donald; Manganiello, Vincent

2014-01-01

By catalyzing hydrolysis of cAMP and cGMP, cyclic nucleotide phosphodiesterases are critical regulators of their intracellular concentrations and their biological effects. Since these intracellular second messengers control many cellular homeostatic processes, dysregulation of their signals and signaling pathways initiate or modulate pathophysiological pathways related to various disease states, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication, chronic obstructive pulmonary disease, and psoriasis. Alterations in expression of PDEs and PDE-gene mutations (especially mutations in PDE6, PDE8B, PDE11A and PDE4) have been implicated in various diseases and cancer pathologies. PDEs also play important role in formation and function of multi-molecular signaling/regulatory complexes called signalosomes. At specific intracellular locations, individual PDEs, together with pathway-specific signaling molecules, regulators, and effectors, are incorporated into specific signalosomes, where they facilitate and regulate compartmentalization of cyclic nucleotide signaling pathways and specific cellular functions. Currently, only a limited number of PDE inhibitors (PDE3, PDE4, PDE5 inhibitors) are used in clinical practice. Future paths to novel drug discovery include the crystal structure-based design approach, which has resulted in generation of more effective family-selective inhibitors, as well as burgeoning development of strategies to alter compartmentalized cyclic nucleotide signaling pathways by selectively targeting individual PDEs and their signalosome partners. PMID:25056711

Activation of the Hedgehog Signaling Pathway in the Developing Lens Stimulates Ectopic FoxE3 Expression and Disruption in Fiber Cell Differentiation

PubMed Central

Kerr, Christine L.; Huang, Jian; Williams, Trevor; West-Mays, Judith A.

2012-01-01

Purpose. The signaling pathways and transcriptional effectors responsible for directing mammalian lens development provide key regulatory molecules that can inform our understanding of human eye defects. The hedgehog genes encode extracellular signaling proteins responsible for patterning and tissue formation during embryogenesis. Signal transduction of this pathway is mediated through activation of the transmembrane proteins smoothened and patched, stimulating downstream signaling resulting in the activation or repression of hedgehog target genes. Hedgehog signaling is implicated in eye development, and defects in hedgehog signaling components have been shown to result in defects of the retina, iris, and lens. Methods. We assessed the consequences of constitutive hedgehog signaling in the developing mouse lens using Cre-LoxP technology to express the conditional M2 smoothened allele in the embryonic head and lens ectoderm. Results. Although initial lens development appeared normal, morphological defects were apparent by E12.5 and became more significant at later stages of embryogenesis. Altered lens morphology correlated with ectopic expression of FoxE3, which encodes a critical gene required for human and mouse lens development. Later, inappropriate expression of the epithelial marker Pax6, and as well as fiber cell markers c-maf and Prox1 also occurred, indicating a failure of appropriate lens fiber cell differentiation accompanied by altered lens cell proliferation and cell death. Conclusions. Our findings demonstrate that the ectopic activation of downstream effectors of the hedgehog signaling pathway in the mouse lens disrupts normal fiber cell differentiation by a mechanism consistent with a sustained epithelial cellular developmental program driven by FoxE3. PMID:22491411

Modeling evolution of crosstalk in noisy signal transduction networks

NASA Astrophysics Data System (ADS)

Tareen, Ammar; Wingreen, Ned S.; Mukhopadhyay, Ranjan

2018-02-01

Signal transduction networks can form highly interconnected systems within cells due to crosstalk between constituent pathways. To better understand the evolutionary design principles underlying such networks, we study the evolution of crosstalk for two parallel signaling pathways that arise via gene duplication. We use a sequence-based evolutionary algorithm and evolve the network based on two physically motivated fitness functions related to information transmission. We find that one fitness function leads to a high degree of crosstalk while the other leads to pathway specificity. Our results offer insights on the relationship between network architecture and information transmission for noisy biomolecular networks.

A cardiac pathway of cyclic GMP-independent signaling of guanylyl cyclase A, the receptor for atrial natriuretic peptide

PubMed Central

Klaiber, Michael; Dankworth, Beatrice; Kruse, Martin; Hartmann, Michael; Nikolaev, Viacheslav O.; Yang, Ruey-Bing; Völker, Katharina; Gaßner, Birgit; Oberwinkler, Heike; Feil, Robert; Freichel, Marc; Groschner, Klaus; Skryabin, Boris V.; Frantz, Stefan; Birnbaumer, Lutz; Pongs, Olaf; Kuhn, Michaela

2011-01-01

Cardiac atrial natriuretic peptide (ANP) regulates arterial blood pressure, moderates cardiomyocyte growth, and stimulates angiogenesis and metabolism. ANP binds to the transmembrane guanylyl cyclase (GC) receptor, GC-A, to exert its diverse functions. This process involves a cGMP-dependent signaling pathway preventing pathological [Ca2+]i increases in myocytes. In chronic cardiac hypertrophy, however, ANP levels are markedly increased and GC-A/cGMP responses to ANP are blunted due to receptor desensitization. Here we show that, in this situation, ANP binding to GC-A stimulates a unique cGMP-independent signaling pathway in cardiac myocytes, resulting in pathologically elevated intracellular Ca2+ levels. This pathway involves the activation of Ca2+‐permeable transient receptor potential canonical 3/6 (TRPC3/C6) cation channels by GC-A, which forms a stable complex with TRPC3/C6 channels. Our results indicate that the resulting cation influx activates voltage-dependent L-type Ca2+ channels and ultimately increases myocyte Ca2+i levels. These observations reveal a dual role of the ANP/GC-A–signaling pathway in the regulation of cardiac myocyte Ca2+i homeostasis. Under physiological conditions, activation of a cGMP-dependent pathway moderates the Ca2+i-enhancing action of hypertrophic factors such as angiotensin II. By contrast, a cGMP-independent pathway predominates under pathophysiological conditions when GC-A is desensitized by high ANP levels. The concomitant rise in [Ca2+]i might increase the propensity to cardiac hypertrophy and arrhythmias. PMID:22027011

Multiple intracellular signaling pathways orchestrate adipocytic differentiation of human bone marrow stromal stem cells.

PubMed

Ali, Dalia; Abuelreich, Sarah; Alkeraishan, Nora; Shwish, Najla Bin; Hamam, Rimi; Kassem, Moustapha; Alfayez, Musaad; Aldahmash, Abdullah; Alajez, Nehad M

2018-02-28

Bone marrow adipocyte formation plays a role in bone homeostasis and whole body energy metabolism. However, the transcriptional landscape and signaling pathways associated with adipocyte lineage commitment and maturation are not fully delineated. Thus, we performed global gene expression profiling during adipocyte differentiation of human bone marrow stromal (mesenchymal) stem cells (hMSCs) and identified 2,589 up-regulated and 2,583 down-regulated mRNA transcripts. Pathway analysis on the up-regulated gene list untraveled enrichment in multiple signaling pathways including insulin receptor signaling, focal Adhesion, metapathway biotransformation, a number of metabolic pathways e.g. selenium metabolism, Benzo(a)pyrene metabolism, fatty acid, triacylglycerol, ketone body metabolism, tryptophan metabolism, and catalytic cycle of mammalian flavin-containing monooxygenase (FMOs). On the other hand, pathway analysis on the down-regulated genes revealed significant enrichment in pathways related to cell cycle regulation. Based on these data, we assessed the effect of pharmacological inhibition of FAK signaling using PF-573228, PF-562271, and InsR/IGF-1R using NVP-AEW541 and GSK-1904529A on adipocyte differentiation. hMSCs exposed to FAK or IGF-1R/InsR inhibitors exhibited fewer adipocyte formation (27-58% inhibition, P <0005). Concordantly, the expression of adipocyte-specific genes AP2, AdipoQ, and CEBPα was significantly reduced. On the other hand, we did not detect significant effects on cell viability as a result of FAK or IGF-1R/InsR inhibition. Our data identified FAK and insulin signaling as important intracellular signaling pathways relevant to bone marrow adipogenesis. © 2018 The Author(s).

The impact of Wnt signalling and hypoxia on osteogenic and cementogenic differentiation in human periodontal ligament cells

PubMed Central

Li, Shuigen; Shao, Jin; Zhou, Yinghong; Friis, Thor; Yao, Jiangwu; Shi, Bin; Xiao, Yin

2016-01-01

Cementum is a periodontal support tissue that is directly connected to the periodontal ligament. It shares common traits with bone tissues, however, unlike bone, the cementum has a limited capacity for regeneration. As a result, following damage the cementum rarely, if ever, regenerates. Periodontal ligament cells (PDLCs) are able to differentiate into osteoblastic and cementogenic lineages according to specific local environmental conditions, including hypoxia, which is induced by inflammation or activation of the Wnt signalling pathway by local loading. The interactions between the Wnt signalling pathway and hypoxia during cementogenesis are of particular interest to improve the understanding of periodontal tissue regeneration. In the present study, osteogenic and cementogenic differentiation of PDLCs was investigated under hypoxic conditions in the presence and absence of Wnt pathway activation. Protein and gene expression of the osteogenic markers type 1 collagen (COL1) and runt-related transcription factor 2 (RUNX2), and cementum protein 1 (CEMP1) were used as markers for osteogenic and cementogenic differentiation, respectively. Wnt signalling activation inhibited cementogenesis, whereas hypoxia alone did not affect PDLC differentiation. However, hypoxia reversed the inhibition of cementogenesis that resulted from overexpression of Wnt signalling. Cross-talk between hypoxia and Wnt signalling pathways was, therefore, demonstrated to be involved in the differentiation of PDLCs to the osteogenic and cementogenic lineages. In summary, the present study suggests that the differentiation of PDLCs into osteogenic and cementogenic lineages is partially regulated by the Wnt signalling pathway and that hypoxia is also involved in this process. PMID:27840938

Novel applications of trophic factors, Wnt and WISP for neuronal repair and regeneration in metabolic disease

PubMed Central

Maiese, Kenneth

2015-01-01

Diabetes mellitus affects almost 350 million individuals throughout the globe resulting in significant morbidity and mortality. Of further concern is the growing population of individuals that remain undiagnosed but are susceptible to the detrimental outcomes of this disorder. Diabetes mellitus leads to multiple complications in the central and peripheral nervous systems that include cognitive impairment, retinal disease, neuropsychiatric disease, cerebral ischemia, and peripheral nerve degeneration. Although multiple strategies are being considered, novel targeting of trophic factors, Wnt signaling, Wnt1 inducible signaling pathway protein 1, and stem cell tissue regeneration are considered to be exciting prospects to overcome the cellular mechanisms that lead to neuronal injury in diabetes mellitus involving oxidative stress, apoptosis, and autophagy. Pathways that involve insulin-like growth factor-1, fibroblast growth factor, epidermal growth factor, and erythropoietin can govern glucose homeostasis and are intimately tied to Wnt signaling that involves Wnt1 and Wnt1 inducible signaling pathway protein 1 (CCN4) to foster control over stem cell proliferation, wound repair, cognitive decline, β-cell proliferation, vascular regeneration, and programmed cell death. Ultimately, cellular metabolism through Wnt signaling is driven by primary metabolic pathways of the mechanistic target of rapamycin and AMP activated protein kinase. These pathways offer precise biological control of cellular metabolism, but are exquisitely sensitive to the different components of Wnt signaling. As a result, unexpected clinical outcomes can ensue and therefore demand careful translation of the mechanisms that govern neural repair and regeneration in diabetes mellitus. PMID:26170801

A Model of an Integrated Immune System Pathway in Homo sapiens and Its Interaction with Superantigen Producing Expression Regulatory Pathway in Staphylococcus aureus: Comparing Behavior of Pathogen Perturbed and Unperturbed Pathway

PubMed Central

Tomar, Namrata; De, Rajat K.

2013-01-01

Response of an immune system to a pathogen attack depends on the balance between the host immune defense and the virulence of the pathogen. Investigation of molecular interactions between the proteins of a host and a pathogen helps in identifying the pathogenic proteins. It is necessary to understand the dynamics of a normally behaved host system to evaluate the capacity of its immune system upon pathogen attack. In this study, we have compared the behavior of an unperturbed and pathogen perturbed host system. Moreover, we have developed a formalism under Flux Balance Analysis (FBA) for the optimization of conflicting objective functions. We have constructed an integrated pathway system, which includes Staphylococcal Superantigen (SAg) expression regulatory pathway and TCR signaling pathway of Homo sapiens. We have implemented the method on this pathway system and observed the behavior of host signaling molecules upon pathogen attack. The entire study has been divided into six different cases, based on the perturbed/unperturbed conditions. In other words, we have investigated unperturbed and pathogen perturbed human TCR signaling pathway, with different combinations of optimization of concentrations of regulatory and signaling molecules. One of these cases has aimed at finding out whether minimization of the toxin production in a pathogen leads to the change in the concentration levels of the proteins coded by TCR signaling pathway genes in the infected host. Based on the computed results, we have hypothesized that the balance between TCR signaling inhibitory and stimulatory molecules can keep TCR signaling system into resting/stimulating state, depending upon the perturbation. The proposed integrated host-pathogen interaction pathway model has accurately reflected the experimental evidences, which we have used for validation purpose. The significance of this kind of investigation lies in revealing the susceptible interaction points that can take back the Staphylococcal Enterotoxin (SE)-challenged system within the range of normal behavior. PMID:24324645

A Systematic Review of Known Mechanisms of Hydroxyurea-induced Foetal Haemoglobin for Treatment of Sickle Cell Disease

PubMed Central

Pule, Gift D.; Mowla, Shaheen; Novitzky, Nicolas; Wiysonge, Charles S.; Wonkam, Ambroise

2016-01-01

Aims To report on molecular mechanisms of foetal haemoglobin (HbF) induction by hydroxyurea (HU) for the treatment of Sickle Cell Disease (SCD). Study Design Systematic review. Results Studies have provided consistent associations between genomic variations in HbF-promoting loci and variable HbF level in response to HU. Numerous signal transduction pathways have been implicated, through the identification of key genomic variants in BCL11A, HBS1L-MYB, SAR1 or XmnI polymorphism that predispose the response to the treatment, and signal transduction pathways, that modulate γ-globin expression (cAMP/cGMP; Giα/JNK/Jun; methylation and microRNA). Three main molecular pathways have been reported: 1) Epigenetic modifications, transcriptional events and signalling pathways involved in HU-mediated response, 2) Signalling pathways involving HU-mediated response and 3) Post-transcriptional pathways (regulation by microRNAs). Conclusions The complete picture of HU-mediated mechanisms of HbF production in SCD remains elusive. Research on post-transcriptional mechanisms could lead to therapeutic targets that may minimize alterations to the cellular transcriptome. PMID:26327494

Possible role of extracellular signal-regulated kinase pathway in regulation of Sox9 mRNA expression in chondrocytes under hydrostatic pressure.

PubMed

Mio, Kensuke; Kirkham, Jennifer; Bonass, William A

2007-12-01

The potential involvement of the extracellular signal-regulated kinase (ERK) pathway in chondrocyte mechanotransduction was tested in bovine chondrocyte-agarose constructs under hydrostatic loading. Results suggested that the ERK pathway may be inhibited by hydrostatic pressure-induced mechanotransduction and may also be a negative regulator of Sox9 mRNA expression, which is an important modulator of chondrocyte function.

The mammalian target of rapamycin signaling pathway regulates myocyte enhancer factor-2C phosphorylation levels through integrin-linked kinase in goat skeletal muscle satellite cells.

PubMed

Wu, Haiqing; Ren, Yu; Pan, Wei; Dong, Zhenguo; Cang, Ming; Liu, Dongjun

2015-11-01

Mammalian target of rapamycin (mTOR) signaling pathway plays a key role in muscle development and is involved in multiple intracellular signaling pathways. Myocyte enhancer factor-2 (MEF2) regulates muscle cell proliferation and differentiation. However, how the mTOR signaling pathway regulates MEF2 activity remains unclear. We isolated goat skeletal muscle satellite cells (gSSCs) as model cells to explore mTOR signaling pathway regulation of MEF2C. We inhibited mTOR activity in gSSCs with PP242 and found that MEF2C phosphorylation was decreased and that muscle creatine kinase (MCK) expression was suppressed. Subsequently, we detected integrin-linked kinase (ILK) using MEF2C coimmunoprecipitation; ILK and MEF2C were colocalized in the gSSCs. We found that inhibiting mTOR activity increased ILK phosphorylation levels and that inhibiting ILK activity with Cpd 22 and knocking down ILK with small interfering RNA increased MEF2C phosphorylation and MCK expression. In the presence of Cpd 22, mTOR activity inhibition did not affect MEF2C phosphorylation. Moreover, ILK dephosphorylated MEF2C in vitro. These results suggest that the mTOR signaling pathway regulates MEF2C positively and regulates ILK negatively and that ILK regulates MEF2C negatively. It appears that the mTOR signaling pathway regulates MEF2C through ILK, further regulating the expression of muscle-related genes in gSSCs. © 2015 International Federation for Cell Biology.

Knockdown of TC-1 enhances radiosensitivity of non-small cell lung cancer via the Wnt/β-catenin pathway.

PubMed

Wu, Dapeng; Li, Lei; Yan, Wei

2016-04-15

Thyroid cancer 1 (TC-1, C8ofr4) is widely expressed in vertebrates and associated with many kinds of tumors. Previous studies indicated that TC-1 functions as a positive regulator in the Wnt/β-catenin signaling pathway in non-small cell lung cancer (NSCLC). However, its exact role and regulation mechanism in radiosensitivity of NSCLC are still unclear. The expression level of TC-1 was measured by qRT-PCR and western blot in NSCLC cell lines. Proliferation and apoptosis of NSCLC cells in response to TC-1 knockdown or/and radiation were determined by MTT assay and flow cytometry, respectively. The activation of the Wnt/β-catenin signaling pathway was further examined by western blotin vitroandin vivo Compared to TC-1 siRNA or radiotherapy alone, TC-1 silencing combined with radiation inhibited cell proliferation and induced apoptosis in NSCLC cell lines by inactivating of the Wnt/β-catenin signaling pathway. Furthermore, inhibition of the Wnt/β-catenin signaling pathway by XAV939, a Wnt/β-catenin signaling inhibitor, contributed to proliferation inhibition and apoptosis induction in NSCLC A549 cells. Combinative treatment of A549 xenografts with TC-1 siRNA and radiation caused significant tumor regression and inactivation of the Wnt/β-catenin signaling pathway relative to TC-1 siRNA or radiotherapy alone. The results fromin vitroandin vivostudies indicated that TC-1 silencing sensitized NSCLC cell lines to radiotherapy through the Wnt/β-catenin signaling pathway. © 2016. Published by The Company of Biologists Ltd.

Knockdown of TC-1 enhances radiosensitivity of non-small cell lung cancer via the Wnt/β-catenin pathway

PubMed Central

Wu, Dapeng; Li, Lei; Yan, Wei

2016-01-01

ABSTRACT Thyroid cancer 1 (TC-1, C8ofr4) is widely expressed in vertebrates and associated with many kinds of tumors. Previous studies indicated that TC-1 functions as a positive regulator in the Wnt/β-catenin signaling pathway in non-small cell lung cancer (NSCLC). However, its exact role and regulation mechanism in radiosensitivity of NSCLC are still unclear. The expression level of TC-1 was measured by qRT-PCR and western blot in NSCLC cell lines. Proliferation and apoptosis of NSCLC cells in response to TC-1 knockdown or/and radiation were determined by MTT assay and flow cytometry, respectively. The activation of the Wnt/β-catenin signaling pathway was further examined by western blot in vitro and in vivo. Compared to TC-1 siRNA or radiotherapy alone, TC-1 silencing combined with radiation inhibited cell proliferation and induced apoptosis in NSCLC cell lines by inactivating of the Wnt/β-catenin signaling pathway. Furthermore, inhibition of the Wnt/β-catenin signaling pathway by XAV939, a Wnt/β-catenin signaling inhibitor, contributed to proliferation inhibition and apoptosis induction in NSCLC A549 cells. Combinative treatment of A549 xenografts with TC-1 siRNA and radiation caused significant tumor regression and inactivation of the Wnt/β-catenin signaling pathway relative to TC-1 siRNA or radiotherapy alone. The results from in vitro and in vivo studies indicated that TC-1 silencing sensitized NSCLC cell lines to radiotherapy through the Wnt/β-catenin signaling pathway. PMID:27029901

An analysis of gene expression data involving examination of signaling pathways activation reveals new insights into the mechanism of action of minoxidil topical foam in men with androgenetic alopecia

PubMed Central

Wu, Jeff; Pappas, Apostolos; Mirmirani, Paradi; McCormick, Thomas S.; Cooper, Kevin D.; Schastnaya, Jane; Ozerov, Ivan V.; Aliper, Alexander; Zhavoronkov, Alex

2017-01-01

ABSTRACT Androgenetic alopecia is the most common form of hair loss. Minoxidil has been approved for the treatment of hair loss, however its mechanism of action is still not fully clarified. In this study, we aimed to elucidate the effects of 5% minoxidil topical foam on gene expression and activation of signaling pathways in vertex and frontal scalp of men with androgenetic alopecia. We identified regional variations in gene expression and perturbed signaling pathways using in silico Pathway Activation Network Decomposition Analysis (iPANDA) before and after treatment with minoxidil. Vertex and frontal scalp of patients showed a generally similar response to minoxidil. Both scalp regions showed upregulation of genes that encode keratin associated proteins and downregulation of ILK, Akt, and MAPK signaling pathways after minoxidil treatment. Our results provide new insights into the mechanism of action of minoxidil topical foam in men with androgenetic alopecia. PMID:28594262

An analysis of gene expression data involving examination of signaling pathways activation reveals new insights into the mechanism of action of minoxidil topical foam in men with androgenetic alopecia.

PubMed

Stamatas, Georgios N; Wu, Jeff; Pappas, Apostolos; Mirmirani, Paradi; McCormick, Thomas S; Cooper, Kevin D; Consolo, Mary; Schastnaya, Jane; Ozerov, Ivan V; Aliper, Alexander; Zhavoronkov, Alex

2017-01-01

Androgenetic alopecia is the most common form of hair loss. Minoxidil has been approved for the treatment of hair loss, however its mechanism of action is still not fully clarified. In this study, we aimed to elucidate the effects of 5% minoxidil topical foam on gene expression and activation of signaling pathways in vertex and frontal scalp of men with androgenetic alopecia. We identified regional variations in gene expression and perturbed signaling pathways using in silico Pathway Activation Network Decomposition Analysis (iPANDA) before and after treatment with minoxidil. Vertex and frontal scalp of patients showed a generally similar response to minoxidil. Both scalp regions showed upregulation of genes that encode keratin associated proteins and downregulation of ILK, Akt, and MAPK signaling pathways after minoxidil treatment. Our results provide new insights into the mechanism of action of minoxidil topical foam in men with androgenetic alopecia.

The diverse functions of Src family kinases in macrophages

PubMed Central

Abram, Clare L.; Lowell, Clifford A.

2015-01-01

Macrophages are key components of the innate immune response. These cells possess a diverse repertoire of receptors that allow them to respond to a host of external stimuli including cytokines, chemokines, and pathogen-associated molecules. Signals resulting from these stimuli activate a number of macrophage functional responses such as adhesion, migration, phagocytosis, proliferation, survival, cytokine release and production of reactive oxygen and nitrogen species. The cytoplasmic tyrosine kinase Src and its family members (SFKs) have been implicated in many intracellular signaling pathways in macrophages, initiated by a diverse set of receptors ranging from integrins to Toll-like receptors. However, it has been difficult to implicate any given member of the family in any specific pathway. SFKs appear to have overlapping and complementary functions in many pathways. Perhaps the function of these enzymes is to modulate the overall intracellular signaling network in macrophages, rather than operating as exclusive signaling switches for defined pathways. In general, SFKs may function more like rheostats, influencing the amplitude of many pathways. PMID:18508521

Hippo vs. Crab: tissue-specific functions of the mammalian Hippo pathway.

PubMed

Nishio, Miki; Maehama, Tomohiko; Goto, Hiroki; Nakatani, Keisuke; Kato, Wakako; Omori, Hirofumi; Miyachi, Yosuke; Togashi, Hideru; Shimono, Yohei; Suzuki, Akira

2017-01-01

The Hippo signaling pathway is a vital suppressor of tumorigenesis that is often inactivated in human cancers. In normal cells, the Hippo pathway is triggered by external forces such as cell crowding, or changes to the extracellular matrix or cell polarity. Once activated, Hippo signaling down-regulates transcription supported by the paralogous cofactors YAP1 and TAZ. The Hippo pathway's functions in normal and cancer biology have been dissected by studies of mutant mice with null or conditional tissue-specific mutations of Hippo signaling elements. In this review, we attempt to systematically summarize results that have been gleaned from detailed in vivo characterizations of these mutants. Our goal is to describe the physiological roles of Hippo signaling in several normal organ systems, as well as to emphasize how disruption of the Hippo pathway, and particularly hyperactivation of YAP1/TAZ, can be oncogenic. © 2017 The Authors Genes to Cells published by Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

A genetic screen for modifiers of Drosophila caspase Dcp-1 reveals caspase involvement in autophagy and novel caspase-related genes.

PubMed

Kim, Young-Il; Ryu, Taewoo; Lee, Judong; Heo, Young-Shin; Ahnn, Joohong; Lee, Seung-Jae; Yoo, OokJoon

2010-01-25

Caspases are cysteine proteases with essential functions in the apoptotic pathway; their proteolytic activity toward various substrates is associated with the morphological changes of cells. Recent reports have described non-apoptotic functions of caspases, including autophagy. In this report, we searched for novel modifiers of the phenotype of Dcp-1 gain-of-function (GF) animals by screening promoter element- inserted Drosophila melanogaster lines (EP lines). We screened approximately 15,000 EP lines and identified 72 Dcp-1-interacting genes that were classified into 10 groups based on their functions and pathways: 4 apoptosis signaling genes, 10 autophagy genes, 5 insulin/IGF and TOR signaling pathway genes, 6 MAP kinase and JNK signaling pathway genes, 4 ecdysone signaling genes, 6 ubiquitination genes, 11 various developmental signaling genes, 12 transcription factors, 3 translation factors, and 11 other unclassified genes including 5 functionally undefined genes. Among them, insulin/IGF and TOR signaling pathway, MAP kinase and JNK signaling pathway, and ecdysone signaling are known to be involved in autophagy. Together with the identification of autophagy genes, the results of our screen suggest that autophagy counteracts Dcp-1-induced apoptosis. Consistent with this idea, we show that expression of eGFP-Atg5 rescued the eye phenotype caused by Dcp-1 GF. Paradoxically, we found that over-expression of full-length Dcp-1 induced autophagy, as Atg8b-GFP, an indicator of autophagy, was increased in the eye imaginal discs and in the S2 cell line. Taken together, these data suggest that autophagy suppresses Dcp-1-mediated apoptotic cell death, whereas Dcp-1 positively regulates autophagy, possibly through feedback regulation. We identified a number of Dcp-1 modifiers that genetically interact with Dcp-1-induced cell death. Our results showing that Dcp-1 and autophagy-related genes influence each other will aid future investigations of the complicated relationships between apoptosis and autophagy.

The calcineurin pathway links hyperpolarization (Kir2.1)-induced Ca2+ signals to human myoblast differentiation and fusion.

PubMed

Konig, Stéphane; Béguet, Anne; Bader, Charles R; Bernheim, Laurent

2006-08-01

In human myoblasts triggered to differentiate, a hyperpolarization, resulting from K+ channel (Kir2.1) activation, allows the generation of an intracellular Ca2+ signal. This signal induces an increase in expression/activity of two key transcription factors of the differentiation process, myogenin and MEF2. Blocking hyperpolarization inhibits myoblast differentiation. The link between hyperpolarization-induced Ca2+ signals and the four main regulatory pathways involved in myoblast differentiation was the object of this study. Of the calcineurin, p38-MAPK, PI3K and CaMK pathways, only the calcineurin pathway was inhibited when Kir2.1-linked hyperpolarization was blocked. The CaMK pathway, although Ca2+ dependent, is unaffected by changes in membrane potential or block of Kir2.1 channels. Concerning the p38-MAPK and PI3K pathways, their activity is present already in proliferating myoblasts and they are unaffected by hyperpolarization or Kir2.1 channel block. We conclude that the Kir2.1-induced hyperpolarization triggers human myoblast differentiation via the activation of the calcineurin pathway, which, in turn, induces expression/activity of myogenin and MEF2.

RACK1 is required for adipogenesis.

PubMed

Kong, Qinghua; Gao, Lan; Niu, Yanfen; Gongpan, Pianchou; Xu, Yuhui; Li, Yan; Xiong, Wenyong

2016-11-01

Adipose tissue plays a critical role in metabolic diseases and the maintenance of energy homeostasis. RACK1 has been identified as an adaptor protein involved in multiple intracellular signal transduction pathways and diseases. However, whether it regulates adipogenesis remains unknown. Here, we reported that RACK1 is expressed in 3T3-L1 cells and murine white adipose tissue and that RACK1 knockdown by shRNA profoundly suppressed adipogenesis by reducing the expression of PPAR-γ and C/EBP-β. Depletion of RACK1 increased β-catenin protein levels and activated Wnt signaling. Furthermore, RACK1 knockdown also suppressed the PI3K-Akt-mTOR-S6K signaling pathway by reducing the PI3K p85α, pAkt T473, and S6K p70. Taken together, these results demonstrate that RACK1 is a novel factor required for adipocyte differentiation by emerging Wnt/β-catenin signaling and PI3K-Akt-mTOR-S6K signaling pathway(s). Copyright © 2016 the American Physiological Society.

Disease implications of the Hippo/YAP pathway

PubMed Central

Plouffe, Steven W; Hong, Audrey W; Guan, Kun-Liang

2015-01-01

The Hippo signaling pathway is important for controlling organ size and tissue homeostasis. Originally identified in Drosophila melanogaster, the core components of the Hippo pathway are highly conserved in mammals. The Hippo pathway can be modulated by a wide range of stimuli, including G protein coupled receptor (GPCR) signaling, changes in the actin cytoskeleton, cell-cell contact, and cell polarity. When activated, the Hippo pathway functions as a tumor suppressor to limit cell growth. However, dysregulation by genetic inactivation of core pathway components, or amplification or gene fusion of its downstream effectors, results in increased cell proliferation and decreased apoptosis and differentiation. Not surprisingly, this can lead to tissue overgrowth, tumorigenesis, and many other diseases. PMID:25702974

Chronic administration of aripiprazole activates GSK3β-dependent signalling pathways, and up-regulates GABAA receptor expression and CREB1 activity in rats

PubMed Central

Pan, Bo; Huang, Xu-Feng; Deng, Chao

2016-01-01

Aripiprazole is a D2-like receptor (D2R) partial agonist with a favourable clinical profile. Previous investigations indicated that acute and short-term administration of aripiprazole had effects on PKA activity, GSK3β-dependent pathways, GABAA receptors, NMDA receptor and CREB1 in the brain. Since antipsychotics are used chronically in clinics, the present study investigated the long-term effects of chronic oral aripiprazole treatment on these cellular signalling pathways, in comparison with haloperidol (a D2R antagonist) and bifeprunox (a potent D2R partial agonist). We found that the Akt-GSK3β pathway was activated by aripiprazole and bifeprunox in the prefrontal cortex; NMDA NR2A levels were reduced by aripiprazole and haloperidol. In the nucleus accumbens, all three drugs increased Akt-GSK3β signalling; in addition, both aripiprazole and haloperidol, but not bifeprunox, increased the expression of Dvl-3, β-catenin and GABAA receptors, NMDA receptor subunits, as well as CREB1 phosphorylation levels. The results suggest that chronic oral administration of aripiprazole affects schizophrenia-related cellular signalling pathways and markers (including Akt-GSK3β signalling, Dvl-GSK3β-β-catenin signalling, GABAA receptor, NMDA receptor and CREB1) in a brain-region-dependent manner; the selective effects of aripiprazole on these signalling pathways might be associated with its unique clinical effects. PMID:27435909

MiRNA-335 suppresses neuroblastoma cell invasiveness by direct targeting of multiple genes from the non-canonical TGF-β signalling pathway

PubMed Central

Lynch, Jennifer; Fay, Joanna; Meehan, Maria; Bryan, Kenneth; Watters, Karen M.; Murphy, Derek M.; Stallings, Raymond L.

2012-01-01

Transforming growth factor-β (TGF-β) signaling regulates many diverse cellular activities through both canonical (SMAD-dependent) and non-canonical branches, which includes the mitogen-activated protein kinase (MAPK), Rho-like guanosine triphosphatase and phosphatidylinositol-3-kinase/AKT pathways. Here, we demonstrate that miR-335 directly targets and downregulates genes in the TGF-β non-canonical pathways, including the Rho-associated coiled-coil containing protein (ROCK1) and MAPK1, resulting in reduced phosphorylation of downstream pathway members. Specifically, inhibition of ROCK1 and MAPK1 reduces phosphorylation levels of the motor protein myosin light chain (MLC) leading to a significant inhibition of the invasive and migratory potential of neuroblastoma cells. Additionally, miR-335 targets the leucine-rich alpha-2-glycoprotein 1 (LRG1) messenger RNA, which similarly results in a significant reduction in the phosphorylation status of MLC and a decrease in neuroblastoma cell migration and invasion. Thus, we link LRG1 to the migratory machinery of the cell, altering its activity presumably by exerting its effect within the non-canonical TGF-β pathway. Moreover, we demonstrate that the MYCN transcription factor, whose coding sequence is highly amplified in a particularly clinically aggressive neuroblastoma tumor subtype, directly binds to a region immediately upstream of the miR-335 transcriptional start site, resulting in transcriptional repression. We conclude that MYCN contributes to neuroblastoma cell migration and invasion, by directly downregulating miR-335, resulting in the upregulation of the TGF-β signaling pathway members ROCK1, MAPK1 and putative member LRG1, which positively promote this process. Our results provide novel insight into the direct regulation of TGF-β non-canonical signaling by miR-335, which in turn is downregulated by MYCN. PMID:22382496

Conservation of protein abundance patterns reveals the regulatory architecture of the EGFR-MAPK pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, T.; Niepel, M.; McDermott, J. E.

It is not known whether cancer cells generally show quantitative differences in the expression of signaling pathway proteins that could dysregulate signal transduction. To explore this issue, we first defined the primary components of the EGF-MAPK pathway in normal human mammary epithelial cells, identifying 16 core proteins and 10 feedback regulators. We then quantified their absolute abundance across a panel of normal and cancer cell lines. We found that core pathway proteins were expressed at very similar levels across all cell types. In contrast, the EGFR and transcriptionally controlled feedback regulators were expressed at highly variable levels. The absolute abundancemore » of most core pathway proteins was between 50,000- 70,000 copies per cell, but the adaptors SOS1, SOS2, and GAB1 were found at far lower levels (2,000-5,000 per cell). MAPK signaling showed saturation in all cells between 3,000-10,000 occupied EGFR, consistent with the idea that low adaptor levels limit signaling. Our results suggest that the core MAPK pathway is essentially invariant across different cell types, with cell- specific differences in signaling likely due to variable levels of feedback regulators. The low abundance of adaptors relative to the EGFR could be responsible for previous observation of saturable signaling, endocytosis, and high affinity EGFR.« less

B-cell receptor signaling as a driver of lymphoma development and evolution.

PubMed

Niemann, Carsten U; Wiestner, Adrian

2013-12-01

The B-cell receptor (BCR) is essential for normal B-cell development and maturation. In an increasing number of B-cell malignancies, BCR signaling is implicated as a pivotal pathway in tumorigenesis. Mechanisms of BCR activation are quite diverse and range from chronic antigenic drive by microbial or viral antigens to autostimulation of B-cells by self-antigens to activating mutations in intracellular components of the BCR pathway. Hepatitis C virus infection can lead to the development of splenic marginal zone lymphoma, while Helicobacter pylori infection is associated with the development of mucosa-associated lymphoid tissue lymphomas. In some of these cases, successful treatment of the infection removes the inciting antigen and results in resolution of the lymphoma. Chronic lymphocytic leukemia has been recognized for decades as a malignancy of auto-reactive B-cells and its clinical course is in part determined by the differential response of the malignant cells to BCR activation. In a number of B-cell malignancies, activating mutations in signal transduction components of the BCR pathway have been identified; prominent examples are activated B-cell-like (ABC) diffuse large B-cell lymphomas (DLBCL) that carry mutations in CD79B and CARD11 and display chronic active BCR signaling resulting in constitutive activation of the NF-κB pathway. Despite considerable heterogeneity in biology and clinical course, many mature B-cell malignancies are highly sensitive to kinase inhibitors that disrupt BCR signaling. Thus, targeted therapy through inhibition of BCR signaling is emerging as a new treatment paradigm for many B-cell malignancies. Here, we review the role of the BCR in the pathogenesis of B-cell malignancies and summarize clinical results of the emerging class of kinase inhibitors that target this pathway. Copyright © 2013. Published by Elsevier Ltd.

Phosphoproteomic Analysis Identifies Signaling Pathways Regulated by Curcumin in Human Colon Cancer Cells.

PubMed

Sato, Tatsuhiro; Higuchi, Yutaka; Shibagaki, Yoshio; Hattori, Seisuke

2017-09-01

Curcumin, a major polyphenol of the spice turmeric, acts as a potent chemopreventive and chemotherapeutic agent in several cancer types, including colon cancer. Although various proteins have been shown to be affected by curcumin, how curcumin exerts its anticancer activity is not fully understood. Phosphoproteomic analyses were performed using SW480 and SW620 human colon cancer cells to identify curcumin-affected signaling pathways. Curcumin inhibited the growth of the two cell lines in a dose-dependent manner. Thirty-nine curcumin-regulated phosphoproteins were identified, five of which are involved in cancer signaling pathways. Detailed analyses revealed that the mTORC1 and p53 signaling pathways are main targets of curcumin. Our results provide insight into the molecular mechanisms of the anticancer activities of curcumin and future molecular targets for its clinical application. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Wnt/β-catenin signaling pathway inhibits the proliferation and apoptosis of U87 glioma cells via different mechanisms

PubMed Central

Gao, Liyang; Chen, Bing; Li, Jinhong; Yang, Fan; Cen, Xuecheng; Liao, Zhuangbing; Long, Xiao’ao

2017-01-01

The Wnt signaling pathway is necessary for the development of the central nervous system and is associated with tumorigenesis in various cancers. However, the mechanism of the Wnt signaling pathway in glioma cells has yet to be elucidated. Small-molecule Wnt modulators such as ICG-001 and AZD2858 were used to inhibit and stimulate the Wnt/β-catenin signaling pathway. Techniques including cell proliferation assay, colony formation assay, Matrigel cell invasion assay, cell cycle assay and Genechip microarray were used. Gene Ontology Enrichment Analysis and Gene Set Enrichment Analysis have enriched many biological processes and signaling pathways. Both the inhibiting and stimulating Wnt/β-catenin signaling pathways could influence the cell cycle, moreover, reduce the proliferation and survival of U87 glioma cells. However, Affymetrix expression microarray indicated that biological processes and networks of signaling pathways between stimulating and inhibiting the Wnt/β-catenin signaling pathway largely differ. We propose that Wnt/β-catenin signaling pathway might prove to be a valuable therapeutic target for glioma. PMID:28837560

Bioinformatics approach reveals systematic mechanism underlying lung adenocarcinoma.

PubMed

Wu, Xiya; Zhang, Wei; Hu, Yunhua; Yi, Xianghua

2015-01-01

The purpose of this work was to explore the systematic molecular mechanism of lung adenocarcinoma and gain a deeper insight into it. Comprehensive bioinformatics methods were applied. Initially, significant differentially expressed genes (DEGs) were analyzed from the Affymetrix microarray data (GSE27262) deposited in the Gene Expression Omnibus (GEO). Subsequently, gene ontology (GO) analysis was performed using online Database for Annotation, Visualization and Integration Discovery (DAVID) software. Finally, significant pathway crosstalk was investigated based on the information derived from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. According to our results, the N-terminal globular domain of the type X collagen (COL10A1) gene and transmembrane protein 100 (TMEM100) gene were identified to be the most significant DEGs in tumor tissue compared with the adjacent normal tissues. The main GO categories were biological process, cellular component and molecular function. In addition, the crosstalk was significantly different between non-small cell lung cancer pathways and inositol phosphate metabolism pathway, focal adhesion signal pathway, vascular smooth muscle contraction signal pathway, peroxisome proliferator-activated receptor (PPAR) signaling pathway and calcium signaling pathway in tumor. Dysfunctional genes and pathways may play key roles in the progression and development of lung adenocarcinoma. Our data provide a systematic perspective for understanding this mechanism and may be helpful in discovering an effective treatment for lung adenocarcinoma.

A critical role of Notch signaling in osteosarcoma invasion and metastasis

PubMed Central

Zhang, Pingyu; Yang, Yanwen; Zweidler-McKay, Patrick A.; Hughes, Dennis P.M.

2010-01-01

Purpose Notch signaling is an important mediator of growth and survival in several cancer types, with Notch pathway genes functioning as oncogenes or tumor suppressors in different cancers. However, the role of Notch in osteosarcoma is unknown. Experimental Design We assessed the expression of Notch pathway genes in human osteosarcoma cell lines and patient samples. We then employed pharmacologic and retroviral manipulation of the Notch pathway and studied the impact on osteosarcoma cell proliferation, survival, anchorage-independent growth, invasion and metastasis in vitro and in vivo. Results Notch pathway genes, including Notch ligand DLL1, Notch 1 and 2, and the Notch target gene HES1 were expressed in osteosarcoma cells, and expression of HES1 was associated with invasive and metastatic potential. Blockade of Notch pathway signaling with a small molecule inhibitor of gamma secretase eliminated invasion in matrigel without affecting cell proliferation, survival, or anchorage-independent growth. Manipulation of Notch and HES1 signaling demonstrated a crucial role for HES1 in osteosarcoma invasiveness and metastasis in vivo. Conclusion These studies identify a new invasion and metastasis-regulating pathway in osteosarcoma and define a novel function for the Notch pathway: regulation of metastasis. Since the Notch pathway can be inhibited pharmacologically, these findings point toward possible new treatments to reduce invasion and metastasis in osteosarcoma. PMID:18483362

Loss of Gi G-Protein-Coupled Receptor Signaling in Osteoblasts Accelerates Bone Fracture Healing.

PubMed

Wang, Liping; Hsiao, Edward C; Lieu, Shirley; Scott, Mark; O'Carroll, Dylan; Urrutia, Ashley; Conklin, Bruce R; Colnot, Celine; Nissenson, Robert A

2015-10-01

G-protein-coupled receptors (GPCRs) are key regulators of skeletal homeostasis and are likely important in fracture healing. Because GPCRs can activate multiple signaling pathways simultaneously, we used targeted disruption of G(i) -GPCR or activation of G(s) -GPCR pathways to test how each pathway functions in the skeleton. We previously demonstrated that blockade of G(i) signaling by pertussis toxin (PTX) transgene expression in maturing osteoblastic cells enhanced cortical and trabecular bone formation and prevented age-related bone loss in female mice. In addition, activation of G(s) signaling by expressing the G(s) -coupled engineered receptor Rs1 in maturing osteoblastic cells induced massive trabecular bone formation but cortical bone loss. Here, we test our hypothesis that the G(i) and G(s) pathways also have distinct functions in fracture repair. We applied closed, nonstabilized tibial fractures to mice in which endogenous G(i) signaling was inhibited by PTX, or to mice with activated G(s) signaling mediated by Rs1. Blockade of endogenous G(i) resulted in a smaller callus but increased bone formation in both young and old mice. PTX treatment decreased expression of Dkk1 and increased Lef1 mRNAs during fracture healing, suggesting a role for endogenous G(i) signaling in maintaining Dkk1 expression and suppressing Wnt signaling. In contrast, adult mice with activated Gs signaling showed a slight increase in the initial callus size with increased callus bone formation. These results show that G(i) blockade and G(s) activation of the same osteoblastic lineage cell can induce different biological responses during fracture healing. Our findings also show that manipulating the GPCR/cAMP signaling pathway by selective timing of G(s) and G(i) -GPCR activation may be important for optimizing fracture repair. © 2015 American Society for Bone and Mineral Research.

Curcumin inhibits tumor epithelial‑mesenchymal transition by downregulating the Wnt signaling pathway and upregulating NKD2 expression in colon cancer cells.

PubMed

Zhang, Zewei; Chen, Haitao; Xu, Chao; Song, Lu; Huang, Lulu; Lai, Yuebiao; Wang, Yuqi; Chen, Hanlu; Gu, Danlin; Ren, Lili; Yao, Qinghua

2016-05-01

Tumor invasion and metastasis are closely associated with epithelial‑mesenchymal transition (EMT). EMT refers to epithelial cells under physiological and pathological conditions that are specific to mesenchymal transition. Curcumin inhibits EMT progression via Wnt signaling. The Wnt signaling pathway is a conservative EMT‑related signaling pathway that is involved in the development of various tumors. In the present study, MTS assays were employed to analyze the proliferation of curcumin‑treated cells. Naked cuticle homolog 2 (NKD2), chemokine receptor 4 (CXCR4) and antibodies associated with EMT were examined in SW620 colorectal cancer cell lines using western blot analysis and real‑time qPCR. NKD2 small‑interfering RNA (siRNA) and CXCR4 expression plasmid was synthesized and transfected into the colorectal cancer cell lines, and NKD2 and CXCR4 expression levels were detected. The results showed that curcumin significantly inhibited the proliferation of colorectal cancer cells and upregulated the expression of NKD2 in SW620 colorectal cancer cells and in the xenograft, resulting in the downregulation of key markers in the Wnt signaling. In addition, the progression of ETM was inhibited due to the overexpression of E‑cadherin as well as the downregulation of vimentin. Curcumin also inhibited tumor metastasis by downregulating the expression of CXCR4 significantly. The results suggested involvement of the NKD2‑Wnt‑CXCR4 signaling pathway in colorectal cancer cells. In addition, curcumin is inhibit this signaling and the development of colorectal cancer.

Curcumin inhibits tumor epithelial-mesenchymal transition by downregulating the Wnt signaling pathway and upregulating NKD2 expression in colon cancer cells

PubMed Central

ZHANG, ZEWEI; CHEN, HAITAO; XU, CHAO; SONG, LU; HUANG, LULU; LAI, YUEBIAO; WANG, YUQI; CHEN, HANLU; GU, DANLIN; REN, LILI; YAO, QINGHUA

2016-01-01

Tumor invasion and metastasis are closely associated with epithelial-mesenchymal transition (EMT). EMT refers to epithelial cells under physiological and pathological conditions that are specific to mesenchymal transition. Curcumin inhibits EMT progression via Wnt signaling. The Wnt signaling pathway is a conservative EMT-related signaling pathway that is involved in the development of various tumors. In the present study, MTS assays were employed to analyze the proliferation of curcumin-treated cells. Naked cuticle homolog 2 (NKD2), chemokine receptor 4 (CXCR4) and antibodies associated with EMT were examined in SW620 colorectal cancer cell lines using western blot analysis and real-time qPCR. NKD2 small-interfering RNA (siRNA) and CXCR4 expression plasmid was synthesized and transfected into the colorectal cancer cell lines, and NKD2 and CXCR4 expression levels were detected. The results showed that curcumin significantly inhibited the proliferation of colorectal cancer cells and upregulated the expression of NKD2 in SW620 colorectal cancer cells and in the xenograft, resulting in the downregulation of key markers in the Wnt signaling. In addition, the progression of ETM was inhibited due to the overexpression of E-cadherin as well as the downregulation of vimentin. Curcumin also inhibited tumor metastasis by downregulating the expression of CXCR4 significantly. The results suggested involvement of the NKD2-Wnt-CXCR4 signaling pathway in colorectal cancer cells. In addition, curcumin is inhibit this signaling and the development of colorectal cancer. PMID:26985708

Resolvin D1 Increases Mucin Secretion in Cultured Rat Conjunctival Goblet Cells via Multiple Signaling Pathways

PubMed Central

Lippestad, Marit; Hodges, Robin R.; Utheim, Tor P.; Serhan, Charles N.; Dartt, Darlene A.

2017-01-01

Purpose Goblet cells in the conjunctiva secrete mucin into the tear film protecting the ocular surface. The proresolution mediator resolvin D1 (RvD1) regulates mucin secretion to maintain homeostasis during physiological conditions and in addition, actively terminates inflammation. We determined the signaling mechanisms used by RvD1 in cultured rat conjunctival goblet cells to increase intracellular [Ca2+] ([Ca2+]i) and induce glycoconjugate secretion. Methods Increase in [Ca2+]i were measured using fura 2/AM and glycoconjugate secretion determined using an enzyme-linked lectin assay with the lectin Ulex Europaeus Agglutinin 1. Signaling pathways activated by RvD1 were studied after goblet cells were pretreated with signaling pathway inhibitors before stimulation with RvD1. The results were compared with results when goblet cells were stimulated with RvD1 alone and percent inhibition calculated. Results The increase in [Ca2+]i stimulated by RvD1 was blocked by inhibitors to phospholipases (PL-) -D, -C, -A2, protein kinase C (PKC), extracellular signal-regulated kinases (ERK)1/2 and Ca2+/calmodulin-dependent kinase (Ca2+/CamK). Glycoconjugate secretion was significantly inhibited by PLD, -C, -A2, ERK1/2 and Ca2+/CamK, but not PKC. Conclusions We conclude that RvD1 increases glycoconjugate secretion from goblet cells via multiple signaling pathways including PLC, PLD, and PLA2, as well as their signaling components ERK1/2 and Ca2+/CamK to preserve the mucous layer and maintain homeostasis by protecting the eye from desiccating stress, allergens, and pathogens. PMID:28892824

G protein-coupled receptors Flop1 and Flop2 inhibit Wnt/β-catenin signaling and are essential for head formation in Xenopus.

PubMed

Miyagi, Asuka; Negishi, Takefumi; Yamamoto, Takamasa S; Ueno, Naoto

2015-11-01

Patterning of the vertebrate anterior-posterior axis is regulated by the coordinated action of growth factors whose effects can be further modulated by upstream and downstream mediators and the cross-talk of different intracellular pathways. In particular, the inhibition of the Wnt/β-catenin signaling pathway by various factors is critically required for anterior specification. Here, we report that Flop1 and Flop2 (Flop1/2), G protein-coupled receptors related to Gpr4, contribute to the regulation of head formation by inhibiting Wnt/β-catenin signaling in Xenopus embryos. Using whole-mount in situ hybridization, we showed that flop1 and flop2 mRNAs were expressed in the neural ectoderm during early gastrulation. Both the overexpression and knockdown of Flop1/2 resulted in altered embryonic head phenotypes, while the overexpression of either Flop1/2 or the small GTPase RhoA in the absence of bone morphogenetic protein (BMP) signaling resulted in ectopic head induction. Examination of the Flops' function in Xenopus embryo animal cap cells showed that they inhibited Wnt/β-catenin signaling by promoting β-catenin degradation through both RhoA-dependent and -independent pathways in a cell-autonomous manner. These results suggest that Flop1 and Flop2 are essential regulators of Xenopus head formation that act as novel inhibitory components of the Wnt/β-catenin signaling pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

Association of Wnt1-inducible signaling pathway protein-1 with the proliferation, migration and invasion in gastric cancer cells.

PubMed

Jia, Shuqin; Qu, Tingting; Feng, Mengmeng; Ji, Ke; Li, Ziyu; Jiang, Wenguo; Ji, Jiafu

2017-06-01

Wnt1-inducible signaling pathway protein-1 is a cysteine-rich protein that belongs to the CCN family, which has been implicated in mediating the occurrence and progression through distinct molecular mechanisms in several tumor types. However, the association of Wnt1-inducible signaling pathway protein-1 with gastric cancer and the related molecular mechanisms remain to be elucidated. Therefore, this study aimed to clarify the biological role of Wnt1-inducible signaling pathway protein-1 in the proliferation, migration, and invasion in gastric cancer cells and further investigated the associated molecular mechanism on these biological functions. We first detected the expression level of Wnt1-inducible signaling pathway protein-1 in gastric cancer, and the reverse transcription polymerase chain reaction have shown that Wnt1-inducible signaling pathway protein-1 expression levels were upregulated in gastric cancer tissues. The expression of Wnt1-inducible signaling pathway protein-1 in gastric cancer cell lines was also detected by quantitative real-time polymerase chain reaction and Western blotting. Furthermore, two gastric cancer cell lines with high expression of Wnt1-inducible signaling pathway protein-1 were selected to explore the biological function of Wnt1-inducible signaling pathway protein-1 in gastric cancer. Function assays indicated that knockdown of Wnt1-inducible signaling pathway protein-1 suppressed cell proliferation, migration, and invasion in BGC-823 and AGS gastric cancer cells. Further investigation of mechanisms suggested that cyclinD1 was identified as one of Wnt1-inducible signaling pathway protein-1 related genes to accelerate proliferation in gastric cancer cells. In addition, one pathway of Wnt1-inducible signaling pathway protein-1 induced migration and invasion was mainly through the enhancement of epithelial-to-mesenchymal transition progression. Taken together, our findings presented the first evidence that Wnt1-inducible signaling pathway protein-1 was upregulated in gastric cancer and acted as an oncogene by promoting proliferation, migration, and invasion in gastric cancer cells.

Caveolin 3-mediated integrin β1 signaling is required for the proliferation of folliculostellate cells in rat anterior pituitary gland under the influence of extracellular matrix.

PubMed

Horiguchi, Kotaro; Fujiwara, Ken; Ilmiawati, Cimi; Kikuchi, Motoshi; Tsukada, Takehiro; Kouki, Tom; Yashiro, Takashi

2011-07-01

Folliculostellate (FS) cells in the anterior pituitary gland are believed to have multifunctional properties. Using transgenic rats that express green fluorescent protein (GFP) specifically in FS cells in the anterior pituitary gland (S100b-GFP rats), we recently revealed that FS cells in primary culture exhibited marked proliferation in the presence of laminin, an extracellular matrix (ECM) component of the basement membrane. In a process referred to as matricrine action, FS cells receive ECM as a signal through their receptors, which results in morphological and functional changes. In this study, we investigated matricrine signaling in FS cells and observed that the proliferation of FS cells is mediated by integrin β1, which is involved in various signaling pathways for cell migration and proliferation in response to ECM. Then, we analyzed downstream events of the integrin β1 signaling pathway in the proliferation of FS cells and identified caveolin 3 as a potential candidate molecule. Caveolin 3 is a membrane protein that binds cholesterol and a number of signaling molecules that interact with integrin β1. Using specific small interfering RNA of caveolin 3, the proliferation of FS cells was inhibited. Furthermore, caveolin 3 drove activation of the mitogen-activated protein kinase (MAPK) signaling cascades, which resulted in upregulation of cyclin D1 in FS cells. These findings suggest that matricrine signaling in the proliferation of FS cells was transduced by a caveolin 3-mediated integrin β1 signaling pathway and subsequent activation of the MAPK pathway. © 2011 Society for Endocrinology

On the Nature of Expansion of Paget’s Disease of Bone

DTIC Science & Technology

2012-10-01

signaling pathway. Gene expression normalized to normal adjacent bone samples. 5 Global expression analysis revealed genes downstream of the Hedgehog ... Hedgehog (Hh) signaling pathway (Figure 5). Again, as in the TLR signaling pathway, specific elements of the Hh signaling pathway showed increased...mutations upregulated expression of genes in the Hedgehog signaling pathway. 7. Discovery that an osteoblastic cell line (PSV10) derived from a PDB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samarzija, Ivana; Beard, Peter, E-mail: peter.beard@epfl.ch

Highlights: Black-Right-Pointing-Pointer Unknown cellular mutations complement papillomavirus-induced carcinogenesis. Black-Right-Pointing-Pointer Hedgehog pathway components are expressed by cervical cancer cells. Black-Right-Pointing-Pointer Hedgehog pathway activators and inhibitors regulate cervical cancer cell biology. Black-Right-Pointing-Pointer Cell immortalization by papillomavirus and activation of Hedgehog are independent. -- Abstract: Human papillomavirus (HPV) infection is considered to be a primary hit that causes cervical cancer. However, infection with this agent, although needed, is not sufficient for a cancer to develop. Additional cellular changes are required to complement the action of HPV, but the precise nature of these changes is not clear. Here, we studied the function of themore » Hedgehog (Hh) signaling pathway in cervical cancer. The Hh pathway can have a role in a number of cancers, including those of liver, lung and digestive tract. We found that components of the Hh pathway are expressed in several cervical cancer cell lines, indicating that there could exists an autocrine Hh signaling loop in these cells. Inhibition of Hh signaling reduces proliferation and survival of the cervical cancer cells and induces their apoptosis as seen by the up-regulation of the pro-apoptotic protein cleaved caspase 3. Our results indicate that Hh signaling is not induced directly by HPV-encoded proteins but rather that Hh-activating mutations are selected in cells initially immortalized by HPV. Sonic Hedgehog (Shh) ligand induces proliferation and promotes migration of the cervical cancer cells studied. Together, these results indicate pro-survival and protective roles of an activated Hh signaling pathway in cervical cancer-derived cells, and suggest that inhibition of this pathway may be a therapeutic option in fighting cervical cancer.« less

TEC protein tyrosine kinase is involved in the Erk signaling pathway induced by HGF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Feifei; Jiang, Yinan; Zheng, Qiping

Research highlights: {yields} TEC is rapidly tyrosine-phosphorylated and activated by HGF-stimulation in vivo or after partial hepatectomy in mice. {yields} TEC enhances the activity of Elk and serum response element (SRE) in HGF signaling pathway in hepatocyte. {yields} TEC promotes hepatocyte proliferation through the Erk-MAPK pathway. -- Abstract: Background/aims: TEC, a member of the TEC family of non-receptor type protein tyrosine kinases, has recently been suggested to play a role in hepatocyte proliferation and liver regeneration. This study aims to investigate the putative mechanisms of TEC kinase regulation of hepatocyte differentiation, i.e. to explore which signaling pathway TEC is involvedmore » in, and how TEC is activated in hepatocyte after hepatectomy and hepatocyte growth factor (HGF) stimulation. Methods: We performed immunoprecipitation (IP) and immunoblotting (IB) to examine TEC tyrosine phosphorylation after partial hepatectomy in mice and HGF stimulation in WB F-344 hepatic cells. The TEC kinase activity was determined by in vitro kinase assay. Reporter gene assay, antisense oligonucleotide and TEC dominant negative mutant (TEC{sup KM}) were used to examine the possible signaling pathways in which TEC is involved. The cell proliferation rate was evaluated by {sup 3}H-TdR incorporation. Results: TEC phosphorylation and kinase activity were increased in 1 h after hepatectomy or HGF treatment. TEC enhanced the activity of Elk and serum response element (SRE). Inhibition of MEK1 suppressed TEC phosphorylation. Blocking TEC activity dramatically decreased the activation of Erk. Reduced TEC kinase activity also suppressed the proliferation of WB F-344 cells. These results suggest TEC is involved in the Ras-MAPK pathway and acts between MEK1 and Erk. Conclusions: TEC promotes hepatocyte proliferation and regeneration and is involved in HGF-induced Erk signaling pathway.« less

Computational modeling of the EGFR network elucidates control mechanisms regulating signal dynamics

PubMed Central

2009-01-01

Background The epidermal growth factor receptor (EGFR) signaling pathway plays a key role in regulation of cellular growth and development. While highly studied, it is still not fully understood how the signal is orchestrated. One of the reasons for the complexity of this pathway is the extensive network of inter-connected components involved in the signaling. In the aim of identifying critical mechanisms controlling signal transduction we have performed extensive analysis of an executable model of the EGFR pathway using the stochastic pi-calculus as a modeling language. Results Our analysis, done through simulation of various perturbations, suggests that the EGFR pathway contains regions of functional redundancy in the upstream parts; in the event of low EGF stimulus or partial system failure, this redundancy helps to maintain functional robustness. Downstream parts, like the parts controlling Ras and ERK, have fewer redundancies, and more than 50% inhibition of specific reactions in those parts greatly attenuates signal response. In addition, we suggest an abstract model that captures the main control mechanisms in the pathway. Simulation of this abstract model suggests that without redundancies in the upstream modules, signal transduction through the entire pathway could be attenuated. In terms of specific control mechanisms, we have identified positive feedback loops whose role is to prolong the active state of key components (e.g., MEK-PP, Ras-GTP), and negative feedback loops that help promote signal adaptation and stabilization. Conclusions The insights gained from simulating this executable model facilitate the formulation of specific hypotheses regarding the control mechanisms of the EGFR signaling, and further substantiate the benefit to construct abstract executable models of large complex biological networks. PMID:20028552

TBK1-targeted suppression of TRIF-dependent signaling pathway of Toll-like receptors by 6-shogaol, an active component of ginger.

PubMed

Park, Se-Jeong; Lee, Mi-Young; Son, Bu-Soon; Youn, Hyung-Sun

2009-07-01

Toll-like receptors (TLRs) are primary sensors that detect a wide variety of microbial components involving induction of innate immune responses. After recognition of microbial components, TLRs trigger the activation of myeloid differential factor 88 (MyD88) and Toll-interleukin-1 (IL-1) receptor domain-containing adapter inducing interferon-beta (TRIF)-dependent downstream signaling pathways. 6-Shoagol, an active ingredient of ginger, inhibits the MyD88-dependent signaling pathway by inhibiting inhibitor-kappaB kinase activity. Inhibitor-kappaB kinase is a key kinase in nuclear factor kappaB (NF-kappaB) activation. However, it is not known whether 6-shogaol inhibits the TRIF-dependent signaling pathway. Our goal was to identify the molecular target of 6-shogaol in the TRIF-dependent pathway of TLRs. 6-Shogaol inhibited the activation of interferon-regulatory factor 3 (IRF3) induced by lipopolysaccharide (LPS) and by polyriboinosinic polyribocytidylic acid (poly[I:C]), overexpression of TRIF, TANK-binding kinase1 (TBK1), and IRF3. Furthermore, 6-shogaol inhibited TBK1 activity in vitro. Together, these results suggest that 6-shogaol inhibits the TRIF-dependent signaling pathway of TLRs by targeting TBK1, and, they imply that 6-shogaol can modulate TLR-derived immune/inflammatory target gene expression induced by microbial infection.

The Fibroblast Growth Factor signaling pathway.

PubMed

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. For further resources related to this article, please visit the WIREs website. © 2015 The Authors. WIREs Developmental Biology published by Wiley Periodicals, Inc.

Pathway and network-based analysis of genome-wide association studies and RT-PCR validation in polycystic ovary syndrome

PubMed Central

Shen, Haoran; Liang, Zhou; Zheng, Saihua; Li, Xuelian

2017-01-01

The purpose of this study was to identify promising candidate genes and pathways in polycystic ovary syndrome (PCOS). Microarray dataset GSE345269 obtained from the Gene Expression Omnibus database includes 7 granulosa cell samples from PCOS patients, and 3 normal granulosa cell samples. Differentially expressed genes (DEGs) were screened between PCOS and normal samples. Pathway enrichment analysis was conducted for DEGs using ClueGO and CluePedia plugin of Cytoscape. A Reactome functional interaction (FI) network of the DEGs was built using ReactomeFIViz, and then network modules were extracted, followed by pathway enrichment analysis for the modules. Expression of DEGs in granulosa cell samples was measured using quantitative RT-PCR. A total of 674 DEGs were retained, which were significantly enriched with inflammation and immune-related pathways. Eight modules were extracted from the Reactome FI network. Pathway enrichment analysis revealed significant pathways of each module: module 0, Regulation of RhoA activity and Signaling by Rho GTPases pathways shared ARHGAP4 and ARHGAP9; module 2, GlycoProtein VI-mediated activation cascade pathway was enriched with RHOG; module 3, Thromboxane A2 receptor signaling, Chemokine signaling pathway, CXCR4-mediated signaling events pathways were enriched with LYN, the hub gene of module 3. Results of RT-PCR confirmed the finding of the bioinformatic analysis that ARHGAP4, ARHGAP9, RHOG and LYN were significantly upregulated in PCOS. RhoA-related pathways, GlycoProtein VI-mediated activation cascade pathway, ARHGAP4, ARHGAP9, RHOG and LYN may be involved in the pathogenesis of PCOS. PMID:28949383

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

Signaling intermediates (MAPK and PI3K) as therapeutic targets in NSCLC.

PubMed

Ciuffreda, Ludovica; Incani, Ursula Cesta; Steelman, Linda S; Abrams, Stephen L; Falcone, Italia; Curatolo, Anais Del; Chappell, William H; Franklin, Richard A; Vari, Sabrina; Cognetti, Francesco; McCubrey, James A; Milella, Michele

2014-01-01

The RAS/RAF/MEK/ ERK and the PI3K/AKT/mTOR pathways govern fundamental physiological processes, such as cell proliferation, differentiation, metabolism, cytoskeleton reorganization and cell death and survival. Constitutive activation of these signal transduction pathways is a required hallmark of cancer and dysregulation, on either genetic or epigenetic grounds, of these pathways has been implicated in the initiation, progression and metastastic spread of lung cances. Targeting components of the MAPK and PI3K cascades is thus an attractive strategy in the development of novel therapeutic approaches to treat lung cancer, although the use of single pathway inhibitors has met with limited clinical success so far. Indeed, the presence of intra- and inter-pathway compensatory loops that re-activate the very same cascade, either upstream or downstream the point of pharmacological blockade, or activate the alternate pathway following the blockade of one signaling cascade has been demonstrated, potentially driving preclinical (and possibly clinical) resistance. Therefore, the blockade of both pathways with combinations of signaling inhibitors might result in a more efficient anti-tumor effect, and thus potentially overcome and/or delay clinical resistance, as compared with single agent. The current review aims at summarizing the current status of preclinical and clinical research with regard to pathway crosstalks between the MAPK and PI3K cascades in NSCLC and the rationale for combined therapeutic pathway targeting.

Bile Acid Signaling Pathways from the Enterohepatic Circulation to the Central Nervous System

PubMed Central

Mertens, Kim L.; Kalsbeek, Andries; Soeters, Maarten R.; Eggink, Hannah M.

2017-01-01

Bile acids are best known as detergents involved in the digestion of lipids. In addition, new data in the last decade have shown that bile acids also function as gut hormones capable of influencing metabolic processes via receptors such as FXR (farnesoid X receptor) and TGR5 (Takeda G protein-coupled receptor 5). These effects of bile acids are not restricted to the gastrointestinal tract, but can affect different tissues throughout the organism. It is still unclear whether these effects also involve signaling of bile acids to the central nervous system (CNS). Bile acid signaling to the CNS encompasses both direct and indirect pathways. Bile acids can act directly in the brain via central FXR and TGR5 signaling. In addition, there are two indirect pathways that involve intermediate agents released upon interaction with bile acids receptors in the gut. Activation of intestinal FXR and TGR5 receptors can result in the release of fibroblast growth factor 19 (FGF19) and glucagon-like peptide 1 (GLP-1), both capable of signaling to the CNS. We conclude that when plasma bile acids levels are high all three pathways may contribute in signal transmission to the CNS. However, under normal physiological circumstances, the indirect pathway involving GLP-1 may evoke the most substantial effect in the brain. PMID:29163019

Identifying Driver Genomic Alterations in Cancers by Searching Minimum-Weight, Mutually Exclusive Sets

PubMed Central

Lu, Songjian; Lu, Kevin N.; Cheng, Shi-Yuan; Hu, Bo; Ma, Xiaojun; Nystrom, Nicholas; Lu, Xinghua

2015-01-01

An important goal of cancer genomic research is to identify the driving pathways underlying disease mechanisms and the heterogeneity of cancers. It is well known that somatic genome alterations (SGAs) affecting the genes that encode the proteins within a common signaling pathway exhibit mutual exclusivity, in which these SGAs usually do not co-occur in a tumor. With some success, this characteristic has been utilized as an objective function to guide the search for driver mutations within a pathway. However, mutual exclusivity alone is not sufficient to indicate that genes affected by such SGAs are in common pathways. Here, we propose a novel, signal-oriented framework for identifying driver SGAs. First, we identify the perturbed cellular signals by mining the gene expression data. Next, we search for a set of SGA events that carries strong information with respect to such perturbed signals while exhibiting mutual exclusivity. Finally, we design and implement an efficient exact algorithm to solve an NP-hard problem encountered in our approach. We apply this framework to the ovarian and glioblastoma tumor data available at the TCGA database, and perform systematic evaluations. Our results indicate that the signal-oriented approach enhances the ability to find informative sets of driver SGAs that likely constitute signaling pathways. PMID:26317392

ROS mediates interferon gamma induced phosphorylation of Src, through the Raf/ERK pathway, in MCF-7 human breast cancer cell line.

PubMed

Zibara, Kazem; Zeidan, Asad; Bjeije, Hassan; Kassem, Nouhad; Badran, Bassam; El-Zein, Nabil

2017-03-01

Interferon gamma (IFN-ɣ) is a pleiotropic cytokine which plays dual contrasting roles in cancer. Although IFN-ɣ has been clinically used to treat various malignancies, it was recently shown to have protumorigenic activities. Reactive oxygen species (ROS) are overproduced in cancer cells, mainly due to NADPH oxidase activity, which results into several changes in signaling pathways. In this study, we examined IFN-ɣ effect on the phosphorylation levels of key signaling proteins, through ROS production, in the human breast cancer cell line MCF-7. After treatment by IFN-ɣ, results showed a significant increase in the phosphorylation of STAT1, Src, raf, AKT, ERK1/2 and p38 signaling molecules, in a time specific manner. Src and Raf were found to be involved in early stages of IFN-ɣ signaling since their phosphorylation increased very rapidly. Selective inhibition of Src-family kinases resulted in an immediate significant decrease in the phosphorylation status of Raf and ERK1/2, but not p38 and AKT. On the other hand, IFN-ɣ resulted in ROS generation, through H 2 O 2 production, whereas pre-treatment with the ROS inhibitor NAC caused ROS inhibition and a significant decrease in the phosphorylation levels of AKT, ERK1/2, p38 and STAT1. Moreover, pretreatment with a selective NOX1 inhibitor resulted in a significant decrease of AKT phosphorylation. Finally, no direct relationship was found between ROS production and calcium mobilization. In summary, IFN-ɣ signaling in MCF-7 cell line is ROS-dependent and follows the Src/Raf/ERK pathway whereas its signaling through the AKT pathway is highly dependent on NOX1.

Microarray pathway analysis indicated that mitogen-activated protein kinase/extracellular signal-regulated kinase and insulin growth factor 1 signaling pathways were inhibited by small interfering RNA against AT-rich interactive domain 1A in endometrial cancer

PubMed Central

Yang, Ye; Bao, Wei; Sang, Zhengyu; Yang, Yongbing; Lu, Meng; Xi, Xiaowei

2018-01-01

Mutations in the gene encoding AT-rich interactive domain 1A (ARID1A) are frequently observed in endometrial cancer (EC) but the molecular mechanisms linking the genetic changes remain to be fully understood. The present study aimed to elucidate the influence of ARID1A mutations on signaling pathways. Missense, synonymous and nonsense heterozygous ARID1A mutations in the EC HEC-1-A cell line were verified by Sanger sequencing. Mutated ARID1A small interfering RNA was transfected into HEC-1-A cells. Biochemical microarray analysis revealed 13 upregulated pathways, 17 downregulated pathways, 14 significantly affected disease states and functions, 662 upstream and 512 downstream genes in mutated ARID1A-depleted HEC-1-A cells, among which the mitogen-activated protein kinase/extracellular signal-regulated kinase and insulin-like growth factor-1 (IGF1) signaling pathways were the 2 most downregulated pathways. Furthermore, the forkhead box protein O1 pathway was upregulated, while the IGF1 receptor, insulin receptor substrate 1 and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit b pathways were downregulated. Carcinoma tumorigenesis, tumor cell mitosis and tumor cell death were significantly upregulated disease states and functions, while cell proliferation and tumor growth were significantly downregulated. The results of the present study suggested that ARID1A may be a potential prognostic and therapeutic molecular drug target for the prevention of EC progression. PMID:29399196

c-Jun controls the efficiency of MAP kinase signaling by transcriptional repression of MAP kinase phosphatases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprowles, Amy; Robinson, Dan; Wu Yimi

2005-08-15

The mammalian JNK signaling pathway regulates the transcriptional response of cells to environmental stress, including UV irradiation. This signaling pathway is composed of a classical MAP kinase cascade; activation results in phosphorylation of the transcription factor substrates c-Jun and ATF2, and leads to changes in gene expression. The defining components of this pathway are conserved in the fission yeast S. pombe, where the genetic studies have shown that the ability of the JNK homolog Spc1 to be activated in response to UV irradiation is dependent on the presence of the transcription factor substrate Atf1. We have used genetic analysis tomore » define the role of c-Jun in activation of the mammalian JNK signaling pathway. Our results show that optimal activation of JNK requires the presence of its transcription factor substrate c-Jun. Mutational analysis shows that the ability of c-Jun to support efficient activation of JNK requires the ability of Jun to bind DNA, suggesting a transcriptional mechanism. Consistent with this, we show that c-Jun represses the expression of several MAP kinase phosphatases. In the absence of c-Jun, the increased expression of MAP kinase phosphatases leads to impaired activation of the ERK, JNK, and p38 MAP kinases after pathway activation. The results show that one function of c-Jun is to regulate the efficiency of signaling by the ERK, p38, and JNK MAP kinases, a function that is likely to affect cellular responses to many different stimuli.« less

Inhibitory masking controls the threshold sensitivity of retinal ganglion cells

PubMed Central

Pan, Feng; Toychiev, Abduqodir; Zhang, Yi; Atlasz, Tamas; Ramakrishnan, Hariharasubramanian; Roy, Kaushambi; Völgyi, Béla; Akopian, Abram

2016-01-01

Key points Retinal ganglion cells (RGCs) in dark‐adapted retinas show a range of threshold sensitivities spanning ∼3 log units of illuminance.Here, we show that the different threshold sensitivities of RGCs reflect an inhibitory mechanism that masks inputs from certain rod pathways.The masking inhibition is subserved by GABAC receptors, probably on bipolar cell axon terminals.The GABAergic masking inhibition appears independent of dopaminergic circuitry that has been shown also to affect RGC sensitivity.The results indicate a novel mechanism whereby inhibition controls the sensitivity of different cohorts of RGCs. This can limit and thereby ensure that appropriate signals are carried centrally in scotopic conditions when sensitivity rather than acuity is crucial. Abstract The responses of rod photoreceptors, which subserve dim light vision, are carried through the retina by three independent pathways. These pathways carry signals with largely different sensitivities. Retinal ganglion cells (RGCs), the output neurons of the retina, show a wide range of sensitivities in the same dark‐adapted conditions, suggesting a divergence of the rod pathways. However, this organization is not supported by the known synaptic morphology of the retina. Here, we tested an alternative idea that the rod pathways converge onto single RGCs, but inhibitory circuits selectively mask signals so that one pathway predominates. Indeed, we found that application of GABA receptor blockers increased the sensitivity of most RGCs by unmasking rod signals, which were suppressed. Our results indicate that inhibition controls the threshold responses of RGCs under dim ambient light. This mechanism can ensure that appropriate signals cross the bottleneck of the optic nerve in changing stimulus conditions. PMID:27350405

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

Murine natural killer immunoreceptors use distinct proximal signaling complexes to direct cell function

PubMed Central

May, Rebecca M.; Okumura, Mariko; Hsu, Chin-Jung; Bassiri, Hamid; Yang, Enjun; Rak, Gregory; Mace, Emily M.; Philip, Naomi H.; Zhang, Weiguo; Baumgart, Tobias; Orange, Jordan S.; Nichols, Kim E.

2013-01-01

Signaling pathways leading to natural killer (NK)–cell effector function are complex and incompletely understood. Here, we investigated the proximal signaling pathways downstream of the immunotyrosine-based activation motif (ITAM) bearing activating receptors. We found that the adaptor molecule SH2 domain-containing leukocyte protein of 76 kD (SLP-76) is recruited to microclusters at the plasma membrane in activated NK cells and that this is required for initiation of downstream signaling and multiple NK-cell effector functions in vitro and in vivo. Surprisingly, we found that 2 types of proximal signaling complexes involving SLP-76 were formed. In addition to the canonical membrane complex formed between SLP-76 and linker for activation of T cells (LAT) family members, a novel LAT family–independent SLP-76–dependent signaling pathway was identified. The LAT family–independent pathway involved the SH2 domain of SLP-76 and adhesion and degranulation-promoting adaptor protein (ADAP). Both the LAT family–dependent and ADAP-dependent pathway contributed to interferon-gamma production and cytotoxicity; however, they were not essential for other SLP-76–dependent events, including phosphorylation of AKT and extracellular signal–related kinase and cellular proliferation. These results demonstrate that NK cells possess an unexpected bifurcation of proximal ITAM-mediated signaling, each involving SLP-76 and contributing to optimal NK-cell function. PMID:23407547

The dipeptide Pro-Asp promotes IGF-1 secretion and expression in hepatocytes by enhancing JAK2/STAT5 signaling pathway.

PubMed

Wang, Songbo; Wang, Guoqing; Zhang, Mengyuan; Zhuang, Lu; Wan, Xiaojuan; Xu, Jingren; Wang, Lina; Zhu, Xiaotong; Gao, Ping; Xi, Qianyun; Zhang, Yongliang; Shu, Gang; Jiang, Qingyan

2016-11-15

It has been implicated that IGF-1 secretion can be regulated by dietary protein. However, whether the dipeptides, one of digested products of dietary protein, have influence on IGF-1 secretion remain largely unknown. Our study aimed to investigate the effects of the dipeptide Pro-Asp on IGF-1 secretion and expression in hepatocytes and to explore the possible underlying mechanisms. Our findings demonstrated that Pro-Asp promoted the secretion and gene expression of IGF-1 in HepG2 cells and primary porcine hepatocytes. Meanwhile, Pro-Asp activated the ERK and Akt signaling pathways, downstream of IGF-1. In addition, Pro-Asp enhanced GH-mediated JAK2/STAT5 signaling pathway, while inhibition of JAK2/STAT5 blocked the promotive effect of Pro-Asp on IGF-1 secretion and expression. Moreover, acute injection of Pro-Asp stimulated IGF-1 expression and activated JAK2/STAT5 signaling pathway in mice liver. Together, these results suggested that the dipeptide Pro-Asp promoted IGF-1 secretion and expression in hepatocytes by enhancing GH-mediated JAK2/STAT5 signaling pathway. Copyright © 2016. Published by Elsevier Ireland Ltd.

Chlorogenic acid induces apoptosis to inhibit inflammatory proliferation of IL-6-induced fibroblast-like synoviocytes through modulating the activation of JAK/STAT and NF-κB signaling pathways

PubMed Central

LOU, LIXIA; ZHOU, JINGWEI; LIU, YUJUN; WEI, YI; ZHAO, JIULI; DENG, JIAGANG; DONG, BIN; ZHU, LINGQUN; WU, AIMING; YANG, YINGXI; CHAI, LIMIN

2016-01-01

Chlorogenic acid (CGA) is the primary constituent of Caulis Lonicerae, a Chinese herb used for the treatment of rheumatoid arthritis (RA). The present study aimed to investigate whether CGA was able to inhibit the proliferation of the fibroblast-like synoviocyte cell line (RSC-364), stimulated by interleukin (IL)-6, through inducing apoptosis. Following incubation with IL-6 or IL-6 and CGA, the cellular proliferation of RSC-364 cells was detected by MTT assay. The ratio of apoptosed cells were detected by flow cytometry. Western blot analysis was performed to observe protein expression levels of key molecules involved in the Janus-activated kinase/signal transducer and activator of transcription 3 (JAK/STAT) signaling pathway [phosphorylated (p)-STAT3, JAK1 and gp130] and the nuclear factor κB (NF-κB) signaling pathway [phosphorylated (p)-inhibitor of κB kinase subunit α/β and NF-κB p50). It was revealed that CGA was able to inhibit the inflammatory proliferation of RSC-364 cells mediated by IL-6 through inducing apoptosis. CGA was also able to suppress the expression levels of key molecules in the JAK/STAT and NF-κB signaling pathways, and inhibit the activation of these signaling pathways in the inflammatory response through IL-6-mediated signaling, thereby resulting in the inhibition of the inflammatory proliferation of synoviocytes. The present results indicated that CGA may have potential as a novel therapeutic agent for inhibiting inflammatory hyperplasia of the synovium through inducing synoviocyte apoptosis in patients with RA. PMID:27168850

An alternative mode of CD43 signal transduction activates pro-survival pathways of T lymphocytes.

PubMed

Bravo-Adame, Maria Elena; Vera-Estrella, Rosario; Barkla, Bronwyn J; Martínez-Campos, Cecilia; Flores-Alcantar, Angel; Ocelotl-Oviedo, Jose Pablo; Pedraza-Alva, Gustavo; Rosenstein, Yvonne

2017-01-01

CD43 is one of the most abundant co-stimulatory molecules on a T-cell surface; it transduces activation signals through its cytoplasmic domain, contributing to modulation of the outcome of T-cell responses. The aim of this study was to uncover new signalling pathways regulated by this sialomucin. Analysis of changes in protein abundance allowed us to identify pyruvate kinase isozyme M2 (PKM2), an enzyme of the glycolytic pathway, as an element potentially participating in the signalling cascade resulting from the engagement of CD43 and the T-cell receptor (TCR). We found that the glycolytic activity of this enzyme was not significantly increased in response to TCR+CD43 co-stimulation, but that PKM2 was tyrosine phosphorylated, suggesting that it was performing moonlight functions. We report that phosphorylation of both Y 105 of PKM2 and of Y 705 of signal transducer and activator of transcription 3 was induced in response to TCR+CD43 co-stimulation, resulting in activation of the mitogen-activated protein kinase kinase 5/extracellular signal-regulated kinase 5 (MEK5/ERK5) pathway. ERK5 and the cAMP response element binding protein (CREB) were activated, and c-Myc and nuclear factor-κB (p65) nuclear localization, as well as Bad phosphorylation, were augmented. Consistent with this, expression of human CD43 in a murine T-cell hybridoma favoured cell survival. Altogether, our data highlight novel signalling pathways for the CD43 molecule in T lymphocytes, and underscore a role for CD43 in promoting cell survival through non-glycolytic functions of metabolic enzymes. © 2016 John Wiley & Sons Ltd.

Herpes simplex virus triggers activation of calcium-signaling pathways

PubMed Central

Cheshenko, Natalia; Del Rosario, Brian; Woda, Craig; Marcellino, Daniel; Satlin, Lisa M.; Herold, Betsy C.

2003-01-01

The cellular pathways required for herpes simplex virus (HSV) invasion have not been defined. To test the hypothesis that HSV entry triggers activation of Ca2+-signaling pathways, the effects on intracellular calcium concentration ([Ca2+]i) after exposure of cells to HSV were examined. Exposure to virus results in a rapid and transient increase in [Ca2+]i. Pretreatment of cells with pharmacological agents that block release of inositol 1,4,5-triphosphate (IP3)–sensitive endoplasmic reticulum stores abrogates the response. Moreover, treatment of cells with these pharmacological agents inhibits HSV infection and prevents focal adhesion kinase (FAK) phosphorylation, which occurs within 5 min after viral infection. Viruses deleted in glycoprotein L or glycoprotein D, which bind but do not penetrate, fail to induce a [Ca2+]i response or trigger FAK phosphorylation. Together, these results support a model for HSV infection that requires activation of IP3-responsive Ca2+-signaling pathways and that is associated with FAK phosphorylation. Defining the pathway of viral invasion may lead to new targets for anti-viral therapy. PMID:14568989

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. © 2013 Wiley Periodicals, Inc.

Targeting Signaling to YAP for the Therapy of NF2

DTIC Science & Technology

2016-12-01

at any step of our newly identified pathway, and to test the preclinical efficacy of lead compounds in xenograft models of NF2. During this grant...Pathway Component AMOTL2 by the mTORC2 Kinase Promotes YAP Signaling, Resulting in Enhanced Glioblastoma Growth and Invasiveness. The Journal of Biological Chemistry. 2015. 290(32):19387-401.

An algorithm for modularization of MAPK and calcium signaling pathways: comparative analysis among different species.

PubMed

Nayak, Losiana; De, Rajat K

2007-12-01

Signaling pathways are large complex biochemical networks. It is difficult to analyze the underlying mechanism of such networks as a whole. In the present article, we have proposed an algorithm for modularization of signal transduction pathways. Unlike studying a signaling pathway as a whole, this enables one to study the individual modules (less complex smaller units) easily and hence to study the entire pathway better. A comparative study of modules belonging to different species (for the same signaling pathway) has been made, which gives an overall idea about development of the signaling pathways over the taken set of species of calcium and MAPK signaling pathways. The superior performance, in terms of biological significance, of the proposed algorithm over an existing community finding algorithm of Newman [Newman MEJ. Modularity and community structure in networks. Proc Natl Acad Sci USA 2006;103(23):8577-82] has been demonstrated using the aforesaid pathways of H. sapiens.

Exercise training and return to a well-balanced diet activate the neuregulin 1/ErbB pathway in skeletal muscle of obese rats.

PubMed

Ennequin, Gaël; Boisseau, Nathalie; Caillaud, Kevin; Chavanelle, Vivien; Gerbaix, Maude; Metz, Lore; Etienne, Monique; Walrand, Stéphane; Masgrau, Aurélie; Guillet, Christelle; Courteix, Daniel; Niu, Airu; Li, Yi-Ping; Capel, Fréderic; Sirvent, Pascal

2015-06-15

Some studies suggest that neuregulin 1 (NRG1) could be involved in the regulation of skeletal muscle energy metabolism in rodents. Here we assessed whether unbalanced diet is associated with alterations of the NRG1 signalling pathway and whether exercise and diet might restore NRG1 signalling in skeletal muscle of obese rats. We show that diet-induced obesity does not impair NRG1 signalling in rat skeletal muscle. We also report that endurance training and a well-balanced diet activate the NRG1 signalling in skeletal muscle of obese rats, possibly via a new mechanism mediated by the protease ADAM17. These results suggest that some beneficial effects of physical activity and diet in obese rats could be partly explained by stimulation of the NRG1 signalling pathway. Some studies suggest that the signalling pathway of neuregulin 1 (NRG1), a protein involved in the regulation of skeletal muscle metabolism, could be altered by nutritional and exercise interventions. We hypothesized that diet-induced obesity could lead to alterations of the NRG1 signalling pathway and that chronic exercise could improve NRG1 signalling in rat skeletal muscle. To test this hypothesis, male Wistar rats received a high fat/high sucrose (HF/HS) diet for 16 weeks. At the end of this period, NRG1 and ErbB expression/activity in skeletal muscle was assessed. The obese rats then continued the HF/HS diet or were switched to a well-balanced diet. Moreover, in both groups, half of the animals also performed low intensity treadmill exercise training. After another 8 weeks, NRG1 and ErbB expression/activity in skeletal muscle were tested again. The 16 week HF/HS diet induced obesity, but did not significantly affect the NRG1/ErbB signalling pathway in rat skeletal muscle. Conversely, after the switch to a well-balanced diet, NRG1 cleavage ratio and ErbB4 amount were increased. Chronic exercise training also promoted NRG1 cleavage, resulting in increased ErbB4 phosphorylation. This result was associated with increased protein expression and phosphorylation ratio of the metalloprotease ADAM17, which is involved in NRG1 shedding. Similarly, in vitro stretch-induced activation of ADAM17 in rat myoblasts induced NRG1 cleavage and ErbB4 activation. These results show that low intensity endurance training and well-balanced diet activate the NRG1-ErbB4 pathway, possibly via the metalloprotease ADAM17, in skeletal muscle of diet-induced obese rats. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Endodermal Hedgehog signals modulate Notch pathway activity in the developing digestive tract mesenchyme

PubMed Central

Kim, Tae-Hee; Kim, Byeong-Moo; Mao, Junhao; Rowan, Sheldon; Shivdasani, Ramesh A.

2011-01-01

The digestive tract epithelium and its adjoining mesenchyme undergo coordinated patterning and growth during development. The signals they exchange in the process are not fully characterized but include ligands of the Hedgehog (Hh) family, which originate in the epithelium and are necessary for mesenchymal cells to expand in number and drive elongation of the developing gut tube. The Notch signaling pathway has known requirements in fetal and adult intestinal epithelial progenitors. We detected Notch pathway activity in the embryonic gut mesenchyme and used conditional knockout mice to study its function. Selective disruption of the Notch effector gene RBP-Jκ (Rbpj) in the mesenchyme caused progressive loss of subepithelial fibroblasts and abbreviated gut length, revealing an unexpected requirement in this compartment. Surprisingly, constitutive Notch activity also induced rapid mesenchymal cell loss and impaired organogenesis, probably resulting from increased cell death and suggesting the need for a delicate balance in Notch signaling. Because digestive tract anomalies in mouse embryos with excess Notch activity phenocopy the absence of Hh signaling, we postulated that endodermal Hh restrains mesenchymal Notch pathway activity. Indeed, Hh-deficient embryos showed Notch overactivity in their defective gut mesenchyme and exposure to recombinant sonic hedgehog could override Notch-induced death of cultured fetal gut mesenchymal cells. These results reveal unexpected interactions between prominent signals in gastrointestinal development and provide a coherent explanation for Hh requirements in mesenchymal cell survival and organ growth. PMID:21750033

Maternal Chromium Restriction Leads to Glucose Metabolism Imbalance in Mice Offspring through Insulin Signaling and Wnt Signaling Pathways

PubMed Central

Zhang, Qian; Sun, Xiaofang; Xiao, Xinhua; Zheng, Jia; Li, Ming; Yu, Miao; Ping, Fan; Wang, Zhixin; Qi, Cuijuan; Wang, Tong; Wang, Xiaojing

2016-01-01

An adverse intrauterine environment, induced by a chromium-restricted diet, is a potential cause of metabolic disease in adult life. Up to now, the relative mechanism has not been clear. C57BL female mice were time-mated and fed either a control diet (CD), or a chromium-restricted diet (CR) throughout pregnancy and the lactation period. After weaning, some offspring continued the diet diagram (CD-CD or CR-CR), while other offspring were transferred to another diet diagram (CD-CR or CR-CD). At 32 weeks of age, glucose metabolism parameters were measured, and the liver from CR-CD group and CD-CD group was analyzed using a gene array. Quantitative real-time polymerase chain reaction (qPCR) and Western blot were used to verify the result of the gene array. A maternal chromium-restricted diet resulted in obesity, hyperglycemia, hyperinsulinemia, increased area under the curve (AUC) of glucose in oral glucose tolerance testing and homeostasis model assessment of insulin resistance (HOMA-IR). There were 463 genes that differed significantly (>1.5-fold change, p < 0.05) between CR-CD offspring (264 up-regulated genes, 199 down-regulated genes) and control offspring. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) analysis revealed that the insulin signaling pathway and Wnt signaling pathway were in the center of the gene network. Our study provides the first evidence that maternal chromium deficiency influences glucose metabolism in pups through the regulation of insulin signaling and Wnt signaling pathways. PMID:27782077

Antitumor activity of taspine by modulating the EGFR signaling pathway of Erk1/2 and Akt in vitro and in vivo.

PubMed

Zhang, Yanmin; Zheng, Lei; Zhang, Jie; Dai, Bingling; Wang, Nan; Chen, Yinnan; He, Langchong

2011-11-01

EGFR, as a critical signaling pathway in many human tumors, has become an important target of cancer drug design. Taspine has shown meaningful angiogenesis activity in previous studies. This paper is to investigate the antitumor action of taspine by modulating the EGFR signaling pathway. The study determined the expression of key signaling molecules of EGFR (EGFR, Akt, p-Akt, Erk, and p-Erk) by Western blot and real-time PCR and analyzed their correlations with subsequent reactions. In addition, the cell proliferation, migration, and EGF production were examined by MTT, transwell system, and ELISA. The antitumor activity in vivo was carried out by xenograft in athymic mice. The results showed that taspine could inhibit A431 and Hek293/EGFR cell proliferation and A431 cell migration as well as EGF production. Compared to the negative control, EGFR, Akt, and phosphorylation of Akt were significantly inhibited by taspine treatment in A431 and HEK293/EGFR cells. Consistent with the inhibition of Akt activity, Erk1/2 and its phosphorylation were reduced. Moreover, taspine inhibited A431 xenograft tumor growth. These results suggest that EGFR activated by EGF and its downstream signaling pathways proteins could be downregulated by taspine in a dose-dependent manner. The antitumor mechanism of taspine through the EGFR pathway lies in the ability to inhibit A431 cell proliferation and migration by reducing EGF secretion. This occurs through the repression of EGFR which mediates not only MAPK (Erk1/2) but also Akt signals. © Georg Thieme Verlag KG Stuttgart · New York.

Transcriptome analysis supports viral infection and fluoride toxicity as contributors to chronic kidney disease of unknown etiology (CKDu) in Sri Lanka.

PubMed

Sayanthooran, Saravanabavan; Gunerathne, Lishanthe; Abeysekera, Tilak D J; Magana-Arachchi, Dhammika N

2018-05-28

Chronic kidney disease of unknown etiology (CKDu), having epidemic characteristics, is being diagnosed increasingly in certain tropical regions of the world, mainly Latin America and Sri Lanka. They have been observed primarily in farming communities and current hypotheses point toward many environmental and occupational triggers. CKDu does not have common etiologies of chronic kidney disease (CKD) such as hypertension, diabetes, or autoimmune disease. We aimed to understand the molecular processes underlying CKDu in Sri Lanka using transcriptome analysis. RNA extracted from whole blood was reverse transcribed and used for microarray analysis using the Human HT-12 v.4 array (Illumina). Pathway analysis was carried out using ingenuity pathway analysis (IPA-Qiagen). Microarray results were validated using real-time PCR of five selected genes. Pathways related to innate immune response, including interferon signaling, inflammasome signaling and TREM1 signaling had the most significant positive activation z scores, where as EIF2 signaling and mTOR signaling had the most significant negative activation z scores. Pathways previously linked to fluoride toxicity; G-protein activation, Cdc42 signaling, Rac signaling and RhoA signaling were activated in CKDu patients. The most significantly activated biological functions were cell death, cell movement and antimicrobial response. Significant toxicological functions were mitochondrial dysfunction, oxidative stress and apoptosis. Based on the molecular pathway analysis in CKDu patients and review of literature, viral infections and fluoride toxicity appear to be contributing to the molecular mechanisms underlying CKDu.

Determinants of cell-to-cell variability in protein kinase signaling.

PubMed

Jeschke, Matthias; Baumgärtner, Stephan; Legewie, Stefan

2013-01-01

Cells reliably sense environmental changes despite internal and external fluctuations, but the mechanisms underlying robustness remain unclear. We analyzed how fluctuations in signaling protein concentrations give rise to cell-to-cell variability in protein kinase signaling using analytical theory and numerical simulations. We characterized the dose-response behavior of signaling cascades by calculating the stimulus level at which a pathway responds ('pathway sensitivity') and the maximal activation level upon strong stimulation. Minimal kinase cascades with gradual dose-response behavior show strong variability, because the pathway sensitivity and the maximal activation level cannot be simultaneously invariant. Negative feedback regulation resolves this trade-off and coordinately reduces fluctuations in the pathway sensitivity and maximal activation. Feedbacks acting at different levels in the cascade control different aspects of the dose-response curve, thereby synergistically reducing the variability. We also investigated more complex, ultrasensitive signaling cascades capable of switch-like decision making, and found that these can be inherently robust to protein concentration fluctuations. We describe how the cell-to-cell variability of ultrasensitive signaling systems can be actively regulated, e.g., by altering the expression of phosphatase(s) or by feedback/feedforward loops. Our calculations reveal that slow transcriptional negative feedback loops allow for variability suppression while maintaining switch-like decision making. Taken together, we describe design principles of signaling cascades that promote robustness. Our results may explain why certain signaling cascades like the yeast pheromone pathway show switch-like decision making with little cell-to-cell variability.

Intervention of electroacupuncture on spinal p38 MAPK/ATF-2/VR-1 pathway in treating inflammatory pain induced by CFA in rats

PubMed Central

2013-01-01

Background Previous studies have demonstrated that p38 MAPK signal transduction pathway plays an important role in the development and maintenance of inflammatory pain. Electroacupuncture (EA) can suppress the inflammatory pain. However, the relationship between EA effect and p38 MAPK signal transduction pathway in inflammatory pain remains poorly understood. It is our hypothesis that p38 MAPK/ATF-2/VR-1 and/or p38 MAPK/ATF-2/COX-2 signal transduction pathway should be activated by inflammatory pain in CFA-injected model. Meanwhile, EA may inhibit the activation of p38 MAPK signal transduction pathway. The present study aims to investigate that anti-inflammatory and analgesic effect of EA and its intervention on the p38 MAPK signal transduction pathway in a rat model of inflammatory pain. Results EA had a pronounced anti-inflammatory and analgesic effect on CFA-induced chronic inflammatory pain in rats. EA could quickly raise CFA-rat’s paw withdrawal thresholds (PWTs) and maintain good and long analgesic effect, while it subdued the ankle swelling of CFA rats only at postinjection day 14. EA could down-regulate the protein expressions of p-p38 MAPK and p-ATF-2, reduced the numbers of p-p38 MAPK-IR cells and p-ATF-2-IR cells in spinal dorsal horn in CFA rats, inhibited the expressions of both protein and mRNA of VR-1, but had no effect on the COX-2 mRNA expression. Conclusions The present study indicates that inhibiting the activation of spinal p38 MAPK/ATF-2/VR-1 pathway may be one of the main mechanisms via central signal transduction pathway in the process of anti-inflammatory pain by EA in CFA rats. PMID:23517865

Drosophila melanogaster Hedgehog cooperates with Frazzled to guide axons through a non-canonical signalling pathway.

PubMed

Ricolo, Delia; Butí, Elisenda; Araújo, Sofia J

2015-08-01

We report that the morphogen Hedgehog (Hh) is an axonal chemoattractant in the midline of Drosophila melanogaster embryos. Hh is present in the ventral nerve cord during axonal guidance and overexpression of hh in the midline causes ectopic midline crossing of FasII-positive axonal tracts. In addition, we show that Hh influences axonal guidance via a non-canonical signalling pathway dependent on Ptc. Our results reveal that the Hh pathway cooperates with the Netrin/Frazzled pathway to guide axons through the midline in invertebrates. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Alternative splicing regulation in tumor necrosis factor-mediated inflammation.

PubMed

López-Urrutia, Eduardo; Campos-Parra, Alma; Herrera, Luis Alonso; Pérez-Plasencia, Carlos

2017-11-01

It is generally accepted that alternative splicing has an effect on disease when it leads to conspicuous changes in relevant proteins, but that the combinatorial effect of several small modifications can have marked outcomes as well. Inflammation is a complex process involving numerous signaling pathways, among which the tumor necrosis factor (TNF) pathway is one of the most studied. Signaling pathways are commonly represented as intricate cascades of molecular interactions that eventually lead to the activation of one or several genes. Alternative splicing is a common means of controlling protein expression in time and space; therefore, it can modulate the outcome of signaling pathways through small changes in their elements. Notably, the overall process is tightly regulated, which is easily overlooked when analyzing the pathway as a whole. The present review summarizes recent studies of the alternative splicing of key players of the TNF pathway leading to inflammation, and hypothesizes on the cumulative results of those modifications and the impact on cancer development.

Alternative splicing regulation in tumor necrosis factor-mediated inflammation

PubMed Central

López-Urrutia, Eduardo; Campos-Parra, Alma; Herrera, Luis Alonso; Pérez-Plasencia, Carlos

2017-01-01

It is generally accepted that alternative splicing has an effect on disease when it leads to conspicuous changes in relevant proteins, but that the combinatorial effect of several small modifications can have marked outcomes as well. Inflammation is a complex process involving numerous signaling pathways, among which the tumor necrosis factor (TNF) pathway is one of the most studied. Signaling pathways are commonly represented as intricate cascades of molecular interactions that eventually lead to the activation of one or several genes. Alternative splicing is a common means of controlling protein expression in time and space; therefore, it can modulate the outcome of signaling pathways through small changes in their elements. Notably, the overall process is tightly regulated, which is easily overlooked when analyzing the pathway as a whole. The present review summarizes recent studies of the alternative splicing of key players of the TNF pathway leading to inflammation, and hypothesizes on the cumulative results of those modifications and the impact on cancer development. PMID:29113151

PAR1 participates in the ability of multidrug resistance and tumorigenesis by controlling Hippo-YAP pathway.

PubMed

Fujimoto, Daisuke; Ueda, Yuki; Hirono, Yasuo; Goi, Takanori; Yamaguchi, Akio

2015-10-27

The Hippo pathway significantly correlates with organ size control and tumorigenesis. The activity of YAP/TAZ, a transducer of the Hippo pathway, is required to sustain self-renewal and tumor-initiation capacities in cancer stem cells (CSCs). But, upstream signals that control the mammalian Hippo pathway have not been well understood. Here, we reveal a connection between the Protease-activated receptor 1 (PAR1) signaling pathway and the Hippo-YAP pathway in gastric cancer stem-like cells. The selective PAR1 agonist TFLLR-NH2 induces an increase in the fraction of side population cells which is enriched in CSCs, and promotes tumorigenesis, multi cancer drug resistance, cell morphological change, and cell invasion which are characteristics of CSCs. In addition, PAR1 activation inhibits the Hippo-YAP pathway kinase Lats via Rho GTPase. Lats kinase inhibition in turn results in increased nuclear localization of dephosphorylated YAP. Furthermore, PAR1 activation confers CSCs related traits via the Hippo-YAP pathway, and the Hippo-YAP pathway correlates with epithelial mesenchymal transition which is induced by PAR1 activation. Our research suggests that the PAR1 signaling deeply participates in the ability of multi drug resistance and tumorigenesis through interactions with the Hippo-YAP pathway signaling in gastric cancer stem-like cells. We presume that inhibited YAP is a new therapeutic target in the treatment human gastric cancer invasion and metastasis by dysregulated PAR1 or its agonists.

Identification of Differentially Expressed Genes in Breast Muscle and Skin Fat of Postnatal Pekin Duck

PubMed Central

Schachtschneider, Kyle Michael; Liu, Xiaolin; Huang, Wei; Xie, Ming; Hou, Shuisheng

2014-01-01

Lean-type Pekin duck is a commercial breed that has been obtained through long-term selection. Investigation of the differentially expressed genes in breast muscle and skin fat at different developmental stages will contribute to a comprehensive understanding of the potential mechanisms underlying the lean-type Pekin duck phenotype. In the present study, RNA-seq was performed on breast muscle and skin fat at 2-, 4- and 6-weeks of age. More than 89% of the annotated duck genes were covered by our RNA-seq dataset. Thousands of differentially expressed genes, including many important genes involved in the regulation of muscle development and fat deposition, were detected through comparison of the expression levels in the muscle and skin fat of the same time point, or the same tissue at different time points. KEGG pathway analysis showed that the differentially expressed genes clustered significantly in many muscle development and fat deposition related pathways such as MAPK signaling pathway, PPAR signaling pathway, Calcium signaling pathway, Fat digestion and absorption, and TGF-beta signaling pathway. The results presented here could provide a basis for further investigation of the mechanisms involved in muscle development and fat deposition in Pekin duck. PMID:25264787

Halobenzoquinone-Induced Alteration of Gene Expression Associated with Oxidative Stress Signaling Pathways.

PubMed

Li, Jinhua; Moe, Birget; Liu, Yanming; Li, Xing-Fang

2018-06-05

Halobenzoquinones (HBQs) are emerging disinfection byproducts (DBPs) that effectively induce reactive oxygen species and oxidative damage in vitro. However, the impacts of HBQs on oxidative-stress-related gene expression have not been investigated. In this study, we examined alterations in the expression of 44 genes related to oxidative-stress-induced signaling pathways in human uroepithelial cells (SV-HUC-1) upon exposure to six HBQs. The results show the structure-dependent effects of HBQs on the studied gene expression. After 2 h of exposure, the expression levels of 9 to 28 genes were altered, while after 8 h of exposure, the expression levels of 29 to 31 genes were altered. Four genes ( HMOX1, NQO1, PTGS2, and TXNRD1) were significantly upregulated by all six HBQs at both exposure time points. Ingenuity pathway analysis revealed that the Nrf2 pathway was significantly responsive to HBQ exposure. Other canonical pathways responsive to HBQ exposure included GSH redox reductions, superoxide radical degradation, and xenobiotic metabolism signaling. This study has demonstrated that HBQs significantly alter the gene expression of oxidative-stress-related signaling pathways and contributes to the understanding of HBQ-DBP-associated toxicity.

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

PubMed Central

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

2016-01-01

Chitosan is one of the most abundant carbohydrate biopolymers in the world, and chitosan oligosaccharide (COS), which is prepared from chitosan, is a plant immunity regulator. The present study aimed to validate the effect of COS on inducing resistance to tobacco mosaic virus (TMV) in Arabidopsis and to investigate the potential defence-related signalling pathways involved. Optimal conditions for the induction of TMV resistance in Arabidopsis were COS pretreatment at 50 mg/L for 1 day prior to inoculation with TMV. Multilevel indices, including phenotype data, and TMV coat protein expression, revealed that COS induced TMV resistance in wild-type and jasmonic acid pathway- deficient (jar1) Arabidopsis plants, but not in salicylic acid pathway deficient (NahG) Arabidopsis plants. Quantitative-PCR and analysis of phytohormone levels confirmed that COS pretreatment enhanced the expression of the defence-related gene PR1, which is a marker of salicylic acid signalling pathway, and increased the amount of salicylic acid in WT and jar1, but not in NahG plants. Taken together, these results confirm that COS induces TMV resistance in Arabidopsis via activation of the salicylic acid signalling pathway. PMID:27189192

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

PubMed

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

2016-05-18

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

Role of insulin, adipocyte hormones, and nutrient-sensing pathways in regulating fuel metabolism and energy homeostasis: a nutritional perspective of diabetes, obesity, and cancer.

PubMed

Marshall, Stephen

2006-08-01

Traditionally, nutrients such as glucose and amino acids have been viewed as substrates for the generation of high-energy molecules and as precursors for the biosynthesis of macromolecules. However, it is now apparent that nutrients also function as signaling molecules in functionally diverse signal transduction pathways. Glucose and amino acids trigger signaling cascades that regulate various aspects of fuel and energy metabolism and control the growth, proliferation, and survival of cells. Here, we provide a functional and regulatory overview of three well-established nutrient signaling pathways-the hexosamine signaling pathway, the mTOR (mammalian target of rapamycin) signaling pathway, and the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Nutrient signaling pathways are interconnected, coupled to insulin signaling, and linked to the release of metabolic hormones from adipose tissue. Thus, nutrient signaling pathways do not function in isolation. Rather, they appear to serve as components of a larger "metabolic regulatory network" that controls fuel and energy metabolism (at the cell, tissue, and whole-body levels) and links nutrient availability with cell growth and proliferation. Understanding the diverse roles of nutrients and delineating nutrient signaling pathways should facilitate drug discovery research and the search for novel therapeutic compounds to prevent and treat various human diseases such as diabetes, obesity, and cancer.

Transcriptomic analyses on muscle tissues of Litopenaeus vannamei provide the first profile insight into the response to low temperature stress.

PubMed

Huang, Wen; Ren, Chunhua; Li, Hongmei; Huo, Da; Wang, Yanhong; Jiang, Xiao; Tian, Yushun; Luo, Peng; Chen, Ting; Hu, Chaoqun

2017-01-01

The Pacific white shrimp (Litopenaeus vannamei) is an important cultured crustacean species worldwide. However, little is known about the molecular mechanism of this species involved in the response to cold stress. In this study, four separate RNA-Seq libraries of L. vannamei were generated from 13°C stress and control temperature. Total 29,662 of Unigenes and overall of 19,619 annotated genes were obtained. Three comparisons were carried out among the four libraries, in which 72 of the top 20% of differentially-expressed genes were obtained, 15 GO and 5 KEGG temperature-sensitive pathways were fished out. Catalytic activity (GO: 0003824) and Metabolic pathways (ko01100) were the most annotated GO and KEGG pathways in response to cold stress, respectively. In addition, Calcium, MAPK cascade, Transcription factor and Serine/threonine-protein kinase signal pathway were picked out and clustered. Serine/threonine-protein kinase signal pathway might play more important roles in cold adaptation, while other three signal pathway were not widely transcribed. Our results had summarized the differentially-expressed genes and suggested the major important signaling pathways and related genes. These findings provide the first profile insight into the molecular basis of L. vannamei response to cold stress.

Transcriptomic analyses on muscle tissues of Litopenaeus vannamei provide the first profile insight into the response to low temperature stress

PubMed Central

Huang, Wen; Ren, Chunhua; Li, Hongmei; Huo, Da; Wang, Yanhong; Jiang, Xiao; Tian, Yushun; Luo, Peng; Hu, Chaoqun

2017-01-01

The Pacific white shrimp (Litopenaeus vannamei) is an important cultured crustacean species worldwide. However, little is known about the molecular mechanism of this species involved in the response to cold stress. In this study, four separate RNA-Seq libraries of L. vannamei were generated from 13°C stress and control temperature. Total 29,662 of Unigenes and overall of 19,619 annotated genes were obtained. Three comparisons were carried out among the four libraries, in which 72 of the top 20% of differentially-expressed genes were obtained, 15 GO and 5 KEGG temperature-sensitive pathways were fished out. Catalytic activity (GO: 0003824) and Metabolic pathways (ko01100) were the most annotated GO and KEGG pathways in response to cold stress, respectively. In addition, Calcium, MAPK cascade, Transcription factor and Serine/threonine-protein kinase signal pathway were picked out and clustered. Serine/threonine-protein kinase signal pathway might play more important roles in cold adaptation, while other three signal pathway were not widely transcribed. Our results had summarized the differentially-expressed genes and suggested the major important signaling pathways and related genes. These findings provide the first profile insight into the molecular basis of L. vannamei response to cold stress. PMID:28575089

Oncogenic Viruses and Tumor Glucose Metabolism: Like Kids in a Candy Store

PubMed Central

Noch, Evan; Khalili, Kamel

2011-01-01

Oncogenic viruses represent a significant public health burden in light of the multitude of malignancies resulting from chronic or spontaneous viral infection and transformation. Though many of the molecular signaling pathways underlying virus-mediated cellular transformation are known, the impact of these viruses on metabolic signaling and phenotype within proliferating tumor cells is less well understood. Whether the interaction of oncogenic viruses with metabolic signaling pathways involves enhanced glucose uptake and glycolysis, both hallmark features of transformed cells, or dysregulation of molecular pathways regulating oxidative stress, viruses are adept at facilitating tumor expansion. Through their effects on cell proliferation pathways, such as the PI3K and MAPK pathways, the cell cycle regulatory proteins, p53 and ATM, and the cell stress response proteins, HIF-1α and AMPK, viruses exert control over critical metabolic signaling cascades. Additionally, oncogenic viruses modulate the tumor metabolomic profile through direct and indirect interaction with glucose transporters, such as GLUT1, and specific glycolytic enzymes, including pyruvate kinase, glucose 6-phosphate dehydrogenase, and hexokinase. Through these pathways, oncogenic viruses alter the phenotypic characteristics of transformed cells and their methods of energy utilization, and it may be possible to develop novel anti-glycolytic therapies to target these dysregulated pathways in virus-derived malignancies. PMID:22234809

A novel stilbene-like compound that inhibits melanoma growth by regulating melanocyte differentiation and proliferation.

PubMed

Stueven, Noah A; Schlaeger, Nicholas M; Monte, Aaron P; Hwang, Sheng-Ping L; Huang, Cheng-Chen

2017-12-15

Melanoma is the most aggressive form of skin cancer. Current challenges to melanoma therapy include the adverse effects from immunobiologics, resistance to drugs targeting the MAPK pathway, intricate interaction of many signal pathways, and cancer heterogeneity. Thus combinational therapy with drugs targeting multiple signaling pathways becomes a new promising therapy. Here, we report a family of stilbene-like compounds called A11 that can inhibit melanoma growth in both melanoma-forming zebrafish embryos and mouse melanoma cells. The growth inhibition by A11 is a result of mitosis reduction but not apoptosis enhancement. Meanwhile, A11 activates both MAPK and Akt signaling pathways. Many A11-treated mouse melanoma cells exhibit morphological changes and resemble normal melanocytes. Furthermore, we found that A11 causes down-regulation of melanocyte differentiation genes, including Pax3 and MITF. Together, our results suggest that A11 could be a new melanoma therapeutic agent by inhibiting melanocyte differentiation and proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

Clostridium perfringens Phospholipase C Induced ROS Production and Cytotoxicity Require PKC, MEK1 and NFκB Activation

PubMed Central

Monturiol-Gross, Laura; Flores-Díaz, Marietta; Pineda-Padilla, Maria Jose; Castro-Castro, Ana Cristina; Alape-Giron, Alberto

2014-01-01

Clostridium perfringens phospholipase C (CpPLC), also called α-toxin, is the most toxic extracellular enzyme produced by this bacteria and is essential for virulence in gas gangrene. At lytic concentrations, CpPLC causes membrane disruption, whereas at sublytic concentrations this toxin causes oxidative stress and activates the MEK/ERK pathway, which contributes to its cytotoxic and myotoxic effects. In the present work, the role of PKC, ERK 1/2 and NFκB signalling pathways in ROS generation induced by CpPLC and their contribution to CpPLC-induced cytotoxicity was evaluated. The results demonstrate that CpPLC induces ROS production through PKC, MEK/ERK and NFκB pathways, the latter being activated by the MEK/ERK signalling cascade. Inhibition of either of these signalling pathways prevents CpPLC's cytotoxic effect. In addition, it was demonstrated that NFκB inhibition leads to a significant reduction in the myotoxicity induced by intramuscular injection of CpPLC in mice. Understanding the role of these signalling pathways could lead towards developing rational therapeutic strategies aimed to reduce cell death during a clostridialmyonecrosis. PMID:24466113

Noise characteristics of the Escherichia coli rotary motor

PubMed Central

2011-01-01

Background The chemotaxis pathway in the bacterium Escherichia coli allows cells to detect changes in external ligand concentration (e.g. nutrients). The pathway regulates the flagellated rotary motors and hence the cells' swimming behaviour, steering them towards more favourable environments. While the molecular components are well characterised, the motor behaviour measured by tethered cell experiments has been difficult to interpret. Results We study the effects of sensing and signalling noise on the motor behaviour. Specifically, we consider fluctuations stemming from ligand concentration, receptor switching between their signalling states, adaptation, modification of proteins by phosphorylation, and motor switching between its two rotational states. We develop a model which includes all signalling steps in the pathway, and discuss a simplified version, which captures the essential features of the full model. We find that the noise characteristics of the motor contain signatures from all these processes, albeit with varying magnitudes. Conclusions Our analysis allows us to address how cell-to-cell variation affects motor behaviour and the question of optimal pathway design. A similar comprehensive analysis can be applied to other two-component signalling pathways. PMID:21951560

The effects of graded levels of calorie restriction: VI. Impact of short-term graded calorie restriction on transcriptomic responses of the hypothalamic hunger and circadian signaling pathways.

PubMed

Derous, Davina; Mitchell, Sharon E; Green, Cara L; Chen, Luonan; Han, Jing-Dong J; Wang, Yingchun; Promislow, Daniel E L; Lusseau, David; Speakman, John R; Douglas, Alex

2016-04-01

Food intake and circadian rhythms are regulated by hypothalamic neuropeptides and circulating hormones, which could mediate the anti-ageing effect of calorie restriction (CR). We tested whether these two signaling pathways mediate CR by quantifying hypothalamic transcripts of male C57BL/6 mice exposed to graded levels of CR (10 % to 40 %) for 3 months. We found that the graded CR manipulation resulted in upregulation of core circadian rhythm genes, which correlated negatively with circulating levels of leptin, insulin-like growth factor 1 (IGF-1), insulin, and tumor necrosis factor alpha (TNF-α). In addition, key components in the hunger signaling pathway were expressed in a manner reflecting elevated hunger at greater levels of restriction, and which also correlated negatively with circulating levels of insulin, TNF-α, leptin and IGF-1. Lastly, phenotypes, such as food anticipatory activity and body temperature, were associated with expression levels of both hunger genes and core clock genes. Our results suggest modulation of the hunger and circadian signaling pathways in response to altered levels of circulating hormones, that are themselves downstream of morphological changes resulting from CR treatment, may be important elements in the response to CR, driving some of the key phenotypic outcomes.

The effects of graded levels of calorie restriction: VI. Impact of short-term graded calorie restriction on transcriptomic responses of the hypothalamic hunger and circadian signaling pathways

PubMed Central

Green, Cara L.; Chen, Luonan; Han, Jing‐Dong J.; Wang, Yingchun; Promislow, Daniel E.L.; Lusseau, David; Speakman, John R.; Douglas, Alex

2016-01-01

Food intake and circadian rhythms are regulated by hypothalamic neuropeptides and circulating hormones, which could mediate the anti‐ageing effect of calorie restriction (CR). We tested whether these two signaling pathways mediate CR by quantifying hypothalamic transcripts of male C57BL/6 mice exposed to graded levels of CR (10 % to 40 %) for 3 months. We found that the graded CR manipulation resulted in upregulation of core circadian rhythm genes, which correlated negatively with circulating levels of leptin, insulin‐like growth factor 1 (IGF‐1), insulin, and tumor necrosis factor alpha (TNF‐α). In addition, key components in the hunger signaling pathway were expressed in a manner reflecting elevated hunger at greater levels of restriction, and which also correlated negatively with circulating levels of insulin, TNF‐α, leptin and IGF‐1. Lastly, phenotypes, such as food anticipatory activity and body temperature, were associated with expression levels of both hunger genes and core clock genes. Our results suggest modulation of the hunger and circadian signaling pathways in response to altered levels of circulating hormones, that are themselves downstream of morphological changes resulting from CR treatment, may be important elements in the response to CR, driving some of the key phenotypic outcomes. PMID:26945906

[Piperine regulates glucose metabolism disorder in HepG2 cells of insulin resistance models via targeting upstream target of AMPK signaling pathway].

PubMed

Wan, Chun-Ping; Wei, Ya-Gai; Li, Xiao-Xue; Zhang, Li-Jun; Yang, Rui; Bao, Zhao-Ri-Ge-Tu

2017-02-01

To investigate the effect of piperine on the disorder of glucose metabolism in the cell model with insulin resistance (IR) and explore the molecules mechanism on intervening the upstream target of AMPK signaling pathway. The insulin resistance models in HepG2 cells were established by fat emulsion stimulation. Then glucose consumption in culture supernatant was detected by GOD-POD method. Enzyme-linked immunosorbent assay(ELISA) was used to measure the levels of leptin(LEP) and adiponectin(APN) in culture supernatant; Real-time quantitative PCR was used to assess the mRNA expression of APN and LEP; and the protein expression levels of LepR, AdipoR1, AdipoR2 and the activation of AMPK signaling pathway were detected by Western blot analysis. The results showed that piperine, rosiglitazone and AMPK agonist AICAR could significantly elevate the glucose consumption in insulin resistance cell models, enhance the level of APN, promote APN mRNA transcripts and increase the protein expression of Adipo receptor. Meanwhile,AMPKα mRNA and р-AMPKα protein expressions were also increased in piperine treated cells, but both LEP mRNA expression and LepR protein expressions were decreased in piperine treated group. The results indicated that piperine could significantly ameliorate the glucose metabolism disorder in insulin resistance cell models through regulating upstream molecules (APN and LEP) of AMPK signaling pathway, and thus activate the AMPK signaling pathway. Copyright© by the Chinese Pharmaceutical Association.

Gene expression profile after activation of RIG-I in 5'ppp-dsRNA challenged DF1.

PubMed

Chen, Yang; Xu, Qi; Li, Yang; Liu, Ran; Huang, Zhengyang; Wang, Bin; Chen, Guohong

2016-12-01

Retinoic acid inducible gene I (RIG-I) can recognize influenza viruses and evoke the innate immune response. RIG-I is absent in the chicken genome, but is conserved in the genome of ducks. Lack of RIG-I renders chickens more susceptible to avian influenza infection, and the clinical symptoms are more prominent than in other poultry. It is unknown whether introduction of duck RIG-I into chicken cells can establish the immunity as is seen in ducks and the role of RIG-I in established immunity is unknown. In this study, a chicken cell strain with stable expression of duRIG-I was established by lentiviral infection, giving DF1/LV5-RIG-I, and a control strain DF1/LV5 was established in parallel. To verify stable, high level expression of duRIG-I in DF1 cells, the levels of duRIG-I mRNA and protein were determined by real-time RT-PCR and Western blot, respectively. Further, 5'triphosphate double stranded RNA (5'ppp-dsRNA) was used to mimic an RNA virus infection and the infected DF1/LV5-RIG-I and DF1/LV5 cells were subjected to high-throughput RNA-sequencing, which yielded 193.46 M reads and 39.07 G bases. A total of 278 differentially expressed genes (DEGs), i.e., duRIG-I-mediated responsive genes, were identified by RNA-seq. Among the 278 genes, 120 DEGs are annotated in the KEGG database, and the most reliable KEGG pathways are likely to be the signaling pathways of RIG-I like receptors. Functional analysis by Gene ontology (GO) indicates that the functions of these DEGs are primarily related to Type I interferon (IFN) signaling, IFN-β-mediated cellular responses and up-regulation of the RIG-I signaling pathway. Based on the shared genes among different pathways, a network representing crosstalk between RIG-I and other signaling pathways was constructed using Cytoscape software. The network suggests that RIG-mediated pathway may crosstalk with the Jak-STAT signaling pathway, Toll-like receptor signaling pathway, Wnt signaling pathway, ubiquitin-mediated proteolysis and MAPK signaling pathway during the transduction of antiviral signals. After screening, a group of key responsive genes in RIG-I-mediated signaling pathways, such as ISG12-2, Mx1, IFIT5, TRIM25, USP18, STAT1, STAT2, IRF1, IRF7 and IRF8, were tested for differential expression by real-time RT-PCR. In summary, by combining our results and the current literature, we propose a RIG-I-mediated signaling network in chickens. Copyright © 2016 Elsevier Ltd. All rights reserved.

Deciphering Signaling Pathway Networks to Understand the Molecular Mechanisms of Metformin Action

PubMed Central

Sun, Jingchun; Zhao, Min; Jia, Peilin; Wang, Lily; Wu, Yonghui; Iverson, Carissa; Zhou, Yubo; Bowton, Erica; Roden, Dan M.; Denny, Joshua C.; Aldrich, Melinda C.; Xu, Hua; Zhao, Zhongming

2015-01-01

A drug exerts its effects typically through a signal transduction cascade, which is non-linear and involves intertwined networks of multiple signaling pathways. Construction of such a signaling pathway network (SPNetwork) can enable identification of novel drug targets and deep understanding of drug action. However, it is challenging to synopsize critical components of these interwoven pathways into one network. To tackle this issue, we developed a novel computational framework, the Drug-specific Signaling Pathway Network (DSPathNet). The DSPathNet amalgamates the prior drug knowledge and drug-induced gene expression via random walk algorithms. Using the drug metformin, we illustrated this framework and obtained one metformin-specific SPNetwork containing 477 nodes and 1,366 edges. To evaluate this network, we performed the gene set enrichment analysis using the disease genes of type 2 diabetes (T2D) and cancer, one T2D genome-wide association study (GWAS) dataset, three cancer GWAS datasets, and one GWAS dataset of cancer patients with T2D on metformin. The results showed that the metformin network was significantly enriched with disease genes for both T2D and cancer, and that the network also included genes that may be associated with metformin-associated cancer survival. Furthermore, from the metformin SPNetwork and common genes to T2D and cancer, we generated a subnetwork to highlight the molecule crosstalk between T2D and cancer. The follow-up network analyses and literature mining revealed that seven genes (CDKN1A, ESR1, MAX, MYC, PPARGC1A, SP1, and STK11) and one novel MYC-centered pathway with CDKN1A, SP1, and STK11 might play important roles in metformin’s antidiabetic and anticancer effects. Some results are supported by previous studies. In summary, our study 1) develops a novel framework to construct drug-specific signal transduction networks; 2) provides insights into the molecular mode of metformin; 3) serves a model for exploring signaling pathways to facilitate understanding of drug action, disease pathogenesis, and identification of drug targets. PMID:26083494

KSHV LANA inhibits TGF-β signaling through epigenetic silencing of the TGF-β type II receptor

PubMed Central

Di Bartolo, Daniel L.; Cannon, Mark; Liu, Yi-Fang; Renne, Rolf; Chadburn, Amy; Boshoff, Chris

2008-01-01

Signaling through the transforming growth factor–β (TGF-β) pathway results in growth inhibition and induction of apoptosis in various cell types. We show that this pathway is blocked in Kaposi sarcoma herpesvirus (KSHV)–infected primary effusion lymphoma through down-regulation of the TGF-β type II receptor (TβRII) by epigenetic mechanisms. Our data also suggest that KSHV infection may result in lower expression of TβRII in Kaposi sarcoma and multicentric Castleman disease. KSHV-encoded LANA associates with the promoter of TβRII and leads to its methylation and to the deacetylation of proximal histones. Reestablishment of signaling through this pathway reduces viability of these cells, inferring that KSHV-mediated blockage of TGF-β signaling plays a role in the establishment and progression of KSHV-associated neoplasia. These data suggest a mechanism whereby KSHV evades both the antiproliferative effects of TGF-β signaling by silencing TβRII gene expression and immune recognition by suppressing TGF-β–responsive immune cells through the elevated secretion of TGF-β1. PMID:18199825

cGMP signalling in pre- and post-conditioning: the role of mitochondria.

PubMed

Costa, Alexandre D T; Pierre, Sandrine V; Cohen, Michael V; Downey, James M; Garlid, Keith D

2008-01-15

Much of cell death from ischaemia/reperfusion in heart and other tissues is generally thought to arise from mitochondrial permeability transition (MPT) in the first minutes of reperfusion. In ischaemic pre-conditioning, agonist binding to G(i) protein-coupled receptors prior to ischaemia triggers a signalling cascade that protects the heart from MPT. We believe that the cytosolic component of this trigger pathway terminates in activation of guanylyl cyclase resulting in increased production of cGMP and subsequent activation of protein kinase G (PKG). PKG phosphorylates a protein on the mitochondrial outer membrane (MOM), which then causes the mitochondrial K(ATP) channel (mitoK(ATP)) on the mitochondrial inner membrane to open, leading to increased production of reactive oxygen species (ROS) by the mitochondria. This implies that the protective signal is somehow transmitted from the MOM to its inner membrane. This is accomplished by a series of intermembrane signalling steps that includes protein kinase C (PKCepsilon) activation. The resulting ROS then activate a second PKC pool which, through another signal transduction pathway termed the mediator pathway, causes inhibition of MPT and reduction in cell death.

Bitter Melon Reduces Head and Neck Squamous Cell Carcinoma Growth by Targeting c-Met Signaling

PubMed Central

Nerurkar, Pratibha; Gonzalez, Juan G.; Crawford, Susan; Varvares, Mark; Ray, Ratna B.

2013-01-01

Head and neck squamous cell carcinoma (HNSCC) remains difficult to treat, and despite of advances in treatment, the overall survival rate has only modestly improved over the past several years. Thus, there is an urgent need for additional therapeutic modalities. We hypothesized that treatment of HNSCC cells with a dietary product such as bitter melon extract (BME) modulates multiple signaling pathways and regresses HNSCC tumor growth in a preclinical model. We observed a reduced cell proliferation in HNSCC cell lines. The mechanistic studies reveal that treatment of BME in HNSCC cells inhibited c-Met signaling pathway. We also observed that BME treatment in HNSCC reduced phosphoStat3, c-myc and Mcl-1 expression, downstream signaling molecules of c-Met. Furthermore, BME treatment in HNSCC cells modulated the expression of key cell cycle progression molecules leading to halted cell growth. Finally, BME feeding in mice bearing HNSCC xenograft tumor resulted in an inhibition of tumor growth and c-Met expression. Together, our results suggested that BME treatment in HNSCC cells modulates multiple signaling pathways and may have therapeutic potential for treating HNSCC. PMID:24147107

Ecm33 is a novel factor involved in efficient glucose uptake for nutrition-responsive TORC1 signaling in yeast.

PubMed

Umekawa, Midori; Ujihara, Masato; Nakai, Daiki; Takematsu, Hiromu; Wakayama, Mamoru

2017-11-01

Glucose uptake is crucial for providing both an energy source and a signal that regulates cell proliferation. Therefore, it is important to clarify the mechanisms underlying glucose uptake and its transmission to intracellular signaling pathways. In this study, we searched for a novel regulatory factor involved in glucose-induced signaling by using Saccharomyces cerevisiae as a eukaryotic model. Requirement of the extracellular protein Ecm33 in efficient glucose uptake and full activation of the nutrient-responsive TOR kinase complex 1 (TORC1) signaling pathway is shown. Cells lacking Ecm33 elicit a series of starvation-induced pathways even in the presence of extracellular high glucose concentration. This results in delayed cell proliferation, reduced ATP, induction of autophagy, and dephosphorylation of the TORC1 substrates Atg13 and Sch9. © 2017 Federation of European Biochemical Societies.

Neuroglian activates Echinoid to antagonize the Drosophila EGF receptor signaling pathway.

PubMed

Islam, Rafique; Wei, Shu-Yi; Chiu, Wei-Hsin; Hortsch, Michael; Hsu, Jui-Chou

2003-05-01

echinoid (ed) encodes an cell-adhesion molecule (CAM) that contains immunoglobulin domains and regulates the EGFR signaling pathway during Drosophila eye development. Based on our previous genetic mosaic and epistatic analysis, we proposed that Ed, via homotypic interactions, activates a novel, as yet unknown pathway that antagonizes EGFR signaling. In this report, we demonstrate that Ed functions as a homophilic adhesion molecule and also engages in a heterophilic trans-interaction with Drosophila Neuroglian (Nrg), an L1-type CAM. Co-expression of ed and nrg in the eye exhibits a strong genetic synergy in inhibiting EGFR signaling. This synergistic effect requires the intracellular domain of Ed, but not that of Nrg. In addition, Ed and Nrg colocalize in the Drosophila eye and are efficiently co-immunoprecipitated. Together, our results suggest a model in which Nrg acts as a heterophilic ligand and activator of Ed, which in turn antagonizes EGFR signaling.

dbl-1/TGF-β and daf-12/NHR Signaling Mediate Cell-Nonautonomous Effects of daf-16/FOXO on Starvation-Induced Developmental Arrest.

PubMed

Kaplan, Rebecca E W; Chen, Yutao; Moore, Brad T; Jordan, James M; Maxwell, Colin S; Schindler, Adam J; Baugh, L Ryan

2015-12-01

Nutrient availability has profound influence on development. In the nematode C. elegans, nutrient availability governs post-embryonic development. L1-stage larvae remain in a state of developmental arrest after hatching until they feed. This "L1 arrest" (or "L1 diapause") is associated with increased stress resistance, supporting starvation survival. Loss of the transcription factor daf-16/FOXO, an effector of insulin/IGF signaling, results in arrest-defective and starvation-sensitive phenotypes. We show that daf-16/FOXO regulates L1 arrest cell-nonautonomously, suggesting that insulin/IGF signaling regulates at least one additional signaling pathway. We used mRNA-seq to identify candidate signaling molecules affected by daf-16/FOXO during L1 arrest. dbl-1/TGF-β, a ligand for the Sma/Mab pathway, daf-12/NHR and daf-36/oxygenase, an upstream component of the daf-12 steroid hormone signaling pathway, were up-regulated during L1 arrest in a daf-16/FOXO mutant. Using genetic epistasis analysis, we show that dbl-1/TGF-β and daf-12/NHR steroid hormone signaling pathways are required for the daf-16/FOXO arrest-defective phenotype, suggesting that daf-16/FOXO represses dbl-1/TGF-β, daf-12/NHR and daf-36/oxygenase. The dbl-1/TGF-β and daf-12/NHR pathways have not previously been shown to affect L1 development, but we found that disruption of these pathways delayed L1 development in fed larvae, consistent with these pathways promoting development in starved daf-16/FOXO mutants. Though the dbl-1/TGF-β and daf-12/NHR pathways are epistatic to daf-16/FOXO for the arrest-defective phenotype, disruption of these pathways does not suppress starvation sensitivity of daf-16/FOXO mutants. This observation uncouples starvation survival from developmental arrest, indicating that DAF-16/FOXO targets distinct effectors for each phenotype and revealing that inappropriate development during starvation does not cause the early demise of daf-16/FOXO mutants. Overall, this study shows that daf-16/FOXO promotes developmental arrest cell-nonautonomously by repressing pathways that promote larval development.

dbl-1/TGF-β and daf-12/NHR Signaling Mediate Cell-Nonautonomous Effects of daf-16/FOXO on Starvation-Induced Developmental Arrest

PubMed Central

Moore, Brad T.; Jordan, James M.; Maxwell, Colin S.; Schindler, Adam J.; Baugh, L. Ryan

2015-01-01

Nutrient availability has profound influence on development. In the nematode C. elegans, nutrient availability governs post-embryonic development. L1-stage larvae remain in a state of developmental arrest after hatching until they feed. This “L1 arrest” (or "L1 diapause") is associated with increased stress resistance, supporting starvation survival. Loss of the transcription factor daf-16/FOXO, an effector of insulin/IGF signaling, results in arrest-defective and starvation-sensitive phenotypes. We show that daf-16/FOXO regulates L1 arrest cell-nonautonomously, suggesting that insulin/IGF signaling regulates at least one additional signaling pathway. We used mRNA-seq to identify candidate signaling molecules affected by daf-16/FOXO during L1 arrest. dbl-1/TGF-β, a ligand for the Sma/Mab pathway, daf-12/NHR and daf-36/oxygenase, an upstream component of the daf-12 steroid hormone signaling pathway, were up-regulated during L1 arrest in a daf-16/FOXO mutant. Using genetic epistasis analysis, we show that dbl-1/TGF-β and daf-12/NHR steroid hormone signaling pathways are required for the daf-16/FOXO arrest-defective phenotype, suggesting that daf-16/FOXO represses dbl-1/TGF-β, daf-12/NHR and daf-36/oxygenase. The dbl-1/TGF-β and daf-12/NHR pathways have not previously been shown to affect L1 development, but we found that disruption of these pathways delayed L1 development in fed larvae, consistent with these pathways promoting development in starved daf-16/FOXO mutants. Though the dbl-1/TGF-β and daf-12/NHR pathways are epistatic to daf-16/FOXO for the arrest-defective phenotype, disruption of these pathways does not suppress starvation sensitivity of daf-16/FOXO mutants. This observation uncouples starvation survival from developmental arrest, indicating that DAF-16/FOXO targets distinct effectors for each phenotype and revealing that inappropriate development during starvation does not cause the early demise of daf-16/FOXO mutants. Overall, this study shows that daf-16/FOXO promotes developmental arrest cell-nonautonomously by repressing pathways that promote larval development. PMID:26656736

Activation of PI3K, Akt, and ERK during early rotavirus infection leads to V-ATPase-dependent endosomal acidification required for uncoating

PubMed Central

Kim, Deok-Song; Kim, Ji-Yun; Park, Jun-Gyu; Alfajaro, Mia Madel; Baek, Yeong-Bin; Cho, Eun-Hyo; Kwon, Joseph; Choi, Jong-Soon; Kang, Mun-Il; Park, Sang-Ik; Cho, Kyoung-Oh

2018-01-01

The cellular PI3K/Akt and/or MEK/ERK signaling pathways mediate the entry process or endosomal acidification during infection of many viruses. However, their roles in the early infection events of group A rotaviruses (RVAs) have remained elusive. Here, we show that late-penetration (L-P) human DS-1 and bovine NCDV RVA strains stimulate these signaling pathways very early in the infection. Inhibition of both signaling pathways significantly reduced production of viral progeny due to blockage of virus particles in the late endosome, indicating that neither of the two signaling pathways is involved in virus trafficking. However, immunoprecipitation assays using antibodies specific for pPI3K, pAkt, pERK and the subunit E of the V-ATPase co-immunoprecipitated the V-ATPase in complex with pPI3K, pAkt, and pERK. Moreover, Duolink proximity ligation assay revealed direct association of the subunit E of the V-ATPase with the molecules pPI3K, pAkt, and pERK, indicating that both signaling pathways are involved in V-ATPase-dependent endosomal acidification. Acidic replenishment of the medium restored uncoating of the RVA strains in cells pretreated with inhibitors specific for both signaling pathways, confirming the above results. Isolated components of the outer capsid proteins, expressed as VP4-VP8* and VP4-VP5* domains, and VP7, activated the PI3K/Akt and MEK/ERK pathways. Furthermore, psoralen-UV-inactivated RVA and CsCl-purified RVA triple-layered particles triggered activation of the PI3K/Akt and MEK/ERK pathways, confirming the above results. Our data demonstrate that multistep binding of outer capsid proteins of L-P RVA strains with cell surface receptors phosphorylates PI3K, Akt, and ERK, which in turn directly interact with the subunit E of the V-ATPase to acidify the late endosome for uncoating of RVAs. This study provides a better understanding of the RVA-host interaction during viral uncoating, which is of importance for the development of strategies aiming at controlling or preventing RVA infections. PMID:29352319

Mechanisms that limit the light stimulus frequency following through the APB sensitive and insensitive rod Off-pathways

PubMed Central

Bai, Xia; Zhu, Junling; Yang, Jinnan; Savoie, Brian T.; Wang, Guo-Yong

2009-01-01

In the retina, rod signal pathways process scotopic visual information. Light decrements are mediated by two distinct groups of rod pathways in the dark adapted retina that can be differentiated on the basis of their sensitivity to the glutamate agonist DL-2-amino-4-phosphonobutyric acid (APB). We have found that the APB sensitive and insensitive rod Off-pathways signal different light decrement information: the APB sensitive rod Off-pathway conveys slow and low frequency light signals, whereas the APB insensitive rod Off-pathways mediate fast and high frequency light signals (Wang, 2006). However, the mechanisms which limit the frequency following through the APB sensitive and insensitive rod Off-pathways remain unknown. In the current study, whole-cell patch-clamp recordings were made from ganglion cells in dark and light adapted mouse retina to identify the mechanisms that limit the frequency following through the APB sensitive and insensitive rod Off-pathways. The results showed that the sites from AII amacrine cells to Off cone bipolar cells are the major mechanisms that limit the frequency following through the APB sensitive rod Off-pathway. In the APB insensitive rod Off-pathways, rods themselves limited the frequency following through these pathways. Moreover, ganglion cells were able to follow higher frequencies under photopic conditions than under scotopic conditions. The Off responses followed lower frequencies than On responses under photopic conditions. This finding was observed in cells that yielded On or Off responses only as well as in On-Off cells. PMID:19406212

Pathway and network-based analysis of genome-wide association studies and RT-PCR validation in polycystic ovary syndrome.

PubMed

Shen, Haoran; Liang, Zhou; Zheng, Saihua; Li, Xuelian

2017-11-01

The purpose of this study was to identify promising candidate genes and pathways in polycystic ovary syndrome (PCOS). Microarray dataset GSE345269 obtained from the Gene Expression Omnibus database includes 7 granulosa cell samples from PCOS patients, and 3 normal granulosa cell samples. Differentially expressed genes (DEGs) were screened between PCOS and normal samples. Pathway enrichment analysis was conducted for DEGs using ClueGO and CluePedia plugin of Cytoscape. A Reactome functional interaction (FI) network of the DEGs was built using ReactomeFIViz, and then network modules were extracted, followed by pathway enrichment analysis for the modules. Expression of DEGs in granulosa cell samples was measured using quantitative RT-PCR. A total of 674 DEGs were retained, which were significantly enriched with inflammation and immune-related pathways. Eight modules were extracted from the Reactome FI network. Pathway enrichment analysis revealed significant pathways of each module: module 0, Regulation of RhoA activity and Signaling by Rho GTPases pathways shared ARHGAP4 and ARHGAP9; module 2, GlycoProtein VI-mediated activation cascade pathway was enriched with RHOG; module 3, Thromboxane A2 receptor signaling, Chemokine signaling pathway, CXCR4-mediated signaling events pathways were enriched with LYN, the hub gene of module 3. Results of RT-PCR confirmed the finding of the bioinformatic analysis that ARHGAP4, ARHGAP9, RHOG and LYN were significantly upregulated in PCOS. RhoA-related pathways, GlycoProtein VI-mediated activation cascade pathway, ARHGAP4, ARHGAP9, RHOG and LYN may be involved in the pathogenesis of PCOS.

Wnt, RSPO and Hippo Signalling in the Intestine and Intestinal Stem Cells.

PubMed

Kriz, Vitezslav; Korinek, Vladimir

2018-01-08

In this review, we address aspects of Wnt, R-Spondin (RSPO) and Hippo signalling, in both healthy and transformed intestinal epithelium. In intestinal stem cells (ISCs), the Wnt pathway is essential for intestinal crypt formation and renewal, whereas RSPO-mediated signalling mainly affects ISC numbers. In human colorectal cancer (CRC), aberrant Wnt signalling is the driving mechanism initiating this type of neoplasia. The signalling role of the RSPO-binding transmembrane proteins, the leucine-rich-repeat-containing G-protein-coupled receptors (LGRs), is possibly more pleiotropic and not only limited to the enhancement of Wnt signalling. There is growing evidence for multiple crosstalk between Hippo and Wnt/β-catenin signalling. In the ON state, Hippo signalling results in serine/threonine phosphorylation of Yes-associated protein (YAP1) and tafazzin (TAZ), promoting formation of the β-catenin destruction complex. In contrast, YAP1 or TAZ dephosphorylation (and YAP1 methylation) results in β-catenin destruction complex deactivation and β-catenin nuclear localization. In the Hippo OFF state, YAP1 and TAZ are engaged with the nuclear β-catenin and participate in the β-catenin-dependent transcription program. Interestingly, YAP1/TAZ are dispensable for intestinal homeostasis; however, upon Wnt pathway hyperactivation, the proteins together with TEA domain (TEAD) transcription factors drive the transcriptional program essential for intestinal cell transformation. In addition, in many CRC cells, YAP1 phosphorylation by YES proto-oncogene 1 tyrosine kinase (YES1) leads to the formation of a transcriptional complex that includes YAP1, β-catenin and T-box 5 (TBX5) DNA-binding protein. YAP1/β-catenin/T-box 5-mediated transcription is necessary for CRC cell proliferation and survival. Interestingly, dishevelled (DVL) appears to be an important mediator involved in both Wnt and Hippo (YAP1/TAZ) signalling and some of the DVL functions were assigned to the nuclear DVL pool. Wnt ligands can trigger alternative signalling that directly involves some of the Hippo pathway components such as YAP1, TAZ and TEADs. By upregulating Wnt pathway agonists, the alternative Wnt signalling can inhibit the canonical Wnt pathway activity.

Regulation of the protein kinase activity of Shaggy(Zeste-white3) by components of the wingless pathway in Drosophila cells and embryos.

PubMed

Ruel, L; Stambolic, V; Ali, A; Manoukian, A S; Woodgett, J R

1999-07-30

The protein-serine kinase Shaggy(Zeste-white3) (Sgg(Zw3)) is the Drosophila homolog of mammalian glycogen synthase kinase-3 and has been genetically implicated in signal transduction pathways necessary for the establishment of patterning. Sgg(Zw3) is a putative component of the Wingless (Wg) pathway, and epistasis analyses suggest that Sgg(Zw3) function is repressed by Wg signaling. Here, we have investigated the biochemical consequences of Wg signaling with respect to the Sgg(Zw3) protein kinase in two types of Drosophila cell lines and in embryos. Our results demonstrate that Sgg(Zw3) activity is inhibited following exposure of cells to Wg protein and by expression of downstream components of Wg signaling, Drosophila frizzled 2 and dishevelled. Wg-dependent inactivation of Sgg(Zw3) is accompanied by serine phosphorylation. We also show that the level of Sgg(Zw3) activity regulates the stability of Armadillo protein and modulates the level of phosphorylation of D-Axin and Armadillo. Together, these results provide direct biochemical evidence in support of the genetic model of Wg signaling and provide a model for dissecting the molecular interactions between the signaling proteins.

Antihistamines modulate the integrin signaling pathway in h9c2 rat cardiomyocytes: Possible association with cardiotoxicity.

PubMed

Yun, J S; Kim, S Y

2015-08-01

The identification of biomarkers for toxicity prediction is crucial for drug development and safety evaluation. The selective and specific biomarkers for antihistamines-induced cardiotoxicity is not well identified yet. In order to evaluate the mechanism of the life-threatening effects caused by antihistamines, we used DNA microarrays to analyze genomic profiles in H9C2 rat cardiomyocytes that were treated with antihistamines. The gene expression profiles from drug-treated cells revealed changes in the integrin signaling pathway, suggesting that cardiac arrhythmias induced by antihistamine treatment may be mediated by changes in integrin-mediated signaling. It has been reported that integrin plays a role in QT prolongation that may induce cardiac arrhythmia. These results indicate that the integrin-mediated signaling pathway induced by antihistamines is involved in various biological mechanisms that lead to cardiac QT prolongation. Therefore, we suggest that genomic profiling of antihistamine-treated cardiomyocytes has the potential to reveal the mechanism of adverse drug reactions, and this signal pathway is applicable to prediction of in vitro cardiotoxicity induced by antihistamines as a biomarker candidate. © The Author(s) 2014.

Programmed cell death as a defence against infection

PubMed Central

Jorgensen, Ine; Rayamajhi, Manira; Miao, Edward A.

2017-01-01

Eukaryotic cells can die from physical trauma, resulting in necrosis. Alternately, they can die via programmed cell death upon stimulation of specific signalling pathways. Here we discuss the utility of four cell death pathways in innate immune defence against bacterial and viral infection: apoptosis, necroptosis, pyroptosis and NETosis. We describe the interactions that interweave different programmed cell death pathways, which create complex signalling networks that cross-guard each other in the evolutionary arms race with pathogens. Finally, we describe how the resulting cell corpses — apoptotic bodies, pore-induced intracellular traps (PITs) and neutrophil extracellular traps (NETs) — promote clearance of infection. PMID:28138137

Menadione (Vitamin K3) decreases melanin synthesis through ERK activation in Mel-Ab cells.

PubMed

Kim, Eun-Hyun; Kim, Myo-Kyoung; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Park, Kyoung-Chan; Kim, Dong-Seok

2013-10-15

Menadione is a synthetic vitamin K3 derivative. Here, we examined the effects of menadione on melanogenesis and its related signaling pathways. Our results showed that melanin content was significantly reduced after menadione treatment in a dose-dependent manner. However, menadione treatment did not reduce tyrosinase activity directly. Wnt signaling is known to play a major role in the control of melanin synthesis. Thus, we tested the effects of menadione treatment on GSK3β and β-catenin signaling, but found that menadione did not influence either of these signaling pathways. We also investigated changes in the phosphorylation of ERK, which is related to melanin regulation. These results indicated that menadione treatment led to the phosphorylation of ERK. Additionally, menadione treatment reduced both MITF and tyrosinase protein levels. Treatment with PD98059, a specific ERK pathway inhibitor, restored menadione-induced melanin reduction and also prevented MITF and tyrosinase downregulation by menadione. These results suggest that the hypopigmentary action of menadione is due to MITF and tyrosinase downregulation by ERK activation. © 2013 Elsevier B.V. All rights reserved.

The proliferation of amplifying neural progenitor cells is impaired in the aging brain and restored by the mTOR pathway activation.

PubMed

Romine, Jennifer; Gao, Xiang; Xu, Xiao-Ming; So, Kwok Fai; Chen, Jinhui

2015-04-01

A decrease in neurogenesis in the aged brain has been correlated with cognitive decline. The molecular signaling that regulates age-related decline in neurogenesis is still not fully understood. We found that different subtypes of neural stem cells (NSCs) in the hippocampus were differentially impaired by aging. The quiescent NSCs decreased slowly, although the active NSCs exhibited a sharp and dramatic decline from the ages of 6-9 months and became more quiescent at an early stage during the aging process. The activity of the mammalian target of rapamycin (mTOR) signal pathway is compromised in the NSCs of the aged brain. Activating the mTOR signaling pathway increased NSC proliferation and promoted neurogenesis in aged mice. In contrast, inhibiting the mTOR signaling pathway decreased NSCs proliferation. These results indicate that an age-associated decline in neurogenesis is mainly because of the reduction in proliferation of active NSCs, at least partially because of the compromise in the mTOR signaling activity. Stimulating the mTOR signaling revitalizes the NSCs, restores their proliferation, and enhances neurogenesis in the hippocampus of the aged brain. Copyright © 2015 Elsevier Inc. All rights reserved.

Treatment with Rhizoma Dioscoreae Extract Has Protective Effect on Osteopenia in Ovariectomized Rats

PubMed Central

Xiang, Lihua; Bai, Dong; Fu, Xiaowei; Wang, Wenlai; Li, Yan; Liu, Hong; Pan, Jinghua; Li, Ya'nan; Xiao, Gary Guishan; Ju, Dahong

2014-01-01

The aims of this study were to evaluate the osteoprotective effect of aqueous extract from Rhizoma Dioscoreae (RDE) on rats with ovariectomy- (OVX-) induced osteopenia. Our results show that RDE could inhibit bone loss of OVX rats after a 12-week treatment. The microarray analysis showed that 68 genes were upregulated and that 100 genes were downregulated in femurs of the RDE group rats compared to those in the OVX group. The Ingenuity Pathway Analysis (IPA) showed that several downregulated genes had the potential to code for proteins that were involved in the Wnt/β-catenin signaling pathway (Sost, Lrp6, Tcf7l2, and Alpl) and the RANKL/RANK signaling pathway (Map2k6 and Nfatc4). These results revealed that the mechanism for an antiosteopenic effect of RDE might lie in the synchronous inhibitory effects on both the bone formation and the bone resorption, which is associated with modulating the Wnt/β-catenin signaling and the RANKL/RANK signaling. PMID:24526913

Treatment with Rhizoma Dioscoreae extract has protective effect on osteopenia in ovariectomized rats.

PubMed

Zhang, Zhiguo; Xiang, Lihua; Bai, Dong; Fu, Xiaowei; Wang, Wenlai; Li, Yan; Liu, Hong; Pan, Jinghua; Li, Ya'nan; Xiao, Gary Guishan; Ju, Dahong

2014-01-01

The aims of this study were to evaluate the osteoprotective effect of aqueous extract from Rhizoma Dioscoreae (RDE) on rats with ovariectomy- (OVX-) induced osteopenia. Our results show that RDE could inhibit bone loss of OVX rats after a 12-week treatment. The microarray analysis showed that 68 genes were upregulated and that 100 genes were downregulated in femurs of the RDE group rats compared to those in the OVX group. The Ingenuity Pathway Analysis (IPA) showed that several downregulated genes had the potential to code for proteins that were involved in the Wnt/ β -catenin signaling pathway (Sost, Lrp6, Tcf7l2, and Alpl) and the RANKL/RANK signaling pathway (Map2k6 and Nfatc4). These results revealed that the mechanism for an antiosteopenic effect of RDE might lie in the synchronous inhibitory effects on both the bone formation and the bone resorption, which is associated with modulating the Wnt/ β -catenin signaling and the RANKL/RANK signaling.

Targeting Signaling to YAP for the Therapy of NF2

DTIC Science & Technology

2016-12-01

any step of our newly identified pathway, and to test the preclinical efficacy of lead compounds in xenograft models of NF2. During this grant, we have...Phosphorylation of the Hippo Pathway Component AMOTL2 by the mTORC2 Kinase Promotes YAP Signaling, Resulting in Enhanced Glioblastoma Growth and Invasiveness. The Journal of Biological Chemistry. 2015. 290(32):19387-401.

Cardiotoxic and Cardioprotective Features of Chronic β-adrenergic Signaling

PubMed Central

Zhang, Xiaoying; Szeto, Christopher; Gao, Erhe; Tang, Mingxin; Jin, Jianguo; Fu, Qin; Makarewich, Catherine; Ai, Xiaojie; Li, Ying; Tang, Allen; Wang, Jenny; Gao, Hui; Wang, Fang; Ge, Xinyi Joy; Kunapuli, Satya P.; Zhou, Lin; Zeng, Chunyu; Xiang, Kevin Yang; Chen, Xiongwen

2012-01-01

Rationale In the failing heart, persistent β-adrenergic receptor (βAR) activation is thought to induce myocyte death by protein kinase A (PKA)-dependent and PKA-independent activation of calcium/calmodulin-dependent kinase II (CaMKII). β-Adrenergic signaling pathways are also capable of activating cardioprotective mechanisms. Objective This study used a novel PKA inhibitor peptide (PKI) to inhibit PKA activity to test the hypothesis that βAR signaling causes cell death through PKA-dependent pathways and cardioprotection through PKA-independent pathways. Methods and Results In PKI transgenic mice, chronic isoproterenol (ISO) failed to induce cardiac hypertrophy, fibrosis, myocyte apoptosis and depressed cardiac function. In cultured adult feline ventricular myocytes (AFVMs), PKA inhibition protected myocytes from death induced by β1-AR agonists by preventing cytosolic and SR Ca2+ overload and CaMKII activation. PKA inhibition revealed a cardioprotective role of β-adrenergic signaling via cAMP/EPAC /Rap1/Rac/ERK pathway. Selective PKA inhibition causes protection in the heart after myocardial infarction (MI) that was superior to β-blocker therapy. Conclusion These results suggest that selective block of PKA could be a novel heart failure therapy. PMID:23104882

PKB/Akt modulates TGF-beta signalling through a direct interaction with Smad3.

PubMed

Remy, Ingrid; Montmarquette, Annie; Michnick, Stephen W

2004-04-01

Transforming growth factor beta (TGF-beta) has a major role in cell proliferation, differentiation and apoptosis in many cell types. Integration of the TGF-beta pathway with other signalling cascades that control the same cellular processes may modulate TGF-beta responses. Here we report the discovery of a new functional link between TGF-beta and growth factor signalling pathways, mediated by a physical interaction between the serine-threonine kinase PKB (protein kinase B)/Akt and the transcriptional activator Smad3. Formation of the complex is induced by insulin, but inhibited by TGF-beta stimulation, placing PKB-Smad3 at a point of convergence between these two pathways. PKB inhibits Smad3 by preventing its phosphorylation, binding to Smad4 and nuclear translocation. In contrast, Smad3 does not inhibit PKB. Inhibition of Smad3 by PKB occurs through a kinase-activity-independent mechanism, resulting in a decrease in Smad3-mediated transcription and protection of cells against TGF-beta-induced apoptosis. Consistently, knockdown of the endogenous PKB gene with small-interfering RNA (siRNA) has the opposite effect. Our results suggest a very simple mechanism for the integration of signals arising from growth-factor- and TGF-beta-mediated pathways.

The canonical Wnt signaling pathway in autism.

PubMed

Zhang, Yinghua; Yuan, Xiangshan; Wang, Zhongping; Li, Ruixi

2014-01-01

Mounting attention is being focused on the canonical Wnt signaling pathway which has been implicated in the pathogenesis of autism in some our and other recent studies. The canonical Wnt pathway is involved in cell proliferation, differentiation and migration, especially during nervous system development. Given its various functions, dysfunction of the canonical Wnt pathway may exert adverse effects on neurodevelopment and therefore leads to the pathogenesis of autism. Here, we review human and animal studies that implicate the canonical Wnt signal transduction pathway in the pathogenesis of autism. We also describe the crosstalk between the canonical Wnt pathway and the Notch signaling pathway in several types of autism spectrum disorders, including Asperger syndrome and Fragile X. Further research on the crosstalk between the canonical Wnt signaling pathway and other signaling cascades in autism may be an efficient avenue to understand the etiology of autism and ultimately lead to alternative medications for autism-like phenotypes.

Dependence of prevalence of contiguous pathways in proteins on structural complexity.

PubMed

Thayer, Kelly M; Galganov, Jesse C; Stein, Avram J

2017-01-01

Allostery is a regulatory mechanism in proteins where an effector molecule binds distal from an active site to modulate its activity. Allosteric signaling may occur via a continuous path of residues linking the active and allosteric sites, which has been suggested by large conformational changes evident in crystal structures. An alternate possibility is that the signal occurs in the realm of ensemble dynamics via an energy landscape change. While the latter was first proposed on theoretical grounds, increasing evidence suggests that such a control mechanism is plausible. A major difficulty for testing the two methods is the ability to definitively determine that a residue is directly involved in allosteric signal transduction. Statistical Coupling Analysis (SCA) is a method that has been successful at predicting pathways, and experimental tests involving mutagenesis or domain substitution provide the best available evidence of signaling pathways. However, ascertaining energetic pathways which need not be contiguous is far more difficult. To date, simple estimates of the statistical significance of a pathway in a protein remain to be established. The focus of this work is to estimate such benchmarks for the statistical significance of contiguous pathways for the null model of selecting residues at random. We found that when 20% of residues in proteins are randomly selected, contiguous pathways at the 6 Å cutoff level were found with success rates of 51% in PDZ, 30% in p53, and 3% in MutS. The results suggest that the significance of pathways may have system specific factors involved. Furthermore, the possible existence of false positives for contiguous pathways implies that signaling could be occurring via alternate routes including those consistent with the energetic landscape model.

Substance P activates both contractile and inflammatory pathways in lymphatics through the neurokinin receptors NK1R and NK3R

PubMed Central

Chakraborty, Sanjukta; Nepiyushchikh, Zhanna; Davis, Michael J.; Zawieja, David C.; Muthuchamy, Mariappan

2010-01-01

Objective The aim of this study was to elucidate the molecular signaling mechanisms by which substance P (SP) modulates lymphatic muscle contraction and to determine whether SP stimulates both contractile as well as inflammatory pathways in the lymphatics. Methods A rat mesenteric lymphatic muscle cell culture model (RMLMCs) and known specific pharmacological inhibitors were utilized to delineate SP mediated signaling pathways in lymphatics. Results We detected expression of neurokinin receptor 1 (NK1R) and neurokinin receptor 3 (NK3R) in RMLMCs. SP stimulation increased phosphorylation of myosin light chain 20 (MLC20) as well as p38 mitogen associated protein kinase (p38-MAPK) and extracellular signal regulated kinase (ERK1/2) indicating activation of both a contractile and a pro-inflammatory MAPK pathway. Pharmacological inhibition of both NK1R and NK3R significantly affected the downstream SP signaling. We further examined whether there was any crosstalk between the two pathways upon SP stimulation. Inhibition of ERK1/2 decreased levels of p-MLC20 after SP activation, in a PKC dependent manner, indicating a potential crosstalk between these two pathways. Conclusions These data provide the first evidence that SP mediated crosstalk between pro-inflammatory and contractile signaling mechanisms exists in the lymphatic system and may be an important bridge between lymphatic function modulation and inflammation. PMID:21166923

Differentiating Human Multipotent Mesenchymal Stromal Cells Regulate microRNAs: Prediction of microRNA Regulation by PDGF During Osteogenesis

PubMed Central

Goff, Loyal A.; Boucher, Shayne; Ricupero, Christopher L.; Fenstermacher, Sara; Swerdel, Mavis; Chase, Lucas; Adams, Christopher; Chesnut, Jonathan; Lakshmipathy, Uma; Hart, Ronald P.

2009-01-01

Objective Human multipotent mesenchymal stromal cells (MSC) have the potential to differentiate into multiple cell types, although little is known about factors that control their fate. Differentiation-specific microRNAs may play a key role in stem cell self renewal and differentiation. We propose that specific intracellular signalling pathways modulate gene expression during differentiation by regulating microRNA expression. Methods Illumina mRNA and NCode microRNA expression analyses were performed on MSC and their differentiated progeny. A combination of bioinformatic prediction and pathway inhibition was used to identify microRNAs associated with PDGF signalling. Results The pattern of microRNA expression in MSC is distinct from that in pluripotent stem cells such as human embryonic stem cells. Specific populations of microRNAs are regulated in MSC during differentiation targeted towards specific cell types. Complementary mRNA expression analysis increases the pool of markers characteristic of MSC or differentiated progeny. To identify microRNA expression patterns affected by signalling pathways, we examined the PDGF pathway found to be regulated during osteogenesis by microarray studies. A set of microRNAs bioinformatically predicted to respond to PDGF signalling was experimentally confirmed by direct PDGF inhibition. Conclusion Our results demonstrate that a subset of microRNAs regulated during osteogenic differentiation of MSCs is responsive to perturbation of the PDGF pathway. This approach not only identifies characteristic classes of differentiation-specific mRNAs and microRNAs, but begins to link regulated molecules with specific cellular pathways. PMID:18657893

Impact of constitutional copy number variants on biological pathway evolution.

PubMed

Poptsova, Maria; Banerjee, Samprit; Gokcumen, Omer; Rubin, Mark A; Demichelis, Francesca

2013-01-23

Inherited Copy Number Variants (CNVs) can modulate the expression levels of individual genes. However, little is known about how CNVs alter biological pathways and how this varies across different populations. To trace potential evolutionary changes of well-described biological pathways, we jointly queried the genomes and the transcriptomes of a collection of individuals with Caucasian, Asian or Yoruban descent combining high-resolution array and sequencing data. We implemented an enrichment analysis of pathways accounting for CNVs and genes sizes and detected significant enrichment not only in signal transduction and extracellular biological processes, but also in metabolism pathways. Upon the estimation of CNV population differentiation (CNVs with different polymorphism frequencies across populations), we evaluated that 22% of the pathways contain at least one gene that is proximal to a CNV (CNV-gene pair) that shows significant population differentiation. The majority of these CNV-gene pairs belong to signal transduction pathways and 6% of the CNV-gene pairs show statistical association between the copy number states and the transcript levels. The analysis suggested possible examples of positive selection within individual populations including NF-kB, MAPK signaling pathways, and Alu/L1 retrotransposition factors. Altogether, our results suggest that constitutional CNVs may modulate subtle pathway changes through specific pathway enzymes, which may become fixed in some populations.

EG-1 interacts with c-Src and activates its signaling pathway.

PubMed

Lu, Ming; Zhang, Liping; Sartippour, Maryam R; Norris, Andrew J; Brooks, Mai N

2006-10-01

EG-1 is significantly elevated in breast, colorectal, and prostate cancers. Overexpression of EG-1 stimulates cellular proliferation, and targeted inhibition blocks mouse xenograft tumor growth. To further clarify the function of EG-1, we investigated its role in c-Src activation. We observed that EG-1 overexpression results in activation of c-Src, but found no evidence that EG-1 is a direct Src substrate. EG-1 also binds to other members of the Src family. Furthermore, EG-1 shows interaction with multiple other SH3- and WW-containing molecules involved in various signaling pathways. These observations suggest that EG-1 may be involved in signaling pathways including c-Src activation.

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

PubMed Central

Rodas-Junco, Beatriz A; Cab-Guillen, Yahaira; Muñoz-Sanchez, J Armando; Vázquez-Flota, Felipe; Monforte-Gonzalez, Miriam; Hérnandez-Sotomayor, S M Teresa

2013-01-01

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

Left-right asymmetry and cardiac looping: implications for cardiac development and congenital heart disease.

PubMed

Kathiriya, I S; Srivastava, D

2000-01-01

Proper morphogenesis and positioning of internal organs requires delivery and interpretation of precise signals along the anterior-posterior, dorsal-ventral, and left-right axes. An elegant signaling cascade determines left- versus right-sided identity in visceral organs in a concordant fashion, resulting in a predictable left-right (LR) organ asymmetry in all vertebrates. The complex morphogenesis of the heart and its connections to the vasculature are particularly dependent upon coordinated LR signaling pathways. Disorganization of LR signals can result in myriad congenital heart defects that are a consequence of abnormal looping and remodeling of the primitive heart tube into a multi-chambered organ. A framework for understanding how LR asymmetric signals contribute to normal organogenesis has emerged and begins to explain the basis of many human diseases of LR asymmetry. Here we review the impact of LR signaling pathways on cardiac development and congenital heart disease.

Zinc Signals and Immunity.

PubMed

Maywald, Martina; Wessels, Inga; Rink, Lothar

2017-10-24

Zinc homeostasis is crucial for an adequate function of the immune system. Zinc deficiency as well as zinc excess result in severe disturbances in immune cell numbers and activities, which can result in increased susceptibility to infections and development of especially inflammatory diseases. This review focuses on the role of zinc in regulating intracellular signaling pathways in innate as well as adaptive immune cells. Main underlying molecular mechanisms and targets affected by altered zinc homeostasis, including kinases, caspases, phosphatases, and phosphodiesterases, will be highlighted in this article. In addition, the interplay of zinc homeostasis and the redox metabolism in affecting intracellular signaling will be emphasized. Key signaling pathways will be described in detail for the different cell types of the immune system. In this, effects of fast zinc flux, taking place within a few seconds to minutes will be distinguish from slower types of zinc signals, also designated as "zinc waves", and late homeostatic zinc signals regarding prolonged changes in intracellular zinc.

Induced Plant Defense Responses against Chewing Insects. Ethylene Signaling Reduces Resistance of Arabidopsis against Egyptian Cotton Worm But Not Diamondback Moth1

PubMed Central

Stotz, Henrik U.; Pittendrigh, Barry R.; Kroymann, Jürgen; Weniger, Kerstin; Fritsche, Jacqueline; Bauke, Antje; Mitchell-Olds, Thomas

2000-01-01

The induction of plant defenses by insect feeding is regulated via multiple signaling cascades. One of them, ethylene signaling, increases susceptibility of Arabidopsis to the generalist herbivore Egyptian cotton worm (Spodoptera littoralis; Lepidoptera: Noctuidae). The hookless1 mutation, which affects a downstream component of ethylene signaling, conferred resistance to Egyptian cotton worm as compared with wild-type plants. Likewise, ein2, a mutant in a central component of the ethylene signaling pathway, caused enhanced resistance to Egyptian cotton worm that was similar in magnitude to hookless1. Moreover, pretreatment of plants with ethephon (2-chloroethanephosphonic acid), a chemical that releases ethylene, elevated plant susceptibility to Egyptian cotton worm. By contrast, these mutations in the ethylene-signaling pathway had no detectable effects on diamondback moth (Plutella xylostella) feeding. It is surprising that this is not due to nonactivation of defense signaling, because diamondback moth does induce genes that relate to wound-response pathways. Of these wound-related genes, jasmonic acid regulates a novel β-glucosidase 1 (BGL1), whereas ethylene controls a putative calcium-binding elongation factor hand protein. These results suggest that a specialist insect herbivore triggers general wound-response pathways in Arabidopsis but, unlike a generalist herbivore, does not react to ethylene-mediated physiological changes. PMID:11080278

Multiple pathways from three types of sugar receptor sites to metabotropic transduction pathways of the blowfly: study by the whole cell-clamp experiments.

PubMed

Kan, Hideko; Kataoka-Shirasugi, Naoko; Amakawa, Taisaku

2011-09-01

Multiple pathways from three types of multiple receptor sites to three types of metabotropic signal transduction pathways were investigated in the whole cell-clamp experiments using isolated labellar sugar receptor neurons (cells) of the adult blowfly, Phormia regina. First, the concentration-response curves of three types of sweet taste components specialized to multiple receptor sites were obtained: sucrose for the pyranose sites (P-sites), fructose for the furanose sites (F-sites), and l-valine for the alkyl sites (R-sites). Next, the effects of inhibitors such as 2', 5'-dideoxyadenosine on adenylyl cyclase in the cAMP pathway, LY 83583 on guanylyl cyclase in the cGMP pathway, and U-73122 on phospholipase C in the IP₃ pathway were examined. The results showed that all of the inhibitors affected each specific target in the second-messenger transduction pathways. The obtained results verified that the P-site corresponded to the cAMP, the F-site to the cGMP, and the R-site to the IP₃ transduction pathway, and that these three signal pathways did not have crossing points. Copyright © 2011 Elsevier Inc. All rights reserved.

Combined Cytological and Transcriptomic Analysis Reveals a Nitric Oxide Signaling Pathway Involved in Cold-Inhibited Camellia sinensis Pollen Tube Growth

PubMed Central

Wang, Weidong; Sheng, Xianyong; Shu, Zaifa; Li, Dongqin; Pan, Junting; Ye, Xiaoli; Chang, Pinpin; Li, Xinghui; Wang, Yuhua

2016-01-01

Nitric oxide (NO) as a signaling molecule plays crucial roles in many abiotic stresses in plant development processes, including pollen tube growth. Here, the signaling networks dominated by NO during cold stress that inhibited Camellia sinensis pollen tube growth are investigated in vitro. Cytological analysis show that cold-induced NO is involved in the inhibition of pollen tube growth along with disruption of the cytoplasmic Ca2+ gradient, increase in ROS content, acidification of cytoplasmic pH and abnormalities in organelle ultrastructure and cell wall component distribution in the pollen tube tip. Furthermore, differentially expressed genes (DEGs)-related to signaling pathway, such as NO synthesis, cGMP, Ca2+, ROS, pH, actin, cell wall, and MAPK cascade signal pathways, are identified and quantified using transcriptomic analyses and qRT-PCR, which indicate a potential molecular mechanism for the above cytological results. Taken together, these findings suggest that a complex signaling network dominated by NO, including Ca2+, ROS, pH, RACs signaling and the crosstalk among them, is stimulated in the C. sinensis pollen tube in response to cold stress, which further causes secondary and tertiary alterations, such as ultrastructural abnormalities in organelles and cell wall construction, ultimately resulting in perturbed pollen tube extension. PMID:27148289

VEGF-induced neoangiogenesis is mediated by NAADP and two-pore channel-2–dependent Ca2+ signaling

PubMed Central

Favia, Annarita; Desideri, Marianna; Gambara, Guido; D’Alessio, Alessio; Ruas, Margarida; Esposito, Bianca; Del Bufalo, Donatella; Parrington, John; Ziparo, Elio; Palombi, Fioretta; Galione, Antony; Filippini, Antonio

2014-01-01

Vascular endothelial growth factor (VEGF) and its receptors VEGFR1/VEGFR2 play major roles in controlling angiogenesis, including vascularization of solid tumors. Here we describe a specific Ca2+ signaling pathway linked to the VEGFR2 receptor subtype, controlling the critical angiogenic responses of endothelial cells (ECs) to VEGF. Key steps of this pathway are the involvement of the potent Ca2+ mobilizing messenger, nicotinic acid adenine-dinucleotide phosphate (NAADP), and the specific engagement of the two-pore channel TPC2 subtype on acidic intracellular Ca2+ stores, resulting in Ca2+ release and angiogenic responses. Targeting this intracellular pathway pharmacologically using the NAADP antagonist Ned-19 or genetically using Tpcn2−/− mice was found to inhibit angiogenic responses to VEGF in vitro and in vivo. In human umbilical vein endothelial cells (HUVECs) Ned-19 abolished VEGF-induced Ca2+ release, impairing phosphorylation of ERK1/2, Akt, eNOS, JNK, cell proliferation, cell migration, and capillary-like tube formation. Interestingly, Tpcn2 shRNA treatment abolished VEGF-induced Ca2+ release and capillary-like tube formation. Importantly, in vivo VEGF-induced vessel formation in matrigel plugs in mice was abolished by Ned-19 and, most notably, failed to occur in Tpcn2−/− mice, but was unaffected in Tpcn1−/− animals. These results demonstrate that a VEGFR2/NAADP/TPC2/Ca2+ signaling pathway is critical for VEGF-induced angiogenesis in vitro and in vivo. Given that VEGF can elicit both pro- and antiangiogenic responses depending upon the balance of signal transduction pathways activated, targeting specific VEGFR2 downstream signaling pathways could modify this balance, potentially leading to more finely tailored therapeutic strategies. PMID:25331892

Macrophages produce IL-33 by activating MAPK signaling pathway during RSV infection.

PubMed

Qi, Feifei; Bai, Song; Wang, Dandan; Xu, Lei; Hu, Haiyan; Zeng, Sheng; Chai, Ruonan; Liu, Beixing

2017-07-01

It has been reported that RSV infection can enhance IL-33 production in lung macrophages. However, little is known about specific signaling pathways for activation of macrophages during RSV infection. In the present study, by using real-time RT-PCR as well as western blot assay, it became clear that RSV infection can enhance not only the expression of mRNAs for MAPK molecules (including p38, JNK1/2, and ERK1/2), but also the levels of MAPK proteins in lung macrophages as well as RAW264.7 cells. Furthermore, infection with RSV resulted in an increased level of phosphorylated MAPK proteins in RAW264.7 cells, suggesting that MAPK signaling pathway may participate in the process of RSV-induced IL-33 secretion by macrophages. In fact, the elevated production of IL-33 in RAW264.7 was attenuated significantly by pretreatment of the cells with special MAPK inhibitor before RSV infection, further confirming the function of MAPKs pathway in RSV-induced IL-33 production in macrophages. In contrast, the expression of NF-κB mRNA as well as the production of NF-κB protein in lung macrophages and RAW264.7 cells was not enhanced markedly after RSV infection. Moreover, RSV infection failed to induce the phosphorylation of NF-κB in RAW264.7 cells, suggesting that NF-κB signaling pathway may be not involved in RSV-induced IL-33 production in macrophages. Conclusion, these results indicate that RSV-induced production of IL-33 in macrophages is dependent on the activation of MAPK signaling pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differences in gene expression profiles and signaling pathways in rhabdomyolysis-induced acute kidney injury.

PubMed

Geng, Xiaodong; Wang, Yuanda; Hong, Quan; Yang, Jurong; Zheng, Wei; Zhang, Gang; Cai, Guangyan; Chen, Xiangmei; Wu, Di

2015-01-01

Rhabdomyolysis is a threatening syndrome because it causes the breakdown of skeletal muscle. Muscle destruction leads to the release of myoglobin, intracellular proteins, and electrolytes into the circulation. The aim of this study was to investigate the differences in gene expression profiles and signaling pathways upon rhabdomyolysis-induced acute kidney injury (AKI). In this study, we used glycerol-induced renal injury as a model of rhabdomyolysis-induced AKI. We analyzed data and relevant information from the Gene Expression Omnibus database (No: GSE44925). The gene expression data for three untreated mice were compared to data for five mice with rhabdomyolysis-induced AKI. The expression profiling of the three untreated mice and the five rhabdomyolysis-induced AKI mice was performed using microarray analysis. We examined the levels of Cyp3a13, Rela, Aldh7a1, Jun, CD14. And Cdkn1a using RT-PCR to determine the accuracy of the microarray results. The microarray analysis showed that there were 1050 downregulated and 659 upregulated genes in the rhabdomyolysis-induced AKI mice compared to the control group. The interactions of all differentially expressed genes in the Signal-Net were analyzed. Cyp3a13 and Rela had the most interactions with other genes. The data showed that Rela and Aldh7a1 were the key nodes and had important positions in the Signal-Net. The genes Jun, CD14, and Cdkn1a were also significantly upregulated. The pathway analysis classified the differentially expressed genes into 71 downregulated and 48 upregulated pathways including the PI3K/Akt, MAPK, and NF-κB signaling pathways. The results of this study indicate that the NF-κB, MAPK, PI3K/Akt, and apoptotic pathways are regulated in rhabdomyolysis-induced AKI.

Signaling Pathway in Early Brain Injury after Subarachnoid Hemorrhage: News Update.

PubMed

Ji, Chengyuan; Chen, Gang

2016-01-01

The annual incidence of subarachnoid hemorrhage (SAH) caused by intracranial aneurysm rupture is approximately 10.5/10 million people in China, making SAH the third most frequently occurring hemorrhage of the intracranial type after cerebral embolism and hypertensive intracerebral hemorrhage. SAH caused by ruptured aneurysm leads to a mortality rate as high as 67 %, and, because of the sudden onset of this disease, approximately 12-15 % of patients die before they can receive effective treatment. Early brain injury (EBI) is the brain damage occurring within the first 72 h after SAH. Two-thirds of mortality caused by SAH occurs within 48 h, mainly as a result of EBI. With the development of molecular biology and medicine microscopy techniques, various signaling pathways involved in EBI after SAH have been revealed. Understanding these signaling pathways may help clinicians treat EBI after SAH and improve long-term prognosis of SAH patients. This chapter summarizes several important signaling pathways implicated in EBI caused by SAH.

The Hippo signaling pathway provides novel anti-cancer drug targets

PubMed Central

Bae, June Sung; Kim, Sun Mi; Lee, Ho

2017-01-01

The Hippo signaling pathway plays a crucial role in cell proliferation, apoptosis, differentiation, and development. Major effectors of the Hippo signaling pathway include the transcriptional co-activators Yes-associated protein 1 (YAP) and WW domain-containing transcription regulator protein 1 (TAZ). The transcriptional activities of YAP and TAZ are affected by interactions with proteins from many diverse signaling pathways as well as responses to the external environment. High YAP and TAZ activity has been observed in many cancer types, and functional dysregulation of Hippo signaling enhances the oncogenic properties of YAP and TAZ and promotes cancer development. Many biological elements, including mechanical strain on the cell, cell polarity/adhesion molecules, other signaling pathways (e.g., G-protein-coupled receptor, epidermal growth factor receptor, Wnt, Notch, and transforming growth factor β/bone morphogenic protein), and cellular metabolic status, can promote oncogenesis through synergistic association with components of the Hippo signaling pathway. Here, we review the signaling networks that interact with the Hippo signaling pathway and discuss the potential of using drugs that inhibit YAP and TAZ activity for cancer therapy. PMID:28035075

The Hippo signaling pathway provides novel anti-cancer drug targets.

PubMed

Bae, June Sung; Kim, Sun Mi; Lee, Ho

2017-02-28

The Hippo signaling pathway plays a crucial role in cell proliferation, apoptosis, differentiation, and development. Major effectors of the Hippo signaling pathway include the transcriptional co-activators Yes-associated protein 1 (YAP) and WW domain-containing transcription regulator protein 1 (TAZ). The transcriptional activities of YAP and TAZ are affected by interactions with proteins from many diverse signaling pathways as well as responses to the external environment. High YAP and TAZ activity has been observed in many cancer types, and functional dysregulation of Hippo signaling enhances the oncogenic properties of YAP and TAZ and promotes cancer development. Many biological elements, including mechanical strain on the cell, cell polarity/adhesion molecules, other signaling pathways (e.g., G-protein-coupled receptor, epidermal growth factor receptor, Wnt, Notch, and transforming growth factor β/bone morphogenic protein), and cellular metabolic status, can promote oncogenesis through synergistic association with components of the Hippo signaling pathway. Here, we review the signaling networks that interact with the Hippo signaling pathway and discuss the potential of using drugs that inhibit YAP and TAZ activity for cancer therapy.

Hydrogen-rich medium protects mouse embryonic fibroblasts from oxidative stress by activating LKB1-AMPK-FoxO1 signal pathway.

PubMed

Lee, Jihyun; Yang, Goowon; Kim, Young-Joo; Tran, Quynh Hoa; Choe, Wonchae; Kang, Insug; Kim, Sung Soo; Ha, Joohun

2017-09-23

Persistent oxidative stress is recognized as a major cause of many pathological conditions as well as ageing. However, most clinical trials of dietary antioxidants have failed to produce successful outcomes in treating oxidative stress-induced diseases. Molecular hydrogen (H 2 ) has recently received considerable attention as a therapeutic agent owing to its novel antioxidant properties, a selective scavenger of hydroxyl and peroxynitrite radicals. Beyond this, numerous reports support that H 2 can modulate the activity of various cellular signal pathways. However, its effect on AMP-activated protein kinase (AMPK) signal pathway, a central regulator of energy hemostasis, has remained almost elusive. Here, we report that hydrogen-rich medium activated LKB1-AMPK signal pathway without ATP depletion, which in turn induced FoxO1-dependent transcription of manganese superoxide dismutase and catalase in mouse embryonic fibroblasts. Moreover, hydrogen-rich media effectively reduced the level of reactive oxygen species in cells treated with hydrogen peroxide and protected these cells from apoptosis in an AMPK-dependent manner. These results suggest that the LKB1-AMPK-FoxO1 signaling pathway is a critical mediator of the antioxidant properties of H 2 , further supporting the idea that H 2 acts as a signaling molecule to serve various physiological functions. Copyright © 2017 Elsevier Inc. All rights reserved.

The olfactory pathway mediates sheltering behavior of Caribbean spiny lobsters, Panulirus argus, to conspecific urine signals.

PubMed

Horner, Amy J; Weissburg, Marc J; Derby, Charles D

2008-03-01

The "noses" of diverse taxa are organized into different subsystems whose functions are often not well understood. The "nose" of decapod crustaceans is organized into two parallel pathways that originate in different populations of antennular sensilla and project to specific neuropils in the brain-the aesthetasc/olfactory lobe pathway and the non-aesthetasc/lateral antennular neuropil pathway. In this study, we investigated the role of these pathways in mediating shelter selection of Caribbean spiny lobsters, Panulirus argus, in response to conspecific urine signals. We compared the behavior of ablated animals and intact controls. Our results show that control and non-aesthetasc ablated lobsters have a significant overall preference for shelters emanating urine over control shelters. Thus the non-aesthetasc pathway does not play a critical role in shelter selection. In contrast, spiny lobsters with aesthetascs ablated did not show a preference for either shelter, suggesting that the aesthetasc/olfactory pathway is important for processing social odors. Our results show a difference in the function of these dual chemosensory pathways in responding to social cues, with the aesthetasc/olfactory lobe pathway playing a major role. We discuss our results in the context of why the noses of many animals contain multiple parallel chemosensory systems.

Far-field photostable optical nanoscopy (PHOTON) for real-time super-resolution single-molecular imaging of signaling pathways of single live cells

NASA Astrophysics Data System (ADS)

Huang, Tao; Browning, Lauren M.; Xu, Xiao-Hong Nancy

2012-04-01

Cellular signaling pathways play crucial roles in cellular functions and design of effective therapies. Unfortunately, study of cellular signaling pathways remains formidably challenging because sophisticated cascades are involved, and a few molecules are sufficient to trigger signaling responses of a single cell. Here we report the development of far-field photostable-optical-nanoscopy (PHOTON) with photostable single-molecule-nanoparticle-optical-biosensors (SMNOBS) for mapping dynamic cascades of apoptotic signaling pathways of single live cells in real-time at single-molecule (SM) and nanometer (nm) resolutions. We have quantitatively imaged single ligand molecules (tumor necrosis factor α, TNFα) and their binding kinetics with their receptors (TNFR1) on single live cells; tracked formation and internalization of their clusters and their initiation of intracellular signaling pathways in real-time; and studied apoptotic signaling dynamics and mechanisms of single live cells with sufficient temporal and spatial resolutions. This study provides new insights into complex real-time dynamic cascades and molecular mechanisms of apoptotic signaling pathways of single live cells. PHOTON provides superior imaging and sensing capabilities and SMNOBS offer unrivaled biocompatibility and photostability, which enable probing of signaling pathways of single live cells in real-time at SM and nm resolutions.Cellular signaling pathways play crucial roles in cellular functions and design of effective therapies. Unfortunately, study of cellular signaling pathways remains formidably challenging because sophisticated cascades are involved, and a few molecules are sufficient to trigger signaling responses of a single cell. Here we report the development of far-field photostable-optical-nanoscopy (PHOTON) with photostable single-molecule-nanoparticle-optical-biosensors (SMNOBS) for mapping dynamic cascades of apoptotic signaling pathways of single live cells in real-time at single-molecule (SM) and nanometer (nm) resolutions. We have quantitatively imaged single ligand molecules (tumor necrosis factor α, TNFα) and their binding kinetics with their receptors (TNFR1) on single live cells; tracked formation and internalization of their clusters and their initiation of intracellular signaling pathways in real-time; and studied apoptotic signaling dynamics and mechanisms of single live cells with sufficient temporal and spatial resolutions. This study provides new insights into complex real-time dynamic cascades and molecular mechanisms of apoptotic signaling pathways of single live cells. PHOTON provides superior imaging and sensing capabilities and SMNOBS offer unrivaled biocompatibility and photostability, which enable probing of signaling pathways of single live cells in real-time at SM and nm resolutions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11739h

The Epoxyeicosatrienoic Acid Pathway Enhances Hepatic Insulin Signaling and is Repressed in Insulin-Resistant Mouse Liver*

PubMed Central

Schäfer, Alexander; Neschen, Susanne; Kahle, Melanie; Sarioglu, Hakan; Gaisbauer, Tobias; Imhof, Axel; Adamski, Jerzy; Hauck, Stefanie M.; Ueffing, Marius

2015-01-01

Although it is widely accepted that ectopic lipid accumulation in the liver is associated with hepatic insulin resistance, the underlying molecular mechanisms have not been well characterized. Here we employed time resolved quantitative proteomic profiling of mice fed a high fat diet to determine which pathways were affected during the transition of the liver to an insulin-resistant state. We identified several metabolic pathways underlying altered protein expression. In order to test the functional impact of a critical subset of these alterations, we focused on the epoxyeicosatrienoic acid (EET) eicosanoid pathway, whose deregulation coincided with the onset of hepatic insulin resistance. These results suggested that EETs may be positive modulators of hepatic insulin signaling. Analyzing EET activity in primary hepatocytes, we found that EETs enhance insulin signaling on the level of Akt. In contrast, EETs did not influence insulin receptor or insulin receptor substrate-1 phosphorylation. This effect was mediated through the eicosanoids, as overexpression of the deregulated enzymes in absence of arachidonic acid had no impact on insulin signaling. The stimulation of insulin signaling by EETs and depression of the pathway in insulin resistant liver suggest a likely role in hepatic insulin resistance. Our findings support therapeutic potential for inhibiting EET degradation. PMID:26070664

Autonomous rexinoid death signaling is suppressed by converging signaling pathways in immature leukemia cells.

PubMed

Benoit, G R; Flexor, M; Besançon, F; Altucci, L; Rossin, A; Hillion, J; Balajthy, Z; Legres, L; Ségal-Bendirdjian, E; Gronemeyer, H; Lanotte, M

2001-07-01

On their own, retinoid X receptor (RXR)-selective ligands (rexinoids) are silent in retinoic acid receptor (RAR)-RXR heterodimers, and no selective rexinoid program has been described as yet in cellular systems. We report here on the rexinoid signaling capacity that triggers apoptosis of immature promyelocytic NB4 cells as a default pathway in the absence of survival factors. Rexinoid-induced apoptosis displays all features of bona fide programmed cell death and is inhibited by RXR, but not RAR antagonists. Several types of survival signals block rexinoid-induced apoptosis. RARalpha agonists switch the cellular response toward differentiation and induce the expression of antiapoptosis factors. Activation of the protein kinase A pathway in the presence of rexinoid agonists induces maturation and blocks immature cell apoptosis. Addition of nonretinoid serum factors also blocks cell death but does not induce cell differentiation. Rexinoid-induced apoptosis is linked to neither the presence nor stability of the promyelocytic leukemia-RARalpha fusion protein and operates also in non-acute promyelocytic leukemia cells. Together our results support a model according to which rexinoids activate in certain leukemia cells a default death pathway onto which several other signaling paradigms converge. This pathway is entirely distinct from that triggered by RAR agonists, which control cell maturation and postmaturation apoptosis.

Differences in gene expression profiles and signaling pathways in rhabdomyolysis-induced acute kidney injury

PubMed Central

Geng, Xiaodong; Wang, Yuanda; Hong, Quan; Yang, Jurong; Zheng, Wei; Zhang, Gang; Cai, Guangyan; Chen, Xiangmei; Wu, Di

2015-01-01

Purpose: Rhabdomyolysis is a threatening syndrome because it causes the breakdown of skeletal muscle. Muscle destruction leads to the release of myoglobin, intracellular proteins, and electrolytes into the circulation. The aim of this study was to investigate the differences in gene expression profiles and signaling pathways upon rhabdomyolysis-induced acute kidney injury (AKI). Methods: In this study, we used glycerol-induced renal injury as a model of rhabdomyolysis-induced AKI. We analyzed data and relevant information from the Gene Expression Omnibus database (No: GSE44925). The gene expression data for three untreated mice were compared to data for five mice with rhabdomyolysis-induced AKI. The expression profiling of the three untreated mice and the five rhabdomyolysis-induced AKI mice was performed using microarray analysis. We examined the levels of Cyp3a13, Rela, Aldh7a1, Jun, CD14. And Cdkn1a using RT-PCR to determine the accuracy of the microarray results. Results: The microarray analysis showed that there were 1050 downregulated and 659 upregulated genes in the rhabdomyolysis-induced AKI mice compared to the control group. The interactions of all differentially expressed genes in the Signal-Net were analyzed. Cyp3a13 and Rela had the most interactions with other genes. The data showed that Rela and Aldh7a1 were the key nodes and had important positions in the Signal-Net. The genes Jun, CD14, and Cdkn1a were also significantly upregulated. The pathway analysis classified the differentially expressed genes into 71 downregulated and 48 upregulated pathways including the PI3K/Akt, MAPK, and NF-κB signaling pathways. Conclusion: The results of this study indicate that the NF-κB, MAPK, PI3K/Akt, and apoptotic pathways are regulated in rhabdomyolysis-induced AKI. PMID:26823722

Amphioxus FGF signaling predicts the acquisition of vertebrate morphological traits.

PubMed

Bertrand, Stephanie; Camasses, Alain; Somorjai, Ildiko; Belgacem, Mohamed R; Chabrol, Olivier; Escande, Marie-Line; Pontarotti, Pierre; Escriva, Hector

2011-05-31

FGF signaling is one of the few cell-cell signaling pathways conserved among all metazoans. The diversity of FGF gene content among different phyla suggests that evolution of FGF signaling may have participated in generating the current variety of animal forms. Vertebrates possess the greatest number of FGF genes, the functional evolution of which may have been implicated in the acquisition of vertebrate-specific morphological traits. In this study, we have investigated the roles of the FGF signal during embryogenesis of the cephalochordate amphioxus, the best proxy for the chordate ancestor. We first isolate the full FGF gene complement and determine the evolutionary relationships between amphioxus and vertebrate FGFs via phylogenetic and synteny conservation analysis. Using pharmacological treatments, we inhibit the FGF signaling pathway in amphioxus embryos in different time windows. Our results show that the requirement for FGF signaling during gastrulation is a conserved character among chordates, whereas this signal is not necessary for neural induction in amphioxus, in contrast to what is known in vertebrates. We also show that FGF signal, acting through the MAPK pathway, is necessary for the formation of the most anterior somites in amphioxus, whereas more posterior somite formation is not FGF-dependent. This result leads us to propose that modification of the FGF signal function in the anterior paraxial mesoderm in an amphioxus-like vertebrate ancestor might have contributed to the loss of segmentation in the preotic paraxial mesoderm of the vertebrate head.

LncRNA mediated regulation of aging pathways in Drosophila melanogaster during dietary restriction.

PubMed

Yang, Deying; Lian, Ting; Tu, Jianbo; Gaur, Uma; Mao, Xueping; Fan, Xiaolan; Li, Diyan; Li, Ying; Yang, Mingyao

2016-09-27

Dietary restriction (DR) extends lifespan in many species which is a well-known phenomenon. Long non-coding RNAs (lncRNAs) play an important role in regulation of cell senescence and important age-related signaling pathways. Here, we profiled the lncRNA and mRNA transcriptome of fruit flies at 7 day and 42 day during DR and fully-fed conditions, respectively. In general, 102 differentially expressed lncRNAs and 1406 differentially expressed coding genes were identified. Most informatively we found a large number of differentially expressed lncRNAs and their targets enriched in GO and KEGG analysis. We discovered some new aging related signaling pathways during DR, such as hippo signaling pathway-fly, phototransduction-fly and protein processing in endoplasmic reticulum etc. Novel lncRNAs XLOC_092363 and XLOC_166557 are found to be located in 10 kb upstream sequences of hairy and ems promoters, respectively. Furthermore, tissue specificity of some novel lncRNAs had been analyzed at 7 day of DR in fly head, gut and fat body. Also the silencing of lncRNA XLOC_076307 resulted in altered expression level of its targets including Gadd45 (involved in FoxO signaling pathway). Together, the results implicated many lncRNAs closely associated with dietary restriction, which could provide a resource for lncRNA in aging and age-related disease field.

Transcriptional Pathways Altered in Response to Vibration in a Model of Hand-Arm Vibration Syndrome

PubMed Central

Waugh, Stacey; Kashon, Michael L.; Li, Shengqiao; Miller, Gerome R.; Johnson, Claud; Krajnak, Kristine

2016-01-01

Objective The aim of this study was to use an established model of vibration-induced injury to assess frequency-dependent changes in transcript expression in skin, artery, and nerve tissues. Methods Transcript expression in tissues from control and vibration-exposed rats (4 h/day for 10 days at 62.5, 125, or 250 Hz; 49 m/s2, rms) was measured. Transcripts affected by vibration were used in bioinformatics analyses to identify molecular- and disease-related pathways associated with exposure to vibration. Results Analyses revealed that cancer-related pathways showed frequency-dependent changes in activation or inhibition. Most notably, the breast-related cancer-1 pathway was affected. Other pathways associated with breast cancer type 1 susceptibility protein related signaling, or associated with cancer and cell cycle/cell survivability were also affected. Conclusion Occupational exposure to vibration may result in DNA damage and alterations in cell signaling pathways that have significant effects on cellular division. PMID:27058473

Overexpression of LncRNA HOTAIR is Associated with Poor Prognosis in Thyroid Carcinoma: A Study Based on TCGA and GEO Data.

PubMed

Li, Hong-Mei; Yang, Hong; Wen, Dong-Yue; Luo, Yi-Huan; Liang, Chun-Yan; Pan, Deng-Hua; Ma, Wei; Chen, Gang; He, Yun; Chen, Jun-Qiang

2017-05-01

The role of long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) in thyroid carcinoma (TC) remains unclear. The current study was aimed to assess the clinical value of HOTAIR expression levels in TC based on publically available data and to evaluate its potential signaling pathways. The expression data of HOTAIR and clinical information concerning TC were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), respectively. Furthermore, 3 online biological databases, Starbase, Cbioportal, and Multi Experiment Matrix, were used to identify HOTAIR-related genes in TC. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Panther pathway analyses were then undertaken to study the most enriched signaling pathways in TC (EASE score<0.1, Bonferroni<0.05). The TCGA results demonstrated that the expression level of HOTAIR in TC tissues was significantly increased compared with non-cancerous tissues (p<0.001). HOTAIR over-expression was significantly associated with poor survival in TC patients (p=0.03). Meta-analyses of GEO datasets revealed a trend consistent with the above results on HOTAIR expression levels in TC (SMD=0.23; 95%CI, 0.00-0.45; p=0.047). Finally, the results of functional analysis for HOTAIR-related genes indicated that HOTAIR might participate in tumorigenesis via the Wnt signaling pathway. In conclusion, our study demonstrates that HOTAIR may be involved in thyroid carcinogenesis, and the over-expression of HOTAIR could act as a biomarker associated with a poor outcome in TC patients. Moreover, the Wnt signaling pathway may be the key pathway regulated by HOTAIR in TC. © Georg Thieme Verlag KG Stuttgart · New York.

Leucine Affects α-Amylase Synthesis through PI3K/Akt-mTOR Signaling Pathways in Pancreatic Acinar Cells of Dairy Calves.

PubMed

Guo, Long; Liang, Ziqi; Zheng, Chen; Liu, Baolong; Yin, Qingyan; Cao, Yangchun; Yao, Junhu

2018-05-23

Dietary nutrient utilization, particularly starch, is potentially limited by digestion in dairy cow small intestine because of shortage of α-amylase. Leucine acts as an effective signal molecular in the mTOR signaling pathway, which regulates a series of biological processes, especially protein synthesis. It has been reported that leucine could affect α-amylase synthesis and secretion in ruminant pancreas, but mechanisms have not been elaborated. In this study, pancreatic acinar (PA) cells were used as a model to determine the cellular signal of leucine influence on α-amylase synthesis. PA cells were isolated from newborn Holstein dairy bull calves and cultured in Dulbecco's modifed Eagle's medium/nutrient mixture F12 liquid media containing four leucine treatments (0, 0.23, 0.45, and 0.90 mM, respectively), following α-amylase activity, zymogen granule, and signal pathway factor expression detection. Rapamycin, a specific inhibitor of mTOR, was also applied to PA cells. Results showed that leucine increased ( p < 0.05) synthesis of α-amylase as well as phosphorylation of PI3K, Akt, mTOR, and S6K1 while reduced ( p < 0.05) GCN2 expression. Inhibition of mTOR signaling downregulated the α-amylase synthesis. In addition, the extracellular leucine dosage significantly influenced intracellular metabolism of isoleucine ( p < 0.05). Overall, leucine regulates α-amylase synthesis through promoting the PI3K/Akt-mTOR pathway and reducing the GCN2 pathway in PA cells of dairy calves. These pathways form the signaling network that controls the protein synthesis and metabolism. It would be of great interest in future studies to explore the function of leucine in ruminant nutrition.

New advances of TMEM88 in cancer initiation and progression, with special emphasis on Wnt signaling pathway.

PubMed

Ge, Yun-Xuan; Wang, Chang-Hui; Hu, Fu-Yong; Pan, Lin-Xin; Min, Jie; Niu, Kai-Yuan; Zhang, Lei; Li, Jun; Xu, Tao

2018-01-01

Transmembrane protein 88 (TMEM88), a newly discovered protein localized on the cell membrane. Recent studies showed that TMEM88 was involved in the regulation of several types of cancer. TMEM88 was expressed at significantly higher levels in breast cancer (BC) cell line than in normal breast cell line with co-localized with Dishevelled (DVL) in the cytoplasm of BC cell line. TMEM88 silencing in the ovarian cancer cell line CP70 resulted in significant upregulation of Wnt downstream genes (c-Myc, cyclin-D1) and other Wnt target genes including JUN, PTIX2, CTNNB1 (β-catenin), further supporting that TMEM88 inhibits canonical Wnt signaling pathway. Wnt signaling pathway has been known to play important roles in many diseases, especially in cancer. For instance, hepatocellular carcinoma (HCC) has become one of the most common tumors harboring mutations in the Wnt signaling pathway. As the inhibitor of Wnt signaling, TMEM88 has been considered to act as an oncogene or a tumor suppressor. Up-regulated TMEM88 or gene therapy approaches could be an effective therapeutic approach against tumor as TMEM88 inhibits Wnt signaling through direct interaction with DVL. Here, we review the current knowledge on the functional role and potential clinical application of TMEM88 in the control of various cancers. Highlights Wnt signaling displays an important role in several pathogenesis of cancer. Wnt signaling pathway is activated during cancer development. TMEM88 has an impact on cancer by inhibiting canonical Wnt signaling. We discuss the importance and new applications of TMEM88 in cancer therapy. © 2017 Wiley Periodicals, Inc.

Reciprocal transcriptional regulation of metabolic and signaling pathways correlates with disease severity in heart failure.

PubMed

Barth, Andreas S; Kumordzie, Ami; Frangakis, Constantine; Margulies, Kenneth B; Cappola, Thomas P; Tomaselli, Gordon F

2011-10-01

Systolic heart failure (HF) is a complex systemic syndrome that can result from a wide variety of clinical conditions and gene mutations. Despite phenotypic similarities, characterized by ventricular dilatation and reduced contractility, the extent of common and divergent gene expression between different forms of HF remains a matter of intense debate. Using a meta-analysis of 28 experimental (mouse, rat, dog) and human HF microarray studies, we demonstrate that gene expression changes are characterized by a coordinated and reciprocal regulation of major metabolic and signaling pathways. In response to a wide variety of stressors in animal models of HF, including ischemia, pressure overload, tachypacing, chronic isoproterenol infusion, Chagas disease, and transgenic mouse models, major metabolic pathways are invariably downregulated, whereas cell signaling pathways are upregulated. In contrast to this uniform transcriptional pattern that recapitulates a fetal gene expression program in experimental animal models of HF, human HF microarray studies displayed a greater heterogeneity, with some studies even showing upregulation of metabolic and downregulation of signaling pathways in end-stage human hearts. These discrepant results between animal and human studies are due to a number of factors, prominently cardiac disease and variable exposure to cold cardioplegic solution in nonfailing human samples, which can downregulate transcripts involved in oxidative phosphorylation (OXPHOS), thus mimicking gene expression patterns observed in failing samples. Additionally, β-blockers and ACE inhibitor use in end-stage human HF was associated with higher levels of myocardial OXPHOS transcripts, thus partially reversing the fetal gene expression pattern. In human failing samples, downregulation of metabolism was associated with hemodynamic markers of disease severity. Irrespective of the etiology, gene expression in failing myocardium is characterized by downregulation of metabolic transcripts and concomitant upregulation of cell signaling pathways. Gene expression changes along this metabolic-signaling axis in mammalian myocardium are a consistent feature in the heterogeneous transcriptional response observed in phenotypically similar models of HF.

Inhibition of the Rac1-WAVE2-Arp2/3 signaling pathway promotes radiosensitivity via downregulation of cofilin-1 in U251 human glioma cells.

PubMed

Zhou, Tao; Wang, Chen-Han; Yan, Hua; Zhang, Rui; Zhao, Jin-Bing; Qian, Chun-Fa; Xiao, Hong; Liu, Hong-Yi

2016-05-01

The Ras-related C3 botulinum toxin substrate 1 (Rac1)-WASP-family verprolin-homologous protein-2 (WAVE2)-actin-related protein 2/3 (Arp2/3) signaling pathway has been identified to be involved in cell migration and invasion in various types of cancer cell. Cofilin‑1 (CFL‑1), which is regulated by the Rac1‑WAVE2‑Arp2/3 signaling pathway, may promote radioresistance in glioma. Therefore, the present study aimed to investigate the potential role of the Rac1‑WAVE2‑Arp2/3 signaling pathway in radioresistance in U251 human glioma cells and elucidate its affect on CFL‑1 expression. Western blot analysis was performed to evaluate the protein expression of CFL‑1. In the present study, Rac1 was inhibited by NSC 23766, WAVE2 was inhibited by transfection with short hairpin (sh)RNA‑WAVE2 using Lipofectamine™ 2000 and Arp2/3 was inhibited by CK‑666. Cell viability was measured using the 3‑(4,5‑dimethylthiazol‑2‑yl)-2,5‑diphenyltetrazolium bromide assay, the cell migration ability was examined by a wound‑healing assay, and the cell invasion ability was assessed using a Transwell culture chamber system. The results showed that inhibition of the Rac1‑WAVE2‑Arp2/3 signaling pathway using NSC 23766, shRNA‑WAVE2 or CK‑666 reduced the cell viability, migration and invasion abilities in U251 human glioma cells, concordant with a reduced expression of CFL‑1. Furthermore, the expression of CFL‑1 was significantly increased in radioresistant U251 glioma cells when compared with normal U251 human glioma cells. These findings indicate that inhibition of the Rac1‑WAVE2‑Arp2/3 signaling pathway may promote radiosensitivity, which may partially result from the downregulation of CFL‑1 in U251 human glioma cells.

Arbuscular mycorrhizal fungal inoculation increases phenolic synthesis in clover roots via hydrogen peroxide, salicylic acid and nitric oxide signaling pathways.

PubMed

Zhang, Rui-Qin; Zhu, Hong-Hui; Zhao, Hai-Quan; Yao, Qing

2013-01-01

Arbuscular mycorrhizal fungi can increase the host resistance to pathogens via promoted phenolic synthesis, however, the signaling pathway responsible for it still remains unclear. In this study, in order to reveal the signaling molecules involved in this process, we inoculated Trifolium repense L. with an arbuscular mycorrhizal fungus (AMF), Glomus mosseae, and monitored the contents of phenolics and signaling molecules (hydrogen peroxide (H(2)O(2)), salicylic acid (SA), and nitric oxide (NO)) in roots, measured the activities of l-phenylalanine ammonia-lyase (PAL) and nitric oxide synthase (NOS), and the expression of pal and chs genes. Results demonstrated that AMF colonization promoted the phenolic synthesis, in parallel with the increase in related enzyme activity and gene expression. Meanwhile, the accumulation of all three signaling molecules was also up-regulated by AMF. This study suggested that AMF increased the phenolic synthesis in roots probably via signaling pathways of H(2)O(2), SA and NO in a signaling cascade. Copyright © 2012 Elsevier GmbH. All rights reserved.

Src regulates sequence-dependent beta-2 adrenergic receptor recycling via cortactin phosphorylation*

PubMed Central

Vistein, Rachel; Puthenveedu, Manojkumar A.

2014-01-01

The recycling of internalized signaling receptors, which has direct functional consequences, is subject to multiple sequence and biochemical requirements. Why signaling receptors recycle via a specialized pathway, unlike many other proteins that recycle by bulk, is a fundamental unanswered question. Here we show that these specialized pathways allow selective control of signaling receptor recycling by heterologous signaling. Using assays to visualize receptor recycling in living cells, we show that the recycling of the beta-2 adrenergic receptor (B2AR), a prototypic signaling receptor, is regulated by Src family kinases. The target of Src is cortactin, an essential factor for B2AR sorting into specialized recycling microdomains on the endosome. Phosphorylation of a single cortactin residue, Y466, regulates the rate of fission of B2AR recycling vesicles from these microdomains, and, therefore, the rate of delivery of B2AR to the cell surface. Together, our results indicate that actin-stabilized microdomains that mediate signaling receptor recycling can serve as a functional point of convergence for crosstalk between signaling pathways. PMID:25077552

Brassinosteroid-Induced Transcriptional Repression and Dephosphorylation-Dependent Protein Degradation Negatively Regulate BIN2-Interacting AIF2 (a BR Signaling-Negative Regulator) bHLH Transcription Factor.

PubMed

Kim, Yoon; Song, Ji-Hye; Park, Seon-U; Jeong, You-Seung; Kim, Soo-Hwan

2017-02-01

Brassinosteroids (BRs) are plant polyhydroxy-steroids that play important roles in plant growth and development via extensive signal integration through direct interactions between regulatory components of different signaling pathways. Recent studies have shown that diverse helix-loop-helix/basic helix-loop-helix (HLH/bHLH) family proteins are actively involved in control of BR signaling pathways and interact with other signaling pathways. In this study, we show that ATBS1-INTERACTING FACTOR 2 (AIF2), a nuclear-localized atypical bHLH transcription factor, specifically interacts with BRASSINOSTEROID-INSENSITIVE 2 (BIN2) among other BR signaling molecules. Overexpression of AIF2 down-regulated transcript expression of growth-promoting genes, thus resulting in retardation of growth. AIF2 renders plants hyposensitive to BR-induced root growth inhibition, but shows little effects on BR-promoted hypocotyl elongation. Notably, AIF2 was dephosphorylated by BR, and the dephosphorylated AIF2 was subject to proteasome-mediated degradation. AIF2 degradation was greatly induced by BR and ABA, but relatively slightly by other hormones such as auxin, gibberellin, cytokinin and ethylene. Moreover, AIF2 transcription was significantly suppressed by a BRI1/BZR1-mediated BR signaling pathway through a direct binding of BRASSINAZOLE RESISTANT 1 (BZR1) to the BR response element (BRRE) region of the AIF2 promoter. In conclusion, our study suggests that BIN2-driven AIF2 phosphorylation could augment the BIN2/AIF2-mediated negative circuit of BR signaling pathways, and the BR-induced transcriptional repression and protein degradation negatively regulate AIF2 transcription factor, reinforcing the BZR1/BES1-mediated positive BR signaling pathway. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Apatinib resensitizes cisplatin-resistant non-small cell lung carcinoma A549 cell through reversing multidrug resistance and suppressing ERK signaling pathway.

PubMed

Liu, Z-L; Jin, B-J; Cheng, C-G; Zhang, F-X; Wang, S-W; Wang, Y; Wu, B

2017-12-01

To observe the reversal effect of apatinib on the resistance to cisplatin (DDP) of A549/cisplatin (A549/DDP) cells and its relevant mechanism. A549/DDP cells were treated with the control method, apatinib alone, DDP alone and DDP combined with apatinib. The cell proliferation was detected by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the cell clone formation assay. The cell apoptosis was detected by Hoechst 33258 staining and annexin V and propidium iodide (PI) double labeling. The changes in apoptotic proteins, multidrug resistance protein 1 (MDR1) and extracellular signal-regulated kinase (ERK) signaling pathway proteins in each group after treatment were detected by Western blotting. MTT assay results showed that compared with A549 cells, A549/DDP cells had obvious resistance to DDP. MTT assay and cell clone formation assay revealed that the tumor inhibition rate of the sub-lethal dose of apatinib (10 μM) combined with DDP was higher than that of DDP alone. The apoptosis detection results indicated that the proportion of apoptotic cells in the apatinib (10 μM) combined with DDP group was significantly increased. Western blotting results revealed that compared with that in parental A549 cells, the expression level of MDR1 in A549/DDP cells was significantly increased, and the ERK signaling pathway was activated. In the apatinib combined with DDP group, the levels of cleaved caspase-3, cleaved caspase-9 and B-cell lymphoma-2 (Bcl-2)-associated X (BAX) proteins were significantly upregulated, while the level of Bcl-2 proteins was downregulated. Apatinib could inhibit the expression of MDR1 and the activity of the ERK signaling pathway in a dose-dependent manner. Apatinib can restore the sensitivity of A549/DDP cells to DDP by down-regulating the expression level of MDR1 and inhibiting the activity of the ERK signaling pathway.

The node-weighted Steiner tree approach to identify elements of cancer-related signaling pathways.

PubMed

Sun, Yahui; Ma, Chenkai; Halgamuge, Saman

2017-12-28

Cancer constitutes a momentous health burden in our society. Critical information on cancer may be hidden in its signaling pathways. However, even though a large amount of money has been spent on cancer research, some critical information on cancer-related signaling pathways still remains elusive. Hence, new works towards a complete understanding of cancer-related signaling pathways will greatly benefit the prevention, diagnosis, and treatment of cancer. We propose the node-weighted Steiner tree approach to identify important elements of cancer-related signaling pathways at the level of proteins. This new approach has advantages over previous approaches since it is fast in processing large protein-protein interaction networks. We apply this new approach to identify important elements of two well-known cancer-related signaling pathways: PI3K/Akt and MAPK. First, we generate a node-weighted protein-protein interaction network using protein and signaling pathway data. Second, we modify and use two preprocessing techniques and a state-of-the-art Steiner tree algorithm to identify a subnetwork in the generated network. Third, we propose two new metrics to select important elements from this subnetwork. On a commonly used personal computer, this new approach takes less than 2 s to identify the important elements of PI3K/Akt and MAPK signaling pathways in a large node-weighted protein-protein interaction network with 16,843 vertices and 1,736,922 edges. We further analyze and demonstrate the significance of these identified elements to cancer signal transduction by exploring previously reported experimental evidences. Our node-weighted Steiner tree approach is shown to be both fast and effective to identify important elements of cancer-related signaling pathways. Furthermore, it may provide new perspectives into the identification of signaling pathways for other human diseases.

Cartography of Pathway Signal Perturbations Identifies Distinct Molecular Pathomechanisms in Malignant and Chronic Lung Diseases

PubMed Central

Arakelyan, Arsen; Nersisyan, Lilit; Petrek, Martin; Löffler-Wirth, Henry; Binder, Hans

2016-01-01

Lung diseases are described by a wide variety of developmental mechanisms and clinical manifestations. Accurate classification and diagnosis of lung diseases are the bases for development of effective treatments. While extensive studies are conducted toward characterization of various lung diseases at molecular level, no systematic approach has been developed so far. Here we have applied a methodology for pathway-centered mining of high throughput gene expression data to describe a wide range of lung diseases in the light of shared and specific pathway activity profiles. We have applied an algorithm combining a Pathway Signal Flow (PSF) algorithm for estimation of pathway activity deregulation states in lung diseases and malignancies, and a Self Organizing Maps algorithm for classification and clustering of the pathway activity profiles. The analysis results allowed clearly distinguish between cancer and non-cancer lung diseases. Lung cancers were characterized by pathways implicated in cell proliferation, metabolism, while non-malignant lung diseases were characterized by deregulations in pathways involved in immune/inflammatory response and fibrotic tissue remodeling. In contrast to lung malignancies, chronic lung diseases had relatively heterogeneous pathway deregulation profiles. We identified three groups of interstitial lung diseases and showed that the development of characteristic pathological processes, such as fibrosis, can be initiated by deregulations in different signaling pathways. In conclusion, this paper describes the pathobiology of lung diseases from systems viewpoint using pathway centered high-dimensional data mining approach. Our results contribute largely to current understanding of pathological events in lung cancers and non-malignant lung diseases. Moreover, this paper provides new insight into molecular mechanisms of a number of interstitial lung diseases that have been studied to a lesser extent. PMID:27200087

Tgf-beta induced Erk phosphorylation of smad linker region regulates smad signaling.

PubMed

Hough, Chris; Radu, Maria; Doré, Jules J E

2012-01-01

The Transforming Growth Factor-Beta (TGF-β) family is involved in regulating a variety of cellular processes such as apoptosis, differentiation, and proliferation. TGF-β binding to a Serine/Threonine kinase receptor complex causes the recruitment and subsequent activation of transcription factors known as smad2 and smad3. These proteins subsequently translocate into the nucleus to negatively or positively regulate gene expression. In this study, we define a second signaling pathway leading to TGF-β receptor activation of Extracellular Signal Regulated Kinase (Erk) in a cell-type dependent manner. TGF-β induced Erk activation was found in phenotypically normal mesenchymal cells, but not normal epithelial cells. By activating phosphotidylinositol 3-kinase (PI3K), TGF-β stimulates p21-activated kinase2 (Pak2) to phosphorylate c-Raf, ultimately resulting in Erk activation. Activation of Erk was necessary for TGF-β induced fibroblast replication. In addition, Erk phosphorylated the linker region of nuclear localized smads, resulting in increased half-life of C-terminal phospho-smad 2 and 3 and increased duration of smad target gene transcription. Together, these data show that in mesenchymal cell types the TGF-β/PI3K/Pak2/Raf/MEK/Erk pathway regulates smad signaling, is critical for TGF-β-induced growth and is part of an integrated signaling web containing multiple interacting pathways rather than discrete smad/non-smad pathways.

Inhibiting core fucosylation attenuates glucose-induced peritoneal fibrosis in rats.

PubMed

Li, Longkai; Shen, Nan; Wang, Nan; Wang, Weidong; Tang, Qingzhu; Du, Xiangning; Carrero, Juan Jesus; Wang, Keping; Deng, Yiyao; Li, Zhitong; Lin, Hongli; Wu, Taihua

2018-06-01

Ultrafiltration failure is a major complication of long-term peritoneal dialysis, resulting in dialysis failure. Peritoneal fibrosis induced by continuous exposure to high glucose dialysate is the major contributor of ultrafiltration failure, for which there is no effective treatment. Overactivation of several signaling pathways, including transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF) pathways, contribute to the development of peritoneal fibrosis. Therefore, simultaneously blocking multiple signaling pathways might be a potential novel method of treating peritoneal fibrosis. Previously, we showed that core fucosylation, an important posttranslational modification of the TGF-β1 receptors, can regulate the activation of TGF-β1 signaling in renal interstitial fibrosis. However, it remains unclear whether core fucosylation affects the progression of peritoneal fibrosis. Herein, we show that core fucosylation was enriched in the peritoneal membrane of rats accompanied by peritoneal fibrosis induced by a high glucose dialysate. Blocking core fucosylation dramatically attenuated peritoneal fibrosis in the rat model achieved by simultaneously inactivating the TGF-β1 and PDGF signaling pathways. Next the protective effects of blocking core fucosylation and imatinib (a selective PDGF receptor inhibitor) on peritoneal fibrosis were compared and found to exhibit a greater inhibitory effect over imatinib alone, suggesting that blocking activation of multiple signaling pathways may have superior inhibitory effects on the development of peritoneal fibrosis. Thus, core fucosylation is essential for the development of peritoneal fibrosis by regulating the activation of multiple signaling pathways. This may be a potential novel target for drug development to treat peritoneal fibrosis. Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Molecular mechanism of TGF-β signaling pathway in colon carcinogenesis and status of curcumin as chemopreventive strategy.

PubMed

Ramamoorthi, Ganesan; Sivalingam, Nageswaran

2014-08-01

Colon cancer is one of the third most common cancer in man, the second most common cancer in women worldwide, and the second leading cause of mortality in the USA. There are a number of molecular pathways that have been implicated in colon carcinogenesis, including TGF-β/Smad signaling pathway. TGF-β (transforming growth factor-beta) signaling pathway has the potential to regulate various biological processes including cell growth, differentiation, apoptosis, extracellular matrix modeling, and immune response. TGF-β signaling pathway acts as a tumor suppressor, but alterations in TGF-β signaling pathway promotes colon cancer cell growth, migration, invasion, angiogenesis, and metastasis. Here we review the role of TGF-β signaling cascade in colon carcinogenesis and multiple molecular targets of curcumin in colon carcinogenesis. Elucidation of the molecular mechanism of curcumin on TGF-β signaling pathway-induced colon carcinogenesis may ultimately lead to novel and more effective treatments for colon cancer.

Non-Smad signaling pathways.

PubMed

Mu, Yabing; Gudey, Shyam Kumar; Landström, Maréne

2012-01-01

Transforming growth factor-beta (TGFβ) is a key regulator of cell fate during embryogenesis and has also emerged as a potent driver of the epithelial-mesenchymal transition during tumor progression. TGFβ signals are transduced by transmembrane type I and type II serine/threonine kinase receptors (TβRI and TβRII, respectively). The activated TβR complex phosphorylates Smad2 and Smad3, converting them into transcriptional regulators that complex with Smad4. TGFβ also uses non-Smad signaling pathways such as the p38 and Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways to convey its signals. Ubiquitin ligase tumor necrosis factor (TNF)-receptor-associated factor 6 (TRAF6) and TGFβ-associated kinase 1 (TAK1) have recently been shown to be crucial for the activation of the p38 and JNK MAPK pathways. Other TGFβ-induced non-Smad signaling pathways include the phosphoinositide 3-kinase-Akt-mTOR pathway, the small GTPases Rho, Rac, and Cdc42, and the Ras-Erk-MAPK pathway. Signals induced by TGFβ are tightly regulated and specified by post-translational modifications of the signaling components, since they dictate the subcellular localization, activity, and duration of the signal. In this review, we discuss recent findings in the field of TGFβ-induced responses by non-Smad signaling pathways.

Energy transport pathway in proteins: Insights from non-equilibrium molecular dynamics with elastic network model.

PubMed

Wang, Wei Bu; Liang, Yu; Zhang, Jing; Wu, Yi Dong; Du, Jian Jun; Li, Qi Ming; Zhu, Jian Zhuo; Su, Ji Guo

2018-06-22

Intra-molecular energy transport between distant functional sites plays important roles in allosterically regulating the biochemical activity of proteins. How to identify the specific intra-molecular signaling pathway from protein tertiary structure remains a challenging problem. In the present work, a non-equilibrium dynamics method based on the elastic network model (ENM) was proposed to simulate the energy propagation process and identify the specific signaling pathways within proteins. In this method, a given residue was perturbed and the propagation of energy was simulated by non-equilibrium dynamics in the normal modes space of ENM. After that, the simulation results were transformed from the normal modes space to the Cartesian coordinate space to identify the intra-protein energy transduction pathways. The proposed method was applied to myosin and the third PDZ domain (PDZ3) of PSD-95 as case studies. For myosin, two signaling pathways were identified, which mediate the energy transductions form the nucleotide binding site to the 50 kDa cleft and the converter subdomain, respectively. For PDZ3, one specific signaling pathway was identified, through which the intra-protein energy was transduced from ligand binding site to the distant opposite side of the protein. It is also found that comparing with the commonly used cross-correlation analysis method, the proposed method can identify the anisotropic energy transduction pathways more effectively.

Involvement of intracellular Zn2+ signaling in LTP at perforant pathway-CA1 pyramidal cell synapse.

PubMed

Tamano, Haruna; Nishio, Ryusuke; Takeda, Atsushi

2017-07-01

Physiological significance of synaptic Zn 2+ signaling was examined at perforant pathway-CA1 pyramidal cell synapses. In vivo long-term potentiation (LTP) at perforant pathway-CA1 pyramidal cell synapses was induced using a recording electrode attached to a microdialysis probe and the recording region was locally perfused with artificial cerebrospinal fluid (ACSF) via the microdialysis probe. Perforant pathway LTP was not attenuated under perfusion with CaEDTA (10 mM), an extracellular Zn 2+ chelator, but attenuated under perfusion with ZnAF-2DA (50 μM), an intracellular Zn 2+ chelator, suggesting that intracellular Zn 2+ signaling is required for perforant pathway LTP. Even in rat brain slices bathed in CaEDTA in ACSF, intracellular Zn 2+ level, which was measured with intracellular ZnAF-2, was increased in the stratum lacunosum-moleculare where perforant pathway-CA1 pyramidal cell synapses were contained after tetanic stimulation. These results suggest that intracellular Zn 2+ signaling, which originates in internal stores/proteins, is involved in LTP at perforant pathway-CA1 pyramidal cell synapses. Because the influx of extracellular Zn 2+ , which originates in presynaptic Zn 2+ release, is involved in LTP at Schaffer collateral-CA1 pyramidal cell synapses, synapse-dependent Zn 2+ dynamics may be involved in plasticity of postsynaptic CA1 pyramidal cells. © 2017 Wiley Periodicals, Inc.

Natural Genetic Variation Influences Protein Abundances in C. elegans Developmental Signalling Pathways

PubMed Central

Singh, Kapil Dev; Roschitzki, Bernd; Snoek, L. Basten; Grossmann, Jonas; Zheng, Xue; Elvin, Mark; Kamkina, Polina; Schrimpf, Sabine P.; Poulin, Gino B.; Kammenga, Jan E.; Hengartner, Michael O.

2016-01-01

Complex traits, including common disease-related traits, are affected by many different genes that function in multiple pathways and networks. The apoptosis, MAPK, Notch, and Wnt signalling pathways play important roles in development and disease progression. At the moment we have a poor understanding of how allelic variation affects gene expression in these pathways at the level of translation. Here we report the effect of natural genetic variation on transcript and protein abundance involved in developmental signalling pathways in Caenorhabditis elegans. We used selected reaction monitoring to analyse proteins from the abovementioned four pathways in a set of recombinant inbred lines (RILs) generated from the wild-type strains N2 (Bristol) and CB4856 (Hawaii) to enable quantitative trait locus (QTL) mapping. About half of the cases from the 44 genes tested showed a statistically significant change in protein abundance between various strains, most of these were however very weak (below 1.3-fold change). We detected a distant QTL on the left arm of chromosome II that affected protein abundance of the phosphatidylserine receptor protein PSR-1, and two separate QTLs that influenced embryonic and ionizing radiation-induced apoptosis on chromosome IV. Our results demonstrate that natural variation in C. elegans is sufficient to cause significant changes in signalling pathways both at the gene expression (transcript and protein abundance) and phenotypic levels. PMID:26985669

TGFβ1-mediated PI3K/Akt and p38 MAP kinase dependent alternative splicing of fibronectin extra domain A in human podocyte culture.

PubMed

Madne, Tarunkumar Hemraj; Dockrell, Mark Edward Carl

2018-04-30

Alternative splicing is an important gene regulation process to distribute proteins in health and diseases. Extra Domain A+ Fibronectin (EDA+Fn) is an alternatively spliced form of fibronectin (Fn) protein, present in the extra cellular matrix (ECM) and a recognised marker of various pathologies. TGFβ1 has been shown to induce alternative splicing of EDA+Fn in many cell types. Podocytes are spectacular cell type and play a key role in filtration and synthesise ECM proteins in renal physiology and pathology. In our previous study we have demonstrated expression and alternative splicing of EDA+Fn in basal condition in human podocytes culture. TGFβ1 further induced the basal expression and alternative splicing of EDA+Fn through Alk5 receptor and SR proteins. In this study, we have investigated TGFβ1 mediated signalling involved in alternative splicing of EDA+Fn in human podocytes. We have performed western blotting to characterise the expression of the EDA+Fn protein and other signalling proteins and RT-PCR to look for signalling pathways involved in regulation of alternative splicing of EDA+Fn in conditionally immortalised human podocytes culture.We have used TGFβ1 as a stimulator and SB431542, SB202190 and LY294002 for inhibitory studies. In this work, we have demonstrated in human podocytes culture TGFβ1 2.5ng/ml induced phosphorylation of Smad1/5/8, Smad2 and Smad3 via the ALK5 receptor. TGFβ1 significantly induced the PI3K/Akt pathway and the PI3K/Akt pathway inhibitor LY294002 significantly downregulated basal as well as TGFβ1 induced alternative splicing of EDA+Fn in human podocytes. In addition to this, TGFβ1 significantly induced the p38 MAP kinase signalling pathway and p38 MAP kinase signalling pathway inhibitor SB202190 downregulated the TGFβ1-mediated alternative splicing of EDA+Fn in human podocytes. The results with PI3K and p38 MAP kinase signalling pathway suggest that inhibiting PI3K signalling pathway downregulated the basal alternative splicing of EDA+Fn in human podocytes and its the inhibition of p38 Map Kinase signalling pathway which had specifically downregulated the TGFβ1 mediated alternative splicing of EDA+Fn in human podocytes culture. Activation of TGFβ1-mediated Smad1/5/8 via Alk5 receptor suggests that TGFβ1 signalling pathway involved Alk5/Alk1 receptor axis signalling in human podocytes.

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. © The Author 2014. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

FGF coordinates air sac development by activation of the EGF ligand Vein through the transcription factor PntP2.

PubMed

Cruz, Josefa; Bota-Rabassedas, Neus; Franch-Marro, Xavier

2015-12-03

How several signaling pathways are coordinated to generate complex organs through regulation of tissue growth and patterning is a fundamental question in developmental biology. The larval trachea of Drosophila is composed of differentiated functional cells and groups of imaginal tracheoblasts that build the adult trachea during metamorphosis. Air sac primordium cells (ASP) are tracheal imaginal cells that form the dorsal air sacs that supply oxygen to the flight muscles of the Drosophila adult. The ASP emerges from the tracheal branch that connects to the wing disc by the activation of both Bnl-FGF/Btl and EGFR signaling pathways. Together, these pathways promote cell migration and proliferation. In this study we demonstrate that Vein (vn) is the EGF ligand responsible for the activation of the EGFR pathway in the ASP. We also find that the Bnl-FGF/Btl pathway regulates the expression of vn through the transcription factor PointedP2 (PntP2). Furthermore, we show that the FGF target gene escargot (esg) attenuates EGFR signaling at the tip cells of the developing ASP, reducing their mitotic rate to allow proper migration. Altogether, our results reveal a link between Bnl-FGF/Btl and EGFR signaling and provide novel insight into how the crosstalk of these pathways regulates migration and growth.

FGF coordinates air sac development by activation of the EGF ligand Vein through the transcription factor PntP2

PubMed Central

Cruz, Josefa; Bota-Rabassedas, Neus; Franch-Marro, Xavier

2015-01-01

How several signaling pathways are coordinated to generate complex organs through regulation of tissue growth and patterning is a fundamental question in developmental biology. The larval trachea of Drosophila is composed of differentiated functional cells and groups of imaginal tracheoblasts that build the adult trachea during metamorphosis. Air sac primordium cells (ASP) are tracheal imaginal cells that form the dorsal air sacs that supply oxygen to the flight muscles of the Drosophila adult. The ASP emerges from the tracheal branch that connects to the wing disc by the activation of both Bnl-FGF/Btl and EGFR signaling pathways. Together, these pathways promote cell migration and proliferation. In this study we demonstrate that Vein (vn) is the EGF ligand responsible for the activation of the EGFR pathway in the ASP. We also find that the Bnl-FGF/Btl pathway regulates the expression of vn through the transcription factor PointedP2 (PntP2). Furthermore, we show that the FGF target gene escargot (esg) attenuates EGFR signaling at the tip cells of the developing ASP, reducing their mitotic rate to allow proper migration. Altogether, our results reveal a link between Bnl-FGF/Btl and EGFR signaling and provide novel insight into how the crosstalk of these pathways regulates migration and growth. PMID:26632449

Proteomic analysis of the signaling pathway mediated by the heterotrimeric Gα protein Pga1 of Penicillium chrysogenum.

PubMed

Carrasco-Navarro, Ulises; Vera-Estrella, Rosario; Barkla, Bronwyn J; Zúñiga-León, Eduardo; Reyes-Vivas, Horacio; Fernández, Francisco J; Fierro, Francisco

2016-10-06

The heterotrimeric Gα protein Pga1-mediated signaling pathway regulates the entire developmental program in Penicillium chrysogenum, from spore germination to the formation of conidia. In addition it participates in the regulation of penicillin biosynthesis. We aimed to advance the understanding of this key signaling pathway using a proteomics approach, a powerful tool to identify effectors participating in signal transduction pathways. Penicillium chrysogenum mutants with different levels of activity of the Pga1-mediated signaling pathway were used to perform comparative proteomic analyses by 2D-DIGE and LC-MS/MS. Thirty proteins were identified which showed differences in abundance dependent on Pga1 activity level. By modifying the intracellular levels of cAMP we could establish cAMP-dependent and cAMP-independent pathways in Pga1-mediated signaling. Pga1 was shown to regulate abundance of enzymes in primary metabolic pathways involved in ATP, NADPH and cysteine biosynthesis, compounds that are needed for high levels of penicillin production. An in vivo phosphorylated protein containing a pleckstrin homology domain was identified; this protein is a candidate for signal transduction activity. Proteins with possible roles in purine metabolism, protein folding, stress response and morphogenesis were also identified whose abundance was regulated by Pga1 signaling. Thirty proteins whose abundance was regulated by the Pga1-mediated signaling pathway were identified. These proteins are involved in primary metabolism, stress response, development and signal transduction. A model describing the pathways through which Pga1 signaling regulates different cellular processes is proposed.

Inhibition of homodimerization of toll-like receptor 4 by 6-shogaol.

PubMed

Ahn, Sang-Il; Lee, Jun-Kyung; Youn, Hyung-Sun

2009-02-28

Toll-like receptors (TLRs) play a critical role in sensing microbial components and inducing innate immune and inflammatory responses by recognizing invading microbial pathogens. Lipopolysaccharide-induced dimerization of TLR4 is required for the activation of downstream signaling pathways including nuclear factor-kappa B (NF-kappaB). Therefore, TLR4 dimerization may be an early regulatory event in activating ligand-induced signaling pathways and induction of subsequent immune responses. Here, we report biochemical evidence that 6-shogaol, the most bioactive component of ginger, inhibits lipopolysaccharide-induced dimerization of TLR4 resulting in the inhibition of NF-kappaB activation and the expression of cyclooxygenase-2. Furthermore, we demonstrate that 6-shogaol can directly inhibit TLR-mediated signaling pathways at the receptor level. These results suggest that 6-shogaol can modulate TLR-mediated inflammatory responses, which may influence the risk of chronic inflammatory diseases.

Activation of DNA Damage Repair Pathways by Murine Polyomavirus

PubMed Central

Heiser, Katie; Nicholas, Catherine; Garcea, Robert L.

2016-01-01

Nuclear replication of DNA viruses activates DNA damage repair (DDR) pathways, which are thought to detect and inhibit viral replication. However, many DNA viruses also depend on these pathways in order to optimally replicate their genomes. We investigated the relationship between murine polyomavirus (MuPyV) and components of DDR signaling pathways including CHK1, CHK2, H2AX, ATR, and DNAPK. We found that recruitment and retention of DDR proteins at viral replication centers was independent of H2AX, as well as the viral small and middle T-antigens. Additionally, infectious virus production required ATR kinase activity, but was independent of CHK1, CHK2, or DNAPK signaling. ATR inhibition did not reduce the total amount of viral DNA accumulated, but affected the amount of virus produced, indicating a defect in virus assembly. These results suggest that MuPyV may utilize a subset of DDR proteins or non-canonical DDR signaling pathways in order to efficiently replicate and assemble. PMID:27529739

Mathematical Justification of Expression-Based Pathway Activation Scoring (PAS).

PubMed

Aliper, Alexander M; Korzinkin, Michael B; Kuzmina, Natalia B; Zenin, Alexander A; Venkova, Larisa S; Smirnov, Philip Yu; Zhavoronkov, Alex A; Buzdin, Anton A; Borisov, Nikolay M

2017-01-01

Although modeling of activation kinetics for various cell signaling pathways has reached a high grade of sophistication and thoroughness, most such kinetic models still remain of rather limited practical value for biomedicine. Nevertheless, recent advancements have been made in application of signaling pathway science for real needs of prescription of the most effective drugs for individual patients. The methods for such prescription evaluate the degree of pathological changes in the signaling machinery based on two types of data: first, on the results of high-throughput gene expression profiling, and second, on the molecular pathway graphs that reflect interactions between the pathway members. For example, our algorithm OncoFinder evaluates the activation of molecular pathways on the basis of gene/protein expression data in the objects of the interest.Yet, the question of assessment of the relative importance for each gene product in a molecular pathway remains unclear unless one call for the methods of parameter sensitivity /stiffness analysis in the interactomic kinetic models of signaling pathway activation in terms of total concentrations of each gene product.Here we show two principal points: 1. First, the importance coefficients for each gene in pathways that were obtained using the extremely time- and labor-consuming stiffness analysis of full-scaled kinetic models generally differ from much easier-to-calculate expression-based pathway activation score (PAS) not more than by 30%, so the concept of PAS is kinetically justified. 2. Second, the use of pathway-based approach instead of distinct gene analysis, due to the law of large numbers, allows restoring the correlation between the similar samples that were examined using different transcriptome investigation techniques.

Role of the NFκB-signaling pathway in cancer

PubMed Central

Zhou, Yujuan; Lin, Jingguan; Wang, Heran; Oyang, Linda; Tian, Yutong; Liu, Lu; Su, Min; Wang, Hui; Cao, Deliang; Liao, Qianjin

2018-01-01

Cancer is a group of cells that malignantly grow and proliferate uncontrollably. At present, treatment modes for cancer mainly comprise surgery, chemotherapy, radiotherapy, molecularly targeted therapy, gene therapy, and immunotherapy. However, the curative effects of these treatments have been limited thus far by specific characteristics of tumors. Abnormal activation of signaling pathways is involved in tumor pathogenesis and plays critical roles in growth, progression, and relapse of cancers. Targeted therapies against effectors in oncogenic signaling have improved the outcomes of cancer patients. NFκB is an important signaling pathway involved in pathogenesis and treatment of cancers. Excessive activation of the NFκB-signaling pathway has been documented in various tumor tissues, and studies on this signaling pathway for targeted cancer therapy have become a hot topic. In this review, we update current understanding of the NFκB-signaling pathway in cancer. PMID:29695914

Social power, conflict policing, and the role of subordination signals in rhesus macaque society.

PubMed

Beisner, Brianne A; Hannibal, Darcy L; Finn, Kelly R; Fushing, Hsieh; McCowan, Brenda

2016-05-01

Policing is a conflict-limiting mechanism observed in many primate species. It is thought to require a skewed distribution of social power for some individuals to have sufficiently high social power to stop others' fights, yet social power has not been examined in most species with policing behavior. We examined networks of subordination signals as a source of social power that permits policing behavior in rhesus macaques. For each of seven captive groups of rhesus macaques, we (a) examined the structure of subordination signal networks and used GLMs to examine the relationship between (b) pairwise dominance certainty and subordination network pathways and (c) policing frequency and social power (group-level convergence in subordination signaling pathways). Networks of subordination signals had perfect linear transitivity, and pairs connected by both direct and indirect pathways of signals had more certain dominance relationships than pairs with no such network connection. Social power calculated using both direct and indirect network pathways showed a heavy-tailed distribution and positively predicted conflict policing. Our results empirically substantiate that subordination signaling is associated with greater dominance relationship certainty and further show that pairs who signal rarely (or not at all) may use information from others' signaling interactions to infer or reaffirm the relative certainty of their own relationships. We argue that the network of formal dominance relationships is central to societal stability because it is important for relationship stability and also supports the additional stabilizing mechanism of policing. © 2016 Wiley Periodicals, Inc.

Hedgehog signal transduction: key players, oncogenic drivers, and cancer therapy

PubMed Central

Pak, Ekaterina; Segal, Rosalind A.

2016-01-01

Summary The Hedgehog (Hh) signaling pathway governs complex developmental processes, including proliferation and patterning within diverse tissues. These activities rely on a tightly-regulated transduction system that converts graded Hh input signals into specific levels of pathway activity. Uncontrolled activation of Hh signaling drives tumor initiation and maintenance. However, recent entry of pathway-specific inhibitors into the clinic reveals mixed patient responses and thus prompts further exploration of pathway activation and inhibition. In this review, we share emerging insights on regulated and oncogenic Hh signaling, supplemented with updates on the development and use of Hh pathway-targeted therapies. PMID:27554855

Activation of the MAPK/ERK Cell-Signaling Pathway in Uterine Smooth Muscle Cells of Women With Adenomyosis.

PubMed

Streuli, Isabelle; Santulli, Pietro; Chouzenoux, Sandrine; Chapron, Charles; Batteux, Frédéric

2015-12-01

We investigated whether the myometrium might be intrinsically different in women with adenomyosis. We studied whether the mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPKs/ERKs) and phosphoinositide 3-kinase/mammalian target of rapamycin/AKT (PI3K/mTOR/AKT) cell-signaling pathways, implicated in the pathogenesis of endometriosis, might also be activated in uterine smooth muscle cells (uSMCs) of women with adenomyosis and measured the production of reactive oxygen species (ROS), proinflammatory mediators that modulate cell proliferation and have been shown to activate the MAPK/ERK pathway in endometriosis. The uSMC cultures were derived from myometrium biopsies obtained during hysterectomy or myomectomy in women with adenomyosis and controls with leiomyoma. Proliferation of uSMCs and in vitro activation of the MAPK/ERK cell-signaling pathway were increased in women with adenomyosis compared to controls. The activation of the PI3K/mTOR/AKT pathway was not significant. The ROS production and ROS detoxification pathways were not different between uSMCs of women with adenomyosis and controls suggesting an ROS-independent activation of the MAPK/ERK pathway. Our results also provide evidence that protein kinase inhibitors and the rapanalogue temsirolimus can control proliferation of uSMCs in vitro suggesting an implication of the MAPK/ERK and the PI3K/mTOR/AKT pathways in proliferation of uSMCs in women with adenomyosis and leiomyomas. © The Author(s) 2015.

Loss of the Drosophila cell polarity regulator Scribbled promotes epithelial tissue overgrowth and cooperation with oncogenic Ras-Raf through impaired Hippo pathway signaling

PubMed Central

2011-01-01

Background Epithelial neoplasias are associated with alterations in cell polarity and excessive cell proliferation, yet how these neoplastic properties are related to one another is still poorly understood. The study of Drosophila genes that function as neoplastic tumor suppressors by regulating both of these properties has significant potential to clarify this relationship. Results Here we show in Drosophila that loss of Scribbled (Scrib), a cell polarity regulator and neoplastic tumor suppressor, results in impaired Hippo pathway signaling in the epithelial tissues of both the eye and wing imaginal disc. scrib mutant tissue overgrowth, but not the loss of cell polarity, is dependent upon defective Hippo signaling and can be rescued by knockdown of either the TEAD/TEF family transcription factor Scalloped or the transcriptional coactivator Yorkie in the eye disc, or reducing levels of Yorkie in the wing disc. Furthermore, loss of Scrib sensitizes tissue to transformation by oncogenic Ras-Raf signaling, and Yorkie-Scalloped activity is required to promote this cooperative tumor overgrowth. The inhibition of Hippo signaling in scrib mutant eye disc clones is not dependent upon JNK activity, but can be significantly rescued by reducing aPKC kinase activity, and ectopic aPKC activity is sufficient to impair Hippo signaling in the eye disc, even when JNK signaling is blocked. In contrast, warts mutant overgrowth does not require aPKC activity. Moreover, reducing endogenous levels of aPKC or increasing Scrib or Lethal giant larvae levels does not promote increased Hippo signaling, suggesting that aPKC activity is not normally rate limiting for Hippo pathway activity. Epistasis experiments suggest that Hippo pathway inhibition in scrib mutants occurs, at least in part, downstream or in parallel to both the Expanded and Fat arms of Hippo pathway regulation. Conclusions Loss of Scrib promotes Yorkie/Scalloped-dependent epithelial tissue overgrowth, and this is also important for driving cooperative tumor overgrowth with oncogenic Ras-Raf signaling. Whether this is also the case in human cancers now warrants investigation since the cell polarity function of Scrib and its capacity to restrain oncogene-mediated transformation, as well as the tissue growth control function of the Hippo pathway, are conserved in mammals. PMID:21955824

Low-dose radiation induces Drosophila innate immunity through Toll pathway activation.

PubMed

Seong, Ki Moon; Kim, Cha Soon; Lee, Byung-Sub; Nam, Seon Young; Yang, Kwang Hee; Kim, Ji-Young; Park, Joong-Jean; Min, Kyung-Jin; Jin, Young-Woo

2012-01-01

Numerous studies report that exposing certain organisms to low-dose radiation induces beneficial effects on lifespan, tumorigenesis, and immunity. By analyzing survival after bacterial infection and antimicrobial peptide gene expression in irradiated flies, we demonstrate that low-dose irradiation of Drosophila enhances innate immunity. Low-dose irradiation of flies significantly increased resistance against gram-positive and gram-negative bacterial infections, as well as expression of several antimicrobial peptide genes. Additionally, low-dose irradiation also resulted in a specific increase in expression of key proteins of the Toll signaling pathway and phosphorylated forms of p38 and JNK. These results indicate that innate immunity is activated after low-dose irradiation through Toll signaling pathway in Drosophila.

Defining a Role for Acid Sphingomyelinase in the p38/Interleukin-6 Pathway*

PubMed Central

Perry, David M.; Newcomb, Benjamin; Adada, Mohamad; Wu, Bill X.; Roddy, Patrick; Kitatani, Kazuyuki; Siskind, Leah; Obeid, Lina M.; Hannun, Yusuf A.

2014-01-01

Acid sphingomyelinase (ASM) is one of the key enzymes involved in regulating the metabolism of the bioactive sphingolipid ceramide in the sphingolipid salvage pathway, yet defining signaling pathways by which ASM exerts its effects has proven difficult. Previous literature has implicated sphingolipids in the regulation of cytokines such as interleukin-6 (IL-6), but the specific sphingolipid pathways and mechanisms involved in inflammatory signaling need to be further elucidated. In this work, we sought to define the role of ASM in IL-6 production because our previous work showed that a parallel pathway of ceramide metabolism, acid β-glucosidase 1, negatively regulates IL-6. First, silencing ASM with siRNA abrogated IL-6 production in response to the tumor promoter, 4β-phorbol 12-myristate 13-acetate (PMA), in MCF-7 cells, in distinction to acid β-glucosidase 1 and acid ceramidase, suggesting specialization of the pathways. Moreover, treating cells with siRNA to ASM or with the indirect pharmacologic inhibitor desipramine resulted in significant inhibition of TNFα- and PMA-induced IL-6 production in MDA-MB-231 and HeLa cells. Knockdown of ASM was found to significantly inhibit PMA-dependent IL-6 induction at the mRNA level, probably ruling out mechanisms of translation or secretion of IL-6. Further, ASM knockdown or desipramine blunted p38 MAPK activation in response to TNFα, revealing a key role for ASM in activating p38, a signaling pathway known to regulate IL-6 induction. Last, knockdown of ASM dramatically blunted invasion of HeLa and MDA-MB-231 cells through Matrigel. Taken together, these results demonstrate that ASM plays a critical role in p38 signaling and IL-6 synthesis with implications for tumor pathobiology. PMID:24951586

Nitrite exerts antioxidant effects, inhibits the mTOR pathway and reverses hypertension-induced cardiac hypertrophy.

PubMed

Guimaraes, Danielle A; Dos Passos, Madla A; Rizzi, Elen; Pinheiro, Lucas C; Amaral, Jefferson H; Gerlach, Raquel F; Castro, Michele M; Tanus-Santos, Jose E

2018-05-20

Cardiac hypertrophy is a common consequence of chronic hypertension and leads to heart failure and premature death. The anion nitrite is now considered as a bioactive molecule able to exert beneficial cardiovascular effects. Previous results showed that nitrite attenuates hypertension-induced increases in reactive oxygen species (ROS) production in the vasculature. Whether antioxidant effects induced by nitrite block critical signaling pathways involved in cardiac hypertrophy induced by hypertension has not been determined yet. The Akt/mTOR signaling pathway is responsible to activate protein synthesis during cardiac remodeling and is activated by increased ROS production, which is commonly found in hypertension. Here, we investigated the effects of nitrite treatment on cardiac remodeling and activation of this hypertrophic signaling pathway in 2 kidney-1 clip (2K1C) hypertension. Sham and 2K1C rats were treated with oral nitrite at 1 or 15 mg/kg for four weeks. Nitrite treatment (15 mg/kg) reduced systolic blood pressure and decreased ROS production in the heart tissue from hypertensive rats. This nitrite dose also blunted hypertension-induced activation of mTOR pathway and cardiac hypertrophy. While the lower nitrite dose (1 mg/kg) did not affect blood pressure, it exerted antioxidant effects and tended to attenuate mTOR pathway activation and cardiac hypertrophy induced by hypertension. Our findings provide strong evidence that nitrite treatment decreases cardiac remodeling induced by hypertension as a result of its antioxidant effects and downregulation of mTOR signaling pathway. This study may help to establish nitrite as an effective therapy in hypertension-induced cardiac hypertrophic remodeling. Copyright © 2018 Elsevier Inc. All rights reserved.

Murine Polyomavirus Cell Surface Receptors Activate Distinct Signaling Pathways Required for Infection.

PubMed

O'Hara, Samantha D; Garcea, Robert L

2016-11-01

Virus binding to the cell surface triggers an array of host responses, including activation of specific signaling pathways that facilitate steps in virus entry. Using mouse polyomavirus (MuPyV), we identified host signaling pathways activated upon virus binding to mouse embryonic fibroblasts (MEFs). Pathways activated by MuPyV included the phosphatidylinositol 3-kinase (PI3K), FAK/SRC, and mitogen-activated protein kinase (MAPK) pathways. Gangliosides and α4-integrin are required receptors for MuPyV infection. MuPyV binding to both gangliosides and the α4-integrin receptors was required for activation of the PI3K pathway; however, either receptor interaction alone was sufficient for activation of the MAPK pathway. Using small-molecule inhibitors, we confirmed that the PI3K and FAK/SRC pathways were required for MuPyV infection, while the MAPK pathway was dispensable. Mechanistically, the PI3K pathway was required for MuPyV endocytosis, while the FAK/SRC pathway enabled trafficking of MuPyV along microtubules. Thus, MuPyV interactions with specific cell surface receptors facilitate activation of signaling pathways required for virus entry and trafficking. Understanding how different viruses manipulate cell signaling pathways through interactions with host receptors could lead to the identification of new therapeutic targets for viral infection. Virus binding to cell surface receptors initiates outside-in signaling that leads to virus endocytosis and subsequent virus trafficking. How different viruses manipulate cell signaling through interactions with host receptors remains unclear, and elucidation of the specific receptors and signaling pathways required for virus infection may lead to new therapeutic targets. In this study, we determined that gangliosides and α4-integrin mediate mouse polyomavirus (MuPyV) activation of host signaling pathways. Of these pathways, the PI3K and FAK/SRC pathways were required for MuPyV infection. Both the PI3K and FAK/SRC pathways have been implicated in human diseases, such as heart disease and cancer, and inhibitors directed against these pathways are currently being investigated as therapies. It is possible that these pathways play a role in human PyV infections and could be targeted to inhibit PyV infection in immunosuppressed patients. Copyright © 2016 O’Hara and Garcea.

MicroRNA-200a suppresses the Wnt/β-catenin signaling pathway by interacting with β-catenin.

PubMed

Su, Juan; Zhang, Anling; Shi, Zhendong; Ma, Feifei; Pu, Peiyu; Wang, Tao; Zhang, Jie; Kang, Chunsheng; Zhang, Qingyu

2012-04-01

The Wnt/β-catenin signaling pathway is crucial for human organ development and is involved in tumor progression of many cancers. Accumulating evidence suggests that the expression of β-catenin is, in part, regulated by specific microRNAs (miRNAs). The purpose of this study was to determine the expression of a recently identified epithelial to mesenchymal transition (EMT)-associated tumor suppressor microRNA (miR)-200a, in cancer cells. We also aimed to identify specific miR-200a target genes and to investigate the antitumor effects of miR-200a on the Wnt/β-catenin signaling pathway. We employed TOP/FOP flash luciferase assays to identify the effect of miR-200a on the Wnt/β-catenin pathway and we confirmed our observations using fluorescence microscopy. To determine target genes of miR-200a, a 3' untranslated region (3' UTR) luciferase assay was performed. Cell viability, invasion and wound healing assays were carried out for functional analysis after miRNA transfection. We further investigated the role of miR-200a in EMT by Western blot analysis. We found fluctuation in the expression of miR-200a that was accompanied by changes in the expression of members of the Wnt/β-catenin signaling pathway. We also determined that miR-200a can directly interact with the 3' UTR of CTNNB1 (the gene that encodes β-catenin) to suppress Wnt/β-catenin signaling. MiR-200a could also influence the biological activities of SGC790 and U251 cells. Our results demonstrate that miR-200a is a new tumor suppressor that can regulate the activity of the Wnt/β-catenin signaling pathway via two mechanisms. MiR-200a is a candidate target for tumor treatment via its regulation of the Wnt/β-catenin signaling pathway.

The inflammatory role of phagocyte apoptotic pathways in rheumatic diseases.

PubMed

Cuda, Carla M; Pope, Richard M; Perlman, Harris

2016-08-23

Rheumatoid arthritis affects nearly 1% of the world's population and is a debilitating autoimmune condition that can result in joint destruction. During the past decade, inflammatory functions have been described for signalling molecules classically involved in apoptotic and non-apoptotic death pathways, including, but not limited to, Toll-like receptor signalling, inflammasome activation, cytokine production, macrophage polarization and antigen citrullination. In light of these remarkable advances in the understanding of inflammatory mechanisms of the death machinery, this Review provides a snapshot of the available evidence implicating death pathways, especially within the phagocyte populations of the innate immune system, in the perpetuation of rheumatoid arthritis and other rheumatic diseases. Elevated levels of signalling mediators of both extrinsic and intrinsic apoptosis, as well as the autophagy, are observed in the joints of patients with rheumatoid arthritis. Furthermore, risk polymorphisms are present in signalling molecules of the extrinsic apoptotic and autophagy death pathways. Although research into the mechanisms underlying these pathways has made considerable progress, this Review highlights areas where further investigation is particularly needed. This exploration is critical, as new discoveries in this field could lead to the development of novel therapies for rheumatoid arthritis and other rheumatic diseases.

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

Wnt affects symmetry and morphogenesis during post-embryonic development in colonial chordates.

PubMed

Di Maio, Alessandro; Setar, Leah; Tiozzo, Stefano; De Tomaso, Anthony W

2015-01-01

Wnt signaling is one of the earliest and most highly conserved regulatory pathways for the establishment of the body axes during regeneration and early development. In regeneration, body axes determination occurs independently of tissue rearrangement and early developmental cues. Modulation of the Wnt signaling in either process has shown to result in unusual body axis phenotypes. Botryllus schlosseri is a colonial ascidian that can regenerate its entire body through asexual budding. This processes leads to an adult body via a stereotypical developmental pathway (called blastogenesis), without proceeding through any embryonic developmental stages. In this study, we describe the role of the canonical Wnt pathway during the early stages of asexual development. We characterized expression of three Wnt ligands (Wnt2B, Wnt5A, and Wnt9A) by in situ hybridization and qRT-PCR. Chemical manipulation of the pathway resulted in atypical budding due to the duplication of the A/P axes, supernumerary budding, and loss of the overall cell apical-basal polarity. Our results suggest that Wnt signaling is used for equivalent developmental processes both during embryogenesis and asexual development in an adult organism, suggesting that patterning mechanisms driving morphogenesis are conserved, independent of embryonic, or regenerative development.

Bioinformatic Integration of Molecular Networks and Major Pathways Involved in Mice Cochlear and Vestibular Supporting Cells.

PubMed

Requena, Teresa; Gallego-Martinez, Alvaro; Lopez-Escamez, Jose A

2018-01-01

Background : Cochlear and vestibular epithelial non-hair cells (ENHCs) are the supporting elements of the cellular architecture in the organ of Corti and the vestibular neuroepithelium in the inner ear. Intercellular and cell-extracellular matrix interactions are essential to prevent an abnormal ion redistribution leading to hearing and vestibular loss. The aim of this study is to define the main pathways and molecular networks in the mouse ENHCs. Methods : We retrieved microarray and RNA-seq datasets from mouse epithelial sensory and non-sensory cells from gEAR portal (http://umgear.org/index.html) and obtained gene expression fold-change between ENHCs and non-epithelial cells (NECs) against HCs for each gene. Differentially expressed genes (DEG) with a log2 fold change between 1 and -1 were discarded. The remaining genes were selected to search for interactions using Ingenuity Pathway Analysis and STRING platform. Specific molecular networks for ENHCs in the cochlea and the vestibular organs were generated and significant pathways were identified. Results : Between 1723 and 1559 DEG were found in the mouse cochlear and vestibular tissues, respectively. Six main pathways showed enrichment in the supporting cells in both tissues: (1) "Inhibition of Matrix Metalloproteases"; (2) "Calcium Transport I"; (3) "Calcium Signaling"; (4) "Leukocyte Extravasation Signaling"; (5) "Signaling by Rho Family GTPases"; and (6) "Axonal Guidance Si". In the mouse cochlea, ENHCs showed a significant enrichment in 18 pathways highlighting "axonal guidance signaling (AGS)" ( p = 4.37 × 10 -8 ) and "RhoGDI Signaling" ( p = 3.31 × 10 -8 ). In the vestibular dataset, there were 20 enriched pathways in ENHCs, the most significant being "Leukocyte Extravasation Signaling" ( p = 8.71 × 10 -6 ), "Signaling by Rho Family GTPases" ( p = 1.20 × 10 -5 ) and "Calcium Signaling" ( p = 1.20 × 10 -5 ). Among the top ranked networks, the most biologically significant network contained the "auditory and vestibular system development and function" terms. We also found 108 genes showing tonotopic gene expression in the cochlear ENHCs. Conclusions : We have predicted the main pathways and molecular networks for ENHCs in the organ of Corti and vestibular neuroepithelium. These pathways will facilitate the design of molecular maps to select novel candidate genes for hearing or vestibular loss to conduct functional studies.

The Response of wnt/ ß-Catenin Signaling Pathway in Osteocytes Under Simulated Microgravity

NASA Astrophysics Data System (ADS)

Yang, Xiao; Sun, Lian-Wen; Liang, Meng; Wang, Xiao-Nan; Fan, Yu-Bo

2015-11-01

Osteocytes were considered as potential sensors of mechanical loading and orchestrate the bone remodeling adapted to mechanical loading. On the other hand, osteocytes are also considered as the unloading sensors in vivo. Previous studies showed that the mechanosensation and mechanotransduction of osteocytes may play an essential role in mediating bone response to microgravity, and one of the most important molecular signaling pathway involved in the mechanotransduction is the Wnt/ ß-catenin signaling pathway. In order to investigate the effect of simulated microgravity on the Wnt/ ß-catenin signaling pathway in osteocytes, MLO-Y4 cells (an osteocyte-like cell line) were cultured under controlled rotation to simulate microgravity for 5 days. The cytoskeleton and ß-catenin nuclear translocation of MLO-Y4 cells were detected by laser scanning confocal microscope and the fluorescence intensity was quantified; the mRNA expressions of upstream and downstream key components in Wnt canonical signaling were detected with RT-PCR. Two regulators of the Wnt/ ß-catenin pathway, NMP4/CIZ and Smads, were also investigated by RT-PCR; finally the expression of Wnt target genes and Sost protein level were detected with the absence or presence of the Sclerostin antibody (Scl-AbI) under simulated microgravity. The results showed that under simulated microgravity, (1) F-actin filaments were disassembled and some short dendritic processes appeared at the cell periphery; (2) the gene expression of Wnt3a, Wnt5a, DKK1, CyclinD1, LEF-1 and CX43 in the simulated microgravity group were significantly lower whereas Wnt1 and Sost in the simulated microgravity group were significantly higher than the control group; (3) the gene and protein level of ß-catenin were reduced, and no ß-catenin nuclear translocation observed; (4) the gene expression of Smad1, Smad4 and Smad7 were significantly lower whereas NMP4/CIZ and Smad3 in the simulated microgravity were significantly higher than the control group; (5) Scl-AbI partially inhibited the down-regulation of simulated microgravity to Wnt target gene expression and Sclerostin protein expression. The results suggested that firstly the cytoskeleton was disturbed in MLO-Y4 by simulated microgravity; secondly the activity of Wnt/ ß-catenin signaling pathway was depressed, with the nuclear translocation of ß-catenin suppressed by simulated microgravity; thirdly the Wnt/ ß-catenin signaling pathway positive regulators (Smads) were decreased, while the negative regulator (NMP4/CIZ) was increased under simulated microgravity; finally Scl-AbI could partially restore the adverse effect of simulated microgravity to Wnt signaling. This study may help us to understand the mechanotransduction alteration of Wnt/ ß-catenin signaling pathway in osteocytes under simulated microgravity, and further may partly clarify the mechanism of microgravity-induced osteoporosis.

Potential Sabotage of Host Cell Physiology by Apicomplexan Parasites for Their Survival Benefits

PubMed Central

Chakraborty, Shalini; Roy, Sonti; Mistry, Hiral Uday; Murthy, Shweta; George, Neena; Bhandari, Vasundhra; Sharma, Paresh

2017-01-01

Plasmodium, Toxoplasma, Cryptosporidium, Babesia, and Theileria are the major apicomplexan parasites affecting humans or animals worldwide. These pathogens represent an excellent example of host manipulators who can overturn host signaling pathways for their survival. They infect different types of host cells and take charge of the host machinery to gain nutrients and prevent itself from host attack. The mechanisms by which these pathogens modulate the host signaling pathways are well studied for Plasmodium, Toxoplasma, Cryptosporidium, and Theileria, except for limited studies on Babesia. Theileria is a unique pathogen taking into account the way it modulates host cell transformation, resulting in its clonal expansion. These parasites majorly modulate similar host signaling pathways, however, the disease outcome and effect is different among them. In this review, we discuss the approaches of these apicomplexan to manipulate the host–parasite clearance pathways during infection, invasion, survival, and egress. PMID:29081773

Apelin-13 upregulates Egr-1 expression in rat vascular smooth muscle cells through the PI3K/Akt and PKC signaling pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Qi-Feng; Yu, Hong-Wei; Sun, Li-Li

Previous studies have shown that Apelin-13 upregulates early growth response factor-1 (Egr-1) via the extracellular signal-regulated protein kinase (ERK) signaling pathway. Apelin-13 induces proliferation and migration of vascular smooth muscle cells (VSMCs) as well as the upregulation of osteopontin (OPN) via the upregulation of Egr-1. This study was designed to further explore the activity of Apelin-13 in VSMCs by investigating members of the mitogen-activated protein kinase (MAPK) family, in particular Jun kinase (JNK) and p38 mitogen-activated protein kinase (P38). We also examined whether the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) and protein kinase C (PKC) signaling pathways were involvedmore » in the regulation of Egr-1 by Apelin-13. We treated rat aortic VSMCs with Apelin-13 and examined the expression of JNK, p-JNK, P38, and p-P38 to investigate whether Apelin-13-mediated increases in Egr-1 occurred through the JNK and P38 signaling pathways. We then pretreated VSMCs with the Gi protein inhibitor pertussis toxin (PTX) and the Gq inhibitor YM254890, added Apelin-13 and looked for changes in Egr-1 expression. Finally, we pretreated with the PI3K inhibitor LY294002 and the PKC inhibitor GF109203X, and treated with Apelin-13. Our results showed that JNK and P38 did not participate in Apelin-13-mediated increase in Egr-1. Instead, Apelin-13 upregulation of Egr-1 was mediated by a PTX-sensitive Gi protein. Apelin-13 did increase ERK phosphorylation through the PI3K/Akt and PKC signaling pathways, resulting in changes in Egr-1 expression. These data provide important targets for future studies to modulate vascular remodeling. - Highlights: • Apelin-13 mediates Egr-1 upregulation in vascular smooth muscle cells via ERK1/2. • The underlying mechanisms are unknown, but exclude Jnk or p38 pathway activation. • Apelin-13 binds to Gi, activating the PI3K/Akt and PKC signaling cascades. • Consequent ERK phosphorylation results in increased Egr-1 expression. • These novel targets may be potential therapies for vascular remodeling diseases.« less

Effect of aromatase inhibitor letrozole on the proliferation of spermatogonia by regulating the MAPK pathway.

PubMed

Wang, Shunde; Wang, Shuhong; Li, Hang; Li, Xiaoxia; Xie, Menglin; Wen, Jiayu; Li, Meicai; Long, Tengbo

2018-06-01

The molecular mechanism of the aromatase inhibitor letrozole was investigated. It promotes the proliferation of spermatogonia by regulating the mitogen-activated protein kinase (MAPK) pathway. Six different concentrations were selected for letrozole in order to incubate mouse spermatogonia [GC-1 spermatogonia (spg)] for 24, 48 and 72 h, respectively. Cell Counting Kit-8 (CCK-8) was used to observe the effect of letrozole on the proliferation of GC-1 spg cells, and the effect was further verified by cell plate clone formation assay. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the effects of letrozole on MAPK signaling pathways [Ras/extracellular signal-regulated kinase 1 (ERK1)/c-Myc], proliferation indexes [Ki-67 and proliferating cell nuclear antigen (PCNA)]. Bromodeoxyuridine (BrdU) staining was used to study the effects of letrozole and MAPK signaling pathways on cell proliferation. The results of CCK-8 showed that the proliferation rate of GC-1 spg cells was improved. Study results also revealed a significant increase in letrozole concentration along with the time of action. The results of plate clone formation assay further indicated that letrozole could significantly promote the proliferation capacity of GC-1 spg cells (p<0.05). The results of RT-PCR and western blot analysis confirmed letrozole significantly activated the expression of Ras/ERK1/c-Myc in the classical MAPK pathway. A significant increase was noted in the protein levels of Ki-67 and PCNA (p<0.05). By contrast, inhibition of the MAPK pathway resulted in a significant decrease in the levels of the above indexes (p<0.05). The number of BrdU cells in the letrozole group was also higher than that of the control group, while the number of BrdU-stained cells in the letrozole + MAPK inhibition group showed a significant decrease in comparison to the letrozole group. In conclusion, letrozole activated the MAPK signaling pathway and promoted the proliferation of mouse spermatogonia GC-1 spg cells. The present study provides a theoretical basis for the clinical application of letrozole.

Neurotoxicity of developmental hypothyroxinemia and hypothyroidism in rats: Impairments of long-term potentiation are mediated by phosphatidylinositol 3-kinase signaling pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yi; Wei, Wei; Wang, Yuan

Neurotoxicity of iodine deficiency-induced hypothyroidism during developmental period results in serious impairments of brain function, such as learning and memory. These impairments are largely irreversible, and the underlying mechanisms remain unclear. In addition to hypothyroidism, iodine deficiency may cause hypothyroxinemia, a relatively subtle form of thyroid hormone deficiency. Neurotoxicity of developmental hypothyroxinemia also potentially impairs learning and memory. However, more direct evidence of the associations between developmental hypothyroxinemia and impairments of learning and memory should be provided, and the underlying mechanisms remain to be elucidated. Thus, in the present study, we investigated the effects of developmental hypothyroxinemia and hypothyroidism onmore » long-term potentiation (LTP), a widely accepted cellular model of learning and memory, in the hippocampal CA1 region. The activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway – a pathway closely associated with synaptic plasticity and learning and memory – was also investigated. Wistar rats were treated with iodine deficient diet or methimazole (MMZ) to induce developmental hypothyroxinemia or hypothyroidism. The results showed that developmental hypothyroxinemia caused by mild iodine deficiency and developmental hypothyroidism caused by severe iodine deficiency or MMZ significantly reduced the field-excitatory postsynaptic potential (f-EPSP) slope and the population spike (PS) amplitude. Decreased activation of the PI3K signaling pathway was also observed in rats subjected to developmental hypothyroxinemia or hypothyroidism. Our results may support the hypothesis that neurotoxicity of both developmental hypothyroxinemia and hypothyroidism causes damages to learning and memory. Our results also suggest that decreased activation of the PI3K signaling pathway may contribute to impairments of LTP caused by neurotoxicity of both developmental hypothyroxinemia and hypothyroidism. - Highlights: • Neurotoxicity of developmental hypothyroxinemia impaired LTP. • Decreased activation of PI3K signaling contributed to LTP impairments. • The recovery of TH after the developmental period did not prevent LTP impairments. • ID diet successfully induced neurotoxicity of developmental hypothyroxinemia.« less

Endocrine Pancreas Development and Regeneration: Noncanonical Ideas From Neural Stem Cell Biology.

PubMed

Masjkur, Jimmy; Poser, Steven W; Nikolakopoulou, Polyxeni; Chrousos, George; McKay, Ronald D; Bornstein, Stefan R; Jones, Peter M; Androutsellis-Theotokis, Andreas

2016-02-01

Loss of insulin-producing pancreatic islet β-cells is a hallmark of type 1 diabetes. Several experimental paradigms demonstrate that these cells can, in principle, be regenerated from multiple endogenous sources using signaling pathways that are also used during pancreas development. A thorough understanding of these pathways will provide improved opportunities for therapeutic intervention. It is now appreciated that signaling pathways should not be seen as "on" or "off" but that the degree of activity may result in wildly different cellular outcomes. In addition to the degree of operation of a signaling pathway, noncanonical branches also play important roles. Thus, a pathway, once considered as "off" or "low" may actually be highly operational but may be using noncanonical branches. Such branches are only now revealing themselves as new tools to assay them are being generated. A formidable source of noncanonical signal transduction concepts is neural stem cells because these cells appear to have acquired unusual signaling interpretations to allow them to maintain their unique dual properties (self-renewal and multipotency). We discuss how such findings from the neural field can provide a blueprint for the identification of new molecular mechanisms regulating pancreatic biology, with a focus on Notch, Hes/Hey, and hedgehog pathways. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Lipopolysaccharide (LPS) of Porphyromonas gingivalis induces IL-1beta, TNF-alpha and IL-6 production by THP-1 cells in a way different from that of Escherichia coli LPS.

PubMed

Diya Zhang; Lili Chen; Shenglai Li; Zhiyuan Gu; Jie Yan

2008-04-01

Lipopolysaccharide (LPS) derived from the periodontal pathogen Porphyromonas gingivalis has been shown to differ from enterobacterial LPS in structure and function; therefore, the Toll-like receptors (TLRs) and the intracellular inflammatory signaling pathways are accordingly different. To elucidate the signal transduction pathway of P. gingivalis, LPS-induced pro-inflammatory cytokine production in the human monocytic cell line THP-1 was measured by ELISA, and the TLRs were determined by the blocking test using anti-TLRs antibodies. In addition, specific inhibitors as well as Phospho-ELISA kits were used to analyze the intracellular signaling pathways. Escherichia coli LPS was used as the control. In this study, P. gingivalis LPS showed the ability to induce cytokine production in THP-1 cells and its induction was significantly (P < 0.05) suppressed by anti-TLR2 antibody or JNK inhibitor, and the phosphorylation level of JNK was significantly increased (P < 0.05). These results indicate that TLR2-JNK is the main signaling pathway of P. gingivalis LPS-induced cytokine production, while the cytokine induction by E. coli LPS was mainly via TLR4-NF-kappaB and TLR4-p38MAPK. This suggests that P. gingivalis LPS differs from E. coli LPS in its signaling pathway in THP-1 cells, and that the TLR2-JNK pathway might play a significant role in P. gingivalis LPS-induced chronic inflammatory periodontal disease.

[Review for treatment effect and signaling pathway regulation of kidney-tonifying traditional Chinese medicine on osteoporosis].

PubMed

Xiao, Ya-Ping; Zeng, Jie; Jiao, Lin-Na; Xu, Xiao-Yu

2018-01-01

The treatment effect and signaling pathway regulation effects of kidney-tonifying traditional Chinese medicine on osteoporosis have been widely studied, but there is no systematic summary currently. This review comprehensively collected and analyzed the traditional Chinese medicines on the treatment and signaling pathway regulation of osteoporosis in recent ten years, such as Epimedii Folium, Drynariae Rhizoma, Cnidii Fructus, Eucommiae Cortex, Psoraleae Fructus and Dipsaci Radix. Based on the existing findings, the following conclusions were obtained: ①kidney-tonifying traditional Chinese medicine treated osteoporosis mainly through BMP-Smads, Wnt/ β -catenin, MAPK, PI3K/AKT signaling pathway to promote osteoblast bone formation and through OPG/RANKL/ RANK, estrogen, CTSK signaling pathway to inhibit osteoclasts of bone resorption. Epimedii Folium, Drynariae Rhizoma, Cnidii Fructus and Psoraleae Fructus up-regulated the expression of key proteins and genes of BMP-Smads and Wnt/ β -catenin signaling pathways to promote bone formation. Epimedii Folium, Drynariae Rhizoma, Cnidii Fructus, Eucommiae Cortex, Psoraleae Fructus and Dipsaci Radix inhibited the bone resorption by mediating the OPG/RANKL/RANK signaling pathway. ②Kidney-tonifying traditional Chinese medicine prevented and treated osteoporosis through a variety of ways: icariin in Epimedii Folium, naringin in Drynariae Rhizoma, osthole in Cnidii Fructus and psoralen in Psoraleae Fructus can regulate BMP-Smads, Wnt/ β -catenin signaling pathway to promote bone formation, but also activate OPG/RANKL/RANK, CTSK and other signaling pathways to inhibit bone resorption. ③The crosstalk of the signaling pathways and the animal experiments of the traditional Chinese medicine on the prevention and treatment of osteoporosis as well as their multi-target mechanism and comprehensive regulation need further clarification. Copyright© by the Chinese Pharmaceutical Association.

Is resistant starch protective against colorectal cancer via modulation of the WNT signalling pathway?

PubMed

Malcomson, Fiona C; Willis, Naomi D; Mathers, John C

2015-08-01

Epidemiological and experimental evidence suggests that non-digestible carbohydrates (NDC) including resistant starch are protective against colorectal cancer. These anti-neoplastic effects are presumed to result from the production of the SCFA, butyrate, by colonic fermentation, which binds to the G-protein-coupled receptor GPR43 to regulate inflammation and other cancer-related processes. The WNT pathway is central to the maintenance of homeostasis within the large bowel through regulation of processes such as cell proliferation and migration and is frequently aberrantly hyperactivated in colorectal cancers. Abnormal WNT signalling can lead to irregular crypt cell proliferation that favours a hyperproliferative state. Butyrate has been shown to modulate the WNT pathway positively, affecting functional outcomes such as apoptosis and proliferation. Butyrate's ability to regulate gene expression results from epigenetic mechanisms, including its role as a histone deacetylase inhibitor and through modulating DNA methylation and the expression of microRNA. We conclude that genetic and epigenetic modulation of the WNT signalling pathway may be an important mechanism through which butyrate from fermentation of resistant starch and other NDC exert their chemoprotective effects.

A transcriptomic study reveals differentially expressed genes and pathways respond to simulated acid rain in Arabidopsis thaliana.

PubMed

Liu, Ting-Wu; Niu, Li; Fu, Bin; Chen, Juan; Wu, Fei-Hua; Chen, Juan; Wang, Wen-Hua; Hu, Wen-Jun; He, Jun-Xian; Zheng, Hai-Lei

2013-01-01

Acid rain, as a worldwide environmental issue, can cause serious damage to plants. In this study, we provided the first case study on the systematic responses of arabidopsis (Arabidopsis thaliana (L.) Heynh.) to simulated acid rain (SiAR) by transcriptome approach. Transcriptomic analysis revealed that the expression of a set of genes related to primary metabolisms, including nitrogen, sulfur, amino acid, photosynthesis, and reactive oxygen species metabolism, were altered under SiAR. In addition, transport and signal transduction related pathways, especially calcium-related signaling pathways, were found to play important roles in the response of arabidopsis to SiAR stress. Further, we compared our data set with previously published data sets on arabidopsis transcriptome subjected to various stresses, including wound, salt, light, heavy metal, karrikin, temperature, osmosis, etc. The results showed that many genes were overlapped in several stresses, suggesting that plant response to SiAR is a complex process, which may require the participation of multiple defense-signaling pathways. The results of this study will help us gain further insights into the response mechanisms of plants to acid rain stress.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adi, Y. A., E-mail: yudi.adi@math.uad.ac.id; Department of Mathematic Faculty of MIPA Universitas Gadjah Mada; Kusumo, F. A.

In this paper we consider a mathematical model of PI3K/AKT signaling pathways in phosphorylation AKT. PI3K/AKT pathway is an important mediator of cytokine signaling implicated in regulation of hematopoiesis. Constitutive activation of PI3K/AKT signaling pathway has been observed in Acute Meyloid Leukemia (AML) it caused by the mutation of Fms-like Tyrosine Kinase 3 in internal tandem duplication (FLT3-ITD), the most common molecular abnormality associated with AML. Depending upon its phosphorylation status, protein interaction, substrate availability, and localization, AKT can phosphorylate or inhibite numerous substrates in its downstream pathways that promote protein synthesis, survival, proliferation, and metabolism. Firstly, we present amore » mass action ordinary differential equation model describing AKT double phosphorylation (AKTpp) in a system with 11 equations. Finally, under the asumtion enzyme catalyst constant and steady state equilibrium, we reduce the system in 4 equation included Michaelis Menten constant. Simulation result suggested that a high concentration of PI3K and/or a low concentration of phospatase increased AKTpp activation. This result also indicates that PI3K is a potential target theraphy in AML.« less

Asymmetric distribution of hypoxia-inducible factor α regulates dorsoventral axis establishment in the early sea urchin embryo.

PubMed

Chang, Wei-Lun; Chang, Yi-Cheng; Lin, Kuan-Ting; Li, Han-Ru; Pai, Chih-Yu; Chen, Jen-Hao; Su, Yi-Hsien

2017-08-15

Hypoxia signaling is an ancient pathway by which animals can respond to low oxygen. Malfunction of this pathway disturbs hypoxic acclimation and can result in various diseases, including cancers. The role of hypoxia signaling in early embryogenesis remains unclear. Here, we show that in the blastula of the sea urchin Strongylocentrotus purpuratus , hypoxia-inducible factor α (HIFα), the downstream transcription factor of the hypoxia pathway, is localized and transcriptionally active on the future dorsal side. This asymmetric distribution is attributable to its oxygen-sensing ability. Manipulations of the HIFα level entrained the dorsoventral axis, as the side with the higher level of HIFα tends to develop into the dorsal side. Gene expression analyses revealed that HIFα restricts the expression of nodal to the ventral side and activates several genes encoding transcription factors on the dorsal side. We also observed that intrinsic hypoxic signals in the early embryos formed a gradient, which was disrupted under hypoxic conditions. Our results reveal an unprecedented role of the hypoxia pathway in animal development. © 2017. Published by The Company of Biologists Ltd.

A mathematical model of phosphorylation AKT in Acute Myeloid Leukemia

NASA Astrophysics Data System (ADS)

Adi, Y. A.; Kusumo, F. A.; Aryati, L.; Hardianti, M. S.

2016-04-01

In this paper we consider a mathematical model of PI3K/AKT signaling pathways in phosphorylation AKT. PI3K/AKT pathway is an important mediator of cytokine signaling implicated in regulation of hematopoiesis. Constitutive activation of PI3K/AKT signaling pathway has been observed in Acute Meyloid Leukemia (AML) it caused by the mutation of Fms-like Tyrosine Kinase 3 in internal tandem duplication (FLT3-ITD), the most common molecular abnormality associated with AML. Depending upon its phosphorylation status, protein interaction, substrate availability, and localization, AKT can phosphorylate or inhibite numerous substrates in its downstream pathways that promote protein synthesis, survival, proliferation, and metabolism. Firstly, we present a mass action ordinary differential equation model describing AKT double phosphorylation (AKTpp) in a system with 11 equations. Finally, under the asumtion enzyme catalyst constant and steady state equilibrium, we reduce the system in 4 equation included Michaelis Menten constant. Simulation result suggested that a high concentration of PI3K and/or a low concentration of phospatase increased AKTpp activation. This result also indicates that PI3K is a potential target theraphy in AML.

Curcumin Stimulates Proliferation of Spinal Cord Neural Progenitor Cells via a Mitogen-Activated Protein Kinase Signaling Pathway

PubMed Central

Son, Sihoon; Cho, Dae-Chul; Kim, Hye-Jeong; Sung, Joo-Kyung; Bae, Jae-Sung

2014-01-01

Objective The aims of our study are to evaluate the effect of curcumin on spinal cord neural progenitor cell (SC-NPC) proliferation and to clarify the mechanisms of mitogen-activated protein (MAP) kinase signaling pathways in SC-NPCs. Methods We established cultures of SC-NPCs, extracted from the spinal cord of Sprague-Dawley rats weighing 250 g to 350 g. We measured proliferation rates of SC-NPCs after curcumin treatment at different dosage. The immuno-blotting method was used to evaluate the MAP kinase signaling protein that contains extracellular signal-regulated kinases (ERKs), p38, c-Jun NH2-terminal kinases (JNKs) and β-actin as the control group. Results Curcumin has a biphasic effect on SC-NPC proliferation. Lower dosage (0.1, 0.5, 1 µM) of curcumin increased SC-NPC proliferation. However, higher dosage decreased SC-NPC proliferation. Also, curcumin stimulates proliferation of SC-NPCs via the MAP kinase signaling pathway, especially involving the p-ERK and p-38 protein. The p-ERK protein and p38 protein levels varied depending on curcumin dosage (0.5 and 1 µM, p<0.05). Conclusion Curcumin can stimulate proliferation of SC-NPCs via ERKs and the p38 signaling pathway in low concentrations. PMID:25289117

Cytosensor Microphysiometer: technology and recent applications.

PubMed

Hafner, F

2000-06-01

The Cytosensor Microphysiometer system detects functional responses from living cells in minutes and offers novel information on cell signalling that is often unobtainable with other assay methods. The principle of the system is based on the measurement of small changes in extracellular acidification, using a light addressable potentiometric sensor (LAPS). Energy metabolism in living cells is tightly coupled to cellular ATP usage, so that any event which perturbs cellular ATP levels--such as receptor activation and initiation of signal transduction--will result in a change in acid excretion. As the extrusion of protons is a very general parameter involved in the activation of nearly all kinds of membrane-bound receptors, receptors can be investigated without prior knowledge of the corresponding signalling pathway. However, by blocking certain signalling pathways inside the cell by means of signal transduction probes, specificity can be brought into the system and the corresponding receptor pathways can easily be elucidated. The aim is to give an overview about Cytosensor Microphysiometer technology and to demonstrate, with the help of some recent applications, the capability of the system to measure acidification rates from a wide variety of cell- and receptor-types coupled to different signal transduction pathways. This feature makes the cytosensor system an ideal tool for acting as a single assay system and circumventing the need for multiple assays.

Lysosomal trafficking regulator Lyst links membrane trafficking to toll-like receptor–mediated inflammatory responses

PubMed Central

Krautkrämer, Martina

2017-01-01

Subcellular compartmentalization of receptor signaling is an emerging principle in innate immunity. However, the functional integration of receptor signaling pathways into membrane trafficking routes and its physiological relevance for immune responses is still largely unclear. In this study, using Lyst-mutant beige mice, we show that lysosomal trafficking regulator Lyst links endolysosomal organization to the selective control of toll-like receptor 3 (TLR3)– and TLR4-mediated proinflammatory responses. Consequently, Lyst-mutant mice showed increased susceptibility to bacterial infection and were largely resistant to endotoxin-induced septic shock. Mechanistic analysis revealed that Lyst specifically controls TLR3- and TLR4-induced endosomal TRIF (TIR domain–containing adapter-inducing interferon β) signaling pathways. Loss of functional Lyst leads to dysregulated phagosomal maturation, resulting in a failure to form an activation-induced Rab7+ endosomal/phagosomal compartment. This specific Rab7+ compartment was further demonstrated to serve as a major site for active TRIF signaling events, thus linking phagosomal maturation to specific TLR signaling pathways. The immunoregulatory role of Lyst on TLR signaling pathways was confirmed in human cells by CRISPR/Cas9-mediated gene inactivation. As mutations in LYST cause human Chédiak-Higashi syndrome, a severe immunodeficiency, our findings also contribute to a better understanding of human disease mechanisms. PMID:27881733

The spatiotemporal order of signaling events unveils the logic of development signaling

PubMed Central

Zhu, Hao; Owen, Markus R.; Mao, Yanlan

2016-01-01

Motivation: Animals from worms and insects to birds and mammals show distinct body plans; however, the embryonic development of diverse body plans with tissues and organs within is controlled by a surprisingly few signaling pathways. It is well recognized that combinatorial use of and dynamic interactions among signaling pathways follow specific logic to control complex and accurate developmental signaling and patterning, but it remains elusive what such logic is, or even, what it looks like. Results: We have developed a computational model for Drosophila eye development with innovated methods to reveal how interactions among multiple pathways control the dynamically generated hexagonal array of R8 cells. We obtained two novel findings. First, the coupling between the long-range inductive signals produced by the proneural Hh signaling and the short-range restrictive signals produced by the antineural Notch and EGFR signaling is essential for generating accurately spaced R8s. Second, the spatiotemporal orders of key signaling events reveal a robust pattern of lateral inhibition conducted by Ato-coordinated Notch and EGFR signaling to collectively determine R8 patterning. This pattern, stipulating the orders of signaling and comparable to the protocols of communication, may help decipher the well-appreciated but poorly defined logic of developmental signaling. Availability and implementation: The model is available upon request. Contact: hao.zhu@ymail.com Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27153573

Light-Mediated Kinetic Control Reveals the Temporal Effect of the Raf/MEK/ERK Pathway in PC12 Cell Neurite Outgrowth

PubMed Central

Zhang, Kai; Duan, Liting; Ong, Qunxiang; Lin, Ziliang; Varman, Pooja Mahendra; Sung, Kijung; Cui, Bianxiao

2014-01-01

It has been proposed that differential activation kinetics allows cells to use a common set of signaling pathways to specify distinct cellular outcomes. For example, nerve growth factor (NGF) and epidermal growth factor (EGF) induce different activation kinetics of the Raf/MEK/ERK signaling pathway and result in differentiation and proliferation, respectively. However, a direct and quantitative linkage between the temporal profile of Raf/MEK/ERK activation and the cellular outputs has not been established due to a lack of means to precisely perturb its signaling kinetics. Here, we construct a light-gated protein-protein interaction system to regulate the activation pattern of the Raf/MEK/ERK signaling pathway. Light-induced activation of the Raf/MEK/ERK cascade leads to significant neurite outgrowth in rat PC12 pheochromocytoma cell lines in the absence of growth factors. Compared with NGF stimulation, light stimulation induces longer but fewer neurites. Intermittent on/off illumination reveals that cells achieve maximum neurite outgrowth if the off-time duration per cycle is shorter than 45 min. Overall, light-mediated kinetic control enables precise dissection of the temporal dimension within the intracellular signal transduction network. PMID:24667437

Inhibition of extracellular matrix mediated TGF-β signalling suppresses endometrial cancer metastasis

PubMed Central

Sahoo, Subhransu S.; Quah, Min Yuan; Nielsen, Sarah; Atkins, Joshua; Au, Gough G.; Cairns, Murray J.; Nahar, Pravin; Lombard, Janine M.; Tanwar, Pradeep S.

2017-01-01

Although aggressive invasion and distant metastases are an important cause of morbidity and mortality in patients with endometrial cancer (EC), the requisite events determining this propensity are currently unknown. Using organotypic three-dimensional culture of endometrial cancer cell lines, we demonstrated anti-correlated TGF-β signalling gene expression patterns that arise among extracellular matrix (ECM)-attached cells. TGF-β pathway seemed to be active in EC cells forming non-glandular colonies in 3D-matrix but weaker in glandular colonies. Functionally we found that out of several ECM proteins, fibronectin relatively promotes Smad phosphorylation suggesting a potential role in regulating TGF-β signalling in non-glandular colonies. Importantly, alteration of TGF-β pathway induced EMT and MET in both type of colonies through slug protein. The results exemplify a crucial role of TGF-β pathway during EC metastasis in human patients and inhibition of the pathway in a murine model impaired tumour cell invasion and metastasis depicting an attractive target for therapeutic intervention of malignant tumour progression. These findings provide key insights into the role of ECM-derived TGF-β signalling to promote endometrial cancer metastasis and offer an avenue for therapeutic targeting of microenvironment derived signals along with tumour cells. PMID:29069715

SOCS3

PubMed Central

Yasukawa, Hideo; Nagata, Takanobu; Oba, Toyoharu; Imaizumi, Tsutomu

2012-01-01

The suppressors of cytokine signaling (SOCS) family of proteins are cytokine-inducible inhibitors of Janus kinase (JAK)-signal transducer and activator of the transcription (STAT) signaling pathways. Among the family, SOCS1 and SOCS3 potently suppress cytokine actions by inhibiting JAK kinase activities. The generation of mice lacking individual SOCS genes has been instrumental in defining the role of individual SOCS proteins in specific cytokine pathways in vivo; SOCS1 is an essential negative regulator of interferon-γ (IFNγ) and SOCS3 is an essential negative regulator of leukemia inhibitory factor (LIF). JAK-STAT3 activating cytokines have exhibited cardioprotective roles in the heart. The cardiac-specific deletion of SOCS3 enhances the activation of cardioprotective signaling pathways, inhibits myocardial apoptosis and fibrosis and results in the inhibition of left ventricular remodeling after myocardial infarction (MI). We propose that myocardial SOCS3 is a key determinant of left ventricular remodeling after MI, and SOCS3 may serve as a novel therapeutic target to prevent left ventricular remodeling after MI. In this review, we discuss the signaling pathways mediated by JAK-STAT and SOCS proteins and their roles in the development of myocardial injury under stress (e.g., pressure overload, viral infection and ischemia). PMID:24058778

Modularized Smad-regulated TGFβ signaling pathway.

PubMed

Li, Yongfeng; Wang, Minli; Carra, Claudio; Cucinotta, Francis A

2012-12-01

The transforming Growth Factor β (TGFβ) signaling pathway is a prominent regulatory signaling pathway controlling various important cellular processes. TGFβ signaling can be induced by several factors including ionizing radiation. The pathway is regulated in a negative feedback loop through promoting the nuclear import of the regulatory Smads and a subsequent expression of inhibitory Smad7, that forms ubiquitin ligase with Smurf2, targeting active TGFβ receptors for degradation. In this work, we proposed a mathematical model to study the Smad-regulated TGFβ signaling pathway. By modularization, we are able to analyze mathematically each component subsystem and recover the nonlinear dynamics of the entire network system. Meanwhile the excitability, a common feature observed in the biological systems, in the TGFβ signaling pathway is discussed and supported as well by numerical simulation, indicating the robustness of the model. Published by Elsevier Inc.

Disruption of Axonal Transport Perturbs Bone Morphogenetic Protein (BMP) - Signaling and Contributes to Synaptic Abnormalities in Two Neurodegenerative Diseases

PubMed Central

Kang, Min Jung; Hansen, Timothy J.; Mickiewicz, Monique; Kaczynski, Tadeusz J.; Fye, Samantha; Gunawardena, Shermali

2014-01-01

Formation of new synapses or maintenance of existing synapses requires the delivery of synaptic components from the soma to the nerve termini via axonal transport. One pathway that is important in synapse formation, maintenance and function of the Drosophila neuromuscular junction (NMJ) is the bone morphogenetic protein (BMP)-signaling pathway. Here we show that perturbations in axonal transport directly disrupt BMP signaling, as measured by its downstream signal, phospho Mad (p-Mad). We found that components of the BMP pathway genetically interact with both kinesin-1 and dynein motor proteins. Thick vein (TKV) vesicle motility was also perturbed by reductions in kinesin-1 or dynein motors. Interestingly, dynein mutations severely disrupted p-Mad signaling while kinesin-1 mutants showed a mild reduction in p-Mad signal intensity. Similar to mutants in components of the BMP pathway, both kinesin-1 and dynein motor protein mutants also showed synaptic morphological defects. Strikingly TKV motility and p-Mad signaling were disrupted in larvae expressing two human disease proteins; expansions of glutamine repeats (polyQ77) and human amyloid precursor protein (APP) with a familial Alzheimer's disease (AD) mutation (APPswe). Consistent with axonal transport defects, larvae expressing these disease proteins showed accumulations of synaptic proteins along axons and synaptic abnormalities. Taken together our results suggest that similar to the NGF-TrkA signaling endosome, a BMP signaling endosome that directly interacts with molecular motors likely exist. Thus problems in axonal transport occurs early, perturbs BMP signaling, and likely contributes to the synaptic abnormalities observed in these two diseases. PMID:25127478

How quantitative measures unravel design principles in multi-stage phosphorylation cascades.

PubMed

Frey, Simone; Millat, Thomas; Hohmann, Stefan; Wolkenhauer, Olaf

2008-09-07

We investigate design principles of linear multi-stage phosphorylation cascades by using quantitative measures for signaling time, signal duration and signal amplitude. We compare alternative pathway structures by varying the number of phosphorylations and the length of the cascade. We show that a model for a weakly activated pathway does not reflect the biological context well, unless it is restricted to certain parameter combinations. Focusing therefore on a more general model, we compare alternative structures with respect to a multivariate optimization criterion. We test the hypothesis that the structure of a linear multi-stage phosphorylation cascade is the result of an optimization process aiming for a fast response, defined by the minimum of the product of signaling time and signal duration. It is then shown that certain pathway structures minimize this criterion. Several popular models of MAPK cascades form the basis of our study. These models represent different levels of approximation, which we compare and discuss with respect to the quantitative measures.

DELLA proteins regulate arbuscule formation in arbuscular mycorrhizal symbiosis

PubMed Central

Floss, Daniela S.; Levy, Julien G.; Lévesque-Tremblay, Véronique; Pumplin, Nathan; Harrison, Maria J.

2013-01-01

Most flowering plants are able to form endosymbioses with arbuscular mycorrhizal fungi. In this mutualistic association, the fungus colonizes the root cortex and establishes elaborately branched hyphae, called arbuscules, within the cortical cells. Arbuscule development requires the cellular reorganization of both symbionts, and the resulting symbiotic interface functions in nutrient exchange. A plant symbiosis signaling pathway controls the development of the symbiosis. Several components of the pathway have been identified, but transcriptional regulators that control downstream pathways for arbuscule formation are still unknown. Here we show that DELLA proteins, which are repressors of gibberellic acid (GA) signaling and function at the nexus of several signaling pathways, are required for arbuscule formation. Arbuscule formation is severely impaired in a Medicago truncatula Mtdella1/Mtdella2 double mutant; GA treatment of wild-type roots phenocopies the della double mutant, and a dominant DELLA protein (della1-Δ18) enables arbuscule formation in the presence of GA. Ectopic expression of della1-Δ18 suggests that DELLA activity in the vascular tissue and endodermis is sufficient to enable arbuscule formation in the inner cortical cells. In addition, expression of della1-Δ18 restores arbuscule formation in the symbiosis signaling pathway mutant cyclops/ipd3, indicating an intersection between DELLA and symbiosis signaling for arbuscule formation. GA signaling also influences arbuscule formation in monocots, and a Green Revolution wheat variety carrying dominant DELLA alleles shows enhanced colonization but a limited growth response to arbuscular mycorrhizal symbiosis. PMID:24297892

DELLA proteins regulate arbuscule formation in arbuscular mycorrhizal symbiosis.

PubMed

Floss, Daniela S; Levy, Julien G; Lévesque-Tremblay, Véronique; Pumplin, Nathan; Harrison, Maria J

2013-12-17

Most flowering plants are able to form endosymbioses with arbuscular mycorrhizal fungi. In this mutualistic association, the fungus colonizes the root cortex and establishes elaborately branched hyphae, called arbuscules, within the cortical cells. Arbuscule development requires the cellular reorganization of both symbionts, and the resulting symbiotic interface functions in nutrient exchange. A plant symbiosis signaling pathway controls the development of the symbiosis. Several components of the pathway have been identified, but transcriptional regulators that control downstream pathways for arbuscule formation are still unknown. Here we show that DELLA proteins, which are repressors of gibberellic acid (GA) signaling and function at the nexus of several signaling pathways, are required for arbuscule formation. Arbuscule formation is severely impaired in a Medicago truncatula Mtdella1/Mtdella2 double mutant; GA treatment of wild-type roots phenocopies the della double mutant, and a dominant DELLA protein (della1-Δ18) enables arbuscule formation in the presence of GA. Ectopic expression of della1-Δ18 suggests that DELLA activity in the vascular tissue and endodermis is sufficient to enable arbuscule formation in the inner cortical cells. In addition, expression of della1-Δ18 restores arbuscule formation in the symbiosis signaling pathway mutant cyclops/ipd3, indicating an intersection between DELLA and symbiosis signaling for arbuscule formation. GA signaling also influences arbuscule formation in monocots, and a Green Revolution wheat variety carrying dominant DELLA alleles shows enhanced colonization but a limited growth response to arbuscular mycorrhizal symbiosis.

Monte Carlo Study Elucidates the Type 1/Type 2 Choice in Apoptotic Death Signaling in Healthy and Cancer Cells

PubMed Central

Raychaudhuri, Subhadip; Raychaudhuri, Somkanya C

2013-01-01

Apoptotic cell death is coordinated through two distinct (type 1 and type 2) intracellular signaling pathways. How the type 1/type 2 choice is made remains a central problem in the biology of apoptosis and has implications for apoptosis related diseases and therapy. We study the problem of type 1/type 2 choice in silico utilizing a kinetic Monte Carlo model of cell death signaling. Our results show that the type 1/type 2 choice is linked to deterministic versus stochastic cell death activation, elucidating a unique regulatory control of the apoptotic pathways. Consistent with previous findings, our results indicate that caspase 8 activation level is a key regulator of the choice between deterministic type 1 and stochastic type 2 pathways, irrespective of cell types. Expression levels of signaling molecules downstream also regulate the type 1/type 2 choice. A simplified model of DISC clustering elucidates the mechanism of increased active caspase 8 generation and type 1 activation in cancer cells having increased sensitivity to death receptor activation. We demonstrate that rapid deterministic activation of the type 1 pathway can selectively target such cancer cells, especially if XIAP is also inhibited; while inherent cell-to-cell variability would allow normal cells stay protected. PMID:24709706

Oxymatrine lightened the inflammatory response of LPS-induced mastitis in mice through affecting NF-κB and MAPKs signaling pathways.

PubMed

Yang, Zhengtao; Yin, Ronglan; Cong, Yunfeng; Yang, Zhanqing; Zhou, Ershun; Wei, Zhengkai; Liu, Zhicheng; Cao, Yongguo; Zhang, Naisheng

2014-12-01

Mastitis, an inflammatory reaction of the mammary gland, is recognized as one of the most costly diseases in dairy cattle. Oxymatrine, one of the alkaloids extracted from Chinese herb Sophora flavescens Ait, has been reported to have many biological activities, such as anti-inflammatory, anti-virus, and anti-hepatic fibrosis properties. The aim of this study was to investigate the protective effect and the anti-inflammatory mechanism of oxymatrine on lipopolysaccharide (LPS)-induced mastitis in mice. The mouse mastitis was induced by 10 μg of LPS for 24 h. Oxymatrine was intraperitoneally administered with the dose of 30, 60, and 120 mg/kg 1 h before and 12 h after LPS induction. The results showed that oxymatrine significantly attenuated the damage of the mammary gland induced by LPS. Oxymatrine inhibited the phosphorylation of NF-κB p65 and IκB in NF-κB signal pathway and reduced the phosphorylation of p38, ERK, and JNK in mitogen-activated protein kinase (MAPKs) signal pathway. The results showed that oxymatrine had a protective effect on LPS-induced mastitis, and the anti-inflammatory mechanism of oxymatrine was related to the inhibition of NF-κB and MAPKs signal pathways.

Bone morphogenetic protein and Notch signalling crosstalk in poor-prognosis, mesenchymal-subtype colorectal cancer.

PubMed

Irshad, Shazia; Bansal, Mukesh; Guarnieri, Paolo; Davis, Hayley; Al Haj Zen, Ayman; Baran, Brygida; Pinna, Claudia Maria Assunta; Rahman, Haseeb; Biswas, Sujata; Bardella, Chiara; Jeffery, Rosemary; Wang, Lai Mun; East, James Edward; Tomlinson, Ian; Lewis, Annabelle; Leedham, Simon John

2017-06-01

The functional role of bone morphogenetic protein (BMP) signalling in colorectal cancer (CRC) is poorly defined, with contradictory results in cancer cell line models reflecting the inherent difficulties of assessing a signalling pathway that is context-dependent and subject to genetic constraints. By assessing the transcriptional response of a diploid human colonic epithelial cell line to BMP ligand stimulation, we generated a prognostic BMP signalling signature, which was applied to multiple CRC datasets to investigate BMP heterogeneity across CRC molecular subtypes. We linked BMP and Notch signalling pathway activity and function in human colonic epithelial cells, and normal and neoplastic tissue. BMP induced Notch through a γ-secretase-independent interaction, regulated by the SMAD proteins. In homeostasis, BMP/Notch co-localization was restricted to cells at the top of the intestinal crypt, with more widespread interaction in some human CRC samples. BMP signalling was downregulated in the majority of CRCs, but was conserved specifically in mesenchymal-subtype tumours, where it interacts with Notch to induce an epithelial-mesenchymal transition (EMT) phenotype. In intestinal homeostasis, BMP-Notch pathway crosstalk is restricted to differentiating cells through stringent pathway segregation. Conserved BMP activity and loss of signalling stringency in mesenchymal-subtype tumours promotes a synergistic BMP-Notch interaction, and this correlates with poor patient prognosis. BMP signalling heterogeneity across CRC subtypes and cell lines can account for previous experimental contradictions. Crosstalk between the BMP and Notch pathways will render mesenchymal-subtype CRC insensitive to γ-secretase inhibition unless BMP activation is concomitantly addressed. © 2017 The Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Chlorogenic Acid Attenuates Lipopolysaccharide-Induced Acute Kidney Injury by Inhibiting TLR4/NF-κB Signal Pathway.

PubMed

Ye, Han-Yang; Jin, Jian; Jin, Ling-Wei; Chen, Yan; Zhou, Zhi-Hong; Li, Zhan-Yuan

2017-04-01

Chlorogenic acid (CGA), a polyphenolic compound, exists widely in medicinal herbs, which has been shown a strong antioxidant and anti-inflammatory effect. This study investigated the protective effects and mechanism of CGA on lipopolysaccharide (LPS)-induced acute kidney injury (AKI). Treatment of CGA successfully ameliorates LPS-induced renal function and pathological damage. Moreover, CGA dose-dependently suppressed LPS-induced blood urea nitrogen (BUN), creatinine levels, and inflammatory cytokines TNF-α, IL-6, and IL-1β in serum and tissue. The relative proteins' expression of TLR4/NF-κB signal pathway was assessed by western blot analysis. Our results showed that CGA dose-dependently attenuated LPS-induced kidney histopathologic changes, serum BUN, and creatinine levels. CGA also suppressed LPS-induced TNF-α, IL-6, and IL-1β production both in serum and kidney tissues. Furthermore, our results showed that CGA significantly inhibited the LPS-induced expression of phosphorylated NF-κB p65 and IκB as well as the expression of TLR4 signal. In conclusion, our results provide a mechanistic explanation for the anti-inflammatory effects of CGA in LPS-induced AKI mice through inhibiting TLR4/NF-κB signaling pathway.

The Murine Ortholog of Notchless, a Direct Regulator of the Notch Pathway in Drosophila melanogaster, Is Essential for Survival of Inner Cell Mass Cells

PubMed Central

Cormier, Sarah; Le Bras, Stéphanie; Souilhol, Céline; Vandormael-Pournin, Sandrine; Durand, Béatrice; Babinet, Charles; Baldacci, Patricia; Cohen-Tannoudji, Michel

2006-01-01

Notch signaling is an evolutionarily conserved pathway involved in intercellular communication and is essential for proper cell fate choices. Numerous genes participate in the modulation of the Notch signaling pathway activity. Among them, Notchless (Nle) is a direct regulator of the Notch activity identified in Drosophila melanogaster. Here, we characterized the murine ortholog of Nle and demonstrated that it has conserved the ability to modulate Notch signaling. We also generated mice deficient for mouse Nle (mNle) and showed that its disruption resulted in embryonic lethality shortly after implantation. In late mNle−/− blastocysts, inner cell mass (ICM) cells died through a caspase 3-dependent apoptotic process. Most deficient embryos exhibited a delay in the temporal down-regulation of Oct4 expression in the trophectoderm (TE). However, mNle-deficient TE was able to induce decidual swelling in vivo and properly differentiated in vitro. Hence, our results indicate that mNle is mainly required in ICM cells, being instrumental for their survival, and raise the possibility that the death of mNle-deficient embryos might result from abnormal Notch signaling during the first steps of development. PMID:16611995

The murine ortholog of notchless, a direct regulator of the notch pathway in Drosophila melanogaster, is essential for survival of inner cell mass cells.

PubMed

Cormier, Sarah; Le Bras, Stéphanie; Souilhol, Céline; Vandormael-Pournin, Sandrine; Durand, Béatrice; Babinet, Charles; Baldacci, Patricia; Cohen-Tannoudji, Michel

2006-05-01

Notch signaling is an evolutionarily conserved pathway involved in intercellular communication and is essential for proper cell fate choices. Numerous genes participate in the modulation of the Notch signaling pathway activity. Among them, Notchless (Nle) is a direct regulator of the Notch activity identified in Drosophila melanogaster. Here, we characterized the murine ortholog of Nle and demonstrated that it has conserved the ability to modulate Notch signaling. We also generated mice deficient for mouse Nle (mNle) and showed that its disruption resulted in embryonic lethality shortly after implantation. In late mNle(-/-) blastocysts, inner cell mass (ICM) cells died through a caspase 3-dependent apoptotic process. Most deficient embryos exhibited a delay in the temporal down-regulation of Oct4 expression in the trophectoderm (TE). However, mNle-deficient TE was able to induce decidual swelling in vivo and properly differentiated in vitro. Hence, our results indicate that mNle is mainly required in ICM cells, being instrumental for their survival, and raise the possibility that the death of mNle-deficient embryos might result from abnormal Notch signaling during the first steps of development.

Introduction of hsa-miR-103a and hsa-miR-1827 and hsa-miR-137 as new regulators of Wnt signaling pathway and their relation to colorectal carcinoma.

PubMed

Fasihi, Ali; M Soltani, Bahram; Atashi, Amir; Nasiri, Shirzad

2018-07-01

Wnt signaling is hyper-activated in most of human cancers including colorectal carcinoma (CRC). Therefore, the introduction of new regulators for Wnt pathway possesses promising diagnostic and therapeutic applications in cancer medicine. Bioinformatics analysis introduced hsa-miR-103a, hsa-miR-1827, and hsa-miR-137 as potential regulators of Wnt signaling pathway. Here, we intended to examine the effect of these human miRNAs on Wnt signaling pathway components, on the cell cycle progression in CRC originated cell lines and their expression in CRC tissues. RT-qPCR results indicated upregulation of hsa-miR-103a, hsa-miR-1827, and downregulation of hsa-miR-137 in CRC tissues. Overexpression of hsa-miR-103a and hsa-miR-1827 in SW480 cells resulted in elevated Wnt activity, detected by both Top/Flash assay and RT-qPCR analysis. Inhibition of Wnt signaling by using PNU-74654 or IWP-2 small molecules suggested that these miRNAs exerts their effect at the β-catenin degradation complex level. Then, RT-qPCR, dual luciferase assay, and western blotting analysis indicated that APC and APC2 transcripts were targeted by hsa-miR-103a, hsa-miR-1827 while, Wnt3a and β-catenin genes were upregulated. However, hsa-miR-137 downregulated Wnt3a and β-catenin genes. Further, hsa-miR-103a and hsa-miR-1827 overexpression resulted in cell cycle progression and reduced apoptotic rate in SW480 cells, unlike hsa-miR-137 overexpression which resulted in cell cycle suppression, detected by flowcytometry and Anexin analysis. Overall, our data introduced hsa-miR-103a, hsa-miR-1827 as onco-miRNAs and hsa-miR-137 as tumor suppressor which exert their effect through regulation of Wnt signaling pathway in CRC and introduced them as potential target for therapy. © 2017 Wiley Periodicals, Inc.

Phosphorylation of Nephrin Triggers Its Internalization by Raft-Mediated Endocytosis

PubMed Central

Qin, Xiao-Song; Shono, Akemi; Yamamoto, Akitsugu; Kurihara, Hidetake; Doi, Toshio

2009-01-01

Proper localization of nephrin determines integrity of the glomerular slit diaphragm. Slit diaphragm proteins assemble into functional signaling complexes on a raft-based platform, but how the trafficking of these proteins coordinates with their signaling function is unknown. Here, we demonstrate that a raft-mediated endocytic (RME) pathway internalizes nephrin. Nephrin internalization was slower with raft-mediated endocytosis than with classic clathrin-mediated endocytosis. Ultrastructurally, the RME pathway consisted of noncoated invaginations and was dependent on cholesterol and dynamin. Nephrin constituted a stable, signaling-competent microdomain through interaction with Fyn, a Src kinase, and podocin, a scaffold protein. Tyrosine phosphorylation of nephrin triggered its own RME-mediated internalization. Protamine-induced hyperphosphorylation of nephrin led to noncoated invaginations predominating over coated pits. These results demonstrate that an RME pathway couples nephrin internalization to its own signaling, suggesting that RME promotes proper spatiotemporal assembly of slit diaphragms during podocyte development or injury. PMID:19850954

Neurotrophic factors switch between two signaling pathways that trigger axonal growth.

PubMed

Paveliev, Mikhail; Lume, Maria; Velthut, Agne; Phillips, Matthew; Arumäe, Urmas; Saarma, Mart

2007-08-01

Integration of multiple inputs from the extracellular environment, such as extracellular matrix molecules and growth factors, is a crucial process for cell function and information processing in multicellular organisms. Here we demonstrate that co-stimulation of dorsal root ganglion neurons with neurotrophic factors (NTFs) - glial-cell-line-derived neurotrophic factor, neurturin or nerve growth factor - and laminin leads to axonal growth that requires activation of Src family kinases (SFKs). A different, SFK-independent signaling pathway evokes axonal growth on laminin in the absence of the NTFs. By contrast, axonal branching is regulated by SFKs both in the presence and in the absence of NGF. We propose and experimentally verify a Boolean model of the signaling network triggered by NTFs and laminin. Our results demonstrate that NTFs provide an environmental cue that triggers a switch between separate pathways in the cell signaling network.

Impaired IL-13-mediated functions of macrophages in STAT6-deficient mice.

PubMed

Takeda, K; Kamanaka, M; Tanaka, T; Kishimoto, T; Akira, S

1996-10-15

IL-13 shares many biologic responses with IL-4. In contrast to well-characterized IL-4 signaling pathways, which utilize STAT6 and 4PS/IRS2, IL-13 signaling pathways are poorly understood. Recent studies performed with STAT6-deficient mice have demonstrated that STAT6 plays an essential role in IL-4 signaling. In this study, the functions of peritoneal macrophages of STAT6-deficient mice in response to IL-13 were analyzed. In STAT6-deficient mice, neither morphologic changes nor augmentation of MHC class II expression in response to IL-13 was observed. In addition, IL-13 did not decrease the nitric oxide production by activated macrophages. Taken together, these results suggest that the macrophage functions in response to IL-13 were impaired in STAT6-deficient mice, indicating that IL-13 and IL-4 share the signaling pathway via STAT6.

Phosphodiesterase inhibitors suppress Lactobacillus casei cell-wall-induced NF-κB and MAPK activations and cell proliferation through protein kinase A--or exchange protein activated by cAMP-dependent signal pathway.

PubMed

Saito, Takekatsu; Sugimoto, Naotoshi; Ohta, Kunio; Shimizu, Tohru; Ohtani, Kaori; Nakayama, Yuko; Nakamura, Taichi; Hitomi, Yashiaki; Nakamura, Hiroyuki; Koizumi, Shoichi; Yachie, Akihiro

2012-01-01

Specific strains of Lactobacillus have been found to be beneficial in treating some types of diarrhea and vaginosis. However, a high mortality rate results from underlying immunosuppressive conditions in patients with Lactobacillus casei bacteremia. Cyclic AMP (cAMP) is a small second messenger molecule that mediates signal transduction. The onset and progression of inflammatory responses are sensitive to changes in steady-state cAMP levels. L. casei cell wall extract (LCWE) develops arteritis in mice through Toll-like receptor-2 signaling. The purpose of this study was to investigate whether intracellular cAMP affects LCWE-induced pathological signaling. LCWE was shown to induce phosphorylation of the nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways and cell proliferation in mice fibroblast cells. Theophylline and phosphodiesterase inhibitor increased intracellular cAMP and inhibited LCWE-induced cell proliferation as well as phosphorylation of NF-κB and MAPK. Protein kinase A inhibitor H89 prevented cAMP-induced MAPK inhibition, but not cAMP-induced NF-κB inhibition. An exchange protein activated by cAMP (Epac) agonist inhibited NF-κB activation but not MAPK activation. These results indicate that an increase in intracellular cAMP prevents LCWE induction of pathological signaling pathways dependent on PKA and Epac signaling.

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.

Parkin mediates neuroprotection through activation of Notch1 signaling.

PubMed

Yoon, Ji-Hye; Ann, Eun-Jung; Kim, Mi-Yeon; Ahn, Ji-Seon; Jo, Eun-Hye; Lee, Hye-Jin; Lee, Hye-Won; Lee, Young Chul; Kim, Jeong-Sun; Park, Hee-Sae

2017-02-04

Parkin, an E3 ubiquitin ligase, is the most frequently mutated gene in hereditary Parkinson's disease. Inactivation of Parkin leads to impairment of the ubiquitin-proteasome system, resulting in the accumulation of misfolded or aggregated proteins and ensuing neurodegeneration. In this study, we show that Parkin positively regulates the Notch1 signaling pathway. Overexpression of Parkin stabilized Notch1-IC protein levels, whereas knockdown of Parkin decreased Notch1-IC protein stability. Notably, overexpression of Parkin disrupted oxidative stress-induced apoptosis in neuronal cells. However, knockdown of Notch1 inhibited Parkin-induced neuronal cell survival. Together, these results indicate that Parkin is a novel regulator of the Notch1 signaling pathway, which promotes neuronal cell survival.

Interaction of Herbal Compounds with Biological Targets: A Case Study with Berberine

PubMed Central

Chen, Xiao-Wu; Di, Yuan Ming; Zhang, Jian; Zhou, Zhi-Wei; Li, Chun Guang; Zhou, Shu-Feng

2012-01-01

Berberine is one of the main alkaloids found in the Chinese herb Huang lian (Rhizoma Coptidis), which has been reported to have multiple pharmacological activities. This study aimed to analyze the molecular targets of berberine based on literature data followed by a pathway analysis using the PANTHER program. PANTHER analysis of berberine targets showed that the most classes of molecular functions include receptor binding, kinase activity, protein binding, transcription activity, DNA binding, and kinase regulator activity. Based on the biological process classification of in vitro berberine targets, those targets related to signal transduction, intracellular signalling cascade, cell surface receptor-linked signal transduction, cell motion, cell cycle control, immunity system process, and protein metabolic process are most frequently involved. In addition, berberine was found to interact with a mixture of biological pathways, such as Alzheimer's disease-presenilin and -secretase pathways, angiogenesis, apoptosis signalling pathway, FAS signalling pathway, Hungtington disease, inflammation mediated by chemokine and cytokine signalling pathways, interleukin signalling pathway, and p53 pathways. We also explored the possible mechanism of action for the anti-diabetic effect of berberine. Further studies are warranted to elucidate the mechanisms of action of berberine using systems biology approach. PMID:23213296

Noncanonical transforming growth factor β signaling in scleroderma fibrosis

PubMed Central

Trojanowska, Maria

2014-01-01

Purpose of review Persistent transforming growth factor β (TGF-β) signaling is the major factor contributing to scleroderma (SSc) fibrosis. This review will summarize recent progress on the noncanonical TGF-β signaling pathways and their role in SSc fibrosis. Recent findings Canonical TGF-β signaling involves activation of the TGF-β receptors and downstream signal transducers Smad2/3. The term noncanonical TGF-β signaling includes a variety of intracellular signaling pathways activated by TGF-β independently of Smad2/3 activation. There is evidence that these pathways play important role in SSc fibrosis. In a subset of SSc fibroblasts, a multiligand receptor complex consisting of TGF-β and CCN2 receptors drives constitutive activation of the Smad1 pathway. CCN2 is also a primary effector of this pathway, thus establishing an autocrine loop that amplifies TGF-β signaling. SSc fibroblasts also demonstrate reduced expression of endogenous antagonists of TGF-β signaling including transcriptional repressors, Friend leukemia integration-1 and perixosome proliferator-activated receptor-γ, as well as inhibitor of Smad3 phosphorylation, PTEN. PTEN is a key mediator of the cross-talk between the sphingosine kinase and the TGF-β pathways. Summary Discovery of the role of noncanonical TGF-β signaling in fibrosis offers new molecular targets for the antifibrotic therapies. Due to the heterogeneous nature of SSc, knowledge of these pathways could help to tailor the therapy to the individual patient depending on the activation status of a specific profibrotic pathway. PMID:19713852

Drosophila Nociceptive Sensitization Requires BMP Signaling via the Canonical SMAD Pathway.

PubMed

Follansbee, Taylor L; Gjelsvik, Kayla J; Brann, Courtney L; McParland, Aidan L; Longhurst, Colin A; Galko, Michael J; Ganter, Geoffrey K

2017-08-30

Nociceptive sensitization is a common feature in chronic pain, but its basic cellular mechanisms are only partially understood. The present study used the Drosophila melanogaster model system and a candidate gene approach to identify novel components required for modulation of an injury-induced nociceptive sensitization pathway presumably downstream of Hedgehog. This study demonstrates that RNAi silencing of a member of the Bone Morphogenetic Protein (BMP) signaling pathway, Decapentaplegic (Dpp), specifically in the Class IV multidendritic nociceptive neuron, significantly attenuated ultraviolet injury-induced sensitization. Furthermore, overexpression of Dpp in Class IV neurons was sufficient to induce thermal hypersensitivity in the absence of injury. The requirement of various BMP receptors and members of the SMAD signal transduction pathway in nociceptive sensitization was also demonstrated. The effects of BMP signaling were shown to be largely specific to the sensitization pathway and not associated with changes in nociception in the absence of injury or with changes in dendritic morphology. Thus, the results demonstrate that Dpp and its pathway play a crucial and novel role in nociceptive sensitization. Because the BMP family is so strongly conserved between vertebrates and invertebrates, it seems likely that the components analyzed in this study represent potential therapeutic targets for the treatment of chronic pain in humans. SIGNIFICANCE STATEMENT This report provides a genetic analysis of primary nociceptive neuron mechanisms that promote sensitization in response to injury. Drosophila melanogaster larvae whose primary nociceptive neurons were reduced in levels of specific components of the BMP signaling pathway, were injured and then tested for nocifensive responses to a normally subnoxious stimulus. Results suggest that nociceptive neurons use the BMP2/4 ligand, along with identified receptors and intracellular transducers to transition to a sensitized state. These findings are consistent with the observation that BMP receptor hyperactivation correlates with bone abnormalities and pain sensitization in fibrodysplasia ossificans progressiva (Kitterman et al., 2012). Because nociceptive sensitization is associated with chronic pain, these findings indicate that human BMP pathway components may represent targets for novel pain-relieving drugs. Copyright © 2017 the authors 0270-6474/17/378524-10$15.00/0.

Drosophila Nociceptive Sensitization Requires BMP Signaling via the Canonical SMAD Pathway

PubMed Central

Follansbee, Taylor L.; Gjelsvik, Kayla J.; Brann, Courtney L.; McParland, Aidan L.

2017-01-01

Nociceptive sensitization is a common feature in chronic pain, but its basic cellular mechanisms are only partially understood. The present study used the Drosophila melanogaster model system and a candidate gene approach to identify novel components required for modulation of an injury-induced nociceptive sensitization pathway presumably downstream of Hedgehog. This study demonstrates that RNAi silencing of a member of the Bone Morphogenetic Protein (BMP) signaling pathway, Decapentaplegic (Dpp), specifically in the Class IV multidendritic nociceptive neuron, significantly attenuated ultraviolet injury-induced sensitization. Furthermore, overexpression of Dpp in Class IV neurons was sufficient to induce thermal hypersensitivity in the absence of injury. The requirement of various BMP receptors and members of the SMAD signal transduction pathway in nociceptive sensitization was also demonstrated. The effects of BMP signaling were shown to be largely specific to the sensitization pathway and not associated with changes in nociception in the absence of injury or with changes in dendritic morphology. Thus, the results demonstrate that Dpp and its pathway play a crucial and novel role in nociceptive sensitization. Because the BMP family is so strongly conserved between vertebrates and invertebrates, it seems likely that the components analyzed in this study represent potential therapeutic targets for the treatment of chronic pain in humans. SIGNIFICANCE STATEMENT This report provides a genetic analysis of primary nociceptive neuron mechanisms that promote sensitization in response to injury. Drosophila melanogaster larvae whose primary nociceptive neurons were reduced in levels of specific components of the BMP signaling pathway, were injured and then tested for nocifensive responses to a normally subnoxious stimulus. Results suggest that nociceptive neurons use the BMP2/4 ligand, along with identified receptors and intracellular transducers to transition to a sensitized state. These findings are consistent with the observation that BMP receptor hyperactivation correlates with bone abnormalities and pain sensitization in fibrodysplasia ossificans progressiva (Kitterman et al., 2012). Because nociceptive sensitization is associated with chronic pain, these findings indicate that human BMP pathway components may represent targets for novel pain-relieving drugs. PMID:28855331

The Hippo Pathway: Immunity and Cancer.

PubMed

Taha, Zaid; J Janse van Rensburg, Helena; Yang, Xiaolong

2018-03-28

Since its discovery, the Hippo pathway has emerged as a central signaling network in mammalian cells. Canonical signaling through the Hippo pathway core components (MST1/2, LATS1/2, YAP and TAZ) is important for development and tissue homeostasis while aberrant signaling through the Hippo pathway has been implicated in multiple pathologies, including cancer. Recent studies have uncovered new roles for the Hippo pathway in immunology. In this review, we summarize the mechanisms by which Hippo signaling in pathogen-infected or neoplastic cells affects the activities of immune cells that respond to these threats. We further discuss how Hippo signaling functions as part of an immune response. Finally, we review how immune cell-intrinsic Hippo signaling modulates the development/function of leukocytes and propose directions for future work.

Fisetin suppresses malignant proliferation in human oral squamous cell carcinoma through inhibition of Met/Src signaling pathways.

PubMed

Li, Yan-Shu; Qin, Xing-Jun; Dai, Wei

2017-01-01

Fisetin (3,7,3',4'-tetrahydroxyflavone) is a dietary flavonoid and has been indicated as a novel anti-cancer agent in several types of cancer cells. However, the mechanisms underlying the effect of fisetin in human oral squamous cell carcinoma (OSCC) remain unclear. Here, we report that fisetin significantly inhibits tumor cell proliferation and induces apoptosis in OSCC (UM-SCC-23 and Tca-8113) cancer cell lines. Further analysis demonstrates that fisetin also inhibits Met/Src signaling pathways using the PathScan ® receptor tyrosine kinases (RTK) Signaling Antibody Array Kit. Fisetin resulted in decreased basal expression of Met and Src protein in UM-SCC-23 cancer cell lines, which validated by western blot. A student's t -test (two-tailed) was used to compare differences between groups. Furthermore, fisetin significantly inhibited the expression of a disintegrin and metalloproteinase 9 (ADAM9) protein in OSCC cells. Taken together, these results provide novel insights into the mechanism of fisetin and suggest potential therapeutic strategies for human OSCC by blocking the Met/Src signaling pathways.

Extracellular growth factors and mitogens cooperate to drive mitochondrial biogenesis

PubMed Central

Echave, Pedro; Machado-da-Silva, Gisela; Arkell, Rebecca S.; Duchen, Michael R.; Jacobson, Jake; Mitter, Richard; Lloyd, Alison C.

2009-01-01

Summary Cells generate new organelles when stimulated by extracellular factors to grow and divide; however, little is known about how growth and mitogenic signalling pathways regulate organelle biogenesis. Using mitochondria as a model organelle, we have investigated this problem in primary Schwann cells, for which distinct factors act solely as mitogens (neuregulin) or as promoters of cell growth (insulin-like growth factor 1; IGF1). We find that neuregulin and IGF1 act synergistically to increase mitochondrial biogenesis and mitochondrial DNA replication, resulting in increased mitochondrial density in these cells. Moreover, constitutive oncogenic Ras signalling results in a further increase in mitochondrial density. This synergistic effect is seen at the global transcriptional level, requires both the ERK and phosphoinositide 3-kinase (PI3K) signalling pathways and is mediated by the transcription factor ERRα. Interestingly, the effect is independent of Akt-TOR signalling, a major regulator of cell growth in these cells. This separation of the pathways that drive mitochondrial biogenesis and cell growth provides a mechanism for the modulation of mitochondrial density according to the metabolic requirements of the cell. PMID:19920079

Insights into significant pathways and gene interaction networks underlying breast cancer cell line MCF-7 treated with 17β-estradiol (E2).

PubMed

Huan, Jinliang; Wang, Lishan; Xing, Li; Qin, Xianju; Feng, Lingbin; Pan, Xiaofeng; Zhu, Ling

2014-01-01

Estrogens are known to regulate the proliferation of breast cancer cells and to alter their cytoarchitectural and phenotypic properties, but the gene networks and pathways by which estrogenic hormones regulate these events are only partially understood. We used global gene expression profiling by Affymetrix GeneChip microarray analysis, with KEGG pathway enrichment, PPI network construction, module analysis and text mining methods to identify patterns and time courses of genes that are either stimulated or inhibited by estradiol (E2) in estrogen receptor (ER)-positive MCF-7 human breast cancer cells. Of the genes queried on the Affymetrix Human Genome U133 plus 2.0 microarray, we identified 628 (12h), 852 (24h) and 880 (48 h) differentially expressed genes (DEGs) that showed a robust pattern of regulation by E2. From pathway enrichment analysis, we found out the changes of metabolic pathways of E2 treated samples at each time point. At 12h time point, the changes of metabolic pathways were mainly focused on pathways in cancer, focal adhesion, and chemokine signaling pathway. At 24h time point, the changes were mainly enriched in neuroactive ligand-receptor interaction, cytokine-cytokine receptor interaction and calcium signaling pathway. At 48 h time point, the significant pathways were pathways in cancer, regulation of actin cytoskeleton, cell adhesion molecules (CAMs), axon guidance and ErbB signaling pathway. Of interest, our PPI network analysis and module analysis found that E2 treatment induced enhancement of PRSS23 at the three time points and PRSS23 was in the central position of each module. Text mining results showed that the important genes of DEGs have relationship with signal pathways, such as ERbB pathway (AREG), Wnt pathway (NDP), MAPK pathway (NTRK3, TH), IP3 pathway (TRA@) and some transcript factors (TCF4, MAF). Our studies highlight the diverse gene networks and metabolic and cell regulatory pathways through which E2 operates to achieve its widespread effects on breast cancer cells. © 2013 Elsevier B.V. All rights reserved.

Activation of Neuregulin 1/ErbB Signaling Is Involved in the Development of TOCP-Induced Delayed Neuropathy.

PubMed

Xu, Hai-Yang; Wang, Pan; Sun, Ying-Jian; Xu, Ming-Yuan; Zhu, Li; Wu, Yi-Jun

2018-01-01

Organophosphate-induced delayed neuropathy (OPIDN) is characterized by progressive axonal degeneration and demyelination of the spinal cord and sciatic nerves. The neuregulin 1/epidermal growth factor receptor (ErbB) signaling pathway is crucial for axonal myelination. In this study, we investigated whether the neuregulin 1/ErbB signaling pathway mediated the progression of OPIDN. Adult hens were given tri- o -cresyl phosphate (TOCP), a typical neuropathic organophosphorus compound, to induce OPIDN. The ErbB inhibitor lapatinib was administered to hens 4 h prior to and 4 days after TOCP exposure. The neuregulin 1/ErbB signaling pathway was examined for their role in maintaining spinal cord and sciatic nerve fiber integrity. Schwann cell line sNF96.2 was used as the in vitro cell model. The in vivo results showed that TOCP (750 mg/kg body weight, p.o .) induced prominent ataxia and significant axon degeneration in the spinal cord and sciatic nerves. Lapatinib (25 mg/kg body weight, p.o .) treatment attenuated OPIDN clinically and histopathlogically and partially prevented the TOCP-induced activation of neuregulin 1/ErbB signaling pathway. Lapatinib also prevented the TOCP-induced inhibition of neuropathy target esterase (NTE), a key enzyme during the development of OPIDN, and the disturbed metabolism of phosphatidylcholine in sciatic nerves. In addition, lapatinib was shown, in vitro , to protect sNF96.2 cells from TOCP-induced dedifferentiation through neuregulin 1/ErbB signaling. Our results suggest that neuregulin 1/ErbB, through regulation of NTE activity in the peripheral nervous system, mediates the progression of OPIDN. Thus, this signal may serve as a potential target for the treatment of OPIDN.

Alterations in ubiquitin ligase Siah-2 and its corepressor N-CoR after P-MAPA immunotherapy and anti-androgen therapy: new therapeutic opportunities for non-muscle invasive bladder cancer

PubMed Central

Garcia, Patrick Vianna; Apolinário, Letícia Montanholi; Böckelmann, Petra Karla; Nunes, Iseu da Silva; Duran, Nelson; Fávaro, Wagner José

2015-01-01

The present study describes the role of the ubiquitin ligase Siah-2 and corepressor N-CoR in controlling androgen receptor (AR) and estrogen receptors (ERα and ERβ) signaling in an appropriate animal model (Fischer 344 female rats) of non-muscle invasive bladder cancer (NMIBC), especially under conditions of anti-androgen therapy with flutamide. Furthermore, this study describes the mechanisms of a promising therapeutic alternative for NMIBC based on Protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride (P-MAPA) intravesical immunotherapy combined with flutamide, involving the interaction among steroid hormone receptors, their regulators and Toll-like receptors (TLRs). Our results demonstrated that increased Siah-2 and AR protein levels and decreased N-CoR, cytochrome P450 (CYP450) and estrogen receptors levels played a critical role in the urothelial carcinogenesis, probably leading to escape of urothelial cancer cells from immune system attack. P-MAPA immunotherapy led to distinct activation of innate immune system TLRs 2 and 4-mediated, resulting in increase of interferon signaling pathway, which was more effective in recovering the immunosuppressive tumor immune microenvironment and in recovering the bladder histology features than BCG (Bacillus Calmette-Guerin) treatments. The AR blockade therapy was important in the modulating of downstream molecules of TLR2 and TLR4 signaling pathway, decreasing the inflammatory cytokines signaling and enhancing the interferon signaling pathway when associated with P-MAPA. Taken together, the data obtained suggest that interferon signaling pathway activation and targeting AR and Siah-2 signals by P-MAPA intravesical immunotherapy alone and/ or in combination with AR blockade may provide novel therapeutic approaches for NMIBC. PMID:26191134

Alterations in ubiquitin ligase Siah-2 and its corepressor N-CoR after P-MAPA immunotherapy and anti-androgen therapy: new therapeutic opportunities for non-muscle invasive bladder cancer.

PubMed

Garcia, Patrick Vianna; Apolinário, Letícia Montanholi; Böckelmann, Petra Karla; da Silva Nunes, Iseu; Duran, Nelson; Fávaro, Wagner José

2015-01-01

The present study describes the role of the ubiquitin ligase Siah-2 and corepressor N-CoR in controlling androgen receptor (AR) and estrogen receptors (ERα and ERβ) signaling in an appropriate animal model (Fischer 344 female rats) of non-muscle invasive bladder cancer (NMIBC), especially under conditions of anti-androgen therapy with flutamide. Furthermore, this study describes the mechanisms of a promising therapeutic alternative for NMIBC based on Protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride (P-MAPA) intravesical immunotherapy combined with flutamide, involving the interaction among steroid hormone receptors, their regulators and Toll-like receptors (TLRs). Our results demonstrated that increased Siah-2 and AR protein levels and decreased N-CoR, cytochrome P450 (CYP450) and estrogen receptors levels played a critical role in the urothelial carcinogenesis, probably leading to escape of urothelial cancer cells from immune system attack. P-MAPA immunotherapy led to distinct activation of innate immune system TLRs 2 and 4-mediated, resulting in increase of interferon signaling pathway, which was more effective in recovering the immunosuppressive tumor immune microenvironment and in recovering the bladder histology features than BCG (Bacillus Calmette-Guerin) treatments. The AR blockade therapy was important in the modulating of downstream molecules of TLR2 and TLR4 signaling pathway, decreasing the inflammatory cytokines signaling and enhancing the interferon signaling pathway when associated with P-MAPA. Taken together, the data obtained suggest that interferon signaling pathway activation and targeting AR and Siah-2 signals by P-MAPA intravesical immunotherapy alone and/ or in combination with AR blockade may provide novel therapeutic approaches for NMIBC.

Suppression of osteogenic activity by regulation of WNT and BMP signaling during titanium particle induced osteolysis.

PubMed

Nam, Ju-Suk; Sharma, Ashish Ranjan; Jagga, Supriya; Lee, Dong-Hyun; Sharma, Garima; Nguyen, Lich Thi; Lee, Yeon Hee; Chang, Jun-Dong; Chakraborty, Chiranjib; Lee, Sang-Soo

2017-03-01

Periprosthetic osteolysis remains the leading obstacle for total joint replacements. Primarily, it was thought that aseptic loosening is mainly caused by macrophage mediated inflammatory process arising from production of wear debris. The role of osteoclasts and its sequential bone resorption ability has been extensively studied, but little is known about impaired osteogenesis during osteolysis. In the current study, we have tried to delineate the regulatory mechanism of osteogenic signals by Ti particles in osteoprogenitor cells as well its participatory role in wear debris induced osteolysis. Implantation of Ti particles on mice calvaria induced pro-inflammatory response, elevated expression of COX2 and reduced the expression of Osterix. Treatment of Ti particles to MC3T3 E-1 cells displayed decreased osteogenic activity including ALP activity, mineralization and mRNA levels several osteogenic genes. Moreover, the basal activity of WNT and BMP signaling pathways was suppressed in MC3T3 E-1 cells treated with Ti particles. As an early response to Ti particles, MC3T3 E-1 cells showed activation of ERK and JNK. Co-inhibition of ERK and JNK with their specific inhibitors resulted in partial recovery of WNT and BMP signaling activity as well as ALP activity and collagen synthesis. Finally, LiCl mediated activation of WNT signaling pathway demonstrated rescue of Ti particle facilitated suppression of Osterix expression in mice calvaria. Our results provide evidences that WNT signaling pathway is regulated by ERK, JNK, and BMP signaling pathway during wear debris induced inflammatory osteolysis and may be considered as suitable therapeutic targets for the treatment. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 912-926, 2017. © 2017 Wiley Periodicals, Inc.

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.

Reinforcement of integrin-mediated T-Lymphocyte adhesion by TNF-induced Inside-out Signaling

NASA Astrophysics Data System (ADS)

Li, Qian; Huth, Steven; Adam, Dieter; Selhuber-Unkel, Christine

2016-07-01

Integrin-mediated leukocyte adhesion to endothelial cells is a crucial step in immunity against pathogens. Whereas the outside-in signaling pathway in response to the pro-inflammatory cytokine tumour necrosis factor (TNF) has already been studied in detail, little knowledge exists about a supposed TNF-mediated inside-out signaling pathway. In contrast to the outside-in signaling pathway, which relies on the TNF-induced upregulation of surface molecules on endothelium, inside-out signaling should also be present in an endothelium-free environment. Using single-cell force spectroscopy, we show here that stimulating Jurkat cells with TNF significantly reinforces their adhesion to fibronectin in a biomimetic in vitro assay for cell-surface contact times of about 1.5 seconds, whereas for larger contact times the effect disappears. Analysis of single-molecule ruptures further demonstrates that TNF strengthens sub-cellular single rupture events at short cell-surface contact times. Hence, our results provide quantitative evidence for the significant impact of TNF-induced inside-out signaling in the T-lymphocyte initial adhesion machinery.

Retrograde signals arise from reciprocal crosstalk within plastids.

PubMed

Enami, Kazuhiko; Tanaka, Kan; Hanaoka, Mitsumasa

2012-01-01

In addition to the cell nucleus, plant cells also possess genomic DNA and gene expression machineries within mitochondria and plastids. In higher plants, retrograde transcriptional regulation of several nuclear genes encoding plastid-located proteins has been observed in response to changes in a wide variety of physiological properties in plastids, including organelle gene expression (OGE) and tetrapyrrole metabolism. This regulation is postulated to be accomplished by plastid-to-nucleus signaling, (1,2) although the overall signal transduction pathway(s) are not well characterized. By applying a specific differentiation system in tobacco Bright Yellow-2 (BY-2) cultured cells, (3,4) we recently reported that the regulatory system of nuclear gene expressions modulated by a plastid signal was also observed during differentiation of plastids into amyloplasts. (5) While retrograde signaling from plastids was previously speculated to consist of several independent pathways, we found inhibition of OGE and perturbation in the cellular content of one tetrapyrrole intermediate, heme, seemed to interact to regulate amyloplast differentiation. Our results thus highlight the possibility that several sources of retrograde signaling in plastids could be integrated in an intraorganellar manner.

Presynaptic Type III Neuregulin1-ErbB signaling targets α7 nicotinic acetylcholine receptors to axons

PubMed Central

Hancock, Melissa L.; Canetta, Sarah E.; Role, Lorna W.; Talmage, David A.

2008-01-01

Type III Neuregulin1 (Nrg1) isoforms are membrane-tethered proteins capable of participating in bidirectional juxtacrine signaling. Neuronal nicotinic acetylcholine receptors (nAChRs), which can modulate the release of a rich array of neurotransmitters, are differentially targeted to presynaptic sites. We demonstrate that Type III Nrg1 back signaling regulates the surface expression of α7 nAChRs along axons of sensory neurons. Stimulation of Type III Nrg1 back signaling induces an increase in axonal surface α7 nAChRs, which results from a redistribution of preexisting intracellular pools of α7 rather than from increased protein synthesis. We also demonstrate that Type III Nrg1 back signaling activates a phosphatidylinositol 3-kinase signaling pathway and that activation of this pathway is required for the insertion of preexisting α7 nAChRs into the axonal plasma membrane. These findings, in conjunction with prior results establishing that Type III Nrg1 back signaling controls gene transcription, demonstrate that Type III Nrg1 back signaling can regulate both short-and long-term changes in neuronal function. PMID:18458158

Presynaptic type III neuregulin1-ErbB signaling targets {alpha}7 nicotinic acetylcholine receptors to axons.

PubMed

Hancock, Melissa L; Canetta, Sarah E; Role, Lorna W; Talmage, David A

2008-05-05

Type III Neuregulin1 (Nrg1) isoforms are membrane-tethered proteins capable of participating in bidirectional juxtacrine signaling. Neuronal nicotinic acetylcholine receptors (nAChRs), which can modulate the release of a rich array of neurotransmitters, are differentially targeted to presynaptic sites. We demonstrate that Type III Nrg1 back signaling regulates the surface expression of alpha7 nAChRs along axons of sensory neurons. Stimulation of Type III Nrg1 back signaling induces an increase in axonal surface alpha7 nAChRs, which results from a redistribution of preexisting intracellular pools of alpha7 rather than from increased protein synthesis. We also demonstrate that Type III Nrg1 back signaling activates a phosphatidylinositol 3-kinase signaling pathway and that activation of this pathway is required for the insertion of preexisting alpha7 nAChRs into the axonal plasma membrane. These findings, in conjunction with prior results establishing that Type III Nrg1 back signaling controls gene transcription, demonstrate that Type III Nrg1 back signaling can regulate both short-and long-term changes in neuronal function.

Presynaptic type III neuregulin1-ErbB signaling targets alpha7 nicotinic acetylcholine receptors to axons.

PubMed

Hancock, Melissa L; Canetta, Sarah E; Role, Lorna W; Talmage, David A

2008-06-01

Type III Neuregulin1 (Nrg1) isoforms are membrane-tethered proteins capable of participating in bidirectional juxtacrine signaling. Neuronal nicotinic acetylcholine receptors (nAChRs), which can modulate the release of a rich array of neurotransmitters, are differentially targeted to presynaptic sites. We demonstrate that Type III Nrg1 back signaling regulates the surface expression of alpha7 nAChRs along axons of sensory neurons. Stimulation of Type III Nrg1 back signaling induces an increase in axonal surface alpha7 nAChRs, which results from a redistribution of preexisting intracellular pools of alpha7 rather than from increased protein synthesis. We also demonstrate that Type III Nrg1 back signaling activates a phosphatidylinositol 3-kinase signaling pathway and that activation of this pathway is required for the insertion of preexisting alpha7 nAChRs into the axonal plasma membrane. These findings, in conjunction with prior results establishing that Type III Nrg1 back signaling controls gene transcription, demonstrate that Type III Nrg1 back signaling can regulate both short-and long-term changes in neuronal function.

naked cuticle targets dishevelled to antagonize Wnt signal transduction

PubMed Central

Rousset, Raphaël; Mack, Judith A.; Wharton, Keith A.; Axelrod, Jeffrey D.; Cadigan, Ken M.; Fish, Matthew P.; Nusse, Roel; Scott, Matthew P.

2001-01-01

In Drosophila embryos the protein Naked cuticle (Nkd) limits the effects of the Wnt signal Wingless (Wg) during early segmentation. nkd loss of function results in segment polarity defects and embryonic death, but how nkd affects Wnt signaling is unknown. Using ectopic expression, we find that Nkd affects, in a cell-autonomous manner, a transduction step between the Wnt signaling components Dishevelled (Dsh) and Zeste-white 3 kinase (Zw3). Zw3 is essential for repressing Wg target-gene transcription in the absence of a Wg signal, and the role of Wg is to relieve this inhibition. Our double-mutant analysis shows that, in contrast to Zw3, Nkd acts when the Wg pathway is active to restrain signal transduction. Yeast two hybrid and in vitro experiments indicate that Nkd directly binds to the basic-PDZ region of Dsh. Specially timed Nkd overexpression is capable of abolishing Dsh function in a distinct signaling pathway that controls planar-cell polarity. Our results suggest that Nkd acts directly through Dsh to limit Wg activity and thus determines how efficiently Wnt signals stabilize Armadillo (Arm)/β-catenin and activate downstream genes. PMID:11274052

Core signaling pathways in ovarian cancer stem cell revealed by integrative analysis of multi-marker genomics data.

PubMed

Zhang, Tianyu; Xu, Jielin; Deng, Siyuan; Zhou, Fengqi; Li, Jin; Zhang, Liwei; Li, Lang; Wang, Qi-En; Li, Fuhai

2018-01-01

Tumor recurrence occurs in more than 70% of ovarian cancer patients, and the majority eventually becomes refractory to treatments. Ovarian Cancer Stem Cells (OCSCs) are believed to be responsible for the tumor relapse and drug resistance. Therefore, eliminating ovarian CSCs is important to improve the prognosis of ovarian cancer patients. However, there is a lack of effective drugs to eliminate OCSCs because the core signaling pathways regulating OCSCs remain unclear. Also it is often hard for biologists to identify a few testable targets and infer driver signaling pathways regulating CSCs from a large number of differentially expression genes in an unbiased manner. In this study, we propose a straightforward and integrative analysis to identify potential core signaling pathways of OCSCs by integrating transcriptome data of OCSCs isolated based on two distinctive markers, ALDH and side population, with regulatory network (Transcription Factor (TF) and Target Interactome) and signaling pathways. We first identify the common activated TFs in two OCSC populations integrating the gene expression and TF-target Interactome; and then uncover up-stream signaling cascades regulating the activated TFs. In specific, 22 activated TFs are identified. Through literature search validation, 15 of them have been reported in association with cancer stem cells. Additionally, 10 TFs are found in the KEGG signaling pathways, and their up-stream signaling cascades are extracted, which also provide potential treatment targets. Moreover, 40 FDA approved drugs are identified to target on the up-stream signaling cascades, and 15 of them have been reported in literatures in cancer stem cell treatment. In conclusion, the proposed approach can uncover the activated up-stream signaling, activated TFs and up-regulated target genes that constitute the potential core signaling pathways of ovarian CSC. Also drugs and drug combinations targeting on the core signaling pathways might be able to eliminate OCSCs. The proposed approach can also be applied for identifying potential activated signaling pathways of other types of cancers.

Distribution and specificity of S-cone ("blue cone") signals in subcortical visual pathways.

PubMed

Martin, Paul R; Lee, Barry B

2014-03-01

We review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset monkeys. We discuss segregation of S-cone recipient (blue-on and blue-off) receptive fields in the dorsal lateral geniculate nucleus and describe their receptive field properties. We treat in some detail the question of detecting weak S-cone signals as an introduction for newcomers to the field. Finally, we briefly consider the question on how S-cone signals are distributed among nongeniculate targets.

Cytokine-mediated inflammation, tumorigenesis, and disease-associated JAK/STAT/SOCS signaling circuits in the CNS.

PubMed

Campbell, Iain L

2005-04-01

Cytokines are plurifunctional mediators of cellular communication. The CNS biology of this family of molecules has been explored by transgenic approaches that targeted the expression of individual cytokine genes to specific cells in the CNS of mice. Such transgenic animals exhibit wide-ranging structural and functional alterations that are linked to the development of distinct neuroinflammatory responses and gene expression profiles specific for each cytokine. The unique actions of individual cytokines result from the activation of specific receptor-coupled cellular signal transduction pathways such as the JAK/STAT tyrosine kinase signaling cascade. The cerebral expression of various STATs, their activation, as well as that of the major physiological inhibitors of this pathway, SOCS1 and SOCS3, is highly regulated in a stimulus- and cell-specific fashion. The role of the key IFN signaling molecules STAT1 or STAT2 was studied in transgenic mice (termed GIFN) with astrocyte-production of IFN-alpha that were null or haploinsufficient for these STAT genes. Surprisingly, these animals developed either more severe and accelerated neurodegeneration with calcification and inflammation (GIFN/STAT1 deficient) or severe immunoinflammation and medulloblastoma (GIFN/STAT2 deficient). STAT dysregulation may result in a signal switch phenomenon in which one cytokine acquires the apparent function of an entirely different cytokine. Therefore, for cytokines such as the IFNs, the receptor-coupled signaling process is complex, involving the coexistence of multiple JAK/STAT as well as alternative pathways. The cellular compartmentalization and balance in the activity of these pathways ultimately determines the repertoire and nature of CNS cytokine actions.

Comprehensive Ex Vivo Transposon Mutagenesis Identifies Genes That Promote Growth Factor Independence and Leukemogenesis.

PubMed

Guo, Yabin; Updegraff, Barrett L; Park, Sunho; Durakoglugil, Deniz; Cruz, Victoria H; Maddux, Sarah; Hwang, Tae Hyun; O'Donnell, Kathryn A

2016-02-15

Aberrant signaling through cytokine receptors and their downstream signaling pathways is a major oncogenic mechanism underlying hematopoietic malignancies. To better understand how these pathways become pathologically activated and to potentially identify new drivers of hematopoietic cancers, we developed a high-throughput functional screening approach using ex vivo mutagenesis with the Sleeping Beauty transposon. We analyzed over 1,100 transposon-mutagenized pools of Ba/F3 cells, an IL3-dependent pro-B-cell line, which acquired cytokine independence and tumor-forming ability. Recurrent transposon insertions could be mapped to genes in the JAK/STAT and MAPK pathways, confirming the ability of this strategy to identify known oncogenic components of cytokine signaling pathways. In addition, recurrent insertions were identified in a large set of genes that have been found to be mutated in leukemia or associated with survival, but were not previously linked to the JAK/STAT or MAPK pathways nor shown to functionally contribute to leukemogenesis. Forced expression of these novel genes resulted in IL3-independent growth in vitro and tumorigenesis in vivo, validating this mutagenesis-based approach for identifying new genes that promote cytokine signaling and leukemogenesis. Therefore, our findings provide a broadly applicable approach for classifying functionally relevant genes in diverse malignancies and offer new insights into the impact of cytokine signaling on leukemia development. ©2015 American Association for Cancer Research.

C/EBPβ and Nuclear Factor of Activated T Cells Differentially Regulate Adamts-1 Induction by Stimuli Associated with Vascular Remodeling

PubMed Central

Oller, Jorge; Alfranca, Arántzazu; Méndez-Barbero, Nerea; Villahoz, Silvia; Lozano-Vidal, Noelia; Martín-Alonso, Mara; Arroyo, Alicia G.; Escolano, Amelia; Armesilla, Angel Luis

2015-01-01

Emerging evidence indicates that the metalloproteinase Adamts-1 plays a significant role in the pathophysiology of vessel remodeling, but little is known about the signaling pathways that control Adamts-1 expression. We show that vascular endothelial growth factor (VEGF), angiotensin-II, interleukin-1β, and tumor necrosis factor α, stimuli implicated in pathological vascular remodeling, increase Adamts-1 expression in endothelial and vascular smooth muscle cells. Analysis of the intracellular signaling pathways implicated in this process revealed that VEGF and angiotensin-II upregulate Adamts-1 expression via activation of differential signaling pathways that ultimately promote functional binding of the NFAT or C/EBPβ transcription factors, respectively, to the Adamts-1 promoter. Infusion of mice with angiotensin-II triggered phosphorylation and nuclear translocation of C/EBPβ proteins in aortic cells concomitantly with an increase in the expression of Adamts-1, further underscoring the importance of C/EBPβ signaling in angiotensin-II-induced upregulation of Adamts-1. Similarly, VEGF promoted NFAT activation and subsequent Adamts-1 induction in aortic wall in a calcineurin-dependent manner. Our results demonstrate that Adamts-1 upregulation by inducers of pathological vascular remodeling is mediated by specific signal transduction pathways involving NFAT or C/EBPβ transcription factors. Targeting of these pathways may prove useful in the treatment of vascular disease. PMID:26217013

Changes in insulin-like growth factor signaling alter phenotypes in Fragile X Mice.

PubMed

Wise, T L

2017-02-01

Fragile X syndrome (FXS) is an inherited form of intellectual disability that is usually caused by expansion of a polymorphic CGG repeat in the 5' untranslated region of the X-linked FMR1 gene, which leads to hypermethylation and transcriptional silencing. Two non-neurological phenotypes of FXS are enlarged testes and connective tissue dysplasia, which could be caused by alterations in a growth factor signaling pathway. FXS patients also frequently have autistic-like symptoms, suggesting that the signaling pathways affected in FXS may overlap with those affected in autism. Identifying these pathways is important for both understanding the effects of FMR1 inactivation and developing treatments for both FXS and autism. Here we show that decreasing the levels of the insulin-like growth factor (Igf) receptor 1 corrects a number of phenotypes in the mouse model of FXS, including macro-orchidism, and that increasing the levels of IGF2 exacerbates the seizure susceptibility phenotype. These results suggest that the pathways altered by the loss of the FMR1-encoded protein (FMRP) may overlap with the pathways affected by changes in Igf signaling or that one or more of the proteins that play a role in Igf signaling could interact with FMRP. They also indicate a new set of potential targets for drug treatment of FXS and autism spectrum disorders. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Comparative Study on the Cellular and Systemic Nutrient Sensing and Intermediary Metabolism after Partial Replacement of Fishmeal by Meat and Bone Meal in the Diet of Turbot (Scophthalmus maximus L.)

PubMed Central

Mai, Kangsen; Zhou, Huihui; Xu, Wei; He, Gen

2016-01-01

This study was designed to examine the cellular and systemic nutrient sensing mechanisms as well as the intermediary metabolism responses in turbot (Scophthalmus maximus L.) fed with fishmeal diet (FM diet), 45% of FM replaced by meat and bone meal diet (MBM diet) or MBM diet supplemented with essential amino acids to match the amino acid profile of FM diet (MBM+AA diet). During the one month feeding trial, feed intake was not affected by the different diets. However, MBM diet caused significant reduction of specific growth rate and nutrient retentions. Compared with the FM diet, MBM diet down-regulated target of rapamycin (TOR) and insulin-like growth factor (IGFs) signaling pathways, whereas up-regulated the amino acid response (AAR) signaling pathway. Moreover, MBM diet significantly decreased glucose and lipid anabolism, while increased muscle protein degradation and lipid catabolism in liver. MBM+AA diet had no effects on improvement of MBM diet deficiencies. Compared with fasted, re-feeding markedly activated the TOR signaling pathway, IGF signaling pathway and glucose, lipid metabolism, while significantly depressed the protein degradation signaling pathway. These results thus provided a comprehensive display of molecular responses and a better explanation of deficiencies generated after fishmeal replacement by other protein sources. PMID:27802317

MicroRNA-1271 inhibits proliferation and promotes apoptosis of multiple myeloma cells through inhibiting smoothened-mediated Hedgehog signaling pathway.

PubMed

Xu, Zhengwei; Huang, Chen; Hao, Dingjun

2017-02-01

MicroRNAs (miRNAs) have emerged as important regulators in multiple myeloma (MM). miR-1271 is a tumor suppressor in many cancer types. However, the biological role of miR-1271 in MM remains unclear. In the present study, we elucidated the biological role of miR-1271 in MM. Results showed that miR-1271 was significantly decreased in primary MM cells from MM patients and MM cell lines. Overexpression of miR-1271 inhibited proliferation and promoted apoptosis of MM cells. Conversely, suppression of miR-1271 showed the opposite effect. Bioinformatics algorithm analysis predicted that smoothened (SMO), the activator of Hedgehog (HH) signaling pathway, was a direct target of miR-1271 that was experimentally verified by a dual-luciferase reporter assay. Furthermore, overexpression of miR-1271 inhibited SMO expression and HH signaling pathway. Conversely, the restoration of SMO expression markedly abolished the effect of miR-1271 overexpression on cell proliferation, apoptosis and HH signaling pathway in MM cells. Taken together, the present study suggests that miR-1271 functions as a tumor suppressor that inhibits proliferation and promotes apoptosis of MM cells through inhibiting SMO-mediated HH signaling pathway. This finding implies that miR-1271 is a potential therapeutic target for the treatment of MM.

Cloning and expression patterns of two Smad genes during embryonic development and shell formation of the Pacific oyster Crassostrea gigas

NASA Astrophysics Data System (ADS)

Liu, Gang; Huan, Pin; Liu, Baozhong

2014-11-01

Increasing evidence indicates that transforming growth factor β (TGF-β) signaling pathways play many important roles in the early development of mollusks. However, limited information is known concerning their detailed mechanisms. Here, we describe the identification, cloning and characterization of two Smad genes, the key components of TGF-β signaling pathways, from the Pacific oyster Crassostrea gigas. Sequence analysis of the two genes, designated as cgi-smad1/ 5/ 8 and cgi-smad4, revealed conserved functional characteristics. The two genes were widely expressed in embryos and larvae, suggesting multiple roles in the early development of C. gigas. The mRNA of the two genes aggregated in the D quadrant and cgi-smad4 was highly expressed on the dorsal side of the gastrula, indicating that TGF-β signaling pathways may be involved in dorsoventral patterning in C. gigas. Furthermore, high expression levels of the two genes in the shell fields of embryos at different stages suggested important roles for TGF-β signaling pathways in particular phases of shell development, including the formation of the initial shell field and the biomineralization of larval shells. The results of this study provide fundamental support for elucidating how TGF-β signaling pathways participate in the early development of bivalve mollusks, and suggest that further work is warranted to this end.

The role of magnocellular signals in oculomotor attentional capture

PubMed Central

Leonard, Carly J.; Luck, Steven J.

2011-01-01

While it is known that salient distractors often capture covert and overt attention, it is unclear whether salience signals that stem from magnocellular visual input have a more dominant role in oculomotor capture than those that result from parvocellular input. Because of the direct anatomical connections between the magnocellular pathway and the superior colliculus, salience signals generated from the magnocellular pathway may produce greater oculomotor capture than those from the parvocellular pathway, which could be potentially harder to overcome with “top-down”, goal-directed guidance. Although previous research has addressed this with regard to magnocellular transients, in the current research we investigated whether a static singleton distractor defined along a dimension visible to the magnocellular pathway would also produce enhanced oculomotor capture. In two experiments, we addressed this possibility by comparing a parvo-biased singleton condition, in which the distractor was defined by isoluminant chromatic color contrast, with a magno+parvo singleton condition, in which the distractor also differed in luminance from the surrounding objects. In both experiments, magno+parvo singletons elicited faster eye movements than parvo-only singletons, presumably reflecting faster information transmission in the magnocellular pathway, but magno+parvo singletons were not significantly more likely to produce oculomotor capture. Thus, although magnocellular salience signals are available more rapidly, they have no sizable advantage over parvocellular salience signals in controlling oculomotor orienting when all stimuli have a common onset. PMID:22076486

Melatonin attenuates angiotensin II-induced cardiomyocyte hypertrophy through the CyPA/CD147 signaling pathway.

PubMed

Su, Hongyan; Li, Jingyuan; Chen, Tongshuai; Li, Na; Xiao, Jie; Wang, Shujian; Guo, Xiaobin; Yang, Yi; Bu, Peili

2016-11-01

Melatonin is well known for its cardioprotective effects; however, whether melatonin exerts therapeutic effects on cardiomyocyte hypertrophy remains to be investigated, as do the mechanisms underlying these effects, if they exist. Cyclophilin A (CyPA) and its corresponding receptor, CD147, which exists in a variety of cells, play crucial roles in modulating reactive oxygen species (ROS) production. In this study, we explored the role of the CyPA/CD147 signaling pathway in angiotensin II (Ang II)-induced cardiomyocyte hypertrophy and the protective effects exerted by melatonin against Ang II-induced injury in cultured H9C2 cells. Cyclosporine A, a specific CyPA/CD147 signaling pathway inhibitor, was used to manipulate CyPA/CD147 activity. H9C2 cells were then subjected to Ang II or CyPA treatment in either the absence or presence of melatonin. Our results indicate that Ang II induces cardiomyocyte hypertrophy through the CyPA/CD147 signaling pathway and promotes ROS production, which can be blocked by melatonin pretreatment in a concentration-dependent manner, in cultured H9C2 cells and that CyPA/CD147 signaling pathway inhibition protects against Ang II-induced cardiomyocyte hypertrophy. The protective effects of melatonin against Ang II-induced cardiomyocyte hypertrophy depend at least partially on CyPA/CD147 inhibition.

Acrylamide up-regulates cyclooxygenase-2 expression through the MEK/ERK signaling pathway in mouse epidermal cells.

PubMed

Lim, Tae-Gyu; Lee, Bo Kyung; Kwon, Jung Yeon; Jung, Sung Keun; Lee, Ki Won

2011-06-01

Acrylamide is formed during cooking processes and is present in many foods. Accumulating evidence suggests that AA is carcinogenic, but the underlying mechanism remains unclear. Here, we investigated the carcinogenesis mechanisms of AA. AA increased the COX-2 expression. Two major transcription factors, AP-1 and NF-κB, were activated by AA treatment. AA induced the ERK phosphorylation, and this was abolished by the treatment of U0126, a pharmacological inhibitor of MEK, an upstream kinase of ERK. AA-induced expression and promoter activity of COX-2 were suppressed by U0126. U0126 treatment attenuated AA-induced transactivation of AP-1 and NF-κB, suggesting that the MEK/ERK signaling pathway regulates COX-2 expression. In addition, myricetin, a natural inhibitor of the MEK/ERK signal pathway, reduced AA-induced activation of the COX-2 promoter as well as activation of AP-1 and NF-κB. Collectively, these results suggest that the ability of AA to up-regulate COX-2 expression through the MEK/ERK signaling pathway underlies AA carcinogenicity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Tofacitinib Represses the Janus Kinase-Signal Transducer and Activators of Transcription Signalling Pathway in Keratinocytes.

PubMed

Srivastava, Ankit; Ståhle, Mona; Pivarcsi, Andor; Sonkoly, Enikö

2018-05-08

Tofacitinib is a Janus kinase (JAK) inhibitor, which has shown efficacy in treating psoriasis. The mode of action of tofacitinib is not completely understood but it has been thought to be mediated by the inhibition of CD4+ T-cell activation. Here, we investigated whether the molecular targets of tofacitinib are expressed in keratinocytes, and whether tofacitinib can modulate the activity of the JAK/Signal Transducer and Activators of Transcription (STAT)-pathway in keratinocytes. Transcriptomic profiling of human keratinocytes treated with IL-22 in combination with tofacitinib revealed that tofacitinib could prevent the majority of IL-22-mediated gene expression changes. Pathway analysis of tofacitinib-regulated genes in keratinocytes revealed enrichment of genes involved in the JAK/STAT signalling pathway. Quantitative real-time-PCR confirmed the upregulation of S100A7 and downregulation of EGR1 expression by IL-22, which was prevented by tofacitinib pre-treatment. These results indicate a direct effect of tofacinitib on keratinocytes, which can have relevance for systemic as well as for topical treatment of psoriasis with tofacitinib.

Interacting signal pathways control defense gene expression in Arabidopsis in response to cell wall-degrading enzymes from Erwinia carotovora.

PubMed

Norman-Setterblad, C; Vidal, S; Palva, E T

2000-04-01

We have characterized the role of salicylic acid (SA)-independent defense signaling in Arabidopsis thaliana in response to the plant pathogen Erwinia carotovora subsp. carotovora. Use of pathway-specific target genes as well as signal mutants allowed us to elucidate the role and interactions of ethylene, jasmonic acid (JA), and SA signal pathways in this response. Gene expression studies suggest a central role for both ethylene and JA pathways in the regulation of defense gene expression triggered by the pathogen or by plant cell wall-degrading enzymes (CF) secreted by the pathogen. Our results suggest that ethylene and JA act in concert in this regulation. In addition, CF triggers another, strictly JA-mediated response inhibited by ethylene and SA. SA does not appear to have a major role in activating defense gene expression in response to CF. However, SA may have a dual role in controlling CF-induced gene expression, by enhancing the expression of genes synergistically induced by ethylene and JA and repressing genes induced by JA alone.

Signals to promote myelin formation and repair

PubMed Central

Taveggia, Carla; Feltri, Maria Laura; Wrabetz, Lawrence

2011-01-01

The myelin sheath wraps large axons in both the CNS and the PNS, and is a key determinant of efficient axonal function and health. Myelin is targeted in a series of diseases, notably multiple sclerosis (MS). In MS, demyelination is associated with progressive axonal damage, which determines the level of patient disability. Few treatments are available for combating myelin damage in MS and related disorders. These treatments, which largely comprise anti-inflammatory drugs, only show limited efficacy in subsets of patients. More-effective treatment of myelin disorders will probably result from early intervention with combinatorial therapies that target inflammation and other processes—for example, signaling pathways that promote remyelination. Indeed, evidence suggests that such pathways might be impaired in pathology and, hence, contribute to the failure of remyelination in such diseases. In this article, we review the molecular basis of signaling pathways that regulate myelination in the CNS and PNS with a focus on differentiation of myelinating glia. We also discuss factors such as extracellular molecules that act as modulators of these pathways. Finally, we consider the few preclinical and clinical trials of agents that augment this signaling. PMID:20404842

Modulatory effects of silibinin in various cell signaling pathways against liver disorders and cancer - A comprehensive review.

PubMed

Polachi, Navaneethakrishnan; Bai, Guirong; Li, Tingyang; Chu, Yang; Wang, Xiangyang; Li, Shuming; Gu, Ning; Wu, Jiang; Li, Wei; Zhang, Yanjun; Zhou, Shuiping; Sun, He; Liu, Changxiao

2016-11-10

Silibinin, a natural flavanone, derived from the milk thistle plant (Silybum marianum), was illustrated for several medicinal uses such as liver-protective, anti-oxidant, anti-cancer, anti-inflammation and many other. However, silibinin has poor absorbance and bioavailability due to low water solubility, thereby limiting its clinical applications and therapeutic efficiency. To overcome this problem, the combination of silibinin with phosphatidylcholine (PC) as a formulation was used to enhance the solubility and bioavailability. The results indicated that silibinin-PC taken orally markedly enhanced bioavailability and therapeutic efficiency. In addition, a deeper understanding of the signaling pathways modulated by silibinin is important to realize its potential in developing targeted therapies against liver disorders and cancer. Silibinin has been shown to inhibit many cell signaling pathways in preclinical models, demonstrating promising effects against liver disorders and cancer through in vitro and in vivo studies. This review summarizes the pharmacokinetic properties, bioavailability, safety data, clinical activities and modulatory effects of silibinin in different cell signaling pathways against liver disorders and cancer. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Signaling pathway cloud regulation for in silico screening and ranking of the potential geroprotective drugs

PubMed Central

Zhavoronkov, Alex; Buzdin, Anton A.; Garazha, Andrey V.; Borisov, Nikolay M.; Moskalev, Alexey A.

2014-01-01

The major challenges of aging research include absence of the comprehensive set of aging biomarkers, the time it takes to evaluate the effects of various interventions on longevity in humans and the difficulty extrapolating the results from model organisms to humans. To address these challenges we propose the in silico method for screening and ranking the possible geroprotectors followed by the high-throughput in vivo and in vitro validation. The proposed method evaluates the changes in the collection of activated or suppressed signaling pathways involved in aging and longevity, termed signaling pathway cloud, constructed using the gene expression data and epigenetic profiles of young and old patients' tissues. The possible interventions are selected and rated according to their ability to regulate age-related changes and minimize differences in the signaling pathway cloud. While many algorithmic solutions to simulating the induction of the old into young metabolic profiles in silico are possible, this flexible and scalable approach may potentially be used to predict the efficacy of the many drugs that may extend human longevity before conducting pre-clinical work and expensive clinical trials. PMID:24624136

On-line metabolic pathway analysis based on metabolic signal flow diagram.

PubMed

Shi, H; Shimizu, K

In this work, an integrated modeling approach based on a metabolic signal flow diagram and cellular energetics was used to model the metabolic pathway analysis for the cultivation of yeast on glucose. This approach enables us to make a clear analysis of the flow direction of the carbon fluxes in the metabolic pathways as well as of the degree of activation of a particular pathway for the synthesis of biomaterials for cell growth. The analyses demonstrate that the main metabolic pathways of Saccharomyces cerevisiae change significantly during batch culture. Carbon flow direction is toward glycolysis to satisfy the increase of requirement for precursors and energy. The enzymatic activation of TCA cycle seems to always be at normal level, which may result in the overflow of ethanol due to its limited capacity. The advantage of this approach is that it adopts both virtues of the metabolic signal flow diagram and the simple network analysis method, focusing on the investigation of the flow directions of carbon fluxes and the degree of activation of a particular pathway or reaction loop. All of the variables used in the model equations were determined on-line; the information obtained from the calculated metabolic coefficients may result in a better understanding of cell physiology and help to evaluate the state of the cell culture process. Copyright 1998 John Wiley & Sons, Inc.

Maintaining embryonic stem cell pluripotency with Wnt signaling.

PubMed

Sokol, Sergei Y

2011-10-01

Wnt signaling pathways control lineage specification in vertebrate embryos and regulate pluripotency in embryonic stem (ES) cells, but how the balance between progenitor self-renewal and differentiation is achieved during axis specification and tissue patterning remains highly controversial. The context- and stage-specific effects of the different Wnt pathways produce complex and sometimes opposite outcomes that help to generate embryonic cell diversity. Although the results of recent studies of the Wnt/β-catenin pathway in ES cells appear to be surprising and controversial, they converge on the same conserved mechanism that leads to the inactivation of TCF3-mediated repression.

MiR-9-5p promotes MSC migration by activating β-catenin signaling pathway.

PubMed

Li, Xianyang; He, Lihong; Yue, Qing; Lu, Junhou; Kang, Naixin; Xu, Xiaojing; Wang, Huihui; Zhang, Huanxiang

2017-07-01

Mesenchymal stem cells (MSCs) have the potential to treat various tissue damages, but the very limited number of cells that migrate to the damaged region strongly restricts their therapeutic applications. Full understanding of mechanisms regulating MSC migration will help to improve their migration ability and therapeutic effects. Increasing evidence shows that microRNAs play important roles in the regulation of MSC migration. In the present study, we reported that miR-9-5p was upregulated in hepatocyte growth factor -treated MSCs and in MSCs with high migration ability. Overexpression of miR-9-5p promoted MSC migration, whereas inhibition of endogenous miR-9-5p decreased MSC migration. To elucidate the underlying mechanism, we screened the target genes of miR-9-5p and report for the first time that CK1α and GSK3β, two inhibitors of β-catenin signaling pathway, were direct targets of miR-9-5p in MSCs and that overexpression of miR-9-5p upregulated β-catenin signaling pathway. In line with these data, inhibition of β-catenin signaling pathway by FH535 decreased the miR-9-5p-promoted migration of MSCs, while activation of β-catenin signaling pathway by LiCl rescued the impaired migration of MSCs triggered by miR-9-5p inhibitor. Furthermore, the formation and distribution of focal adhesions as well as the reorganization of F-actin were affected by the expression of miR-9-5p. Collectively, these results demonstrate that miR-9-5p promotes MSC migration by upregulating β-catenin signaling pathway, shedding light on the optimization of MSCs for cell replacement therapy through manipulating the expression level of miR-9-5p. Copyright © 2017 the American Physiological Society.

An essential role for the Id1/PI3K/Akt/NFkB/survivin signalling pathway in promoting the proliferation of endothelial progenitor cells in vitro.

PubMed

Li, Wei; Wang, Hang; Kuang, Chun-Yan; Zhu, Jin-Kun; Yu, Yang; Qin, Zhe-Xue; Liu, Jie; Huang, Lan

2012-04-01

The enhancement of re-endothelialisation is a critical therapeutic option for repairing injured blood vessels. Endothelial progenitor cells (EPCs) are the major source of cells that participate in endothelium repair and contribute to re-endothelialisation by reducing neointima formation after vascular injury. The over-expression of the inhibitor of differentiation or DNA binding 1 (Id1) significantly improved EPC proliferation. This study aimed to investigate the effects of Id1 on the phosphatidylinositol-3-kinase (PI3K)/Akt/nuclear factor kappa B (NFκB)/survivin signalling pathway and its significance in promoting EPC proliferation in vitro. Spleen-derived EPCs were cultured as previously described. Id1 was presented at low levels in EPCs, and was rapidly up-regulated by stimulation with vascular endothelial growth factor. We demonstrated that transient transfection of Id1 into EPCs activated the PI3K/Akt/NFκB/survivin signalling pathway and promoted EPC proliferation. The proliferation of EPCs was extensively inhibited by silencing of endogenous Id1, and knockdown of Id1 expression led to suppression of PI3K/Akt/NFκB/survivin signalling pathway in EPCs. In addition, blockade by the PI3K-specific inhibitor LY294002, Akt inhibitor, the NFκB inhibitor BAY 11-7082, the survivin inhibitor Curcumin, or the survivin inhibitor YM155 reduced the effects of Id1 transfection. These results suggest that the Id1/PI3K/Akt/NFκB/survivin signalling pathway plays a critical role in EPC proliferation. The Id1/PI3K/Akt/NFκB/survivin signalling pathway may represent a novel therapeutic target in the prevention of restenosis after vascular injury.

An interplay between 2 signaling pathways: Melatonin-cAMP and IP{sub 3}–Ca{sup 2+} signaling pathways control intraerythrocytic development of the malaria parasite Plasmodium falciparum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furuyama, Wakako; Enomoto, Masahiro; Mossaad, Ehab

Highlights: • A melatonin receptor antagonist blocked Ca{sup 2+} oscillation in P. falciparum and inhibited parasite growth. • P. falciparum development is controlled by Ca{sup 2+}- and cAMP-signaling pathways. • The cAMP-signaling pathway at ring form and late trophozoite stages governs parasite growth of P. falciparum. - Abstract: Plasmodium falciparum spends most of its asexual life cycle within human erythrocytes, where proliferation and maturation occur. Development into the mature forms of P. falciparum causes severe symptoms due to its distinctive sequestration capability. However, the physiological roles and the molecular mechanisms of signaling pathways that govern development are poorly understood. Ourmore » previous study showed that P. falciparum exhibits stage-specific spontaneous Calcium (Ca{sup 2+}) oscillations in ring and early trophozoites, and the latter was essential for parasite development. In this study, we show that luzindole (LZ), a selective melatonin receptor antagonist, inhibits parasite growth. Analyses of development and morphology of LZ-treated P. falciparum revealed that LZ severely disrupted intraerythrocytic maturation, resulting in parasite death. When LZ was added at ring stage, the parasite could not undergo further development, whereas LZ added at the trophozoite stage inhibited development from early into late schizonts. Live-cell Ca{sup 2+} imaging showed that LZ treatment completely abolished Ca{sup 2+} oscillation in the ring forms while having little effect on early trophozoites. Further, the melatonin-induced cAMP increase observed at ring and late trophozoite stage was attenuated by LZ treatment. These suggest that a complex interplay between IP{sub 3}–Ca{sup 2+} and cAMP signaling pathways is involved in intraerythrocytic development of P. falciparum.« less

Altered Expression of Wnt Signaling Pathway Components in Osteogenesis of Mesenchymal Stem Cells in Osteoarthritis Patients.

PubMed

Tornero-Esteban, Pilar; Peralta-Sastre, Ascensión; Herranz, Eva; Rodríguez-Rodríguez, Luis; Mucientes, Arkaitz; Abásolo, Lydia; Marco, Fernando; Fernández-Gutiérrez, Benjamín; Lamas, José Ramón

2015-01-01

Osteoarthritis (OA) is characterized by altered homeostasis of joint cartilage and bone, whose functional properties rely on chondrocytes and osteoblasts, belonging to mesenchymal stem cells (MSCs). WNT signaling acts as a hub integrating and crosstalking with other signaling pathways leading to the regulation of MSC functions. The aim of this study was to evaluate the existence of a differential signaling between Healthy and OA-MSCs during osteogenesis. MSCs of seven OA patients and six healthy controls were isolated, characterised and expanded. During in vitro osteogenesis, cells were recovered at days 1, 10 and 21. RNA and protein content was obtained. Expression of WNT pathway genes was evaluated using RT-qPCR. Functional studies were also performed to study the MSC osteogenic commitment and functional and post-traslational status of β-catenin and several receptor tyrosine kinases. Several genes were downregulated in OA-MSCs during osteogenesis in vitro. These included soluble Wnts, inhibitors, receptors, co-receptors, several kinases and transcription factors. Basal levels of β-catenin were higher in OA-MSCs, but calcium deposition and expression of osteogenic genes was similar between Healthy and OA-MSCs. Interestingly an increased phosphorylation of p44/42 MAPK (ERK1/2) signaling node was present in OA-MSCs. Our results point to the existence in OA-MSCs of alterations in expression of Wnt pathway components during in vitro osteogenesis that are partially compensated by post-translational mechanisms modulating the function of other pathways. We also point the relevance of other signaling pathways in OA pathophysiology suggesting their role in the maintenance of joint homeostasis through modulation of MSC osteogenic potential.

Zinc Signals and Immunity

PubMed Central

Maywald, Martina; Wessels, Inga; Rink, Lothar

2017-01-01

Zinc homeostasis is crucial for an adequate function of the immune system. Zinc deficiency as well as zinc excess result in severe disturbances in immune cell numbers and activities, which can result in increased susceptibility to infections and development of especially inflammatory diseases. This review focuses on the role of zinc in regulating intracellular signaling pathways in innate as well as adaptive immune cells. Main underlying molecular mechanisms and targets affected by altered zinc homeostasis, including kinases, caspases, phosphatases, and phosphodiesterases, will be highlighted in this article. In addition, the interplay of zinc homeostasis and the redox metabolism in affecting intracellular signaling will be emphasized. Key signaling pathways will be described in detail for the different cell types of the immune system. In this, effects of fast zinc flux, taking place within a few seconds to minutes will be distinguish from slower types of zinc signals, also designated as “zinc waves”, and late homeostatic zinc signals regarding prolonged changes in intracellular zinc. PMID:29064429

Hippo signaling pathway in cardiovascular development and diseases.

PubMed

Wang, Yong-yu; Yu, Wei; Zhou, Bin

2017-07-20

Cardiovascular diseases have become the leading cause of death in the world. Understanding the development of cardiovascular system and the pathogenesis of cardiovascular diseases will promote the generation of novel preventive and therapeutic strategy. The Hippo pathway is a recently identified signaling cascade that plays a critical role in organ size control, cell proliferation, apoptosis and fate determination of stem cells. Gene knockout and transgenic mouse models have revealed that the Hippo signaling pathway is involved in heart development, cardiomyocyte proliferation, apoptosis, hypertrophy and cardiac regeneration. The Hippo signaling pathway also regulates vascular development, differentiation and various functions of vascular cells. Dysregulation of the Hippo signaling pathway leads to different kinds of cardiovascular diseases, such as myocardial infarction, cardiac hypertrophy, neointima formation and atherosclerosis. In this review, we briefly summarize current research on the roles and regulation mechanisms of the Hippo signaling pathway in cardiovascular development and diseases.

Intersection of AHR and Wnt Signaling in Development, Health, and Disease

PubMed Central

Schneider, Andrew J.; Branam, Amanda M.; Peterson, Richard E.

2014-01-01

The AHR (aryl hydrocarbon receptor) and Wnt (wingless-related MMTV integration site) signaling pathways have been conserved throughout evolution. Appropriately regulated signaling through each pathway is necessary for normal development and health, while dysregulation can lead to developmental defects and disease. Though both pathways have been vigorously studied, there is relatively little research exploring the possibility of crosstalk between these pathways. In this review, we provide a brief background on (1) the roles of both AHR and Wnt signaling in development and disease, and (2) the molecular mechanisms that characterize activation of each pathway. We also discuss the need for careful and complete experimental evaluation of each pathway and describe existing research that explores the intersection of AHR and Wnt signaling. Lastly, to illustrate in detail the intersection of AHR and Wnt signaling, we summarize our recent findings which show that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced disruption of Wnt signaling impairs fetal prostate development. PMID:25286307

TCF3, a novel positive regulator of osteogenesis, plays a crucial role in miR-17 modulating the diverse effect of canonical Wnt signaling in different microenvironments

PubMed Central

Liu, W; Liu, Y; Guo, T; Hu, C; Luo, H; Zhang, L; Shi, S; Cai, T; Ding, Y; Jin, Y

2013-01-01

Wnt signaling pathways are a highly conserved pathway, which plays an important role from the embryonic development to bone formation. The effect of Wnt pathway on osteogenesis relies on their cellular environment and the expression of target genes. However, the molecular mechanism of that remains unclear. On the basis of the preliminary results, we observed the contrary effect of canonical Wnt signaling on osteogenic differentiation of periodontal ligament stem cells (PDLSCs) in the different culture environment. Furthermore, we found that the expression level of miR-17 was also varied with the change in the culture environment. Therefore, we hypothesized that miR-17 and canonical Wnt signaling may have potential interactions, particularly the inner regulation relationship in different microenvironments. In this paper, we observed that canonical Wnt signaling promoted osteogenesis of PDLSCs in the fully culture medium, while inhibited it in the osteogenic differentiation medium. Interestingly, alteration in the expression level of endogenous miR-17 could partially reverse the different effect of canonical Wnt signaling. Furthermore, the role of miR-17 was because of its target gene TCF3 (transcription factor 3), a key transcription factor of canonical Wnt pathway. Overexpression of TCF3 attenuated the effect of miR-17 on modulating canonical Wnt signaling. Finally, we elucidated that TCF3 enhanced osteogenesis both in vitro and in vivo. In brief, the different level of miR-17 was the main cause of the different effect of canonical Wnt signaling, and TCF3 was the crucial node of miR-17–canonial Wnt signaling regulation loop. This understanding of microRNAs regulating signaling pathways in different microenvironments may pave the way for fine-tuning the process of osteogenesis in bone-related disorders. PMID:23492770

TCF3, a novel positive regulator of osteogenesis, plays a crucial role in miR-17 modulating the diverse effect of canonical Wnt signaling in different microenvironments.

PubMed

Liu, W; Liu, Y; Guo, T; Hu, C; Luo, H; Zhang, L; Shi, S; Cai, T; Ding, Y; Jin, Y

2013-03-14

Wnt signaling pathways are a highly conserved pathway, which plays an important role from the embryonic development to bone formation. The effect of Wnt pathway on osteogenesis relies on their cellular environment and the expression of target genes. However, the molecular mechanism of that remains unclear. On the basis of the preliminary results, we observed the contrary effect of canonical Wnt signaling on osteogenic differentiation of periodontal ligament stem cells (PDLSCs) in the different culture environment. Furthermore, we found that the expression level of miR-17 was also varied with the change in the culture environment. Therefore, we hypothesized that miR-17 and canonical Wnt signaling may have potential interactions, particularly the inner regulation relationship in different microenvironments. In this paper, we observed that canonical Wnt signaling promoted osteogenesis of PDLSCs in the fully culture medium, while inhibited it in the osteogenic differentiation medium. Interestingly, alteration in the expression level of endogenous miR-17 could partially reverse the different effect of canonical Wnt signaling. Furthermore, the role of miR-17 was because of its target gene TCF3 (transcription factor 3), a key transcription factor of canonical Wnt pathway. Overexpression of TCF3 attenuated the effect of miR-17 on modulating canonical Wnt signaling. Finally, we elucidated that TCF3 enhanced osteogenesis both in vitro and in vivo. In brief, the different level of miR-17 was the main cause of the different effect of canonical Wnt signaling, and TCF3 was the crucial node of miR-17-canonial Wnt signaling regulation loop. This understanding of microRNAs regulating signaling pathways in different microenvironments may pave the way for fine-tuning the process of osteogenesis in bone-related disorders.

Identification of critical paralog groups with indispensable roles in the regulation of signaling flow

PubMed Central

Modos, Dezso; Brooks, Johanne; Fazekas, David; Ari, Eszter; Vellai, Tibor; Csermely, Peter; Korcsmaros, Tamas; Lenti, Katalin

2016-01-01

Extensive cross-talk between signaling pathways is required to integrate the myriad of extracellular signal combinations at the cellular level. Gene duplication events may lead to the emergence of novel functions, leaving groups of similar genes - termed paralogs - in the genome. To distinguish critical paralog groups (CPGs) from other paralogs in human signaling networks, we developed a signaling network-based method using cross-talk annotation and tissue-specific signaling flow analysis. 75 CPGs were found with higher degree, betweenness centrality, closeness, and ‘bowtieness’ when compared to other paralogs or other proteins in the signaling network. CPGs had higher diversity in all these measures, with more varied biological functions and more specific post-transcriptional regulation than non-critical paralog groups (non-CPG). Using TGF-beta, Notch and MAPK pathways as examples, SMAD2/3, NOTCH1/2/3 and MEK3/6-p38 CPGs were found to regulate the signaling flow of their respective pathways. Additionally, CPGs showed a higher mutation rate in both inherited diseases and cancer, and were enriched in drug targets. In conclusion, the results revealed two distinct types of paralog groups in the signaling network: CPGs and non-CPGs. Thus highlighting the importance of CPGs as compared to non-CPGs in drug discovery and disease pathogenesis. PMID:27922122

Regulation of Monocarboxylic Acid Transporter 1 Trafficking by the Canonical Wnt/β-Catenin Pathway in Rat Brain Endothelial Cells Requires Cross-talk with Notch Signaling*

PubMed Central

Sneve, Mary; Haroldson, Thomas A.; Smith, Jeffrey P.

2016-01-01

The transport of monocarboxylate fuels such as lactate, pyruvate, and ketone bodies across brain endothelial cells is mediated by monocarboxylic acid transporter 1 (MCT1). Although the canonical Wnt/β-catenin pathway is required for rodent blood-brain barrier development and for the expression of associated nutrient transporters, the role of this pathway in the regulation of brain endothelial MCT1 is unknown. Here we report expression of nine members of the frizzled receptor family by the RBE4 rat brain endothelial cell line. Furthermore, activation of the canonical Wnt/β-catenin pathway in RBE4 cells via nuclear β-catenin signaling with LiCl does not alter brain endothelial Mct1 mRNA but increases the amount of MCT1 transporter protein. Plasma membrane biotinylation studies and confocal microscopic examination of mCherry-tagged MCT1 indicate that increased transporter results from reduced MCT1 trafficking from the plasma membrane via the endosomal/lysosomal pathway and is facilitated by decreased MCT1 ubiquitination following LiCl treatment. Inhibition of the Notch pathway by the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester negated the up-regulation of MCT1 by LiCl, demonstrating a cross-talk between the canonical Wnt/β-catenin and Notch pathways. Our results are important because they show, for the first time, the regulation of MCT1 in cerebrovascular endothelial cells by the multifunctional canonical Wnt/β-catenin and Notch signaling pathways. PMID:26872974

Resistance to MEK inhibitors: should we co-target upstream?

PubMed

Poulikakos, Poulikos I; Solit, David B

2011-03-29

Aberrant activation of the ERK pathway is common in human tumors. This pathway consists of a three-tiered kinase module [comprising the kinases RAF, mitogen-activated protein kinase (MAPK) kinase (MEK), and extracellular signal-regulated kinase (ERK)] that functions as a negative feedback amplifier to confer robustness and stabilization of pathway output. Because this pathway is frequently dysregulated in human cancers, intense efforts are under way to develop selective inhibitors of the ERK pathway as anticancer drugs. Although promising results have been reported in early trials for inhibitors of RAF or MEK, resistance invariably occurs. Amplification of the upstream oncogenic driver of ERK signaling has been identified as a mechanism for MEK inhibitor resistance in cells with mutant BRAF or KRAS. Increased abundance of the oncogenic driver (either KRAS or BRAF in the appropriate cellular context) in response to prolonged drug treatment results in increased flux through the ERK pathway and restoration of ERK activity above the threshold required for cell growth. For patients with BRAF mutant tumors, the results suggest that the addition of a RAF inhibitor to a MEK inhibitor may delay or overcome drug resistance. The data thus provide a mechanistic basis for ongoing trials testing concurrent treatment with RAF and MEK inhibitors.

Signalling Network Construction for Modelling Plant Defence Response

PubMed Central

Miljkovic, Dragana; Stare, Tjaša; Mozetič, Igor; Podpečan, Vid; Petek, Marko; Witek, Kamil; Dermastia, Marina; Lavrač, Nada; Gruden, Kristina

2012-01-01

Plant defence signalling response against various pathogens, including viruses, is a complex phenomenon. In resistant interaction a plant cell perceives the pathogen signal, transduces it within the cell and performs a reprogramming of the cell metabolism leading to the pathogen replication arrest. This work focuses on signalling pathways crucial for the plant defence response, i.e., the salicylic acid, jasmonic acid and ethylene signal transduction pathways, in the Arabidopsis thaliana model plant. The initial signalling network topology was constructed manually by defining the representation formalism, encoding the information from public databases and literature, and composing a pathway diagram. The manually constructed network structure consists of 175 components and 387 reactions. In order to complement the network topology with possibly missing relations, a new approach to automated information extraction from biological literature was developed. This approach, named Bio3graph, allows for automated extraction of biological relations from the literature, resulting in a set of (component1, reaction, component2) triplets and composing a graph structure which can be visualised, compared to the manually constructed topology and examined by the experts. Using a plant defence response vocabulary of components and reaction types, Bio3graph was applied to a set of 9,586 relevant full text articles, resulting in 137 newly detected reactions between the components. Finally, the manually constructed topology and the new reactions were merged to form a network structure consisting of 175 components and 524 reactions. The resulting pathway diagram of plant defence signalling represents a valuable source for further computational modelling and interpretation of omics data. The developed Bio3graph approach, implemented as an executable language processing and graph visualisation workflow, is publically available at http://ropot.ijs.si/bio3graph/and can be utilised for modelling other biological systems, given that an adequate vocabulary is provided. PMID:23272172

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Xinhua; Wang, Xiaoyuan; Hu, Xiongke

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) expressionmore » 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.« less

Next-generation sequencing analysis of gene regulation in the rat model of retinopathy of prematurity.

PubMed

Griffith, Rachel M; Li, Hu; Zhang, Nan; Favazza, Tara L; Fulton, Anne B; Hansen, Ronald M; Akula, James D

2013-08-01

The purpose of this study was to identify the genes, biochemical signaling pathways, and biological themes involved in the pathogenesis of retinopathy of prematurity (ROP). Next-generation sequencing (NGS) was performed on the RNA transcriptome of rats with the Penn et al. (Pediatr Res 36:724-731, 1994) oxygen-induced retinopathy model of ROP at the height of vascular abnormality, postnatal day (P) 19, and normalized to age-matched, room-air-reared littermate controls. Eight custom-developed pathways with potential relevance to known ROP sequelae were evaluated for significant regulation in ROP: The three major Wnt signaling pathways, canonical, planar cell polarity (PCP), and Wnt/Ca(2+); two signaling pathways mediated by the Rho GTPases RhoA and Cdc42, which are, respectively, thought to intersect with canonical and non-canonical Wnt signaling; nitric oxide signaling pathways mediated by two nitric oxide synthase (NOS) enzymes, neuronal (nNOS) and endothelial (eNOS); and the retinoic acid (RA) signaling pathway. Regulation of other biological pathways and themes was detected by gene ontology using the Kyoto Encyclopedia of Genes and Genomes and the NIH's Database for Annotation, Visualization, and Integrated Discovery's GO terms databases. Canonical Wnt signaling was found to be regulated, but the non-canonical PCP and Wnt/Ca(2+) pathways were not. Nitric oxide signaling, as measured by the activation of nNOS and eNOS, was also regulated, as was RA signaling. Biological themes related to protein translation (ribosomes), neural signaling, inflammation and immunity, cell cycle, and cell death were (among others) highly regulated in ROP rats. These several genes and pathways identified by NGS might provide novel targets for intervention in ROP.

Recent insights into brassinosteroid signaling in plants: its dual control of plant immunity and stomatal development.

PubMed

Kong, Xiangpei; Pan, Jiaowen; Cai, Guohua; Li, Dequan

2012-11-01

Brassinosteroid (BR) signaling, plant innate immunity, and stomatal developments are three pathways that are initiated by receptor-like kinases. This commentary focuses on the latest findings in the role of BR signaling in plant immunity and stomatal development that provide some insight into the molecular mechanism of the BR signal pathway interacting with other receptor signaling pathways.

The MEK-ERK pathway negatively regulates bim expression through the 3' UTR in sympathetic neurons

PubMed Central

2011-01-01

Background Apoptosis plays a critical role during neuronal development and disease. Developing sympathetic neurons depend on nerve growth factor (NGF) for survival during the late embryonic and early postnatal period and die by apoptosis in its absence. The proapoptotic BH3-only protein Bim increases in level after NGF withdrawal and is required for NGF withdrawal-induced death. The regulation of Bim expression in neurons is complex and this study describes a new mechanism by which an NGF-activated signalling pathway regulates bim gene expression in sympathetic neurons. Results We report that U0126, an inhibitor of the prosurvival MEK-ERK pathway, increases bim mRNA levels in sympathetic neurons in the presence of NGF. We find that this effect is independent of PI3-K-Akt and JNK-c-Jun signalling and is not mediated by the promoter, first exon or first intron of the bim gene. By performing 3' RACE and microinjection experiments with a new bim-LUC+3'UTR reporter construct, we show that U0126 increases bim expression via the bim 3' UTR. We demonstrate that this effect does not involve a change in bim mRNA stability and by using PD184352, a specific MEK1/2-ERK1/2 inhibitor, we show that this mechanism involves the MEK1/2-ERK1/2 pathway. Finally, we demonstrate that inhibition of MEK/ERK signalling independently reduces cell survival in NGF-treated sympathetic neurons. Conclusions These results suggest that in sympathetic neurons, MEK-ERK signalling negatively regulates bim expression via the 3' UTR and that this regulation is likely to be at the level of transcription. This data provides further insight into the different mechanisms by which survival signalling pathways regulate bim expression in neurons. PMID:21762482

Disruption of the ErbB signaling in adolescence increases striatal dopamine levels and affects learning and hedonic-like behavior in the adult mouse.

PubMed

Golani, Idit; Tadmor, Hagar; Buonanno, Andres; Kremer, Ilana; Shamir, Alon

2014-11-01

The ErbB signaling pathway has been genetically and functionally implicated in schizophrenia. Numerous findings support the dysregulation of Neuregulin (NRG) and epidermal growth factor (EGF) signaling in schizophrenia. However, it is unclear whether alterations of these pathways in the adult brain or during development are involved in the pathophysiology of schizophrenia. Herein we characterized the behavioral profile and molecular changes resulting from pharmacologically blocking the ErbB signaling pathway during a critical period in the development of decision making, planning, judgments, emotions, social cognition and cognitive skills, namely adolescence. We demonstrate that chronic administration of the pan-ErbB kinase inhibitor JNJ-28871063 (JNJ) to adolescent mice elevated striatal dopamine levels and reduced preference for sucrose without affecting locomotor activity and exploratory behavior. In adulthood, adolescent JNJ-treated mice continue to consume less sucrose and needed significantly more correct-response trials to reach the learning criterion during the discrimination phase of the T-maze reversal learning task than their saline-injected controls. In addition, JNJ mice exhibited deficit in reference memory but not in working memory as measured in the radial arm maze. Inhibition of the pathway during adolescence did not affect exploratory behavior and locomotor activity in the open field, social interaction, social memory, and reversal learning in adult mice. Our data suggest that alteration of ErbB signaling during adolescence resulted in changes in the dopaminergic systems that emerge in pathological learning and hedonic behavior in adulthood, and pinpoints the possible role of the pathway in the development of cognitive skills and motivated behavior. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

Prenatal cadmium exposure dysregulates sonic hedgehog and Wnt/beta-catenin signaling in the thymus resulting in altered thymocyte development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, Miranda L.; Brundage, Kathleen M.; Schafer, Rosana

2010-01-15

Cadmium (Cd) is both an environmental pollutant and a component of cigarette smoke. Although evidence demonstrates that adult exposure to Cd causes changes in the immune system, there are limited reports in the literature of immunomodulatory effects of prenatal exposure to Cd. The sonic hedgehog (Shh) and Wnt/beta-catenin pathways are required for thymocyte maturation. Several studies have demonstrated that Cd exposure affects these pathways in different organ systems. This study was designed to investigate the effect of prenatal Cd exposure on thymocyte development, and to determine if these effects were linked to dysregulation of Shh and Wnt/beta-catenin pathways. Pregnant C57Bl/6more » mice were exposed to an environmentally relevant dose (10 ppm) of Cd throughout pregnancy and effects on the thymus were assessed on the day of birth. Thymocyte phenotype was determined by flow cytometry. A Gli:luciferase reporter cell line was used to measure Shh signaling. Transcription of target genes and translation of key components of both signaling pathways were assessed using real-time RT-PCR and western blot, respectively. Prenatal Cd exposure increased the number of CD4{sup +} cells and a subpopulation of double-negative cells (DN; CD4{sup -}CD8{sup -}), DN4 (CD44{sup -}CD25{sup -}). Shh and Wnt/beta-catenin signaling were both decreased in the thymus. Target genes of Shh (Patched1 and Gli1) and Wnt/beta-catenin (c-fos, and c-myc) were affected differentially among thymocyte subpopulations. These findings suggest that prenatal exposure to Cd dysregulates two signaling pathways in the thymus, resulting in altered thymocyte development.« less

Fibroblast growth factor and cyclic AMP (cAMP) synergistically activate gene expression at a cAMP response element.

PubMed Central

Tan, Y; Low, K G; Boccia, C; Grossman, J; Comb, M J

1994-01-01

Growth factors and cyclic AMP (cAMP) are known to activate distinct intracellular signaling pathways. Fibroblast growth factor (FGF) activates ras-dependent kinase cascades, resulting in the activation of MAP kinases, whereas cAMP activates protein kinase A. In this study, we report that growth factors and cAMP act synergistically to stimulate proenkephalin gene expression. Positive synergy between growth factor- and cAMP-activated signaling pathways on gene expression has not been previously reported, and we suggest that these synergistic interactions represent a useful model for analyzing interactions between these pathways. Transfection and mutational studies indicate that both FGF-dependent gene activation and cAMP-dependent gene activation require cAMP response element 2 (CRE-2), a previously characterized cAMP-dependent regulatory element. Furthermore, multiple copies of this element are sufficient to confer FGF regulation upon a minimal promoter, indicating that FGF and cAMP signaling converge upon transcription factors acting at CRE-2. Among many different ATF/AP-1 factors tested, two factors, ATF-3 and c-Jun, stimulate proenkephalin transcription in an FGF- or Ras-dependent fashion. Finally, we show that ATF-3 and c-Jun form heterodimeric complexes in SK-N-MC cells and that the levels of both proteins are increased in response to FGF but not cAMP. Together, these results indicate that growth factor- and cAMP-dependent signaling pathways converge at CRE-2 to synergistically stimulate gene expression and that ATF-3 and c-Jun regulate proenkephalin transcription in response to both growth factor- and cAMP-dependent intracellular signaling pathways. Images PMID:7935470

Signal transduction by beta1 integrin receptors in human chondrocytes in vitro: collaboration with the insulin-like growth factor-I receptor.

PubMed

Shakibaei, M; John, T; De Souza, P; Rahmanzadeh, R; Merker, H J

1999-09-15

We have examined the mechanism by which collagen-binding integrins co-operate with insulin-like growth factor-I (IGF-I) receptors (IGF-IR) to regulate chondrocyte phenotype and differentiation. Adhesion of chondrocytes to anti-beta1 integrin antibodies or collagen type II leads to phosphorylation of cytoskeletal and signalling proteins localized at focal adhesions, including alpha-actinin, vinculin, paxillin and focal adhesion kinase (FAK). These stimulate docking proteins such as Shc (Src-homology collagen). Moreover, exposure of collagen type II-cultured chondrocytes to IGF-I leads to co-immunoprecipitation of Shc protein with the IGF-IR and with beta1, alpha1 and alpha5 integrins, but not with alpha3 integrin. Shc then associates with growth factor receptor-bound protein 2 (Grb2), an adaptor protein and extracellular signal-regulated kinase. The expression of the docking protein Shc occurs only when chondrocytes are bound to collagen type II or integrin antibodies and increases when IGF-I is added, suggesting a collaboration between integrins and growth factors in a common/shared biochemical signalling pathway. Furthermore, these results indicate that focal adhesion assembly may facilitate signalling via Shc, a potential common target for signal integration between integrin and growth-factor signalling regulatory pathways. Thus, the collagen-binding integrins and IGF-IR co-operate to regulate focal adhesion components and these signalling pathways have common targets (Shc-Grb2 complex) in subcellular compartments, thereby linking to the Ras-mitogen-activated protein kinase signalling pathway. These events may play a role during chondrocyte differentiation.

Gα73B is a downstream effector of JAK/STAT signalling and a regulator of Rho1 in Drosophila haematopoiesis.

PubMed

Bausek, Nina; Zeidler, Martin P

2014-01-01

JAK/STAT signalling regulates many essential developmental processes including cell proliferation and haematopoiesis, whereas its inappropriate activation is associated with the majority of myeloproliferative neoplasias and numerous cancers. Furthermore, high levels of JAK/STAT pathway signalling have also been associated with enhanced metastatic invasion by cancerous cells. Strikingly, gain-of-function mutations in the single Drosophila JAK homologue, Hopscotch, result in haemocyte neoplasia, inappropriate differentiation and the formation of melanised haemocyte-derived 'tumour' masses; phenotypes that are partly orthologous to human gain-of-function JAK2-associated pathologies. Here we show that Gα73B, a novel JAK/STAT pathway target gene, is necessary for JAK/STAT-mediated tumour formation in flies. In addition, although Gα73B does not affect haemocyte differentiation, it does regulate haemocyte morphology and motility under non-pathological conditions. We show that Gα73B is required for constitutive, but not injury-induced, activation of Rho1 and for the localisation of Rho1 into filopodia upon haemocyte activation. Consistent with these results, we also show that Rho1 interacts genetically with JAK/STAT signalling, and that wild-type levels of Rho1 are necessary for tumour formation. Our findings link JAK/STAT transcriptional outputs, Gα73B activity and Rho1-dependent cytoskeletal rearrangements and cell motility, therefore connecting a pathway associated with cancer with a marker indicative of invasiveness. As such, we suggest a mechanism by which JAK/STAT pathway signalling may promote metastasis.

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. © 2015 FEBS.

Two White Spot Syndrome Virus MicroRNAs Target the Dorsal Gene To Promote Virus Infection in Marsupenaeus japonicus Shrimp

PubMed Central

Ren, Qian; Huang, Xin; Cui, Yalei; Sun, Jiejie; Wang, Wen

2017-01-01

ABSTRACT In eukaryotes, microRNAs (miRNAs) serve as regulators of many biological processes, including virus infection. An miRNA can generally target diverse genes during virus-host interactions. However, the regulation of gene expression by multiple miRNAs has not yet been extensively explored during virus infection. This study found that the Spaztle (Spz)-Toll-Dorsal-antilipopolysaccharide factor (ALF) signaling pathway plays a very important role in antiviral immunity against invasion of white spot syndrome virus (WSSV) in shrimp (Marsupenaeus japonicus). Dorsal, the central gene in the Toll pathway, was targeted by two viral miRNAs (WSSV-miR-N13 and WSSV-miR-N23) during WSSV infection. The regulation of Dorsal expression by viral miRNAs suppressed the Spz-Toll-Dorsal-ALF signaling pathway in shrimp in vivo, leading to virus infection. Our study contributes novel insights into the viral miRNA-mediated Toll signaling pathway during the virus-host interaction. IMPORTANCE An miRNA can target diverse genes during virus-host interactions. However, the regulation of gene expression by multiple miRNAs during virus infection has not yet been extensively explored. The results of this study indicated that the shrimp Dorsal gene, the central gene in the Toll pathway, was targeted by two viral miRNAs during infection with white spot syndrome virus. Regulation of Dorsal expression by viral miRNAs suppressed the Spz-Toll-Dorsal-ALF signaling pathway in shrimp in vivo, leading to virus infection. Our study provides new insight into the viral miRNA-mediated Toll signaling pathway in virus-host interactions. PMID:28179524

Two White Spot Syndrome Virus MicroRNAs Target the Dorsal Gene To Promote Virus Infection in Marsupenaeus japonicus Shrimp.

PubMed

Ren, Qian; Huang, Xin; Cui, Yalei; Sun, Jiejie; Wang, Wen; Zhang, Xiaobo

2017-04-15

In eukaryotes, microRNAs (miRNAs) serve as regulators of many biological processes, including virus infection. An miRNA can generally target diverse genes during virus-host interactions. However, the regulation of gene expression by multiple miRNAs has not yet been extensively explored during virus infection. This study found that the Spaztle (Spz)-Toll-Dorsal-antilipopolysaccharide factor (ALF) signaling pathway plays a very important role in antiviral immunity against invasion of white spot syndrome virus (WSSV) in shrimp ( Marsupenaeus japonicus ). Dorsal , the central gene in the Toll pathway, was targeted by two viral miRNAs (WSSV-miR-N13 and WSSV-miR-N23) during WSSV infection. The regulation of Dorsal expression by viral miRNAs suppressed the Spz-Toll-Dorsal-ALF signaling pathway in shrimp in vivo , leading to virus infection. Our study contributes novel insights into the viral miRNA-mediated Toll signaling pathway during the virus-host interaction. IMPORTANCE An miRNA can target diverse genes during virus-host interactions. However, the regulation of gene expression by multiple miRNAs during virus infection has not yet been extensively explored. The results of this study indicated that the shrimp Dorsal gene, the central gene in the Toll pathway, was targeted by two viral miRNAs during infection with white spot syndrome virus. Regulation of Dorsal expression by viral miRNAs suppressed the Spz-Toll-Dorsal-ALF signaling pathway in shrimp in vivo , leading to virus infection. Our study provides new insight into the viral miRNA-mediated Toll signaling pathway in virus-host interactions. Copyright © 2017 American Society for Microbiology.

Differences in expression of genes in the MyD88 and TRIF signalling pathways and methylation of TLR4 and TRIF in Tibetan chickens and DaHeng S03 chickens infected with Salmonella enterica serovar enteritidis.

PubMed

Li, Xiaocheng; Zhang, Peng; Jiang, Xiaosong; Du, Huarui; Yang, Chaowu; Zhang, Zengrong; Men, Shuai; Zhang, Zhikun; Jiang, Wei; Wang, Hongning

2017-07-01

Salmonella enterica serovar (S. enteritidis) is a pathogenic bacterium that can cause symptoms of food poisoning, leading to death of poultry, resulting in serious economic losses. The MyD88 and TRIF signalling pathways play important roles in activating innate and adaptive immunity in chickens infected with S. enteritidis. The objective of the present study was to characterize in vivo mRNA expressions, protein levels and methylation levels of genes in the above two pathways in both Tibetan chickens and DaHeng S03 chickens infected with S. enteritidis. MyD88-dependent and TRIF-dependent signalling pathway were activated by infection, and the MyD88 signalling pathway induced cytokines LITAF and IL-8 played important roles in fighting against the S. enteritidis infection in vivo. The TLR4 methylation might alter expression of genes involved in the MyD88 signalling pathway, and thus different breeds of chickens might show differences in susceptibility to the S. enteritidis. The increased expression of INF β was activated by S. enteritidis, but its expressions were different in levels of mRNA and protein in Tibetan chickens and DaHeng chickens, suggesting its functions on the resistance to S. enteritidis infection in chickens. This study contributes to the understanding of two pathways activated in response to S. enteritidis infection, and gives indications on the mechanisms underlying resistance of Tibetan chickens and DaHeng chickens to S. enteritidis. Copyright © 2017 Elsevier B.V. All rights reserved.

Nuclear factor of activated T-cells 5 increases intestinal goblet cell differentiation through an mTOR/Notch signaling pathway

PubMed Central

Zhou, Yuning; Wang, Qingding; Weiss, Heidi L.; Evers, B. Mark

2014-01-01

The intestinal mucosa undergoes a continual process of proliferation, differentiation, and apoptosis that is regulated by multiple signaling pathways. Previously, we have shown that the nuclear factor of activated T-cells 5 (NFAT5) is involved in the regulation of intestinal enterocyte differentiation. Here we show that treatment with sodium chloride (NaCl), which activates NFAT5 signaling, increased mTORC1 repressor regulated in development and DNA damage response 1 (REDD1) protein expression and inhibited mTOR signaling; these alterations were attenuated by knockdown of NFAT5. Knockdown of NFAT5 activated mammalian target of rapamycin (mTOR) signaling and significantly inhibited REDD1 mRNA expression and protein expression. Consistently, overexpression of NFAT5 increased REDD1 expression. In addition, knockdown of REDD1 activated mTOR and Notch signaling, whereas treatment with mTOR inhibitor rapamycin repressed Notch signaling and increased the expression of the goblet cell differentiation marker mucin 2 (MUC2). Moreover, knockdown of NFAT5 activated Notch signaling and decreased MUC2 expression, while overexpression of NFAT5 inhibited Notch signaling and increased MUC2 expression. Our results demonstrate a role for NFAT5 in the regulation of mTOR signaling in intestinal cells. Importantly, these data suggest that NFAT5 participates in the regulation of intestinal homeostasis via the suppression of mTORC1/Notch signaling pathway. PMID:25057011

Growth retardation induced by avian leukosis virus subgroup J associated with down-regulated Wnt/β-catenin pathway.

PubMed

Feng, Weiguo; Zhou, Defang; Meng, Wei; Li, Gen; Zhuang, Pingping; Pan, Zhifang; Wang, Guihua; Cheng, Ziqiang

2017-03-01

Avian leukosis virus subgroup J (ALV-J), an oncogenic retrovirus, induces growth retardation and neoplasia in chickens, leading to enormous economic losses in poultry industry. Increasing evidences showed several signal pathways involved in ALV-J infection. However, what signaling pathway involved in growth retardation is largely unknown. To explore the possible signaling pathway, we tested the cell proliferation and associated miRNAs in ALV-J infected CEF cells by CCK-8 and Hiseq, respectively. The results showed that cell proliferation was significantly inhibited by ALV-J and three associated miRNAs were identified to target Wnt/β-catenin pathway. To verify the Wnt/β-catenin pathway involved in cell growth retardation, we analyzed the key molecules of Wnt pathway in ALV-J infected CEF cells. Our data demonstrated that protein expression of β-catenin was decreased significantly post ALV-J infection compared with the normal (P < 0.05). The impact of this down-regulation caused low expression of known target genes (Axin2, CyclinD1, Tcf4 and Lef1). Further, to obtain in vivo evidence, we set up an ALV-J infection model. Post 7 weeks infection, ALV-J infected chickens showed significant growth retardation. Subsequent tests showed that the expression of β-catenin, Tcf1, Tcf4, Lef1, Axin2 and CyclinD1 were down-regulated in muscles of growth retardation chickens. Taken together, all data demonstrated that chicken growth retardation caused by ALV-J associated with down-regulated Wnt/β-catenin signaling pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

High cell surface death receptor expression determines type I versus type II signaling.

PubMed

Meng, Xue Wei; Peterson, Kevin L; Dai, Haiming; Schneider, Paula; Lee, Sun-Hee; Zhang, Jin-San; Koenig, Alexander; Bronk, Steve; Billadeau, Daniel D; Gores, Gregory J; Kaufmann, Scott H

2011-10-14

Previous studies have suggested that there are two signaling pathways leading from ligation of the Fas receptor to induction of apoptosis. Type I signaling involves Fas ligand-induced recruitment of large amounts of FADD (FAS-associated death domain protein) and procaspase 8, leading to direct activation of caspase 3, whereas type II signaling involves Bid-mediated mitochondrial perturbation to amplify a more modest death receptor-initiated signal. The biochemical basis for this dichotomy has previously been unclear. Here we show that type I cells have a longer half-life for Fas message and express higher amounts of cell surface Fas, explaining the increased recruitment of FADD and subsequent signaling. Moreover, we demonstrate that cells with type II Fas signaling (Jurkat or HCT-15) can signal through a type I pathway upon forced receptor overexpression and that shRNA-mediated Fas down-regulation converts cells with type I signaling (A498) to type II signaling. Importantly, the same cells can exhibit type I signaling for Fas and type II signaling for TRAIL (TNF-α-related apoptosis-inducing ligand), indicating that the choice of signaling pathway is related to the specific receptor, not some other cellular feature. Additional experiments revealed that up-regulation of cell surface death receptor 5 levels by treatment with 7-ethyl-10-hydroxy-camptothecin converted TRAIL signaling in HCT116 cells from type II to type I. Collectively, these results suggest that the type I/type II dichotomy reflects differences in cell surface death receptor expression.

Genomic and transcriptome analyses reveal that MAPK- and phosphatidylinositol-signaling pathways mediate tolerance to 5-hydroxymethyl-2-furaldehyde for industrial yeast Saccharomyces cerevisiae

PubMed Central

Zhou, Qian; Liu, Z. Lewis; Ning, Kang; Wang, Anhui; Zeng, Xiaowei; Xu, Jian

2014-01-01

The industrial yeast Saccharomyces cerevisiae is a traditional ethanologenic agent and a promising biocatalyst for advanced biofuels production using lignocellulose mateials. Here we present the genomic background of type strain NRRL Y-12632 and its transcriptomic response to 5-hydroxymethyl-2-furaldehyde (HMF), a commonly encountered toxic compound liberated from lignocellulosic-biomass pretreatment, in dissecting the genomic mechanisms of yeast tolerance. Compared with the genome of laboratory model strain S288C, we identified more than 32,000 SNPs in Y-12632 with 23,000 missense and nonsense SNPs. Enriched sequence mutations occurred for genes involved in MAPK- and phosphatidylinositol (PI)- signaling pathways in strain Y-12632, with 41 and 13 genes containing non-synonymous SNPs, respectively. Many of these mutated genes displayed consistent up-regulated signature expressions in response to challenges of 30 mM HMF. Analogous single-gene deletion mutations of these genes showed significantly sensitive growth response on a synthetic medium containing 20 mM HMF. Our results suggest at least three MAPK-signaling pathways, especially for the cell-wall integrity pathway, and PI-signaling pathways to be involved in mediation of yeast tolerance against HMF in industrial yeast Saccharomyces cerevisiae. Higher levels of sequence variations were also observed for genes involved in purine and pyrimidine metabolism pathways. PMID:25296911

Transcriptional Pathways Altered in Response to Vibration in a Model of Hand-Arm Vibration Syndrome.

PubMed

Waugh, Stacey; Kashon, Michael L; Li, Shengqiao; Miller, Gerome R; Johnson, Claud; Krajnak, Kristine

2016-04-01

The aim of this study was to use an established model of vibration-induced injury to assess frequency-dependent changes in transcript expression in skin, artery, and nerve tissues. Transcript expression in tissues from control and vibration-exposed rats (4 h/day for 10 days at 62.5, 125, or 250 Hz; 49 m/s, rms) was measured. Transcripts affected by vibration were used in bioinformatics analyses to identify molecular- and disease-related pathways associated with exposure to vibration. Analyses revealed that cancer-related pathways showed frequency-dependent changes in activation or inhibition. Most notably, the breast-related cancer-1 pathway was affected. Other pathways associated with breast cancer type 1 susceptibility protein related signaling, or associated with cancer and cell cycle/cell survivability were also affected. Occupational exposure to vibration may result in DNA damage and alterations in cell signaling pathways that have significant effects on cellular division.

ECTODERMAL WNT/β-CATENIN SIGNALING SHAPES THE MOUSE FACE

PubMed Central

Reid, Bethany S.; Yang, Hui; Melvin, Vida Senkus; Taketo, Makoto M.; Williams, Trevor

2010-01-01

The canonical Wnt/β-catenin pathway is an essential component of multiple developmental processes. To investigate the role of this pathway in the ectoderm during facial morphogenesis, we generated conditional β-catenin mouse mutants using a novel ectoderm-specific Cre recombinase transgenic line. Our results demonstrate that ablating or stabilizing β-catenin in the embryonic ectoderm causes dramatic changes in facial morphology. There are accompanying alterations in the expression of Fgf8 and Shh, key molecules that establish a signaling center critical for facial patterning, the frontonasal ectodermal zone (FEZ). These data indicate that Wnt/β-catenin signaling within the ectoderm is critical for facial development and further suggest that this pathway is an important mechanism for generating the diverse facial shapes of vertebrates during evolution. PMID:21087601

A novel MPL point mutation resulting in thrombopoietin-independent activation.

PubMed

Abe, M; Suzuki, K; Inagaki, O; Sassa, S; Shikama, H

2002-08-01

Thrombopoietin (TPO) and its receptor (MPL) are important regulators of megakaryopoiesis. MPL belongs to a cytokine receptor superfamily. To date, all constitutively active MPL mutants have been artificially constructed with amino acid substitutions in the transmembrane domain or extracellular domain of the protein, and they activate signal transduction pathways in Ba/F3 cells that can also be activated by the normal MPL. In this paper, we report a novel spontaneously occurring mutation of MPL, with an amino acid substitution of Trp(508) to Ser(508) in the intracellular domain of MPL, that induces the factor-independent growth of Ba/F3 cells. Examination of intracellular signaling pathways demonstrated that the mutant MPL protein constitutively activates three distinct signaling pathways, SHC-Ras-Raf-MAPK/JNK, JAK-STAT, and PI3K-Akt-Bad.

Hedgehog pathway as a potential treatment target in human cholangiocarcinoma.

PubMed

Riedlinger, Dorothee; Bahra, Marcus; Boas-Knoop, Sabine; Lippert, Steffen; Bradtmöller, Maren; Guse, Katrin; Seehofer, Daniel; Bova, Roberta; Sauer, Igor M; Neuhaus, Peter; Koch, Arend; Kamphues, Carsten

2014-08-01

Innovative treatment concepts targeting essential signaling pathways may offer new chances for patients suffering from cholangiocarcinoma (CCC). For that, we performed a systematic molecular genetic analysis concerning the Hedgehog activity in human CCC samples and analyzed the effect of Hh inhibition on CCC cells in vitro and in vivo. Activation of the Hh pathway was analyzed in 50 human CCC samples using quantitative polymerase chain reaction (qPCR). The efficacy of Hh inhibition using cyclopamine and BMS-833923 was evaluated in vitro. In addition, the effect of BMS-833923, alone or in combination with gemcitabine, was analyzed in vivo in a murine subcutaneous xenograft model. Expression analysis revealed a significant activation of the Hh-signaling pathway in nearly 50% of CCCs. Hh inhibition resulted in a significant decrease in cell proliferation of CCC cells. Moreover, a distinct inhibition of tumor growth could be seen as a result of a combined therapy with BMS-833923 and gemcitabine in CCC xenografts. The results of our study suggest that the Hh pathway plays a relevant role at least in a subset of human CCC. Inhibition of this pathway may represent a possible treatment option for CCC patients in which the Hh pathway is activated. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Involvement of TrkB- and p75NTR-signaling pathways in two contrasting forms of long-lasting synaptic plasticity

NASA Astrophysics Data System (ADS)

Sakuragi, Shigeo; Tominaga-Yoshino, Keiko; Ogura, Akihiko

2013-11-01

The repetition of experience is often necessary to establish long-lasting memory. However, the cellular mechanisms underlying this repetition-dependent consolidation of memory remain unclear. We previously observed in organotypic slice cultures of the rodent hippocampus that repeated inductions of long-term potentiation (LTP) led to a slowly developing long-lasting synaptic enhancement coupled with synaptogenesis. We also reported that repeated inductions of long-term depression (LTD) produced a long-lasting synaptic suppression coupled with synapse elimination. We proposed these phenomena as useful in vitro models for analyzing repetition-dependent consolidation. Here, we hypothesized that the enhancement and suppression are mediated by the brain-derived neurotrophic factor (BDNF)-TrkB signaling pathway and the proBDNF-p75NTR pathway, respectively. When we masked the respective pathways, reversals of the enhancement and suppression resulted. These results suggest the alternative activation of the p75NTR pathway by BDNF under TrkB-masking conditions and of the TrkB pathway by proBDNF under p75NTR-masking conditions, thus supporting the aforementioned hypothesis.

Genetic Polymorphism in Extracellular Regulators of Wnt Signaling Pathway

PubMed Central

Sharma, Ashish Ranjan; Seo, Eun-Min; Nam, Ju-Suk

2015-01-01

The Wnt signaling pathway is mediated by a family of secreted glycoproteins through canonical and noncanonical mechanism. The signaling pathways are regulated by various modulators, which are classified into two classes on the basis of their interaction with either Wnt or its receptors. Secreted frizzled-related proteins (sFRPs) are the member of class that binds to Wnt protein and antagonizes Wnt signaling pathway. The other class consists of Dickkopf (DKK) proteins family that binds to Wnt receptor complex. The present review discusses the disease related association of various polymorphisms in Wnt signaling modulators. Furthermore, this review also highlights that some of the sFRPs and DKKs are unable to act as an antagonist for Wnt signaling pathway and thus their function needs to be explored more extensively. PMID:25945348

The Hippo Pathway: Immunity and Cancer

PubMed Central

J. Janse van Rensburg, Helena

2018-01-01

Since its discovery, the Hippo pathway has emerged as a central signaling network in mammalian cells. Canonical signaling through the Hippo pathway core components (MST1/2, LATS1/2, YAP and TAZ) is important for development and tissue homeostasis while aberrant signaling through the Hippo pathway has been implicated in multiple pathologies, including cancer. Recent studies have uncovered new roles for the Hippo pathway in immunology. In this review, we summarize the mechanisms by which Hippo signaling in pathogen-infected or neoplastic cells affects the activities of immune cells that respond to these threats. We further discuss how Hippo signaling functions as part of an immune response. Finally, we review how immune cell-intrinsic Hippo signaling modulates the development/function of leukocytes and propose directions for future work. PMID:29597279

The Wnt signaling pathway in familial exudative vitreoretinopathy and Norrie disease.

PubMed

Warden, Scott M; Andreoli, Christopher M; Mukai, Shizuo

2007-01-01

The Wnt signaling pathway is highly conserved among species and has an important role in many cell biological processes throughout the body. This signaling cascade is involved in regulating ocular growth and development, and recent findings indicate that this is particularly true in the retina. Mutations involving different aspects of the Wnt signaling pathway are being linked to several diseases of retinal development. The aim of this article is to first review the Wnt signaling pathway. We will then describe two conditions, familial exudative vitreoretinopathy (FEVR) and Norrie disease (ND), which have been shown to be caused in part by defects in the Wnt signaling cascade.

E4orf1 induction in adipose tissue promotes insulin-independent signaling in the adipocyte

PubMed Central

Kusminski, Christine M.; Gallardo-Montejano, Violeta I.; Wang, Zhao V.; Hegde, Vijay; Bickel, Perry E.; Dhurandhar, Nikhil V.; Scherer, Philipp E.

2015-01-01

Background/Purpose Type 2 diabetes remains a worldwide epidemic with major pathophysiological changes as a result of chronic insulin resistance. Insulin regulates numerous biochemical pathways related to carbohydrate and lipid metabolism. Methods We have generated a novel mouse model that allows us to constitutively activate, in an inducible fashion, the distal branch of the insulin signaling transduction pathway specifically in adipocytes. Results Using the adenoviral 36 E4orf1 protein, we chronically stimulate locally the Ras-ERK-MAPK signaling pathway. At the whole body level, this leads to reduced body-weight gain under a high fat diet challenge. Despite overlapping glucose tolerance curves, there is a reduced requirement for insulin action under these conditions. The mice further exhibit reduced circulating adiponectin levels that ultimately lead to impaired lipid clearance, and inflamed and fibrotic white adipose tissues. Nevertheless, they are protected from diet-induced hepatic steatosis. As we observe constitutively elevated p-Akt levels in the adipocytes, even under conditions of low insulin levels, this pinpoints enhanced Ras-ERK-MAPK signaling in transgenic adipocytes as a potential alternative route to bypass proximal insulin signaling events. Conclusion We conclude that E4orf1 expression in the adipocyte leads to enhanced baseline activation of the distal insulin signaling node, yet impaired insulin receptor stimulation in the presence of insulin, with important implications for the regulation of adiponectin secretion. The resulting systemic phenotype is complex, yet highlights the powerful nature of manipulating selective branches of the insulin signaling network within the adipocyte. PMID:26500839

Bioactive nanofibers enable the identification of thrombospondin 2 as a key player in enamel regeneration.

PubMed

Huang, Zhan; Newcomb, Christina J; Lei, Yaping; Zhou, Yan; Bornstein, Paul; Amendt, Brad A; Stupp, Samuel I; Snead, Malcolm L

2015-08-01

Tissue regeneration and development involves highly synchronized signals both between cells and with the extracellular environment. Biomaterials can be tuned to mimic specific biological signals and control cell response(s). As a result, these materials can be used as tools to elucidate cell signaling pathways and candidate molecules involved with cellular processes. In this work, we explore enamel-forming cells, ameloblasts, which have a limited regenerative capacity. By exposing undifferentiated cells to a self-assembling matrix bearing RGDS epitopes, we elicited a regenerative signal at will that subsequently led to the identification of thrombospondin 2 (TSP2), an extracellular matrix protein that has not been previously recognized as a key player in enamel development and regeneration. Targeted disruption of the thrombospondin 2 gene (Thbs2) resulted in enamel formation with a disordered architecture that was highly susceptible to wear compared to their wild-type counterparts. To test the regenerative capacity, we injected the bioactive matrix into the enamel organ and discovered that the enamel organic epithelial cells in TSP-null mice failed to polarize on the surface of the artificial matrix, greatly reducing integrin β1 and Notch1 expression levels, which represent signaling pathways known to be associated with TSP2. These results suggest TSP2 plays an important role in regulating cell-matrix interactions during enamel formation. Exploiting the signaling pathways activated by biomaterials can provide insight into native signaling mechanisms crucial for tooth development and cell-based strategies for enamel regeneration. Copyright © 2015 Elsevier Ltd. All rights reserved.

PI3K is required for both basal and LPA-induced DNA synthesis in oral carcinoma cells.

PubMed

Aasrum, Monica; Tjomsland, Vegard; Thoresen, G Hege; De Angelis, Paula M; Christoffersen, Thoralf; Brusevold, Ingvild J

2016-07-01

The glycerophospholipid lysophosphatidic acid (LPA), which is present in most tissues and in high concentrations in saliva, may exert profound effects on oral cancer cells. We have investigated mitogenic signalling induced by LPA in the two oral carcinoma cell lines, D2 and E10, focusing on the role of EGFR transactivation and downstream pathways. Two oral squamous carcinoma cell lines, D2 and E10, were analysed for effects of LPA on signalling pathways and induction of DNA synthesis. Pathway activation was investigated by examining phosphorylation of signalling proteins and by the use of specific pathway inhibitors. The D2 cells had higher levels of activated signalling proteins and higher DNA synthesis activity in the basal condition than E10 cells. EGF did not induce proliferation in D2 cells, whereas LPA induced proliferation in both cell lines, by mechanisms depending on EGFR transactivation. Release of EGFR ligands was involved in basal and LPA-induced proliferation in both D2 and E10 cells. The proliferation in D2 cells was dependent on the PI3K/Akt pathway, but not the MEK/ERK pathway. In E10 cells, the PI3K/Akt, MEK/ERK and p38 pathways were all involved in the proliferation. Transactivation of EGFR is required for LPA-induced DNA synthesis in D2 and E10 cells. Our results also show that although proliferation of oral carcinoma cells is regulated by several pathways, and differentially in E10 and D2 cells, the PI3K pathway has a crucial role in both cell lines. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A role for lipid-mediated signaling in plant gravitropism.

PubMed

Smith, Caroline M; Desai, Mintu; Land, Eric S; Perera, Imara Y

2013-01-01

Gravitropism is a universal plant response. It is initiated by the sensing of the primary signal (mass or pressure), which is then converted into chemical signals that are transduced and propagated in a precise spatial and temporal fashion, resulting in a differential growth response. Our thesis is that membrane lipids and lipid-mediated signaling pathways play critical roles in the initial signaling and in the establishment of polarity. In this review, we highlight results from recent literature and discuss the major questions that remain unanswered.

Intricacies of hedgehog signaling pathways: A perspective in tumorigenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kar, Swayamsiddha; Deb, Moonmoon; Sengupta, Dipta

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 themore » 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.« less

Transforming growth factor β-activated kinase 1 transcriptionally suppresses hepatitis B virus replication.

PubMed

Pang, Jinke; Zhang, Geng; Lin, Yong; Xie, Zhanglian; Liu, Hongyan; Tang, Libo; Lu, Mengji; Yan, Ran; Guo, Haitao; Sun, Jian; Hou, Jinlin; Zhang, Xiaoyong

2017-01-03

Hepatitis B Virus (HBV) replication in hepatocytes is restricted by the host innate immune system and related intracellular signaling pathways. Transforming growth factor β-activated kinase 1 (TAK1) is a key mediator of toll-like receptors and pro-inflammatory cytokine signaling pathways. Here, we report that silencing or inhibition of endogenous TAK1 in hepatoma cell lines leads to an upregulation of HBV replication, transcription, and antigen expression. In contrast, overexpression of TAK1 significantly suppresses HBV replication, while an enzymatically inactive form of TAK1 exerts no effect. By screening TAK1-associated signaling pathways with inhibitors and siRNAs, we found that the MAPK-JNK pathway was involved in TAK1-mediated HBV suppression. Moreover, TAK1 knockdown or JNK pathway inhibition induced the expression of farnesoid X receptor α, a transcription factor that upregulates HBV transcription. Finally, ectopic expression of TAK1 in a HBV hydrodynamic injection mouse model resulted in lower levels of HBV DNA and antigens in both liver and serum. In conclusion, our data suggest that TAK1 inhibits HBV primarily at viral transcription level through activation of MAPK-JNK pathway, thus TAK1 represents an intrinsic host restriction factor for HBV replication in hepatocytes.

Gene expression analysis of colorectal cancer by bioinformatics strategy.

PubMed

Cui, Meng; Yuan, Junhua; Li, Jun; Sun, Bing; Li, Tao; Li, Yuantao; Wu, Guoliang

2014-10-01

We used bioinformatics technology to analyze gene expression profiles involved in colorectal cancer tissue samples and healthy controls. In this paper, we downloaded the gene expression profile GSE4107 from Gene Expression Omnibus (GEO) database, in which a total of 22 chips were available, including normal colonic mucosa tissue from normal healthy donors (n=10), colorectal cancer tissue samples from colorectal patients (n=33). To further understand the biological functions of the screened DGEs, the KEGG pathway enrichment analysis were conducted. Then we built a transcriptome network to study differentially co-expressed links. A total of 3151 DEGs of CRC were selected. Besides, total 164 DCGs (Differentially Coexpressed Gene, DCG) and 29279 DCLs (Differentially Co-expressed Link, DCL) were obtained. Furthermore, the significantly enriched KEGG pathways were Endocytosis, Calcium signaling pathway, Vascular smooth muscle contraction, Linoleic acid metabolism, Arginine and proline metabolism, Inositol phosphate metabolism and MAPK signaling pathway. Our results show that the generation of CRC involves multiple genes, TFs and pathways. Several signal and immune pathways are linked to CRC and give us more clues in the process of CRC. Hence, our work would pave ways for novel diagnosis of CRC, and provided theoretical guidance into cancer therapy.

Down-regulated non-coding RNA (lncRNA-ANCR) promotes osteogenic differentiation of periodontal ligament stem cells.

PubMed

Jia, Qian; Jiang, Wenkai; Ni, Longxing

2015-02-01

Our studies aimed to figure out how anti-differentiation noncoding RNA (ANCR) regulates the proliferation and osteogenic differentiation of periodontal ligament stem cells (PDLSCs). In this study, we used lentivirus infection to down-regulate the expression of ANCR in PDLSCs. Then we compared the proliferation of control cells and PDLSC/ANCR-RNAi cells by Cell Counting Kit-8. And the osteogenic differentiation of control cells and PDLSC/ANCR-RNAi cells were evaluated by Alkaline phosphatase (ALP) activity quantification and Alizarin red staining. WNT inhibitor was used to analyze the relationship between ANCR and canonical WNT signalling pathway. The expression of osteogenic differentiation marker mRNAs, DKK1, GSK3-β and β-catenin were evaluated by qRT-PCR. The results showed that down-regulated ANCR promoted proliferation of PDLSCs. Down-regulated ANCR also promoted osteogenic differentiation of PDLSCs by up-regulating osteogenic differentiation marker genes. After the inhibition of canonical WNT signalling pathway, the osteogenic differentiation of PDLSC/ANCR-RNAi cells was inhibited too. qRT-PCR results also demonstrated that canonical WNT signalling pathway was activated for ANCR-RNAi on PDLSCs during the procedure of proliferation and osteogenic induction. These results indicated that ANCR was a key regulator of the proliferation and osteogenic differentiation of PDLSCs, and its regulating effects was associated with the canonical WNT signalling pathway, thus offering a new target for oral stem cell differentiation studies that could also facilitate oral tissue engineering. Copyright © 2014. Published by Elsevier Ltd.

Investigating β-adrenergic-induced cardiac hypertrophy through computational approach: classical and non-classical pathways.

PubMed

Khalilimeybodi, Ali; Daneshmehr, Alireza; Sharif-Kashani, Babak

2018-07-01

The chronic stimulation of β-adrenergic receptors plays a crucial role in cardiac hypertrophy and its progression to heart failure. In β-adrenergic signaling, in addition to the well-established classical pathway, Gs/AC/cAMP/PKA, activation of non-classical pathways such as Gi/PI3K/Akt/GSK3β and Gi/Ras/Raf/MEK/ERK contribute in cardiac hypertrophy. The signaling network of β-adrenergic-induced hypertrophy is very complex and not fully understood. So, we use a computational approach to investigate the dynamic response and contribution of β-adrenergic mediators in cardiac hypertrophy. The proposed computational model provides insights into the effects of β-adrenergic classical and non-classical pathways on the activity of hypertrophic transcription factors CREB and GATA4. The results illustrate that the model captures the dynamics of the main signaling mediators and reproduces the experimental observations well. The results also show that despite the low portion of β2 receptors out of total cardiac β-adrenergic receptors, their contribution in the activation of hypertrophic mediators and regulation of β-adrenergic-induced hypertrophy is noticeable and variations in β1/β2 receptors ratio greatly affect the ISO-induced hypertrophic response. The model results illustrate that GSK3β deactivation after β-adrenergic receptor stimulation has a major influence on CREB and GATA4 activation and consequent cardiac hypertrophy. Also, it is found through sensitivity analysis that PKB (Akt) activation has both pro-hypertrophic and anti-hypertrophic effects in β-adrenergic signaling.

Mechanotransduction signaling in podocytes from fluid flow shear stress.

PubMed

Srivastava, Tarak; Dai, Hongying; Heruth, Daniel P; Alon, Uri S; Garola, Robert E; Zhou, Jianping; Duncan, R Scott; El-Meanawy, Ashraf; McCarthy, Ellen T; Sharma, Ram; Johnson, Mark L; Savin, Virginia J; Sharma, Mukut

2018-01-01

Recently, we and others have found that hyperfiltration-associated increase in biomechanical forces, namely, tensile stress and fluid flow shear stress (FFSS), can directly and distinctly alter podocyte structure and function. The ultrafiltrate flow over the major processes and cell body generates FFSS to podocytes. Our previous work suggests that the cyclooxygenase-2 (COX-2)-PGE 2 -PGE 2 receptor 2 (EP2) axis plays an important role in mechanoperception of FFSS in podocytes. To address mechanotransduction of the perceived stimulus through EP2, cultured podocytes were exposed to FFSS (2 dyn/cm 2 ) for 2 h. Total RNA from cells at the end of FFSS treatment, 2-h post-FFSS, and 24-h post-FFSS was used for whole exon array analysis. Differentially regulated genes ( P < 0.01) were analyzed using bioinformatics tools Enrichr and Ingenuity Pathway Analysis to predict pathways/molecules. Candidate pathways were validated using Western blot analysis and then further confirmed to be resulting from a direct effect of PGE 2 on podocytes. Results show that FFSS-induced mechanotransduction as well as exogenous PGE 2 activate the Akt-GSK3β-β-catenin (Ser552) and MAPK/ERK but not the cAMP-PKA signal transduction cascades. These pathways are reportedly associated with FFSS-induced and EP2-mediated signaling in other epithelial cells as well. The current regimen for treating hyperfiltration-mediated injury largely depends on targeting the renin-angiotensin-aldosterone system. The present study identifies specific transduction mechanisms and provides novel information on the direct effect of FFSS on podocytes. These results suggest that targeting EP2-mediated signaling pathways holds therapeutic significance for delaying progression of chronic kidney disease secondary to hyperfiltration.

The p38 mitogen-activated protein kinase signaling pathway is involved in regulating low-density lipoprotein receptor-related protein 1-mediated β-amyloid protein internalization in mouse brain.

PubMed

Ma, Kai-Ge; Lv, Jia; Hu, Xiao-Dan; Shi, Li-Li; Chang, Ke-Wei; Chen, Xin-Lin; Qian, Yi-Hua; Yang, Wei-Na; Qu, Qiu-Min

2016-07-01

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Recently, increasing evidence suggests that intracellular β-amyloid protein (Aβ) alone plays a pivotal role in the progression of AD. Therefore, understanding the signaling pathway and proteins that control Aβ internalization may provide new insight for regulating Aβ levels. In the present study, the regulation of Aβ internalization by p38 mitogen-activated protein kinases (MAPK) through low-density lipoprotein receptor-related protein 1 (LRP1) was analyzed in vivo. The data derived from this investigation revealed that Aβ1-42 were internalized by neurons and astrocytes in mouse brain, and were largely deposited in mitochondria and lysosomes, with some also being found in the endoplasmic reticulum. Aβ1-42-LRP1 complex was formed during Aβ1-42 internalization, and the p38 MAPK signaling pathway was activated by Aβ1-42 via LRP1. Aβ1-42 and LRP1 were co- localized in the cells of parietal cortex and hippocampus. Furthermore, the level of LRP1-mRNA and LRP1 protein involved in Aβ1-42 internalization in mouse brain. The results of this investigation demonstrated that Aβ1-42 induced an LRP1-dependent pathway that related to the activation of p38 MAPK resulting in internalization of Aβ1-42. These results provide evidence supporting a key role for the p38 MAPK signaling pathway which is involved in the regulation of Aβ1-42 internalization in the parietal cortex and hippocampus of mouse through LRP1 in vivo. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tenebrio molitor Gram-negative-binding protein 3 (TmGNBP3) is essential for inducing downstream antifungal Tenecin 1 gene expression against infection with Beauveria bassiana JEF-007.

PubMed

Yang, Yi-Ting; Lee, Mi Rong; Lee, Se Jin; Kim, Sihyeon; Nai, Yu-Shin; Kim, Jae Su

2017-05-23

The Toll signaling pathway is responsible for defense against both Gram-positive bacteria and fungi. Gram-negative binding protein 3 (GNBP3) has a strong affinity for the fungal cell wall component, β-1,3-glucan, which can activate the prophenoloxidase (proPO) cascade and induce the Toll signaling pathway. Myeloid differentiation factor 88 (MyD88) is an intracellular adaptor protein involved in the Toll signaling pathway. In this study, we monitored the response of 5 key genes (TmGNBP3, TmMyD88, and Tenecin 1, 2, and 3) in the Toll pathway of the mealworm Tenebrio molitor immune system against the fungus Beauveria bassiana JEF-007 using RT-PCR. TmGNBP3, Tenecin 1, and Tenecin 2 were significantly upregulated after fungal infection. To better understand the roles of the Toll signaling pathway in the mealworm immune system, TmGNBP3 and TmMyD88 were knocked down by RNAi silencing. Target gene expression levels decreased at 2 d postknockdown and were dramatically reduced at 6 d post-dsRNA injection. Therefore, mealworms were compromised by B. bassiana JEF-007 at 6 d post-dsRNA injection. Silencing of TmMyD88 and TmGNBP3 resulted in reduced resistance of the host to fungal infection. Particularly, reducing TmGNBP3 levels obviously downregulated Tenecin 1 and Tenecin 2 expression levels, whereas silencing TmMyD88 expression resulted in decreased Tenecin 2 expression. These results indicate that TmGNBP3 is essential to induce downstream antifungal peptide Tenecin 1 expression against B. bassiana JEF-007. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Exercise training and return to a well-balanced diet activate the neuregulin 1/ErbB pathway in skeletal muscle of obese rats

PubMed Central

Ennequin, Gaël; Boisseau, Nathalie; Caillaud, Kevin; Chavanelle, Vivien; Gerbaix, Maude; Metz, Lore; Etienne, Monique; Walrand, Stéphane; Masgrau, Aurélie; Guillet, Christelle; Courteix, Daniel; Niu, Airu; Li, Yi-Ping; Capel, Fréderic; Sirvent, Pascal

2015-01-01

Some studies suggest that the signalling pathway of neuregulin 1 (NRG1), a protein involved in the regulation of skeletal muscle metabolism, could be altered by nutritional and exercise interventions. We hypothesized that diet-induced obesity could lead to alterations of the NRG1 signalling pathway and that chronic exercise could improve NRG1 signalling in rat skeletal muscle. To test this hypothesis, male Wistar rats received a high fat/high sucrose (HF/HS) diet for 16 weeks. At the end of this period, NRG1 and ErbB expression/activity in skeletal muscle was assessed. The obese rats then continued the HF/HS diet or were switched to a well-balanced diet. Moreover, in both groups, half of the animals also performed low intensity treadmill exercise training. After another 8 weeks, NRG1 and ErbB expression/activity in skeletal muscle were tested again. The 16 week HF/HS diet induced obesity, but did not significantly affect the NRG1/ErbB signalling pathway in rat skeletal muscle. Conversely, after the switch to a well-balanced diet, NRG1 cleavage ratio and ErbB4 amount were increased. Chronic exercise training also promoted NRG1 cleavage, resulting in increased ErbB4 phosphorylation. This result was associated with increased protein expression and phosphorylation ratio of the metalloprotease ADAM17, which is involved in NRG1 shedding. Similarly, in vitro stretch-induced activation of ADAM17 in rat myoblasts induced NRG1 cleavage and ErbB4 activation. These results show that low intensity endurance training and well-balanced diet activate the NRG1-ErbB4 pathway, possibly via the metalloprotease ADAM17, in skeletal muscle of diet-induced obese rats. PMID:25820551

Expression profiling analysis: Uncoupling protein 2 deficiency improves hepatic glucose, lipid profiles and insulin sensitivity in high-fat diet-fed mice by modulating expression of genes in peroxisome proliferator-activated receptor signaling pathway.

PubMed

Zhou, Mei-Cen; Yu, Ping; Sun, Qi; Li, Yu-Xiu

2016-03-01

Uncoupling protein 2 (UCP2), which was an important mitochondrial inner membrane protein associated with glucose and lipid metabolism, widely expresses in all kinds of tissues including hepatocytes. The present study aimed to explore the impact of UCP2 deficiency on glucose and lipid metabolism, insulin sensitivity and its effect on the liver-associated signaling pathway by expression profiling analysis. Four-week-old male UCP2-/- mice and UCP2+/+ mice were randomly assigned to four groups: UCP2-/- on a high-fat diet, UCP2-/- on a normal chow diet, UCP2+/+ on a high-fat diet and UCP2+/+ on a normal chow diet. The differentially expressed genes in the four groups on the 16th week were identified by Affymetrix gene array. The results of intraperitoneal glucose tolerance test and insulin tolerance showed that blood glucose and β-cell function were improved in the UCP2-/- group on high-fat diet. Enhanced insulin sensitivity was observed in the UCP2-/- group. The differentially expressed genes were mapped to 23 pathways (P < 0.05). We concentrated on the 'peroxisome proliferator-activated receptor (PPAR) signaling pathway' (P = 3.19 × 10(-11)), because it is closely associated with the regulation of glucose and lipid profiles. In the PPAR signaling pathway, seven genes (PPARγ, Dbi, Acsl3, Lpl, Me1, Scd1, Fads2) in the UCP2-/- mice were significantly upregulated. The present study used gene arrays to show that activity of the PPAR signaling pathway involved in the improvement of glucose and lipid metabolism in the liver of UCP2-deficient mice on a long-term high-fat diet. The upregulation of genes in the PPAR signaling pathway could explain our finding that UCP2 deficiency ameliorated insulin sensitivity. The manipulation of UCP2 protein expression could represent a new strategy for the prevention and treatment of diabetes.

The mucin MUC4 and its membrane partner ErbB2 regulate biological properties of human CAPAN-2 pancreatic cancer cells via different signalling pathways.

PubMed

Jonckheere, Nicolas; Skrypek, Nicolas; Merlin, Johann; Dessein, Anne Frédérique; Dumont, Patrick; Leteurtre, Emmanuelle; Harris, Ann; Desseyn, Jean-Luc; Susini, Christiane; Frénois, Frédéric; Van Seuningen, Isabelle

2012-01-01

The mucin MUC4 and its membrane partner the ErbB2 oncogenic receptor are potential interacting partners in human pancreatic tumour development. However, the way they function is still largely unknown. In this work, we aimed to identify the cellular mechanisms and the intracellular signalling pathways under the control of both ErbB2 and MUC4 in a human pancreatic adenocarcinomatous cell line. Using co-immunoprecipitation and GST pull-down, we show that MUC4 and ErbB2 interact in the human pancreatic adenocarcinomatous cell line CAPAN-2 via the EGF domains of MUC4. Stable cell clones were generated in which either MUC4 or ErbB2 were knocked down (KD) by a shRNA approach. Biological properties of these cells were then studied in vitro and in vivo. Our results show that ErbB2-KD cells are more apoptotic and less proliferative (decreased cyclin D1 and increased p27kip1 expression) while migration and invasive properties were not altered. MUC4-KD clones were less proliferative with decreased cyclin D1 expression, G1 cell cycle arrest and altered ErbB2/ErbB3 expression. Their migration properties were reduced whereas invasive properties were increased. Importantly, inhibition of ErbB2 and MUC4 expression did not impair the same signalling pathways (inhibition of MUC4 expression affected the JNK pathway whereas that of ErbB2 altered the MAPK pathway). Finally, ErbB2-KD and MUC4-KD cells showed impaired tumour growth in vivo. Our results show that ErbB2 and MUC4, which interact physically, activate different intracellular signalling pathways to regulate biological properties of CAPAN-2 pancreatic cancer cells.

Neuronal suppressor of cytokine signaling-3 deficiency enhances hypothalamic leptin-dependent phosphatidylinositol 3-kinase signaling.

PubMed

Metlakunta, Anantha S; Sahu, Maitrayee; Yasukawa, Hideo; Dhillon, Sandeep S; Belsham, Denise D; Yoshimura, Akihiko; Sahu, Abhiram

2011-05-01

Suppressor of cytokine signaling-3 (SOCS3) is thought to be involved in the development of central leptin resistance and obesity by inhibiting STAT3 pathway. Because phosphatidylinositol 3-kinase (PI3K) pathway plays an important role in transducing leptin action in the hypothalamus, we examined whether SOCS3 exerted an inhibition on this pathway. We first determined whether leptin sensitivity in the hypothalamic PI3K pathway was increased in brain-specific Socs3-deficient (NesKO) mice. In NesKO mice, hypothalamic insulin receptor substrate-1 (IRS1)-associated PI3K activity was significantly increased at 30 min and remained elevated up to 2 h after leptin intraperitoneal injection, but in wild-type (WT) littermates, the significant increase was only at 30 min. Hypothalamic p-STAT3 levels were increased up to 5 h in NesKO as opposed to 2 h in WT mice. In food-restricted WT mice with reduced body weight, leptin increased hypothalamic PI3K activity only at 30 min, and p-STAT3 levels at 30-120 min postinjection. These results suggest increased leptin sensitivity in both PI3K and STAT3 pathways in the hypothalamus of NesKO mice, which was not due to a lean phenotype. In the next experiment with a clonal hypothalamic neuronal cell line expressing proopiomelanocortin, we observed that whereas leptin significantly increased IRS1-associated PI3K activity and p-JAK2 levels in cells transfected with control vector, it failed to do so in SOCS3-overexpressed cells. Altogether, these results imply a SOCS3 inhibition of the PI3K pathway of leptin signaling in the hypothalamus, which may be one of the mechanisms behind the development of central leptin resistance and obesity.

Neuronal suppressor of cytokine signaling-3 deficiency enhances hypothalamic leptin-dependent phosphatidylinositol 3-kinase signaling

PubMed Central

Metlakunta, Anantha S.; Sahu, Maitrayee; Yasukawa, Hideo; Dhillon, Sandeep S.; Belsham, Denise D.; Yoshimura, Akihiko

2011-01-01

Suppressor of cytokine signaling-3 (SOCS3) is thought to be involved in the development of central leptin resistance and obesity by inhibiting STAT3 pathway. Because phosphatidylinositol 3-kinase (PI3K) pathway plays an important role in transducing leptin action in the hypothalamus, we examined whether SOCS3 exerted an inhibition on this pathway. We first determined whether leptin sensitivity in the hypothalamic PI3K pathway was increased in brain-specific Socs3-deficient (NesKO) mice. In NesKO mice, hypothalamic insulin receptor substrate-1 (IRS1)-associated PI3K activity was significantly increased at 30 min and remained elevated up to 2 h after leptin intraperitoneal injection, but in wild-type (WT) littermates, the significant increase was only at 30 min. Hypothalamic p-STAT3 levels were increased up to 5 h in NesKO as opposed to 2 h in WT mice. In food-restricted WT mice with reduced body weight, leptin increased hypothalamic PI3K activity only at 30 min, and p-STAT3 levels at 30–120 min postinjection. These results suggest increased leptin sensitivity in both PI3K and STAT3 pathways in the hypothalamus of NesKO mice, which was not due to a lean phenotype. In the next experiment with a clonal hypothalamic neuronal cell line expressing proopiomelanocortin, we observed that whereas leptin significantly increased IRS1-associated PI3K activity and p-JAK2 levels in cells transfected with control vector, it failed to do so in SOCS3-overexpressed cells. Altogether, these results imply a SOCS3 inhibition of the PI3K pathway of leptin signaling in the hypothalamus, which may be one of the mechanisms behind the development of central leptin resistance and obesity. PMID:21325649

Amphiregulin and PTEN evoke a multimodal mechanism of acquired resistance to PI3K inhibition

PubMed Central

Edgar, Kyle A.; Crocker, Lisa; Cheng, Eric; Wagle, Marie-Claire; Wongchenko, Matthew; Yan, Yibing; Wilson, Timothy R.; Dompe, Nicholas; Neve, Richard M.; Belvin, Marcia; Sampath, Deepak; Friedman, Lori S.; Wallin, Jeffrey J.

2014-01-01

Phosphoinositide-3 kinase (PI3K) signaling pathway alterations occur broadly in cancer and PI3K is a promising therapeutic target. Here, we investigated acquired resistance to GDC-0941, a PI3K inhibitor in clinical trials. Colorectal cancer (CRC) cells made to be resistant to GDC-0941 were discovered to secrete amphiregulin, which resulted in increased EGFR/MAPK signaling. Moreover, prolonged PI3K pathway inhibition in cultured cells over a period of months led to a secondary loss of PTEN in 40% of the CRC lines with acquired resistance to PI3K inhibition. In the absence of PI3K inhibitor, these PTEN-null PI3K inhibitor-resistant clones had elevated PI3K pathway signaling and decreased sensitivity to MAPK pathway inhibitors. Importantly, PTEN loss was not able to induce resistance to PI3K inhibitors in the absence of amphiregulin, indicating a multimodal mechanism of acquired resistance. The combination of PI3K and MAPK pathway inhibitors overcame acquired resistance in vitro and in vivo. PMID:25053989

Amphiregulin and PTEN evoke a multimodal mechanism of acquired resistance to PI3K inhibition.

PubMed

Edgar, Kyle A; Crocker, Lisa; Cheng, Eric; Wagle, Marie-Claire; Wongchenko, Matthew; Yan, Yibing; Wilson, Timothy R; Dompe, Nicholas; Neve, Richard M; Belvin, Marcia; Sampath, Deepak; Friedman, Lori S; Wallin, Jeffrey J

2014-03-01

Phosphoinositide-3 kinase (PI3K) signaling pathway alterations occur broadly in cancer and PI3K is a promising therapeutic target. Here, we investigated acquired resistance to GDC-0941, a PI3K inhibitor in clinical trials. Colorectal cancer (CRC) cells made to be resistant to GDC-0941 were discovered to secrete amphiregulin, which resulted in increased EGFR/MAPK signaling. Moreover, prolonged PI3K pathway inhibition in cultured cells over a period of months led to a secondary loss of PTEN in 40% of the CRC lines with acquired resistance to PI3K inhibition. In the absence of PI3K inhibitor, these PTEN-null PI3K inhibitor-resistant clones had elevated PI3K pathway signaling and decreased sensitivity to MAPK pathway inhibitors. Importantly, PTEN loss was not able to induce resistance to PI3K inhibitors in the absence of amphiregulin, indicating a multimodal mechanism of acquired resistance. The combination of PI3K and MAPK pathway inhibitors overcame acquired resistance in vitro and in vivo.

Signal Transduction Inhibitor Therapy for Lymphoma

PubMed Central

Witzig, Thomas E.; Gupta, Mamta

2013-01-01

Current research in lymphoma is focused on two areas of lymphoma biology—the signal transduction pathways used to maintain the growth of malignant lymphocytes and the role of the tumor microenvironment in lymphoma growth and survival. This review focuses on three signaling pathways: the phosphatidylinositol 3-kinase/mammalian target of rapamycin (PI3K/mTOR) pathway, the B-cell receptor/spleen tyrosine kinase (BCR/Syk) pathway, and the protein kinase C-beta (PKC-β) pathway, known to be important to lymphoma cells. The mTOR inhibitors temsirolimus and everolimus have demonstrated antitumor activity in all types of lymphoma, the Syk inhibitor fostamatinib has activity in diffuse large B-cell lymphoma and chronic lymphocytic leukemia, and the PKC-β inhibitor enzastaurin is being used as consolidation therapy after remission in diffuse large B-cell lymphoma. This review discusses the biology behind the development of each new agent and the results of initial clinical trials. The goal is to provide the hematologist/oncologist background information on these new agents and understand their current and potential role in the management of patients. PMID:21239804

Activation of DNA damage repair pathways by murine polyomavirus.

PubMed

Heiser, Katie; Nicholas, Catherine; Garcea, Robert L

2016-10-01

Nuclear replication of DNA viruses activates DNA damage repair (DDR) pathways, which are thought to detect and inhibit viral replication. However, many DNA viruses also depend on these pathways in order to optimally replicate their genomes. We investigated the relationship between murine polyomavirus (MuPyV) and components of DDR signaling pathways including CHK1, CHK2, H2AX, ATR, and DNAPK. We found that recruitment and retention of DDR proteins at viral replication centers was independent of H2AX, as well as the viral small and middle T-antigens. Additionally, infectious virus production required ATR kinase activity, but was independent of CHK1, CHK2, or DNAPK signaling. ATR inhibition did not reduce the total amount of viral DNA accumulated, but affected the amount of virus produced, indicating a defect in virus assembly. These results suggest that MuPyV may utilize a subset of DDR proteins or non-canonical DDR signaling pathways in order to efficiently replicate and assemble. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Astaxanthin inhibits NF-κB and Wnt/β-catenin signaling pathways via inactivation of Erk/MAPK and PI3K/Akt to induce intrinsic apoptosis in a hamster model of oral cancer.

PubMed

Kavitha, K; Kowshik, J; Kishore, T Kranthi Kiran; Baba, Abdul Basit; Nagini, S

2013-10-01

The oncogenic transcription factors NF-κB and β-catenin, constitutively activated by upstream serine/threonine kinases control several cellular processes implicated in malignant transformation including apoptosis evasion. The aim of this study was to investigate the chemopreventive effects of astaxanthin, an antioxidant carotenoid, in the hamster buccal pouch (HBP) carcinogenesis model based on its ability to modulate NF-κB and Wnt signaling pathways and induce apoptosis. We determined the effect of dietary supplementation of astaxanthin on the oncogenic signaling pathways - NF-κB and Wnt/β-catenin, their upstream activator kinases - Erk/MAPK and PI-3K/Akt, and the downstream event - apoptosis evasion by real-time quantitative RT-PCR, western blot, and immunohistochemical analyses. We found that astaxanthin inhibits NF-κB and Wnt signaling by downregulating the key regulatory enzymes IKKβ and GSK-3β. Analysis of gene expression and docking interactions revealed that inhibition of these pathways may be mediated via inactivation of the upstream signaling kinases Erk/Akt by astaxanthin. Astaxanthin also induced caspase-mediated mitochondrial apoptosis by downregulating the expression of antiapoptotic Bcl-2, p-Bad, and survivin and upregulating proapoptotic Bax and Bad, accompanied by efflux of Smac/Diablo and cytochrome-c into the cytosol, and induced cleavage of poly (ADP-ribose) polymerase (PARP). The results provide compelling evidence that astaxanthin exerts chemopreventive effects by concurrently inhibiting phosphorylation of transcription factors and signaling kinases and inducing intrinsic apoptosis. Astaxanthin targets key molecules in oncogenic signaling pathways and induces apoptosis and is a promising candidate agent for cancer prevention and therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

PKC signaling is involved in the regulation of progranulin (acrogranin/PC-cell-derived growth factor/granulin-epithelin precursor) protein expression in human ovarian cancer cell lines.

PubMed

Diaz-Cueto, Laura; Arechavaleta-Velasco, Fabian; Diaz-Arizaga, Adriana; Dominguez-Lopez, Pablo; Robles-Flores, Martha

2012-07-01

Overexpression of progranulin (also named acrogranin, PC-cell-derived growth factor, or granulin-epithelin precursor) is associated with ovarian cancer, specifically with cell proliferation, malignancy, chemoresistance, and shortened overall survival. The objective of the current study is to identify the signaling pathways involved in the regulation of progranulin expression in ovarian cancer cell lines. We studied the relation of protein kinase C (PKC), phosphatidylinositol 3-kinase, protein kinase A, P38, extracellular signal-regulated kinase, and Akt pathways on the modulation of progranulin expression levels in NIH-OVCAR-3 and SK-OV-3 ovarian cancer cell lines. The different pathways were examined using pharmacological inhibitors (calphostin C, LY294002, H89, SB203580, PD98059, and Akt Inhibitor), and mRNA and protein progranulin expression were analyzed by reverse transcriptase polymerase chain reaction and Western blot techniques, respectively. Inhibition of PKC signal transduction pathway by calphostin C decreased in a dose-dependent manner protein but not mRNA levels of progranulin in both ovarian cancer cell lines. LY294002 but not wortmannin, which are phosphatidylinositol 3-kinase inhibitors, also diminished the expression of progranulin in both cell lines. In addition, LY294002 treatment produced a significant reduction in cell viability. Inhibition of protein kinase A, P38, extracellular signal-regulated kinase, and Akt did not affect progranulin protein expression. These results suggest that the PKC signaling is involved in the regulation of progranulin protein expression in 2 different ovarian cancer cell lines. Inhibiting these intracellular signal transduction pathways may provide a future therapeutic target for hindering the cellular proliferation and invasion in ovarian cancer produced by progranulin.

Genome-wide network analysis of Wnt signaling in three pediatric cancers

NASA Astrophysics Data System (ADS)

Bao, Ju; Lee, Ho-Jin; Zheng, Jie J.

2013-10-01

Genomic structural alteration is common in pediatric cancers, and analysis of data generated by the Pediatric Cancer Genome Project reveals such tumor-related alterations in many Wnt signaling-associated genes. Most pediatric cancers are thought to arise within developing tissues that undergo substantial expansion during early organ formation, growth and maturation, and Wnt signaling plays an important role in this development. We examined three pediatric tumors--medullobastoma, early T-cell precursor acute lymphoblastic leukemia, and retinoblastoma--that show multiple genomic structural variations within Wnt signaling pathways. We mathematically modeled this pathway to investigate the effects of cancer-related structural variations on Wnt signaling. Surprisingly, we found that an outcome measure of canonical Wnt signaling was consistently similar in matched cancer cells and normal cells, even in the context of different cancers, different mutations, and different Wnt-related genes. Our results suggest that the cancer cells maintain a normal level of Wnt signaling by developing multiple mutations.

Ras signaling in aging and metabolic regulation.

PubMed

Slack, Cathy

2017-12-07

Aberrant signal transduction downstream of the Ras GTPase has a well-established role in tumorigenesis. Mutations that result in hyperactivation of Ras are responsible for a third of all human cancers. Hence, small molecule inhibitors of the Ras signal transduction cascade have been under intense focus as potential cancer treatments. In both invertebrate and mammalian models, emerging evidence has also implicated components of the Ras signaling pathway in aging and metabolic regulation. Here, I review the current evidence for Ras signaling in these newly discovered roles highlighting the interactions between the Ras pathway and other longevity assurance mechanisms. Defining the role of Ras signaling in maintaining age-related health may have important implications for the development of interventions that could not only increase lifespan but also delay the onset and/or progression of age-related functional decline.

Epigallocatechin-3-Gallate Reduces Neuronal Apoptosis in Rats after Middle Cerebral Artery Occlusion Injury via PI3K/AKT/eNOS Signaling Pathway

PubMed Central

Zhonghang, Xu; Tongtong, Liu; Wanshu, Guo

2018-01-01

Background/Aims Epigallocatechin-3-gallate (EGCG) has neuroprotective effects and the ability to resist amyloidosis. This study observed the protective effect of EGCG against neuronal injury in rat models of middle cerebral artery occlusion (MCAO) and investigated the mechanism of action of PI3K/AKT/eNOS signaling pathway. Methods Rat models of permanent MCAO were established using the suture method. Rat behavior was measured using neurological deficit score. Pathology and apoptosis were measured using HE staining and TUNEL. Oxidative stress and brain injury markers were examined using ELISA. Apoptosis-related proteins and PI3K/AKT/eNOS signaling pathway were determined using western blot assay and immunohistochemistry. Results EGCG decreased neurological function score, protected nerve cells, inhibited neuronal apoptosis, and inhibited oxidative stress injury and brain injury markers level after MCAO. EGCG reduced the apoptotic rate of neurons, increased the expression of Bcl-2, and decreased the expression of Caspase-3 and Bax. After LY294002 suppressed the PI3K pathway, the protective effect of EGCG decreased after administration of PI3K inhibitors. Conclusion EGCG has a protective effect on rat brain injury induced by MCAO, possibly by modulating the PI3K/AKT/eNOS signaling pathway. PMID:29770336

Encoding of social signals in all three electrosensory pathways of Eigenmannia virescens.

PubMed

Stöckl, Anna; Sinz, Fabian; Benda, Jan; Grewe, Jan

2014-11-01

Extracting complementary features in parallel pathways is a widely used strategy for a robust representation of sensory signals. Weakly electric fish offer the rare opportunity to study complementary encoding of social signals in all of its electrosensory pathways. Electrosensory information is conveyed in three parallel pathways: two receptor types of the tuberous (active) system and one receptor type of the ampullary (passive) system. Modulations of the fish's own electric field are sensed by these receptors and used in navigation, prey detection, and communication. We studied the neuronal representation of electric communication signals (called chirps) in the ampullary and the two tuberous pathways of Eigenmannia virescens. We first characterized different kinds of chirps observed in behavioral experiments. Since Eigenmannia chirps simultaneously drive all three types of receptors, we studied their responses in in vivo electrophysiological recordings. Our results demonstrate that different electroreceptor types encode different aspects of the stimuli and each appears best suited to convey information about a certain chirp type. A decoding analysis of single neurons and small populations shows that this specialization leads to a complementary representation of information in the tuberous and ampullary receptors. This suggests that a potential readout mechanism should combine information provided by the parallel processing streams to improve chirp detectability. Copyright © 2014 the American Physiological Society.

Application of Petri net based analysis techniques to signal transduction pathways

PubMed Central

Sackmann, Andrea; Heiner, Monika; Koch, Ina

2006-01-01

Background Signal transduction pathways are usually modelled using classical quantitative methods, which are based on ordinary differential equations (ODEs). However, some difficulties are inherent in this approach. On the one hand, the kinetic parameters involved are often unknown and have to be estimated. With increasing size and complexity of signal transduction pathways, the estimation of missing kinetic data is not possible. On the other hand, ODEs based models do not support any explicit insights into possible (signal-) flows within the network. Moreover, a huge amount of qualitative data is available due to high-throughput techniques. In order to get information on the systems behaviour, qualitative analysis techniques have been developed. Applications of the known qualitative analysis methods concern mainly metabolic networks. Petri net theory provides a variety of established analysis techniques, which are also applicable to signal transduction models. In this context special properties have to be considered and new dedicated techniques have to be designed. Methods We apply Petri net theory to model and analyse signal transduction pathways first qualitatively before continuing with quantitative analyses. This paper demonstrates how to build systematically a discrete model, which reflects provably the qualitative biological behaviour without any knowledge of kinetic parameters. The mating pheromone response pathway in Saccharomyces cerevisiae serves as case study. Results We propose an approach for model validation of signal transduction pathways based on the network structure only. For this purpose, we introduce the new notion of feasible t-invariants, which represent minimal self-contained subnets being active under a given input situation. Each of these subnets stands for a signal flow in the system. We define maximal common transition sets (MCT-sets), which can be used for t-invariant examination and net decomposition into smallest biologically meaningful functional units. Conclusion The paper demonstrates how Petri net analysis techniques can promote a deeper understanding of signal transduction pathways. The new concepts of feasible t-invariants and MCT-sets have been proven to be useful for model validation and the interpretation of the biological system behaviour. Whereas MCT-sets provide a decomposition of the net into disjunctive subnets, feasible t-invariants describe subnets, which generally overlap. This work contributes to qualitative modelling and to the analysis of large biological networks by their fully automatic decomposition into biologically meaningful modules. PMID:17081284

Aldolase positively regulates of the canonical Wnt signaling pathway

PubMed Central

2014-01-01

The Wnt signaling pathway is an evolutionary conserved system, having pivotal roles during animal development. When over-activated, this signaling pathway is involved in cancer initiation and progression. The canonical Wnt pathway regulates the stability of β-catenin primarily by a destruction complex containing a number of different proteins, including Glycogen synthase kinase 3β (GSK-3β) and Axin, that promote proteasomal degradation of β-catenin. As this signaling cascade is modified by various proteins, novel screens aimed at identifying new Wnt signaling regulators were conducted in our laboratory. One of the different genes that were identified as Wnt signaling activators was Aldolase C (ALDOC). Here we report that ALDOC, Aldolase A (ALDOA) and Aldolase B (ALDOB) activate Wnt signaling in a GSK-3β-dependent mechanism, by disrupting the GSK-3β-Axin interaction and targeting Axin to the dishevelled (Dvl)-induced signalosomes that positively regulate the Wnt pathway thus placing the Aldolase proteins as novel Wnt signaling regulators. PMID:24993527

Insights into the origin and evolution of the plant hormone signaling machinery.

PubMed

Wang, Chunyang; Liu, Yang; Li, Si-Shen; Han, Guan-Zhu

2015-03-01

Plant hormones modulate plant growth, development, and defense. However, many aspects of the origin and evolution of plant hormone signaling pathways remain obscure. Here, we use a comparative genomic and phylogenetic approach to investigate the origin and evolution of nine major plant hormone (abscisic acid, auxin, brassinosteroid, cytokinin, ethylene, gibberellin, jasmonate, salicylic acid, and strigolactone) signaling pathways. Our multispecies genome-wide analysis reveals that: (1) auxin, cytokinin, and strigolactone signaling pathways originated in charophyte lineages; (2) abscisic acid, jasmonate, and salicylic acid signaling pathways arose in the last common ancestor of land plants; (3) gibberellin signaling evolved after the divergence of bryophytes from land plants; (4) the canonical brassinosteroid signaling originated before the emergence of angiosperms but likely after the split of gymnosperms and angiosperms; and (5) the origin of the canonical ethylene signaling pathway postdates shortly the emergence of angiosperms. Our findings might have important implications in understanding the molecular mechanisms underlying the emergence of land plants. © 2015 American Society of Plant Biologists. All Rights Reserved.

Fas- and Mitochondria-Mediated Signaling Pathway Involved in Osteoblast Apoptosis Induced by AlCl3.

PubMed

Xu, Feibo; Ren, Limin; Song, Miao; Shao, Bing; Han, Yanfei; Cao, Zheng; Li, Yanfei

2018-07-01

Aluminum (Al) is known to induce apoptosis of osteoblasts (OBs). However, the mechanism is not yet established. To investigate the apoptotic mechanism of OBs induced by aluminum trichloride (AlCl 3 ), the primary OBs from the craniums of fetal Wistar rats were exposed to 0 mg/mL (control group, CG), 0.06 mg/mL (low-dose group, LG), 0.12 mg/mL (mid-dose group, MG), and 0.24 mg/mL (high-dose group, HG) AlCl 3 for 24 h, respectively. We observed that AlCl 3 induced OB apoptosis with the appearance of apoptotic morphology and increase of apoptosis rate. Additionally, AlCl 3 treatment activated mitochondrial-mediated signaling pathway, accompanied by mitochondrial membrane potential (ΔΨm) depolarization, release of cytochrome c from the mitochondria to the cytoplasm, as well as survival signal-related factor caspase-9 and caspase-3 activation. AlCl 3 exposure also activated Fas/Fas ligand signaling pathway, presented as Fas, Fas ligand, and Fas-associated death domain expression enhancement and caspase-8 activation, as well as the hydrolysis of Bid to truncated Bid, suggesting that the Fas-mediated signaling pathway might aggravate mitochondria-mediated OB apoptosis through hydrolyzing Bid. Furthermore, AlCl 3 exposure inhibited Bcl-2 protein expression and increased the expressions of Bax, Bak, and Bim in varying degrees. These results indicated that AlCl 3 exposure induced OB apoptosis through activating Fas- and mitochondria-mediated signaling pathway and disrupted B-cell lymphoma-2 family proteins.

YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yi-Ting; Ding, Jing-Ya; Li, Ming-Yang

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 tomore » 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-overexpression phenotype in P19 cells. Black-Right-Pointing-Pointer Knockdown of Gli2 rescues the Yap-overexpression phenotype in cortical progenitors.« less

PepO, a CovRS-controlled endopeptidase, disrupts Streptococcus pyogenes quorum sensing.

PubMed

Wilkening, Reid V; Chang, Jennifer C; Federle, Michael J

2016-01-01

Group A Streptococcus (GAS, Streptococcus pyogenes) is a human-restricted pathogen with a capacity to both colonize asymptomatically and cause illnesses ranging from pharyngitis to necrotizing fasciitis. An understanding of how and when GAS switches between genetic programs governing these different lifestyles has remained an enduring mystery and likely requires carefully tuned environmental sensors to activate and silence genetic schemes when appropriate. Herein, we describe the relationship between the Control of Virulence (CovRS, CsrRS) two-component system and the Rgg2/3 quorum-sensing pathway. We demonstrate that responses of CovRS to the stress signals Mg(2+) and a fragment of the antimicrobial peptide LL-37 result in modulated activity of pheromone signaling of the Rgg2/3 pathway through a means of proteolysis of SHP peptide pheromones. This degradation is mediated by the cytoplasmic endopeptidase PepO, which is the first identified enzymatic silencer of an RRNPP-type quorum-sensing pathway. These results suggest that under conditions in which the virulence potential of GAS is elevated (i.e. enhanced virulence gene expression), cellular responses mediated by the Rgg2/3 pathway are abrogated and allow individuals to escape from group behavior. These results also indicate that Rgg2/3 signaling is instead functional during non-virulent GAS lifestyles. © 2015 John Wiley & Sons Ltd.

NetPath: a public resource of curated signal transduction pathways

PubMed Central

2010-01-01

We have developed NetPath as a resource of curated human signaling pathways. As an initial step, NetPath provides detailed maps of a number of immune signaling pathways, which include approximately 1,600 reactions annotated from the literature and more than 2,800 instances of transcriptionally regulated genes - all linked to over 5,500 published articles. We anticipate NetPath to become a consolidated resource for human signaling pathways that should enable systems biology approaches. PMID:20067622

Wnt signaling activates Shh signaling in early postnatal intervertebral discs, and re-activates Shh signaling in old discs in the mouse.

PubMed

Winkler, Tamara; Mahoney, Eric J; Sinner, Debora; Wylie, Christopher C; Dahia, Chitra Lekha

2014-01-01

Intervertebral discs (IVDs) are strong fibrocartilaginous joints that connect adjacent vertebrae of the spine. As discs age they become prone to failure, with neurological consequences that are often severe. Surgical repair of discs treats the result of the disease, which affects as many as one in seven people, rather than its cause. An ideal solution would be to repair degenerating discs using the mechanisms of their normal differentiation. However, these mechanisms are poorly understood. Using the mouse as a model, we previously showed that Shh signaling produced by nucleus pulposus cells activates the expression of differentiation markers, and cell proliferation, in the postnatal IVD. In the present study, we show that canonical Wnt signaling is required for the expression of Shh signaling targets in the IVD. We also show that Shh and canonical Wnt signaling pathways are down-regulated in adult IVDs. Furthermore, this down-regulation is reversible, since re-activation of the Wnt or Shh pathways in older discs can re-activate molecular markers of the IVD that are lost with age. These data suggest that biological treatments targeting Wnt and Shh signaling pathways may be feasible as a therapeutic for degenerative disc disease.

Alcohol resistance in Drosophila is modulated by the Toll innate immune pathway.

PubMed

Troutwine, B R; Ghezzi, A; Pietrzykowski, A Z; Atkinson, N S

2016-04-01

A growing body of evidence has shown that alcohol alters the activity of the innate immune system and that changes in innate immune system activity can influence alcohol-related behaviors. Here, we show that the Toll innate immune signaling pathway modulates the level of alcohol resistance in Drosophila. In humans, a low level of response to alcohol is correlated with increased risk of developing an alcohol use disorder. The Toll signaling pathway was originally discovered in, and has been extensively studied in Drosophila. The Toll pathway is a major regulator of innate immunity in Drosophila, and mammalian Toll-like receptor signaling has been implicated in alcohol responses. Here, we use Drosophila-specific genetic tools to test eight genes in the Toll signaling pathway for effects on the level of response to ethanol. We show that increasing the activity of the pathway increases ethanol resistance whereas decreasing the pathway activity reduces ethanol resistance. Furthermore, we show that gene products known to be outputs of innate immune signaling are rapidly induced following ethanol exposure. The interaction between the Toll signaling pathway and ethanol is rooted in the natural history of Drosophila melanogaster. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Emerging evidence on the role of the Hippo/YAP pathway in liver physiology and cancer.

PubMed

Yimlamai, Dean; Fowl, Brendan H; Camargo, Fernando D

2015-12-01

The Hippo pathway and its regulatory target, YAP, has recently emerged as an important biochemical signaling pathway that tightly governs epithelial tissue growth. Initially defined in Drosophilia, this pathway has shown remarkable conservation in vertebrate systems with many components of the Hippo/YAP pathway showing biochemical and functional conservation. The liver is particularly sensitive to changes in Hippo/YAP signaling with rapid increases in liver size becoming manifest on the order of days to weeks after perturbation. The first identified direct targets of Hippo/YAP signaling were pro-proliferative and anti-apoptotic gene programs, but recent work has now implicated this pathway in cell fate choice, stem cell maintenance/renewal, epithelial to mesenchymal transition, and oncogenesis. The mechanisms by which Hippo/YAP signaling is changed endogenously are beginning to come to light as well as how this pathway interacts with other signaling pathways, and important details for designing new therapeutic interventions. This review focuses on the known roles for Hippo/YAP signaling in the liver and promising avenues for future study. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

In Hyperthermia Increased ERK and WNT Signaling Suppress Colorectal Cancer Cell Growth

PubMed Central

Bordonaro, Michael; Shirasawa, Senji; Lazarova, Darina L.

2016-01-01

Although neoplastic cells exhibit relatively higher sensitivity to hyperthermia than normal cells, hyperthermia has had variable success as an anti-cancer therapy. This variable outcome might be due to the fact that cancer cells themselves have differential degrees of sensitivity to high temperature. We hypothesized that the varying sensitivity of colorectal cancer (CRC) cells to hyperthermia depends upon the differential induction of survival pathways. Screening of such pathways revealed that Extracellular Signal-Regulated Kinase (ERK) signaling is augmented by hyperthermia, and the extent of this modulation correlates with the mutation status of V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS). Through clonal growth assays, apoptotic analyses and transcription reporter assays of CRC cells that differ only in KRAS mutation status we established that mutant KRAS cells are more sensitive to hyperthermia, as they exhibit sustained ERK signaling hyperactivation and increased Wingless/Integrated (WNT)/beta-catenin signaling. We propose that whereas increased levels of WNT and ERK signaling and a positive feedback between the two pathways is a major obstacle in anti-cancer therapy today, under hyperthermia the hyperinduction of the pathways and their positive crosstalk contribute to CRC cell death. Ascertaining the causative association between types of mutations and hyperthermia sensitivity may allow for a mutation profile-guided application of hyperthermia as an anti-cancer therapy. Since KRAS and WNT signaling mutations are prevalent in CRC, our results suggest that hyperthermia-based therapy might benefit a significant number, but not all, CRC patients. PMID:27187477

Xtalk: a path-based approach for identifying crosstalk between signaling pathways

PubMed Central

Tegge, Allison N.; Sharp, Nicholas; Murali, T. M.

2016-01-01

Motivation: Cells communicate with their environment via signal transduction pathways. On occasion, the activation of one pathway can produce an effect downstream of another pathway, a phenomenon known as crosstalk. Existing computational methods to discover such pathway pairs rely on simple overlap statistics. Results: We present Xtalk, a path-based approach for identifying pairs of pathways that may crosstalk. Xtalk computes the statistical significance of the average length of multiple short paths that connect receptors in one pathway to the transcription factors in another. By design, Xtalk reports the precise interactions and mechanisms that support the identified crosstalk. We applied Xtalk to signaling pathways in the KEGG and NCI-PID databases. We manually curated a gold standard set of 132 crosstalking pathway pairs and a set of 140 pairs that did not crosstalk, for which Xtalk achieved an area under the receiver operator characteristic curve of 0.65, a 12% improvement over the closest competing approach. The area under the receiver operator characteristic curve varied with the pathway, suggesting that crosstalk should be evaluated on a pathway-by-pathway level. We also analyzed an extended set of 658 pathway pairs in KEGG and to a set of more than 7000 pathway pairs in NCI-PID. For the top-ranking pairs, we found substantial support in the literature (81% for KEGG and 78% for NCI-PID). We provide examples of networks computed by Xtalk that accurately recovered known mechanisms of crosstalk. Availability and implementation: The XTALK software is available at http://bioinformatics.cs.vt.edu/~murali/software. Crosstalk networks are available at http://graphspace.org/graphs?tags=2015-bioinformatics-xtalk. Contact: ategge@vt.edu, murali@cs.vt.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26400040

MicroRNA-30e promotes hepatocyte proliferation and inhibits apoptosis in cecal ligation and puncture-induced sepsis through the JAK/STAT signaling pathway by binding to FOSL2.

PubMed

Ling, Lan; Zhang, Shan-Hong; Zhi, Li-Da; Li, Hong; Wen, Qian-Kuan; Li, Gang; Zhang, Wen-Jia

2018-05-19

Hepatocyte proliferation and apoptosis are critical cellular behaviors in rat liver as a result of a liver injury. Herein, we performed this study in order to evaluate the role of miR-30e and its target Fos-Related Antigen-2 (FOSL2) in septic rats through the JAK/STAT signaling pathway. Rat models of sepsis were induced by cecal ligation and puncture. Enzyme-linked immunosorbent assay (ELISA) was performed to access serum levels of lipopolysaccharide (LPS), inflammatory factors, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) to confirm the successful establishment of the model. The hepatocytes were subject to miR-30e mimics, miR-30e inhibitors or siRNA-FOSL2. The expressions of miR-30e, FOSL2, apoptosis- and, JAK/STAT signaling pathway-related genes in liver tissues and hepatocytes were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. MTT assay and flow cytometry were performed to evaluate hepatocyte viability and apoptosis, respectively. The results obtained revealed that in the septic rats, serum levels of inflammatory factors, LPS, ALT and AST, as well as the expression of FOSL2 were elevated and the JAK/STAT signaling pathway was activated, while there was a reduction in the expression of miR-30e. An initial bioinformatics prediction followed by a confirmatory dual-luciferase reporter assay determined that miR-30e targeted and negatively regulated FOSL2 expression. MiR-30e inhibited the activation of JSK2/STAT3 signaling pathway by reducing FOSL2 expression, while miR-30e enhanced hepatocyte proliferation and decreased hepatocyte cell apoptosis in septic rats. These findings indicated that miR-30e may serve as an independent therapeutic target for sepsis, due to its ability to inhibit apoptosis and induce proliferation of hepatocytes by targeted inhibition of FOSL2 through the JAK/STAT signaling pathway. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Hippo Pathway: An Emerging Regulator of Craniofacial and Dental Development.

PubMed

Wang, J; Martin, J F

2017-10-01

The evolutionarily conserved Hippo signaling pathway is a vital regulator of organ size that fine-tunes cell proliferation, apoptosis, and differentiation. A number of important studies have revealed critical roles of Hippo signaling and its effectors Yap (Yes-associated protein) and Taz (transcriptional coactivator with PDZ binding motif) in tissue development, homeostasis, and regeneration, as well as in tumorigenesis. In addition, recent studies have shown evidence of crosstalk between the Hippo pathway and other key signaling pathways, such as Wnt signaling, that not only regulates developmental processes but also contributes to disease pathogenesis. In this review, we summarize the major discoveries in the field of Hippo signaling and what has been learned about its regulation and crosstalk with other signaling pathways, with a particular focus on recent findings involving the Hippo-Yap pathway in craniofacial and tooth development. New and exciting studies of the Hippo pathway are anticipated that will significantly improve our understanding of the molecular mechanisms of human craniofacial and tooth development and disease and will ultimately lead to the development of new therapies.

Endophyte-host cross talk as a signaling determinant for grass mutualisms: Presumptive evidence

USDA-ARS?s Scientific Manuscript database

The general term crosstalk is used to describe interactive signaling pathways that are operationally defined, usually at the molecular or genetic level, without regards to negative or positive results. However, this term has evolved to indicate studies of signaling between components of different p...

Resveratrol inhibits LPS-induced mice mastitis through attenuating the MAPK and NF-κB signaling pathway.

PubMed

Zhang, Xu; Wang, Yanan; Xiao, Chong; Wei, Zhengkai; Wang, Jingjing; Yang, Zhengtao; Fu, Yunhe

2017-06-01

Resveratrol is a natural polyphenol extracted from mangy plants. It has been reported that resveratrol show multitudinous positive role in biology such as anti-oxidant, anti-nociception and anti-inflammatory effects. Therefore, the present study devotes to test the effect of resveratrol on LPS-induced mastitis in mice. Resveratrol was administered intraperitoneally 1 h before LPS treatment. And the anti-inflammatory effect of resveratrol was measured by histopathological examination, MPO assay, real-time PCR and western blotting analysis. The results showed that resveratrol significantly reduced the LPS-induced mammary histopathological changes. Meanwhile, it sharply attenuated the activity of MPO. The result also indicated that the resveratrol can decrease the expression of pro-inflammatory cytokines TNF-α and IL-1β. From the results of western blotting, resveratrol suppressed the expression of phosphorylation of p65 and IκB from NF-κB signal pathway and phosphorylation of p38 and ERK from MAPK signal pathway. These findings suggested that resveratrol may inhibit the inflammatory response in the mastitis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Down-regulation of Notch signaling pathway reverses the Th1/Th2 imbalance in tuberculosis patients.

PubMed

Li, Qifeng; Zhang, Hui; Yu, Liang; Wu, Chao; Luo, Xinhui; Sun, He; Ding, Jianbing

2018-01-01

Th1/Th2 imbalance to Th2 is of significance in the peripheral immune responses in Tuberculosis (TB) development. However, the mechanisms for Th1/Th2 imbalance are still not well determined. Notch signaling pathway is involved in the peripheral T cell activation and effector cell differentiation. However, whether it affects Th1/Th2 imbalance in TB patients is still not known. Here, we used γ-secretase inhibitor (DAPT) to treat the peripheral blood mononuclear cells (PBMCs) from healthy people or individuals with latent or active TB infection in vitro, respectively. Then, the Th1/Th2 ratios were determined by flow cytometry, and cytokines of IFN-γ, IL-4, IL-10 in the culture supernatant were measured by CBA method. The Notch signal pathway associated proteins Hes1, GATA3 and T-bet were quantitated by real-time PCR or immunoblotting. Our results showed that DAPT effectively inhibited the protein level of Hes1. In TB patients, the Th2 ratio increased in the PBMCs, alone with the high expression of GATA3 and IL-4, resulting in the high ratios of Th2/Th1 and GATA3/T-bet in TB patients. However, Th2 cells ratio decreased after blocking the Notch signaling pathway by DAPT and the Th2/Th1 ratio in TB patients were DAPT dose-dependent, accompanied by the decrease of IL-4 and GATA3. But, its influence on Th1 ratio and Th1 related T-bet and IFN-γ levels were not significant. In conclusion, our results suggest that blocking Notch signaling by DAPT could inhibit Th2 responses and restore Th1/Th2 imbalance in TB patients. Copyright © 2017. Published by Elsevier B.V.

The roles of DNA damage-dependent signals and MAPK cascades in tributyltin-induced germline apoptosis in Caenorhabditis elegans.

PubMed

Wang, Yun; Wang, Shunchang; Luo, Xun; Yang, Yanan; Jian, Fenglei; Wang, Xuemin; Xie, Lucheng

2014-08-01

The induction of apoptosis is recognized to be a major mechanism of tributyltin (TBT) toxicity. However, the underlying signaling pathways for TBT-induced apoptosis remain unclear. In this study, using the nematode Caenorhabditis elegans, we examined whether DNA damage response (DDR) pathway and mitogen-activated protein kinase (MAPK) signaling cascades are involved in TBT-induced germline apoptosis and cell cycle arrest. Our results demonstrated that exposing worms to TBT at the dose of 10nM for 6h significantly increased germline apoptosis in N2 strain. Germline apoptosis was absent in strains that carried ced-3 or ced-4 loss-of-function alleles, indicating that both caspase protein CED-3 and Apaf-1 protein CED-4 were required for TBT-induced apoptosis. TBT-induced apoptosis was blocked in the Bcl-2 gain-of-function strain ced-9(n1950), whereas TBT induced a minor increase in the BH3-only protein EGL-1 mutated strain egl-1(n1084n3082). Checkpoint proteins HUS-1 and CLK-2 exerted proapoptotic effects, and the null mutation of cep-1, the homologue of tumor suppressor gene p53, significantly inhibited TBT-induced apoptosis. Apoptosis in the loss-of-function strains of ERK, JNK and p38 MAPK signaling pathways were completely or mildly suppressed under TBT stress. These results were supported by the results of mRNA expression levels of corresponding genes. The present study indicated that TBT-induced apoptosis required the core apoptotic machinery, and that DDR genes and MAPK pathways played essential roles in signaling the processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Regulation of Hippo signalling by p38 signalling

PubMed Central

Huang, Dashun; Li, Xiaojiao; Sun, Li; Huang, Ping; Ying, Hao; Wang, Hui; Wu, Jiarui; Song, Haiyun

2016-01-01

The Hippo signalling pathway has a crucial role in growth control during development, and its dysregulation contributes to tumorigenesis. Recent studies uncover multiple upstream regulatory inputs into Hippo signalling, which affects phosphorylation of the transcriptional coactivator Yki/YAP/TAZ by Wts/Lats. Here we identify the p38 mitogen-activated protein kinase (MAPK) pathway as a new upstream branch of the Hippo pathway. In Drosophila, overexpression of MAPKK gene licorne (lic), or MAPKKK gene Mekk1, promotes Yki activity and induces Hippo target gene expression. Loss-of-function studies show that lic regulates Hippo signalling in ovary follicle cells and in the wing disc. Epistasis analysis indicates that Mekk1 and lic affect Hippo signalling via p38b and wts. We further demonstrate that the Mekk1-Lic-p38b cascade inhibits Hippo signalling by promoting F-actin accumulation and Jub phosphorylation. In addition, p38 signalling modulates actin filaments and Hippo signalling in parallel to small GTPases Ras, Rac1, and Rho1. Lastly, we show that p38 signalling regulates Hippo signalling in mammalian cell lines. The Lic homologue MKK3 promotes nuclear localization of YAP via the actin cytoskeleton. Upregulation or downregulation of the p38 pathway regulates YAP-mediated transcription. Our work thus reveals a conserved crosstalk between the p38 MAPK pathway and the Hippo pathway in growth regulation. PMID:27402810

Involvement of zebrafish RIG-I in NF-κB and IFN signaling pathways: insights into functional conservation of RIG-I in antiviral innate immunity.

PubMed

Nie, Li; Zhang, Ying-sheng; Dong, Wei-ren; Xiang, Li-xin; Shao, Jian-zhong

2015-01-01

The retinoic acid-inducible gene I (RIG-I) is a critical sensor for host recognition of RNA virus infection and initiation of antiviral signaling pathways in mammals. However, data on the occurrence and functions of this molecule in lower vertebrates are limited. In this study, we characterized an RIG-I homolog (DrRIG-I) from zebrafish. Structurally, this DrRIG-I shares a number of conserved functional domains/motifs with its mammalian counterparts, namely, caspase activation and recruitment domain, DExD/H box, a helicase domain, and a C-terminal domain. Functionally, stimulation with DrRIG-I CARD in zebrafish embryos significantly activated the NF-κB and IFN signaling pathways, leading to the expression of TNF-α, IL-8 and IFN-induced Mx, ISG15, and viperin. However, knockdown of TRIM25 (a pivotal activator for RIG-I receptors) significantly suppressed the induced activation of IFN signaling. Results suggested the functional conservation of RIG-I receptors in the NF-κB and IFN signaling pathways between teleosts and mammals, providing a perspective into the evolutionary history of RIG-I-mediated antiviral innate immunity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Neural computational modeling reveals a major role of corticospinal gating of central oscillations in the generation of essential tremor.

PubMed

Qu, Hong-En; Niu, Chuanxin M; Li, Si; Hao, Man-Zhao; Hu, Zi-Xiang; Xie, Qing; Lan, Ning

2017-12-01

Essential tremor, also referred to as familial tremor, is an autosomal dominant genetic disease and the most common movement disorder. It typically involves a postural and motor tremor of the hands, head or other part of the body. Essential tremor is driven by a central oscillation signal in the brain. However, the corticospinal mechanisms involved in the generation of essential tremor are unclear. Therefore, in this study, we used a neural computational model that includes both monosynaptic and multisynaptic corticospinal pathways interacting with a propriospinal neuronal network. A virtual arm model is driven by the central oscillation signal to simulate tremor activity behavior. Cortical descending commands are classified as alpha or gamma through monosynaptic or multisynaptic corticospinal pathways, which converge respectively on alpha or gamma motoneurons in the spinal cord. Several scenarios are evaluated based on the central oscillation signal passing down to the spinal motoneurons via each descending pathway. The simulated behaviors are compared with clinical essential tremor characteristics to identify the corticospinal pathways responsible for transmitting the central oscillation signal. A propriospinal neuron with strong cortical inhibition performs a gating function in the generation of essential tremor. Our results indicate that the propriospinal neuronal network is essential for relaying the central oscillation signal and the production of essential tremor.

Naringin Stimulates Osteogenic Differentiation of Rat Bone Marrow Stromal Cells via Activation of the Notch Signaling Pathway

PubMed Central

Yu, Guo-yong; Zheng, Gui-zhou; Chang, Bo; Hu, Qin-xiao; Lin, Fei-xiang; Liu, De-zhong; Wu, Chu-cheng; Du, Shi-xin

2016-01-01

Naringin is a major flavonoid found in grapefruit and is an active compound extracted from the Chinese herbal medicine Rhizoma Drynariae. Naringin is a potent stimulator of osteogenic differentiation and has potential application in preventing bone loss. However, the signaling pathway underlying its osteogenic effect remains unclear. We hypothesized that the osteogenic activity of naringin involves the Notch signaling pathway. Rat bone marrow stromal cells (BMSCs) were cultured in osteogenic medium containing-naringin, with or without DAPT (an inhibitor of Notch signaling), the effects on ALP activity, calcium deposits, osteogenic genes (ALP, BSP, and cbfa1), adipogenic maker gene PPARγ2 levels, and Notch expression were examined. We found that naringin dose-dependently increased ALP activity and Alizarin red S staining, and treatment at the optimal concentration (50 μg/mL) increased mRNA levels of osteogenic genes and Notch1 expression, while decreasing PPARγ2 mRNA levels. Furthermore, treatment with DAPT partly reversed effects of naringin on BMSCs, as judged by decreases in naringin-induced ALP activity, calcium deposits, and osteogenic genes expression, as well as upregulation of PPARγ2 mRNA levels. These results suggest that the osteogenic effect of naringin partly involves the Notch signaling pathway. PMID:27069482

ECSIT links TLR and BMP signaling in FOP connective tissue progenitor cells.

PubMed

Wang, Haitao; Behrens, Edward M; Pignolo, Robert J; Kaplan, Frederick S

2018-04-01

Clinical and laboratory observations strongly suggest that the innate immune system induces flare-ups in the setting of dysregulated bone morphogenetic protein (BMP) signaling in fibrodysplasia ossificans progressiva (FOP). In order to investigate the signaling substrates of this hypothesis, we examined toll-like receptor (TLR) activation and bone morphogenetic protein (BMP) signaling in connective tissue progenitor cells (CTPCs) from FOP patients and unaffected individuals. We found that inflammatory stimuli broadly activate TLR expression in FOP CTPCs and that TLR3/TLR4 signaling amplifies BMP pathway signaling through both ligand dependent and independent mechanisms. Importantly, Evolutionarily Conserved Signaling Intermediate in the Toll Pathway (ECSIT) integrates TLR injury signaling with dysregulated BMP pathway signaling in FOP CTPCs. These findings provide novel insight into the cell autonomous integration of injury signals from the innate immune system with dysregulated response signals from the BMP signaling pathway and provide new exploratory targets for therapeutic approaches to blocking the induction and amplification of FOP lesions. Copyright © 2018 Elsevier Inc. All rights reserved.

Petri net-based method for the analysis of the dynamics of signal propagation in signaling pathways.

PubMed

Hardy, Simon; Robillard, Pierre N

2008-01-15

Cellular signaling networks are dynamic systems that propagate and process information, and, ultimately, cause phenotypical responses. Understanding the circuitry of the information flow in cells is one of the keys to understanding complex cellular processes. The development of computational quantitative models is a promising avenue for attaining this goal. Not only does the analysis of the simulation data based on the concentration variations of biological compounds yields information about systemic state changes, but it is also very helpful for obtaining information about the dynamics of signal propagation. This article introduces a new method for analyzing the dynamics of signal propagation in signaling pathways using Petri net theory. The method is demonstrated with the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) regulation network. The results constitute temporal information about signal propagation in the network, a simplified graphical representation of the network and of the signal propagation dynamics and a characterization of some signaling routes as regulation motifs.

Essential Role of Protein-tyrosine Phosphatase 1B in the Modulation of Insulin Signaling by Acetaminophen in Hepatocytes*

PubMed Central

Mobasher, Maysa Ahmed; de Toro-Martín, Juan; González-Rodríguez, Águeda; Ramos, Sonia; Letzig, Lynda G.; James, Laura P.; Muntané, Jordi; Álvarez, Carmen; Valverde, Ángela M.

2014-01-01

Many drugs are associated with the development of glucose intolerance or deterioration in glycemic control in patients with pre-existing diabetes. We have evaluated the cross-talk between signaling pathways activated by acetaminophen (APAP) and insulin signaling in hepatocytes with or without expression of the protein-tyrosine phosphatase 1B (PTP1B) and in wild-type and PTP1B-deficient mice chronically treated with APAP. Human primary hepatocytes, Huh7 hepatoma cells with silenced PTP1B, mouse hepatocytes from wild-type and PTP1B-deficient mice, and a mouse model of chronic APAP treatment were used to examine the mechanisms involving PTP1B in the effects of APAP on glucose homeostasis and hepatic insulin signaling. In APAP-treated human hepatocytes at concentrations that did not induce death, phosphorylation of JNK and PTP1B expression and enzymatic activity were increased. APAP pretreatment inhibited activation of the early steps of insulin signaling and decreased Akt phosphorylation. The effects of APAP in insulin signaling were prevented by suramin, a PTP1B inhibitor, or rosiglitazone that decreased PTP1B levels. Likewise, PTP1B deficiency in human or mouse hepatocytes protected against APAP-mediated impairment in insulin signaling. These signaling pathways were modulated in mice with chronic APAP treatment, resulting in protection against APAP-mediated hepatic insulin resistance and alterations in islet alpha/beta cell ratio in PTP1B−/− mice. Our results demonstrate negative cross-talk between signaling pathways triggered by APAP and insulin signaling in hepatocytes, which is in part mediated by PTP1B. Moreover, our in vivo data suggest that chronic use of APAP may be associated with insulin resistance in the liver. PMID:25204659

E4orf1 induction in adipose tissue promotes insulin-independent signaling in the adipocyte.

PubMed

Kusminski, Christine M; Gallardo-Montejano, Violeta I; Wang, Zhao V; Hegde, Vijay; Bickel, Perry E; Dhurandhar, Nikhil V; Scherer, Philipp E

2015-10-01

Type 2 diabetes remains a worldwide epidemic with major pathophysiological changes as a result of chronic insulin resistance. Insulin regulates numerous biochemical pathways related to carbohydrate and lipid metabolism. We have generated a novel mouse model that allows us to constitutively activate, in an inducible fashion, the distal branch of the insulin signaling transduction pathway specifically in adipocytes. Using the adenoviral 36 E4orf1 protein, we chronically stimulate locally the Ras-ERK-MAPK signaling pathway. At the whole body level, this leads to reduced body-weight gain under a high fat diet challenge. Despite overlapping glucose tolerance curves, there is a reduced requirement for insulin action under these conditions. The mice further exhibit reduced circulating adiponectin levels that ultimately lead to impaired lipid clearance, and inflamed and fibrotic white adipose tissues. Nevertheless, they are protected from diet-induced hepatic steatosis. As we observe constitutively elevated p-Akt levels in the adipocytes, even under conditions of low insulin levels, this pinpoints enhanced Ras-ERK-MAPK signaling in transgenic adipocytes as a potential alternative route to bypass proximal insulin signaling events. We conclude that E4orf1 expression in the adipocyte leads to enhanced baseline activation of the distal insulin signaling node, yet impaired insulin receptor stimulation in the presence of insulin, with important implications for the regulation of adiponectin secretion. The resulting systemic phenotype is complex, yet highlights the powerful nature of manipulating selective branches of the insulin signaling network within the adipocyte.

Influence of Acute and Chronic Exercise on Glucose Uptake

PubMed Central

Röhling, Martin; Herder, Christian; Stemper, Theodor; Müssig, Karsten

2016-01-01

Insulin resistance plays a key role in the development of type 2 diabetes. It arises from a combination of genetic predisposition and environmental and lifestyle factors including lack of physical exercise and poor nutrition habits. The increased risk of type 2 diabetes is molecularly based on defects in insulin signaling, insulin secretion, and inflammation. The present review aims to give an overview on the molecular mechanisms underlying the uptake of glucose and related signaling pathways after acute and chronic exercise. Physical exercise, as crucial part in the prevention and treatment of diabetes, has marked acute and chronic effects on glucose disposal and related inflammatory signaling pathways. Exercise can stimulate molecular signaling pathways leading to glucose transport into the cell. Furthermore, physical exercise has the potential to modulate inflammatory processes by affecting specific inflammatory signaling pathways which can interfere with signaling pathways of the glucose uptake. The intensity of physical training appears to be the primary determinant of the degree of metabolic improvement modulating the molecular signaling pathways in a dose-response pattern, whereas training modality seems to have a secondary role. PMID:27069930

Whole-Exome Sequencing to Identify Novel Biological Pathways Associated With Infertility After Pelvic Inflammatory Disease.

PubMed

Taylor, Brandie D; Zheng, Xiaojing; Darville, Toni; Zhong, Wujuan; Konganti, Kranti; Abiodun-Ojo, Olayinka; Ness, Roberta B; O'Connell, Catherine M; Haggerty, Catherine L

2017-01-01

Ideal management of sexually transmitted infections (STI) may require risk markers for pathology or vaccine development. Previously, we identified common genetic variants associated with chlamydial pelvic inflammatory disease (PID) and reduced fecundity. As this explains only a proportion of the long-term morbidity risk, we used whole-exome sequencing to identify biological pathways that may be associated with STI-related infertility. We obtained stored DNA from 43 non-Hispanic black women with PID from the PID Evaluation and Clinical Health Study. Infertility was assessed at a mean of 84 months. Principal component analysis revealed no population stratification. Potential covariates did not significantly differ between groups. Sequencing kernel association test was used to examine associations between aggregates of variants on a single gene and infertility. The results from the sequencing kernel association test were used to choose "focus genes" (P < 0.01; n = 150) for subsequent Ingenuity Pathway Analysis to identify "gene sets" that are enriched in biologically relevant pathways. Pathway analysis revealed that focus genes were enriched in canonical pathways including, IL-1 signaling, P2Y purinergic receptor signaling, and bone morphogenic protein signaling. Focus genes were enriched in pathways that impact innate and adaptive immunity, protein kinase A activity, cellular growth, and DNA repair. These may alter host resistance or immunopathology after infection. Targeted sequencing of biological pathways identified in this study may provide insight into STI-related infertility.

An integrated analysis of genes and functional pathways for aggression in human and rodent models.

PubMed

Zhang-James, Yanli; Fernàndez-Castillo, Noèlia; Hess, Jonathan L; Malki, Karim; Glatt, Stephen J; Cormand, Bru; Faraone, Stephen V

2018-06-01

Human genome-wide association studies (GWAS), transcriptome analyses of animal models, and candidate gene studies have advanced our understanding of the genetic architecture of aggressive behaviors. However, each of these methods presents unique limitations. To generate a more confident and comprehensive view of the complex genetics underlying aggression, we undertook an integrated, cross-species approach. We focused on human and rodent models to derive eight gene lists from three main categories of genetic evidence: two sets of genes identified in GWAS studies, four sets implicated by transcriptome-wide studies of rodent models, and two sets of genes with causal evidence from online Mendelian inheritance in man (OMIM) and knockout (KO) mice reports. These gene sets were evaluated for overlap and pathway enrichment to extract their similarities and differences. We identified enriched common pathways such as the G-protein coupled receptor (GPCR) signaling pathway, axon guidance, reelin signaling in neurons, and ERK/MAPK signaling. Also, individual genes were ranked based on their cumulative weights to quantify their importance as risk factors for aggressive behavior, which resulted in 40 top-ranked and highly interconnected genes. The results of our cross-species and integrated approach provide insights into the genetic etiology of aggression.

Roles of MAPK pathway activation during cytokine induction in BEAS-2B cells exposed to fine World Trade Center (WTC) dust.

PubMed

Wang, Shang; Prophete, Colette; Soukup, Joleen M; Chen, Lung-Chi; Costa, Max; Ghio, Andrew; Qu, Qingshan; Cohen, Mitchell D; Chen, Haobin

2010-01-01

The World Trade Center (WTC) collapse on September 11, 2001 released copious amounts of particulate matter (PM) into the atmosphere of New York City. Follow-up studies on persons exposed to the dusts have revealed a severely increased rate for asthma and other respiratory illnesses. There have only been a few studies that have sought to discern the possible mechanisms underlying these untoward pathologies. In one study, an increased cytokine release was detected in cells exposed to WTC fine dusts (PM₂.₅ fraction or WTC₂.₅). However, the mechanism(s) for these increases has yet to be fully defined. Because activation of the mitogen-activated protein kinase (MAPK) signaling pathways is known to cause cytokine induction, the current study was undertaken to analyze the possible involvement of these pathways in any increased cytokine formation by lung epithelial cells (as BEAS-2B cells) exposed to WTC₂.₅. Our results showed that exposure to WTC₂.₅ for 5 hr increased interleukin-6 (IL-6) mRNA expression in BEAS-2B cells, as well as its protein levels in the culture media, in a dose-dependent manner. Besides IL-6, cytokine multiplex analyses revealed that formation of IL-8 and -10 was also elevated by the exposure. Both extracellular signal-regulated kinase (ERK) and p38, but not c-Jun N-terminal protein kinase, signaling pathways were found to be activated in cells exposed to WTC₂.₅. Inactivation of ERK signaling pathways by PD98059 effectively blocked IL-6, -8, and -10 induction by WTC₂.₅; the p38 kinase inhibitor SB203580 significantly decreased induction of IL-8 and -10. Together, our data demonstrated activation of MAPK signaling pathway(s) likely played an important role in the WTC₂.₅-induced formation of several inflammatory (and, subsequently, anti-inflammatory) cytokines. The results are important in that they help to define one mechanism via which the WTC dusts may have acted to cause the documented increases in asthma and other inflammation-associated respiratory dysfunctions in the individuals exposed to the dusts released from the WTC collapse.

Intercellular signaling pathways active during intervertebral disc growth, differentiation, and aging.

PubMed

Dahia, Chitra Lekha; Mahoney, Eric J; Durrani, Atiq A; Wylie, Christopher

2009-03-01

Intervertebral discs at different postnatal ages were assessed for active intercellular signaling pathways. To generate a spatial and temporal map of the signaling pathways active in the postnatal intervertebral disc (IVD). The postnatal IVD is a complex structure, consisting of 3 histologically distinct components, the nucleus pulposus, fibrous anulus fibrosus, and endplate. These differentiate and grow during the first 9 weeks of age in the mouse. Identification of the major signaling pathways active during and after the growth and differentiation period will allow functional analysis using mouse genetics and identify targets for therapy for individual components of the disc. Antibodies specific for individual cell signaling pathways were used on cryostat sections of IVD at different postnatal ages to identify which components of the IVD were responding to major classes of intercellular signal, including sonic hedgehog, Wnt, TGFbeta, FGF, and BMPs. We present a spatial/temporal map of these signaling pathways during growth, differentiation, and aging of the disc. During growth and differentiation of the disc, its different components respond at different times to different intercellular signaling ligands. Most of these are dramatically downregulated at the end of disc growth.

Design, synthesis, and evaluation of asymmetric EF24 analogues as potential anti-cancer agents for lung cancer.

PubMed

Wu, Jianzhang; Wu, Shoubiao; Shi, Lingyi; Zhang, Shanshan; Ren, Jiye; Yao, Song; Yun, Di; Huang, Lili; Wang, Jiabing; Li, Wulan; Wu, Xiaoping; Qiu, Peihong; Liang, Guang

2017-01-05

The nuclear factor-kappa B (NF-κB) signaling pathway has been targeted for the therapy of various cancers, including lung cancer. EF24 was considered as a potent inhibitor of NF-κB signaling pathway. In this study, a series of asymmetric EF24 analogues were synthesized and evaluated for their anti-cancer activity against three lung cancer cell lines (A549, LLC, H1650). Most of the compounds exhibited good anti-tumor activity. Among them, compound 81 showed greater cytotoxicity than EF24. Compound 81 also possessed a potent anti-migration and anti-proliferative ability against A549 cells in a concentration-dependent manner. Moreover, compound 81 induced lung cancer cells death by inhibiting NF-κB signaling pathway, and activated the JNK-mitochondrial apoptotic pathway by increasing reactive oxygen species (ROS) generation resulting in apoptosis. In summary, compound 81 is a valuable candidate for anti-lung cancer therapy. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Coordinate responses to alkaline pH stress in budding yeast

PubMed Central

Serra-Cardona, Albert; Canadell, David; Ariño, Joaquín

2015-01-01

Alkalinization of the medium represents a stress condition for the budding yeast Saccharomyces cerevisiae to which this organism responds with profound remodeling of gene expression. This is the result of the modulation of a substantial number of signaling pathways whose participation in the alkaline response has been elucidated within the last ten years. These regulatory inputs involve not only the conserved Rim101/PacC pathway, but also the calcium-activated phosphatase calcineurin, the Wsc1-Pkc1-Slt2 MAP kinase, the Snf1 and PKA kinases and oxidative stress-response pathways. The uptake of many nutrients is perturbed by alkalinization of the environment and, consequently, an impact on phosphate, iron/copper and glucose homeostatic mechanisms can also be observed. The analysis of available data highlights cases in which diverse signaling pathways are integrated in the gene promoter to shape the appropriate response pattern. Thus, the expression of different genes sharing the same signaling network can be coordinated, allowing functional coupling of their gene products. PMID:28357292

Activation of the RLR/MAVS Signaling Pathway by the L Protein of Mopeia Virus

PubMed Central

Zhang, Lei-Ke; Xin, Qi-Lin; Zhu, Sheng-Lin; Wan, Wei-Wei; Wang, Wei

2016-01-01

ABSTRACT The family Arenaviridae includes several important human pathogens that can cause severe hemorrhagic fever and greatly threaten public health. As a major component of the innate immune system, the RLR/MAVS signaling pathway is involved in recognizing viral components and initiating antiviral activity. It has been reported that arenavirus infection can suppress the innate immune response, and NP and Z proteins of pathogenic arenaviruses can disrupt RLR/MAVS signaling, thus inhibiting production of type I interferon (IFN-I). However, recent studies have shown elevated IFN-I levels in certain arenavirus-infected cells. The mechanism by which arenavirus infection induces IFN-I responses remains unclear. In this study, we determined that the L polymerase (Lp) of Mopeia virus (MOPV), an Old World (OW) arenavirus, can activate the RLR/MAVS pathway and thus induce the production of IFN-I. This activation is associated with the RNA-dependent RNA polymerase activity of Lp. This study provides a foundation for further studies of interactions between arenaviruses and the innate immune system and for the elucidation of arenavirus pathogenesis. IMPORTANCE Distinct innate immune responses are observed when hosts are infected with different arenaviruses. It has been widely accepted that NP and certain Z proteins of arenaviruses inhibit the RLR/MAVS signaling pathway. The viral components responsible for the activation of the RLR/MAVS signaling pathway remain to be determined. In the current study, we demonstrate for the first time that the Lp of MOPV, an OW arenavirus, can activate the RLR/MAVS signaling pathway and thus induce the production of IFN-I. Based on our results, we proposed that dynamic interactions exist among Lp-produced RNA, NP, and the RLR/MAVS signaling pathway, and the outcome of these interactions may determine the final IFN-I response pattern: elevated or reduced. Our study provides a possible explanation for how IFN-I can become activated during arenavirus infection and may help us gain insights into the interactions that form between different arenavirus components and the innate immune system. PMID:27605671

SMAD4 feedback regulates the canonical TGF-β signaling pathway to control granulosa cell apoptosis.

PubMed

Du, Xing; Pan, Zengxiang; Li, Qiqi; Liu, Honglin; Li, Qifa

2018-02-02

Canonical TGF-β signals are transduced from the cell surface to the cytoplasm, and then translocated into the nucleus, a process that involves ligands (TGF-β1), receptors (TGFBR2/1), receptor-activated SMADs (SMAD2/3), and the common SMAD (SMAD4). Here we provide evidence that SMAD4, a core component of the canonical TGF-β signaling pathway, regulates the canonical TGF-β signaling pathway in porcine granulosa cells (GCs) through a feedback mechanism. Genome-wide analysis and qRT-PCR revealed that SMAD4 affected miRNA biogenesis in GCs. Interestingly, TGFBR2, the type II receptor of the canonical TGF-β signaling pathway, was downregulated in SMAD4-silenced GCs and found to be a common target of SMAD4-inhibited miRNAs. miR-425, the most significantly elevated miRNA in SMAD4-silenced GCs, mediated the SMAD4 feedback regulation of the TGF-β signaling pathway. This was accomplished through a direct interaction between the transcription factor SMAD4 and the miR-425 promoter, and a direct interaction between miR-425 and the TGFBR2 3'-UTR. Furthermore, miR-425 enhanced GC apoptosis by targeting TGFBR2 and the canonical TGF-β signaling pathway, which was rescued by SMAD4 and TGF-β1. Overall, our findings demonstrate that a positive feedback mechanism exists within the canonical TGF-β signaling pathway. This study also provides new insights into mechanism underlying the canonical TGF-β signaling pathway, which regulates GC function and follicular development.

Levodopa/Benserazide Loaded Microspheres Alleviate L-dopa Induced Dyskinesia through Preventing the Over-Expression of D1R/Shp-2/ERK1/2 Signaling Pathway in a Rat Model of Parkinson's Disease

PubMed Central

Wan, Ying; Wu, Na; Song, Lu; Wang, Xijin; Liu, Zhenguo; Yuan, Weien; Gan, Jing

2017-01-01

Background: The long-term intermittent Levodopa (L-dopa) stimulation contributes to an aberrant activation of D1 receptor (D1R) mediated extracellular signal-regulated kinases1/2 (ERK1/2) in the striatal medium spiny neurons, resulting in the occurrence of L-dopa induced dyskinesia (LID). Recently, a novel signaling pathway, D1R/Shp-2/ERK1/2, was proposed to be required for the occurrence of LID. Here we designed the study in which two different methods of L-dopa delivery [continuous dopamine stimulation (CDS) vs. intermittent dopamine stimulation] were used to further identify: (1) the role of D1R/Shp-2/ERK1/2 signaling pathway in the occurrence of LID; (2) whether CDS alleviated LID though preventing the over-expression of the D1R/Shp-2/ERK1/2 signaling pathway. Methods: 6-OHDA-lesioned rat models of Parkinson's disease (PD) were randomly divided into two groups to receive intermittent L-dopa stimulation (L-dopa/benserazide standard group, LS group) or CDS (L-dopa/benserazide loaded microspheres, LBM group) for 21 days. Dyskinesia and anti-parkinsonian effect were compared between the two groups through the AIMs assessment and cylinder test. The critical protein changes in the D1R/Shp-2/ERK1/2 signaling pathway were compared between the two groups through Western blotting. Results: Intermittent L-dopa administration induced serious dyskinetic movements in the 6-OHDA-lesioned rats, and the anti-parkinsonian effect of L-dopa was gradually counteracted by the occurrence of dyskinesia. Intermittent L-dopa administration enhanced the expression of membrane D1R, and induced a robust increase of phosphorylation of Shp-2, Src, DARPP-32, and ERK1/2 in the 6-OHDA-lesioned striatum. In contrast, CDS played a dose-dependent anti-parkinsonian role, without inducing such apparent dyskinetic movements. Moreover, CDS induced no change of membrane D1R expression or phosphorylation of Shp-2, Src, DARPP-32, and ERK1/2 in the 6-OHDA-lesioned striatum. Conclusion: The aberrant activation of D1R/Shp-2 complex was evidenced to be required for the D1R mediating ERK1/2 phosphorylation and the occurrence of LID. CDS effectively prevented the overexpression of D1R/Shp-2/ERK1/2 signaling pathway, resulting in the reduction of LID in 6-OHDA-lesioned rats model of PD. PMID:29093677

The MST/Hippo Pathway and Cell Death: A Non-Canonical Affair

PubMed Central

Fallahi, Emma; O’Driscoll, Niamh A.; Matallanas, David

2016-01-01

The MST/Hippo signalling pathway was first described over a decade ago in Drosophila melanogaster and the core of the pathway is evolutionary conserved in mammals. The mammalian MST/Hippo pathway regulates organ size, cell proliferation and cell death. In addition, it has been shown to play a central role in the regulation of cellular homeostasis and it is commonly deregulated in human tumours. The delineation of the canonical pathway resembles the behaviour of the Hippo pathway in the fly where the activation of the core kinases of the pathway prevents the proliferative signal mediated by the key effector of the pathway YAP. Nevertheless, several lines of evidence support the idea that the mammalian MST/Hippo pathway has acquired new features during evolution, including different regulators and effectors, crosstalk with other essential signalling pathways involved in cellular homeostasis and the ability to actively trigger cell death. Here we describe the current knowledge of the mechanisms that mediate MST/Hippo dependent cell death, especially apoptosis. We include evidence for the existence of complex signalling networks where the core proteins of the pathway play a central role in controlling the balance between survival and cell death. Finally, we discuss the possible involvement of these signalling networks in several human diseases such as cancer, diabetes and neurodegenerative disorders. PMID:27322327

Dissecting Cell-Fate Determination Through Integrated Mathematical Modeling of the ERK/MAPK Signaling Pathway.

PubMed

Shin, Sung-Young; Nguyen, Lan K

2017-01-01

The past three decades have witnessed an enormous progress in the elucidation of the ERK/MAPK signaling pathway and its involvement in various cellular processes. Because of its importance and complex wiring, the ERK pathway has been an intensive subject for mathematical modeling, which facilitates the unraveling of key dynamic properties and behaviors of the pathway. Recently, however, it became evident that the pathway does not act in isolation but closely interacts with many other pathways to coordinate various cellular outcomes under different pathophysiological contexts. This has led to an increasing number of integrated, large-scale models that link the ERK pathway to other functionally important pathways. In this chapter, we first discuss the essential steps in model development and notable models of the ERK pathway. We then use three examples of integrated, multipathway models to investigate how crosstalk of ERK signaling with other pathways regulates cell-fate decision-making in various physiological and disease contexts. Specifically, we focus on ERK interactions with the phosphoinositide-3 kinase (PI3K), c-Jun N-terminal kinase (JNK), and β-adrenergic receptor (β-AR) signaling pathways. We conclude that integrated modeling in combination with wet-lab experimentation have been and will be instrumental in gaining an in-depth understanding of ERK signaling in multiple biological contexts.