The Transcription Factor EB Links Cellular Stress to the Immune Response



PubMed Central

Nabar, Neel R.; Kehrl, John H.

2017-01-01

The transcription factor EB (TFEB) is the master transcriptional regulator of autophagy and lysosome biogenesis. Recent advances have led to a paradigm shift in our understanding of lysosomes from a housekeeping cellular waste bin to a dynamically regulated pathway that is efficiently turned up or down based on cellular needs. TFEB coordinates the cellular response to nutrient deprivation and other forms of cell stress through the lysosome system, and regulates a myriad of cellular processes associated with this system including endocytosis, phagocytosis, autophagy, and lysosomal exocytosis. Autophagy and the endolysosomal system are critical to both the innate and adaptive arms of the immune system, with functions in effector cell priming and direct pathogen clearance. Recent studies have linked TFEB to the regulation of the immune response through the endolysosmal pathway and by direct transcriptional activation of immune related genes. In this review, we discuss the current understanding of TFEB’s function and the molecular mechanisms behind TFEB activation. Finally, we discuss recent advances linking TFEB to the immune response that positions lysosomal signaling as a potential target for immune modulation. PMID:28656016

The Transcription Factor EB Links Cellular Stress to the Immune Response

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PubMed

Nabar, Neel R; Kehrl, John H

2017-06-01

The transcription factor EB (TFEB) is the master transcriptional regulator of autophagy and lysosome biogenesis. Recent advances have led to a paradigm shift in our understanding of lysosomes from a housekeeping cellular waste bin to a dynamically regulated pathway that is efficiently turned up or down based on cellular needs. TFEB coordinates the cellular response to nutrient deprivation and other forms of cell stress through the lysosome system, and regulates a myriad of cellular processes associated with this system including endocytosis, phagocytosis, autophagy, and lysosomal exocytosis. Autophagy and the endolysosomal system are critical to both the innate and adaptive arms of the immune system, with functions in effector cell priming and direct pathogen clearance. Recent studies have linked TFEB to the regulation of the immune response through the endolysosmal pathway and by direct transcriptional activation of immune related genes. In this review, we discuss the current understanding of TFEB's function and the molecular mechanisms behind TFEB activation. Finally, we discuss recent advances linking TFEB to the immune response that positions lysosomal signaling as a potential target for immune modulation.

Correlation of cellular factors and differential scrapie prion permissiveness in ovine microglia

USDA-ARS?s Scientific Manuscript database

Prion diseases are fatal neurodegenerative disorders by which the native cellular prion protein (PrP-C) is misfolded into an accumulating, disease-associated isoform (PrP-D). To improve the understanding of prion pathogenesis and develop effective treatments, it is essential to elucidate factors con...

Human Cortical Neural Stem Cells Expressing Insulin-Like Growth Factor-I: A Novel Cellular Therapy for Alzheimer’s Disease

PubMed Central

McGinley, Lisa M.; Sims, Erika; Lunn, J. Simon; Kashlan, Osama N.; Chen, Kevin S.; Bruno, Elizabeth S.; Pacut, Crystal M.; Hazel, Tom; Johe, Karl; Sakowski, Stacey A.

2016-01-01

Alzheimer’s disease (AD) is the most prevalent age-related neurodegenerative disorder and a leading cause of dementia. Current treatment fails to modify underlying disease pathologies and very little progress has been made to develop effective drug treatments. Cellular therapies impact disease by multiple mechanisms, providing increased efficacy compared with traditional single-target approaches. In amyotrophic lateral sclerosis, we have shown that transplanted spinal neural stem cells (NSCs) integrate into the spinal cord, form synapses with the host, improve inflammation, and reduce disease-associated pathologies. Our current goal is to develop a similar “best in class” cellular therapy for AD. Here, we characterize a novel human cortex-derived NSC line modified to express insulin-like growth factor-I (IGF-I), HK532-IGF-I. Because IGF-I promotes neurogenesis and synaptogenesis in vivo, this enhanced NSC line offers additional environmental enrichment, enhanced neuroprotection, and a multifaceted approach to treating complex AD pathologies. We show that autocrine IGF-I production does not impact the cell secretome or normal cellular functions, including proliferation, migration, or maintenance of progenitor status. However, HK532-IGF-I cells preferentially differentiate into gamma-aminobutyric acid-ergic neurons, a subtype dysregulated in AD; produce increased vascular endothelial growth factor levels; and display an increased neuroprotective capacity in vitro. We also demonstrate that HK532-IGF-I cells survive peri-hippocampal transplantation in a murine AD model and exhibit long-term persistence in targeted brain areas. In conclusion, we believe that harnessing the benefits of cellular and IGF-I therapies together will provide the optimal therapeutic benefit to patients, and our findings support further preclinical development of HK532-IGF-I cells into a disease-modifying intervention for AD. Significance There is no cure for Alzheimer’s disease (AD) and

Plant Abiotic Stress Proteomics: The Major Factors Determining Alterations in Cellular Proteome

PubMed Central

Kosová, Klára; Vítámvás, Pavel; Urban, Milan O.; Prášil, Ilja T.; Renaut, Jenny

2018-01-01

HIGHLIGHTS: Major environmental and genetic factors determining stress-related protein abundance are discussed.Major aspects of protein biological function including protein isoforms and PTMs, cellular localization and protein interactions are discussed.Functional diversity of protein isoforms and PTMs is discussed. Abiotic stresses reveal profound impacts on plant proteomes including alterations in protein relative abundance, cellular localization, post-transcriptional and post-translational modifications (PTMs), protein interactions with other protein partners, and, finally, protein biological functions. The main aim of the present review is to discuss the major factors determining stress-related protein accumulation and their final biological functions. A dynamics of stress response including stress acclimation to altered ambient conditions and recovery after the stress treatment is discussed. The results of proteomic studies aimed at a comparison of stress response in plant genotypes differing in stress adaptability reveal constitutively enhanced levels of several stress-related proteins (protective proteins, chaperones, ROS scavenging- and detoxification-related enzymes) in the tolerant genotypes with respect to the susceptible ones. Tolerant genotypes can efficiently adjust energy metabolism to enhanced needs during stress acclimation. Stress tolerance vs. stress susceptibility are relative terms which can reflect different stress-coping strategies depending on the given stress treatment. The role of differential protein isoforms and PTMs with respect to their biological functions in different physiological constraints (cellular compartments and interacting partners) is discussed. The importance of protein functional studies following high-throughput proteome analyses is presented in a broader context of plant biology. In summary, the manuscript tries to provide an overview of the major factors which have to be considered when interpreting data from proteomic

Expression of a transmembrane phosphotyrosine phosphatase inhibits cellular response to platelet-derived growth factor and insulin-like growth factor-1.

PubMed

Mooney, R A; Freund, G G; Way, B A; Bordwell, K L

1992-11-25

Tyrosine phosphorylation is a mechanism of signal transduction shared by many growth factor receptors and oncogene products. Phosphotyrosine phosphatases (PTPases) potentially modulate or counter-regulate these signaling pathways. To test this hypothesis, the transmembrane PTPase CD45 (leukocyte common antigen) was expressed in the murine cell line C127. Hormone-dependent autophosphorylation of the platelet-derived growth factor (PDGF) and insulin-like growth factor-1 (IGF-1) receptors was markedly reduced in cells expressing the transmembrane PTPase. Tyrosine phosphorylation of other PDGF-dependent phosphoproteins (160, 140, and 55 kDa) and IGF-1-dependent phosphoproteins (145 kDa) was similarly decreased. Interestingly, the pattern of growth factor-independent tyrosine phosphorylations was comparable in cells expressing the PTPase and control cells. This suggests a selectivity or accessibility of the PTPase limited to a subset of cellular phosphotyrosyl proteins. The maximum mitogenic response to PDGF and IGF-1 in cells expressing the PTPase was decreased by 67 and 71%, respectively. These results demonstrate that a transmembrane PTPase can both affect the tyrosine phosphorylation state of growth factor receptors and modulate proximal and distal cellular responses to the growth factors.

Viral and Cellular Factors Involved in Phloem Transport of Plant Viruses

PubMed Central

Hipper, Clémence; Brault, Véronique; Ziegler-Graff, Véronique; Revers, Frédéric

2013-01-01

Phloem transport of plant viruses is an essential step in the setting-up of a complete infection of a host plant. After an initial replication step in the first cells, viruses spread from cell-to-cell through mesophyll cells, until they reach the vasculature where they rapidly move to distant sites in order to establish the infection of the whole plant. This last step is referred to as systemic transport, or long-distance movement, and involves virus crossings through several cellular barriers: bundle sheath, vascular parenchyma, and companion cells for virus loading into sieve elements (SE). Viruses are then passively transported within the source-to-sink flow of photoassimilates and are unloaded from SE into sink tissues. However, the molecular mechanisms governing virus long-distance movement are far from being understood. While most viruses seem to move systemically as virus particles, some viruses are transported in SE as viral ribonucleoprotein complexes (RNP). The nature of the cellular and viral factors constituting these RNPs is still poorly known. The topic of this review will mainly focus on the host and viral factors that facilitate or restrict virus long-distance movement. PMID:23745125

A parallelized three-dimensional cellular automaton model for grain growth during additive manufacturing

NASA Astrophysics Data System (ADS)

Lian, Yanping; Lin, Stephen; Yan, Wentao; Liu, Wing Kam; Wagner, Gregory J.

2018-05-01

In this paper, a parallelized 3D cellular automaton computational model is developed to predict grain morphology for solidification of metal during the additive manufacturing process. Solidification phenomena are characterized by highly localized events, such as the nucleation and growth of multiple grains. As a result, parallelization requires careful treatment of load balancing between processors as well as interprocess communication in order to maintain a high parallel efficiency. We give a detailed summary of the formulation of the model, as well as a description of the communication strategies implemented to ensure parallel efficiency. Scaling tests on a representative problem with about half a billion cells demonstrate parallel efficiency of more than 80% on 8 processors and around 50% on 64; loss of efficiency is attributable to load imbalance due to near-surface grain nucleation in this test problem. The model is further demonstrated through an additive manufacturing simulation with resulting grain structures showing reasonable agreement with those observed in experiments.

A parallelized three-dimensional cellular automaton model for grain growth during additive manufacturing

NASA Astrophysics Data System (ADS)

Lian, Yanping; Lin, Stephen; Yan, Wentao; Liu, Wing Kam; Wagner, Gregory J.

2018-01-01

In this paper, a parallelized 3D cellular automaton computational model is developed to predict grain morphology for solidification of metal during the additive manufacturing process. Solidification phenomena are characterized by highly localized events, such as the nucleation and growth of multiple grains. As a result, parallelization requires careful treatment of load balancing between processors as well as interprocess communication in order to maintain a high parallel efficiency. We give a detailed summary of the formulation of the model, as well as a description of the communication strategies implemented to ensure parallel efficiency. Scaling tests on a representative problem with about half a billion cells demonstrate parallel efficiency of more than 80% on 8 processors and around 50% on 64; loss of efficiency is attributable to load imbalance due to near-surface grain nucleation in this test problem. The model is further demonstrated through an additive manufacturing simulation with resulting grain structures showing reasonable agreement with those observed in experiments.

Cellular Transcription Factors Induced in Trigeminal Ganglia during Dexamethasone-Induced Reactivation from Latency Stimulate Bovine Herpesvirus 1 Productive Infection and Certain Viral Promoters

PubMed Central

Workman, Aspen; Eudy, James; Smith, Lynette; Frizzo da Silva, Leticia; Sinani, Devis; Bricker, Halie; Cook, Emily; Doster, Alan

2012-01-01

Bovine herpesvirus 1 (BHV-1), an alphaherpesvirinae subfamily member, establishes latency in sensory neurons. Elevated corticosteroid levels, due to stress, reproducibly triggers reactivation from latency in the field. A single intravenous injection of the synthetic corticosteroid dexamethasone (DEX) to latently infected calves consistently induces reactivation from latency. Lytic cycle viral gene expression is detected in sensory neurons within 6 h after DEX treatment of latently infected calves. These observations suggested that DEX stimulated expression of cellular genes leads to lytic cycle viral gene expression and productive infection. In this study, a commercially available assay—Bovine Gene Chip—was used to compare cellular gene expression in the trigeminal ganglia (TG) of calves latently infected with BHV-1 versus DEX-treated animals. Relative to TG prepared from latently infected calves, 11 cellular genes were induced more than 10-fold 3 h after DEX treatment. Pentraxin three, a regulator of innate immunity and neurodegeneration, was stimulated 35- to 63-fold after 3 or 6 h of DEX treatment. Two transcription factors, promyelocytic leukemia zinc finger (PLZF) and Slug were induced more than 15-fold 3 h after DEX treatment. PLZF or Slug stimulated productive infection 20- or 5-fold, respectively, and Slug stimulated the late glycoprotein C promoter more than 10-fold. Additional DEX-induced transcription factors also stimulated productive infection and certain viral promoters. These studies suggest that DEX-inducible cellular transcription factors and/or signaling pathways stimulate lytic cycle viral gene expression, which subsequently leads to successful reactivation from latency in a small subset of latently infected neurons. PMID:22190728

Global analysis of bacterial transcription factors to predict cellular target processes.

PubMed

Doerks, Tobias; Andrade, Miguel A; Lathe, Warren; von Mering, Christian; Bork, Peer

2004-03-01

Whole-genome sequences are now available for >100 bacterial species, giving unprecedented power to comparative genomics approaches. We have applied genome-context methods to predict target processes that are regulated by transcription factors (TFs). Of 128 orthologous groups of proteins annotated as TFs, to date, 36 are functionally uncharacterized; in our analysis we predict a probable cellular target process or biochemical pathway for half of these functionally uncharacterized TFs.

Intracellular Localization and Cellular Factors Interaction of HTLV-1 and HTLV-2 Tax Proteins: Similarities and Functional Differences

PubMed Central

Bertazzoni, Umberto; Turci, Marco; Avesani, Francesca; Di Gennaro, Gianfranco; Bidoia, Carlo; Romanelli, Maria Grazia

2011-01-01

Human T-lymphotropic viruses type 1 (HTLV-1) and type 2 (HTLV-2) present very similar genomic structures but HTLV-1 is more pathogenic than HTLV-2. Is this difference due to their transactivating Tax proteins, Tax-1 and Tax-2, which are responsible for viral and cellular gene activation? Do Tax-1 and Tax-2 differ in their cellular localization and in their interaction pattern with cellular factors? In this review, we summarize Tax-1 and Tax-2 structural and phenotypic properties, their interaction with factors involved in signal transduction and their localization-related behavior within the cell. Special attention will be given to the distinctions between Tax-1 and Tax-2 that likely play an important role in their transactivation activity. PMID:21994745

Novel vascular endothelial growth factor blocker improves cellular viability and reduces hypobaric hypoxia-induced vascular leakage and oedema in rat brain.

PubMed

Saraswat, Deepika; Nehra, Sarita; Chaudhary, Kamal; CVS, Siva Prasad

2015-05-01

Vascular endothelial growth factor (VEGF) is an important cerebral angiogenic and permeability factor under hypoxia. There is a need to find effective molecules that may ameliorate hypoxia-induced cerebral oedema. In silico identification of novel candidate molecules that block VEGF-A site were identified and validated with a Ramachandran plot. The active site residues of VEGF-A were detected by Pocketfinder, CASTp, and DogSiteScorer. Based on in silico data, three VEGF-A blocker (VAB) candidate molecules (VAB1, VAB2, and VAB3) were checked for improvement in cellular viability and regulation of VEGF levels in N2a cells under hypoxia (0.5% O2 ). Additionally, the best candidate molecule's efficacy was assessed in male Sprague-Dawley rats for its ameliorative effect on cerebral oedema and vascular leakage under hypobaric hypoxia 7260 m. All experimental results were compared with the commercially available VEGF blocker sunitinib. Vascular endothelial growth factor-A blocker 1 was found most effective in increasing cellular viability and maintaining normal VEGF levels under hypoxia (0.5% oxygen) in N2a cells. Vascular endothelial growth factor-A blocker 1 effectively restored VEGF levels, decreased cerebral oedema, and reduced vascular leakage under hypobaric hypoxia when compared to sunitinib-treated rats. Vascular endothelial growth factor-A blocker 1 may be a promising candidate molecule for ameliorating hypobaric hypoxia-induced vasogenic oedema by regulating VEGF levels. © 2015 Wiley Publishing Asia Pty Ltd.

Modeling of time dependent localized flow shear stress and its impact on cellular growth within additive manufactured titanium implants.

PubMed

Zhang, Ziyu; Yuan, Lang; Lee, Peter D; Jones, Eric; Jones, Julian R

2014-11-01

Bone augmentation implants are porous to allow cellular growth, bone formation and fixation. However, the design of the pores is currently based on simple empirical rules, such as minimum pore and interconnects sizes. We present a three-dimensional (3D) transient model of cellular growth based on the Navier-Stokes equations that simulates the body fluid flow and stimulation of bone precursor cellular growth, attachment, and proliferation as a function of local flow shear stress. The model's effectiveness is demonstrated for two additive manufactured (AM) titanium scaffold architectures. The results demonstrate that there is a complex interaction of flow rate and strut architecture, resulting in partially randomized structures having a preferential impact on stimulating cell migration in 3D porous structures for higher flow rates. This novel result demonstrates the potential new insights that can be gained via the modeling tool developed, and how the model can be used to perform what-if simulations to design AM structures to specific functional requirements. © 2014 Wiley Periodicals, Inc.

Modeling of time dependent localized flow shear stress and its impact on cellular growth within additive manufactured titanium implants

PubMed Central

Zhang, Ziyu; Yuan, Lang; Lee, Peter D; Jones, Eric; Jones, Julian R

2014-01-01

Bone augmentation implants are porous to allow cellular growth, bone formation and fixation. However, the design of the pores is currently based on simple empirical rules, such as minimum pore and interconnects sizes. We present a three-dimensional (3D) transient model of cellular growth based on the Navier–Stokes equations that simulates the body fluid flow and stimulation of bone precursor cellular growth, attachment, and proliferation as a function of local flow shear stress. The model's effectiveness is demonstrated for two additive manufactured (AM) titanium scaffold architectures. The results demonstrate that there is a complex interaction of flow rate and strut architecture, resulting in partially randomized structures having a preferential impact on stimulating cell migration in 3D porous structures for higher flow rates. This novel result demonstrates the potential new insights that can be gained via the modeling tool developed, and how the model can be used to perform what-if simulations to design AM structures to specific functional requirements. PMID:24664988

Mechanisms for Variation of Cellular P Stoichiometry: Diverse Cellular Phosphorus Allocation Strategies Across Microbial Groups from the Sargasso Sea

NASA Astrophysics Data System (ADS)

Popendorf, K.; Duhamel, S.

2016-02-01

Phosphorus is the least abundant of the three major macronutrients that define the canonical Redfield ratio, but its place in the backbone of nucleic acids and as an energy trafficking molecule lays a lower bound of cellular phosphorus content that is essential for all life. In addition to forming DNA, RNA, and adenosine triphosphate (ATP), significant amounts of cellular phosphorus may also be allocated to the production of phospholipids and polyphosphate. These latter two biochemicals in particular may occur in significant but highly variable amounts across different microbial groups, and the variation in cellular allocation to these biochemicals may be a contributing factor in defining the elemental stoichiometry of microbes. We investigated this variation in cellular phosphorus allocation across the most abundant microbial groups in the P-depleted Sargasso Sea: Prochlorococcus, Synechococcus, and heterotrophic bacteria. By coupling radioisotope tracing of phosphate and ATP with cell sorting flow cytometry and subsequent biochemical extractions, we made novel measurements of the P allocation to DNA, phospholipids, and polyphosphate in individual microbial groups from environmental populations. These results provide new insights into the cellular mechanisms of variation in stoichiometry and different microbial strategies for adaptation to low-P environments.

A nucleator arms race: cellular control of actin assembly.

PubMed

Campellone, Kenneth G; Welch, Matthew D

2010-04-01

For over a decade, the actin-related protein 2/3 (ARP2/3) complex, a handful of nucleation-promoting factors and formins were the only molecules known to directly nucleate actin filament formation de novo. However, the past several years have seen a surge in the discovery of mammalian proteins with roles in actin nucleation and dynamics. Newly recognized nucleation-promoting factors, such as WASP and SCAR homologue (WASH), WASP homologue associated with actin, membranes and microtubules (WHAMM), and junction-mediating regulatory protein (JMY), stimulate ARP2/3 activity at distinct cellular locations. Formin nucleators with additional biochemical and cellular activities have also been uncovered. Finally, the Spire, cordon-bleu and leiomodin nucleators have revealed new ways of overcoming the kinetic barriers to actin polymerization.

Insulin-like growth factor-I, physical activity, and control of cellular anabolism.

PubMed

Nindl, Bradley C

2010-01-01

The underlying mechanisms responsible for mediating the beneficial outcomes of exercise undoubtedly are many, but the insulin-like growth factor-I (IGF-I) system is emerging as an important and central hormonal axis that plays a significant role concerning cellular anabolism. This introductory article summarizes the intent and the content for papers presented as part of a 2008 American College of Sports Medicine national symposium entitled "Insulin-like Growth Factor-I, Physical Activity, and Control of Cellular Anabolism." The individual authors and their papers are as follows: Jan Frystyk authoring "The relationship between exercise and the growth hormone/insulin-like growth factor-I axis," Greg Adams authoring "IGF-I signaling in skeletal muscle and the potential for cytokine interactions," and Brad Nindl authoring "Insulin-like growth factor-I as a biomarker of health, fitness, and training status." These papers focus on 1) different assay methodologies for IGF-I within the paradigm of exercise studies, 2) research demonstrating that intracellular signaling components associated with several proinflammatory cytokines have the potential to interact with anabolic signaling processes in skeletal muscle, and 3) an overview of IGF-I as a biomarker related to exercise training, muscle and bone remodeling, body composition, cognition, and cancer. When summed in total, the contribution that these papers will make will undoubtedly involve bringing attention to the vast regulatory complexity of the IGF-I system and will hopefully convince the reader that the IGF-I system warrants further detailed scientific inquiry to resolve many unanswered questions and paradoxical experimental findings. The IGF-I system remains one of the most intriguing and captivating marvels of human physiology that seems central in mediating numerous adaptations from physical activity.

Cellular immune responses to platelet factor 4 and heparin complexes in patients with heparin-induced thrombocytopenia.

PubMed

Nazy, Ishac; Clare, Rumi; Staibano, Phillip; Warkentin, Theodore E; Larche, Mark; Moore, Jane C; Smith, James W; Whitlock, Richard P; Kelton, John G; Arnold, Donald M

2018-05-03

Heparin-induced thrombocytopenia (HIT) is an adverse reaction to heparin characterized by thrombocytopenia and thrombotic complications. HIT is caused by pathogenic antibodies that bind to complexes of platelet factor 4 and heparin (PF4/heparin) leading to platelet activation and inducing a hypercoagulable state. Previous studies have shown immunity to PF4/heparin occurs early in life even before heparin exposure; however, the immunogenesis of HIT is not well characterized. The aim of this study was to investigate cellular proliferation in response to PF4/heparin complexes in patients with HIT. Peripheral blood mononuclear cells (PBMCs) from healthy controls (n = 30), postoperative cardiac surgery patients who underwent cardiopulmonary bypass (CPB, n = 17), and patients with confirmed HIT (n = 41) were cultured with PF4 and PF4/heparin. Cellular proliferation was assessed by 3 H-thymidine uptake and 5-ethynyl-2'-deoxyuridine (EdU) detection. PBMCs proliferated in the presence of PF4 and was enhanced by the addition of heparin in all study groups. CPB and HIT patients exhibited significantly higher proliferative responses compared to healthy controls. PBMC proliferation was antigen-specific, depended on the presence of platelets, and only CD14 + cells were identified as proliferating cells. Culture supernatants were tested for the levels of regulatory cytokines and both CPB and HIT patients produced significantly lower levels of IL-10 and TGF-β1 compared to healthy controls. These findings further demonstrate that cellular immune sensitization to PF4/heparin occurs before heparin exposure and suggests that immune dysregulation can contribute to the immunogenesis of HIT. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Role of Fatty Acid Kinase in Cellular Lipid Homeostasis and SaeRS-Dependent Virulence Factor Expression in Staphylococcus aureus.

PubMed

Ericson, Megan E; Subramanian, Chitra; Frank, Matthew W; Rock, Charles O

2017-08-01

The SaeRS two-component system is a master activator of virulence factor transcription in Staphylococcus aureus , but the cellular factors that control its activity are unknown. Fatty acid (FA) kinase is a two-component enzyme system required for extracellular FA uptake and SaeRS activity. Here, we demonstrate the existence of an intracellular nonesterified FA pool in S. aureus that is elevated in strains lacking FA kinase activity. SaeRS-mediated transcription is restored in FA kinase-negative strains when the intracellular FA pool is reduced either by growth with FA-depleted bovine serum albumin to extract the FA into the medium or by the heterologous expression of Neisseria gonorrhoeae acyl-acyl carrier protein synthetase to activate FA for phospholipid synthesis. These data show that FAs act as negative regulators of SaeRS signaling, and FA kinase activates SaeRS-dependent virulence factor production by lowering inhibitory FA levels. Thus, FA kinase plays a role in cellular lipid homeostasis by activating FA for incorporation into phospholipid, and it indirectly regulates SaeRS signaling by maintaining a low intracellular FA pool. IMPORTANCE The SaeRS two-component system is a master transcriptional activator of virulence factor production in response to the host environment in S. aureus , and strains lacking FA kinase have severely attenuated SaeRS-dependent virulence factor transcription. FA kinase is required for the activation of exogenous FAs, and it plays a role in cellular lipid homeostasis by recycling cellular FAs into the phospholipid biosynthetic pathway. Activation of the sensor kinase, SaeS, is mediated by its membrane anchor domain, and the FAs which accumulate in FA kinase knockout strains are potent inhibitors of SaeS-dependent signaling. This work identifies FAs as physiological effectors for the SaeRS system and reveals a connection between cellular lipid homeostasis and the regulation of virulence factor transcription. FA kinase is widely

Rewiring of cellular membrane homeostasis by picornaviruses.

PubMed

Belov, George A; Sztul, Elizabeth

2014-09-01

Viruses are obligatory intracellular parasites and utilize host elements to support key viral processes, including penetration of the plasma membrane, initiation of infection, replication, and suppression of the host's antiviral defenses. In this review, we focus on picornaviruses, a family of positive-strand RNA viruses, and discuss the mechanisms by which these viruses hijack the cellular machinery to form and operate membranous replication complexes. Studies aimed at revealing factors required for the establishment of viral replication structures identified several cellular-membrane-remodeling proteins and led to the development of models in which the virus used a preexisting cellular-membrane-shaping pathway "as is" for generating its replication organelles. However, as more data accumulate, this view is being increasingly questioned, and it is becoming clearer that viruses may utilize cellular factors in ways that are distinct from the normal functions of these proteins in uninfected cells. In addition, the proteincentric view is being supplemented by important new studies showing a previously unappreciated deep remodeling of lipid homeostasis, including extreme changes to phospholipid biosynthesis and cholesterol trafficking. The data on viral modifications of lipid biosynthetic pathways are still rudimentary, but it appears once again that the viruses may rewire existing pathways to generate novel functions. Despite remarkable progress, our understanding of how a handful of viral proteins can completely overrun the multilayered, complex mechanisms that control the membrane organization of a eukaryotic cell remains very limited. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

A Biosensor of S100A4 Metastasis Factor Activation: Inhibitor Screening and Cellular Activation Dynamics†

PubMed Central

Garrett, Sarah C.; Hodgson, Louis; Rybin, Andrew; Toutchkine, Alexei; Hahn, Klaus M.; Lawrence, David S.; Bresnick, Anne R.

2011-01-01

S100A4, a member of the S100 family of Ca2+-binding proteins, displays elevated expression in malignant human tumors compared with benign tumors, and increased expression correlates strongly with poor patient survival. S100A4 has a direct role in metastatic progression, likely due to the modulation of actomyosin cytoskeletal dynamics, which results in increased cellular motility. We developed a fluorescent biosensor (Mero-S100A4) that reports on the Ca2+-bound, activated form of S100A4. Direct attachment of a novel solvatochromatic reporter dye to S100A4 results in a sensor that, upon activation, undergoes a 3-fold enhancement in fluorescence, thus providing a sensitive assay for use in vitro and in vivo. In cells, localized activation of S100A4 at the cell periphery is observed during random migration and following stimulation with lysophosphatidic acid, a known activator of cell motility and proliferation. Additionally, a screen against a library of FDA-approved drugs with the biosensor identified an array of phenothiazines as inhibitors of myosin-II associated S100A4 function. These data demonstrate the utility of the new biosensor both for drug discovery and for probing the cellular dynamics controlled by the S100A4 metastasis factor. PMID:18154362

Transcription Factors MYOCD, SRF, Mesp1 and SMARCD3 Enhance the Cardio-Inducing Effect of GATA4, TBX5, and MEF2C during Direct Cellular Reprogramming

PubMed Central

Christoforou, Nicolas; Chellappan, Malathi; Adler, Andrew F.; Kirkton, Robert D.; Wu, Tianyi; Addis, Russell C.; Bursac, Nenad; Leong, Kam W.

2013-01-01

Transient overexpression of defined combinations of master regulator genes can effectively induce cellular reprogramming: the acquisition of an alternative predicted phenotype from a differentiated cell lineage. This can be of particular importance in cardiac regenerative medicine wherein the heart lacks the capacity to heal itself, but simultaneously contains a large pool of fibroblasts. In this study we determined the cardio-inducing capacity of ten transcription factors to actuate cellular reprogramming of mouse embryonic fibroblasts into cardiomyocyte-like cells. Overexpression of transcription factors MYOCD and SRF alone or in conjunction with Mesp1 and SMARCD3 enhanced the basal but necessary cardio-inducing effect of the previously reported GATA4, TBX5, and MEF2C. In particular, combinations of five or seven transcription factors enhanced the activation of cardiac reporter vectors, and induced an upregulation of cardiac-specific genes. Global gene expression analysis also demonstrated a significantly greater cardio-inducing effect when the transcription factors MYOCD and SRF were used. Detection of cross-striated cells was highly dependent on the cell culture conditions and was enhanced by the addition of valproic acid and JAK inhibitor. Although we detected Ca2+ transient oscillations in the reprogrammed cells, we did not detect significant changes in resting membrane potential or spontaneously contracting cells. This study further elucidates the cardio-inducing effect of the transcriptional networks involved in cardiac cellular reprogramming, contributing to the ongoing rational design of a robust protocol required for cardiac regenerative therapies. PMID:23704920

Cellular functions of TIP60.

PubMed

Sapountzi, Vasileia; Logan, Ian R; Robson, Craig N

2006-01-01

TIP60 was originally identified as a cellular acetyltransferase protein that interacts with HIV-1 Tat. As a consequence, the role of TIP60 in transcriptional regulation has been investigated intensively. Recent data suggest that TIP60 has more divergent functions than originally thought and roles for TIP60 in many processes, such as cellular signalling, DNA damage repair, cell cycle and checkpoint control and apoptosis are emerging. TIP60 is a tightly regulated transcriptional coregulator, acting in a large multiprotein complex for a range of transcription factors including androgen receptor, Myc, STAT3, NF-kappaB, E2F1 and p53. This usually involves recruitment of TIP60 acetyltransferase activities to chromatin. Additionally, in response to DNA double strand breaks, TIP60 is recruited to DNA lesions where it participates both in the initial as well as the final stages of repair. Here, we describe how TIP60 is a multifunctional enzyme involved in multiple nuclear transactions.

Viral Proteinase Requirements for the Nucleocytoplasmic Relocalization of Cellular Splicing Factor SRp20 during Picornavirus Infections

PubMed Central

Fitzgerald, Kerry D.; Chase, Amanda J.; Cathcart, Andrea L.; Tran, Genevieve P.

2013-01-01

Infection of mammalian cells by picornaviruses results in the nucleocytoplasmic redistribution of certain host cell proteins. These viruses interfere with import-export pathways, allowing for the cytoplasmic accumulation of nuclear proteins that are then available to function in viral processes. We recently described the cytoplasmic relocalization of cellular splicing factor SRp20 during poliovirus infection. SRp20 is an important internal ribosome entry site (IRES) trans-acting factor (ITAF) for poliovirus IRES-mediated translation; however, it is not known whether other picornaviruses utilize SRp20 as an ITAF and direct its cytoplasmic relocalization. Also, the mechanism by which poliovirus directs the accumulation of SRp20 in the cytoplasm of the infected cell is currently unknown. Work described in this report demonstrated that infection by another picornavirus (coxsackievirus B3) causes SRp20 to relocalize from the nucleus to the cytoplasm of HeLa cells, similar to poliovirus infection; however, SRp20 is relocalized to a somewhat lesser extent in the cytoplasm of HeLa cells during infection by yet another picornavirus (human rhinovirus 16). We show that expression of poliovirus 2A proteinase is sufficient to cause the nucleocytoplasmic redistribution of SRp20. Following expression of poliovirus 2A proteinase in HeLa cells, we detect cleavage of specific nuclear pore proteins known to be cleaved during poliovirus infection. We also find that expression of human rhinovirus 16 2A proteinase alone can cause efficient cytoplasmic relocalization of SRp20, despite the lower levels of SRp20 relocalization observed during rhinovirus infection compared to poliovirus. Taken together, these results further define the mechanism of SRp20 cellular redistribution during picornavirus infections, and they provide additional insight into some of the differences observed between human rhinovirus and other enterovirus infections. PMID:23255796

Transforming growth factor-beta1 mediates cellular response to DNA damage in situ

NASA Technical Reports Server (NTRS)

Ewan, Kenneth B.; Henshall-Powell, Rhonda L.; Ravani, Shraddha A.; Pajares, Maria Jose; Arteaga, Carlos; Warters, Ray; Akhurst, Rosemary J.; Barcellos-Hoff, Mary Helen

2002-01-01

Transforming growth factor (TGF)-beta1 is rapidly activated after ionizing radiation, but its specific role in cellular responses to DNA damage is not known. Here we use Tgfbeta1 knockout mice to show that radiation-induced apoptotic response is TGF-beta1 dependent in the mammary epithelium, and that both apoptosis and inhibition of proliferation in response to DNA damage decrease as a function of TGF-beta1 gene dose in embryonic epithelial tissues. Because apoptosis in these tissues has been shown previously to be p53 dependent, we then examined p53 protein activation. TGF-beta1 depletion, by either gene knockout or by using TGF-beta neutralizing antibodies, resulted in decreased p53 Ser-18 phosphorylation in irradiated mammary gland. These data indicate that TGF-beta1 is essential for rapid p53-mediated cellular responses that mediate cell fate decisions in situ.

Toll immune signal activates cellular immune response via eicosanoids.

PubMed

Shafeeq, Tahir; Ahmed, Shabbir; Kim, Yonggyun

2018-07-01

Upon immune challenge, insects recognize nonself. The recognition signal will propagate to nearby immune effectors. It is well-known that Toll signal pathway induces antimicrobial peptide (AMP) gene expression. Eicosanoids play crucial roles in mediating the recognition signal to immune effectors by enhancing humoral immune response through activation of AMP synthesis as well as cellular immune responses, suggesting a functional cross-talk between Toll and eicosanoid signals. This study tested a cross-talk between these two signals. Two signal transducing factors (MyD88 and Pelle) of Toll immune pathway were identified in Spodoptera exigua. RNA interference (RNAi) of either SeMyD88 or SePelle expression interfered with the expression of AMP genes under Toll signal pathway. Bacterial challenge induced PLA 2 enzyme activity. However, RNAi of these two immune factors significantly suppressed the induction of PLA 2 enzyme activity. Furthermore, RNAi treatment prevented gene expression of cellular PLA 2 . Inhibition of PLA 2 activity reduced phenoloxidase activity and subsequent suppression in cellular immune response measured by hemocyte nodule formation. However, immunosuppression induced by RNAi of Toll signal molecules was significantly reversed by addition of arachidonic acid (AA), a catalytic product of PLA 2 . The addition also significantly reduced the enhanced fungal susceptibility of S. exigua treated by RNAi against two Toll signal molecules. These results indicate that there is a cross-talk between Toll and eicosanoid signals in insect immunity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Clinical factors that influence the cellular responses of saphenous veins used for arterial bypass.

PubMed

Sobel, Michael; Kikuchi, Shinsuke; Chen, Lihua; Tang, Gale L; Wight, Tom N; Kenagy, Richard D

2018-06-15

When an autogenous vein is harvested and used for arterial bypass, it suffers physical and biologic injuries that may set in motion the cellular processes that lead to wall thickening, fibrosis, stenosis, and ultimately graft failure. Whereas the injurious effects of surgical preparation of the vein conduit have been extensively studied, little is known about the influence of the clinical environment of the donor leg from which the vein is obtained. We studied the cellular responses of fresh saphenous vein samples obtained before implantation in 46 patients undergoing elective lower extremity bypass surgery. Using an ex vivo model of response to injury, we quantified the outgrowth of cells from explants of the adventitial and medial layers of the vein. We correlated this cellular outgrowth with the clinical characteristics of the patients, including the Wound, Ischemia, and foot Infection classification of the donor leg for ischemia, wounds, and infection as well as smoking and diabetes. Cellular outgrowth was significantly faster and more robust from the adventitial layer than from the medial layer. The factors of leg ischemia (P < .001), smoking (P = .042), and leg infection (P = .045) were associated with impaired overall outgrowth from the adventitial tissue on multivariable analysis. Only ischemia (P = .046) was associated with impaired outgrowth of smooth muscle cells (SMCs) from the medial tissue. Co-culture of adventitial cells and SMCs propagated from vein explants revealed that adventitial cells significantly inhibited the growth of SMCs, whereas SMCs promoted the growth of adventitial cells. The AA genotype of the -838C>A p27 polymorphism (previously associated with superior graft patency) enhanced these effects, whereas the factor of smoking attenuated adventitial cell inhibition of SMC growth. Comparing gene expression, the cells cultured from the media overexpress Kyoto Encyclopedia of Genes and Genomes pathways associated with inflammation and

TRIENNIAL GROWTH AND DEVELOPMENT SYMPOSIUM: Factors influencing bovine intramuscular adipose tissue development and cellularity.

PubMed

Albrecht, E; Schering, L; Liu, Y; Komolka, K; Kühn, C; Wimmers, K; Gotoh, T; Maak, S

2017-05-01

Appearance, distribution, and amount of intramuscular fat (IMF), often referred to as marbling, are highly variable and depend on environmental and genetic factors. On the molecular level, the concerted action of several drivers, including hormones, receptors, transcription factors, etc., determines where clusters of adipocytes arise. Therefore, the aim of future studies remains to identify such factors as biological markers of IMF to increase the ability to identify animals that deposit IMF early in age to increase efficiency of high-quality meat production. In an attempt to unravel the cellular development of marbling, we investigated the abundance of markers for adipogenic differentiation during fattening of cattle and the transcriptome of muscle and dissected IMF. Markers of different stages of adipogenic differentiation are well known from cell culture experiments. They are usually transiently expressed, such as delta-like homolog 1 (DLK1) that is abundant in preadipocytes and absent during differentiation to mature adipocytes. It is even a greater challenge to detect those markers in live animals. Within skeletal muscles, hyperplasia and hypertrophy of adipocytes can be observed throughout life. Therefore, development of marbling requires, on the cellular level, recruitment, proliferation, and differentiation of adipogenic cells to store excess energy in the form of lipids in new cells. In a recent study, we investigated the localization and abundance of early markers of adipogenic differentiation, such as DLK1, in bovine muscle tissue. An inverse relationship between IMF content and number of DLK1-positive cells in bovine muscle was demonstrated. Considering the cellular environment of differentiating adipocytes in muscle and the secretory action of adipocytes and myocytes, it becomes obvious that cross talk between cells via adipokines and myokines may be important for IMF development. Secreted proteins can act on other cells, inhibiting or stimulating

Cellular uptake mediated by epidermal growth factor receptor facilitates the intracellular activity of phosphorothioate-modified antisense oligonucleotides

PubMed Central

Wang, Shiyu; Allen, Nickolas; Vickers, Timothy A; Revenko, Alexey S; Sun, Hong; Liang, Xue-hai; Crooke, Stanley T

2018-01-01

Abstract Chemically modified antisense oligonucleotides (ASOs) with phosphorothioate (PS) linkages have been extensively studied as research and therapeutic agents. PS-ASOs can enter the cell and trigger cleavage of complementary RNA by RNase H1 even in the absence of transfection reagent. A number of cell surface proteins have been identified that bind PS-ASOs and mediate their cellular uptake; however, the mechanisms that lead to productive internalization of PS-ASOs are not well understood. Here, we characterized the interaction between PS-ASOs and epidermal growth factor receptor (EGFR). We found that PS-ASOs trafficked together with EGF and EGFR into clathrin-coated pit structures. Their co-localization was also observed at early endosomes and inside enlarged late endosomes. Reduction of EGFR decreased PS-ASO activity without affecting EGF-mediated signaling pathways and overexpression of EGFR increased PS-ASO activity in cells. Furthermore, reduction of EGFR delays PS-ASO trafficking from early to late endosomes. Thus, EGFR binds to PS-ASOs at the cell surface and mediates essential steps for active (productive) cellular uptake of PS-ASOs through its cargo-dependent trafficking processes which migrate PS-ASOs from early to late endosomes. This EGFR-mediated process can also serve as an additional model to better understand the mechanism of intracellular uptake and endosomal release of PS-ASOs. PMID:29514240

Adenovirus Type 5 Early Region 1B 55K Oncoprotein-Dependent Degradation of Cellular Factor Daxx Is Required for Efficient Transformation of Primary Rodent Cells▿

PubMed Central

Schreiner, Sabrina; Wimmer, Peter; Groitl, Peter; Chen, Shuen-Yuan; Blanchette, Paola; Branton, Philip E.; Dobner, Thomas

2011-01-01

Early region 1B 55K (E1B-55K) from adenovirus type 5 (Ad5) is a multifunctional regulator of lytic infection and contributes in vitro to complete cell transformation of primary rodent cells in combination with Ad5 E1A. Inhibition of p53 activated transcription plays a key role in processes by which E1B-55K executes its oncogenic potential. Nevertheless, additional functions of E1B-55K or further protein interactions with cellular factors of DNA repair, transcription, and apoptosis, including Mre11, PML, and Daxx, may also contribute to the transformation process. In line with previous results, we performed mutational analysis to define a Daxx interaction motif within the E1B-55K polypeptide. The results from these studies showed that E1B-55K/Daxx binding is not required for inhibition of p53-mediated transactivation or binding and degradation of cellular factors (p53/Mre11). Surprisingly, these mutants lost the ability to degrade Daxx and showed reduced transforming potential in primary rodent cells. In addition, we observed that E1B-55K lacking the SUMO-1 conjugation site (SCS/K104R) was sufficient for Daxx interaction but no longer capable of E1B-55K-dependent proteasomal degradation of the cellular factor Daxx. These results, together with the observation that E1B-55K SUMOylation is required for efficient transformation, provides evidence for the idea that SUMO-1-conjugated E1B-55K-mediated degradation of Daxx plays a key role in adenoviral oncogenic transformation. We assume that the viral protein contributes to cell transformation through the modulation of Daxx-dependent pathways. This further substantiates the assumption that further mechanisms for efficient transformation of primary cells can be separated from functions required for the inhibition of p53-stimulated transcription. PMID:21697482

NAD(H) and NADP(H) Redox Couples and Cellular Energy Metabolism.

PubMed

Xiao, Wusheng; Wang, Rui-Sheng; Handy, Diane E; Loscalzo, Joseph

2018-01-20

The nicotinamide adenine dinucleotide (NAD + )/reduced NAD + (NADH) and NADP + /reduced NADP + (NADPH) redox couples are essential for maintaining cellular redox homeostasis and for modulating numerous biological events, including cellular metabolism. Deficiency or imbalance of these two redox couples has been associated with many pathological disorders. Recent Advances: Newly identified biosynthetic enzymes and newly developed genetically encoded biosensors enable us to understand better how cells maintain compartmentalized NAD(H) and NADP(H) pools. The concept of redox stress (oxidative and reductive stress) reflected by changes in NAD(H)/NADP(H) has increasingly gained attention. The emerging roles of NAD + -consuming proteins in regulating cellular redox and metabolic homeostasis are active research topics. The biosynthesis and distribution of cellular NAD(H) and NADP(H) are highly compartmentalized. It is critical to understand how cells maintain the steady levels of these redox couple pools to ensure their normal functions and simultaneously avoid inducing redox stress. In addition, it is essential to understand how NAD(H)- and NADP(H)-utilizing enzymes interact with other signaling pathways, such as those regulated by hypoxia-inducible factor, to maintain cellular redox homeostasis and energy metabolism. Additional studies are needed to investigate the inter-relationships among compartmentalized NAD(H)/NADP(H) pools and how these two dinucleotide redox couples collaboratively regulate cellular redox states and cellular metabolism under normal and pathological conditions. Furthermore, recent studies suggest the utility of using pharmacological interventions or nutrient-based bioactive NAD + precursors as therapeutic interventions for metabolic diseases. Thus, a better understanding of the cellular functions of NAD(H) and NADP(H) may facilitate efforts to address a host of pathological disorders effectively. Antioxid. Redox Signal. 28, 251-272.

Prenatal Alcohol Exposure and Cellular Differentiation

PubMed Central

Veazey, Kylee J.; Muller, Daria; Golding, Michael C.

2013-01-01

Exposure to alcohol significantly alters the developmental trajectory of progenitor cells and fundamentally compromises tissue formation (i.e., histogenesis). Emerging research suggests that ethanol can impair mammalian development by interfering with the execution of molecular programs governing differentiation. For example, ethanol exposure disrupts cellular migration, changes cell–cell interactions, and alters growth factor signaling pathways. Additionally, ethanol can alter epigenetic mechanisms controlling gene expression. Normally, lineage-specific regulatory factors (i.e., transcription factors) establish the transcriptional networks of each new cell type; the cell’s identity then is maintained through epigenetic alterations in the way in which the DNA encoding each gene becomes packaged within the chromatin. Ethanol exposure can induce epigenetic changes that do not induce genetic mutations but nonetheless alter the course of fetal development and result in a large array of patterning defects. Two crucial enzyme complexes—the Polycomb and Trithorax proteins—are central to the epigenetic programs controlling the intricate balance between self-renewal and the execution of cellular differentiation, with diametrically opposed functions. Prenatal ethanol exposure may disrupt the functions of these two enzyme complexes, altering a crucial aspect of mammalian differentiation. Characterizing the involvement of Polycomb and Trithorax group complexes in the etiology of fetal alcohol spectrum disorders will undoubtedly enhance understanding of the role that epigenetic programming plays in this complex disorder. PMID:24313167

Serratia marcescens Suppresses Host Cellular Immunity via the Production of an Adhesion-inhibitory Factor against Immunosurveillance Cells*

PubMed Central

Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

2014-01-01

Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis. PMID:24398686

Serratia marcescens suppresses host cellular immunity via the production of an adhesion-inhibitory factor against immunosurveillance cells.

PubMed

Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

2014-02-28

Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis.

Addition of Alanyl-Glutamine to Dialysis Fluid Restores Peritoneal Cellular Stress Responses – A First-In-Man Trial

PubMed Central

Boehm, Michael; Herzog, Rebecca; Gruber, Katharina; Lichtenauer, Anton Michael; Kuster, Lilian; Csaicsich, Dagmar; Gleiss, Andreas; Alper, Seth L.; Aufricht, Christoph; Vychytil, Andreas

2016-01-01

Background Peritonitis and ultrafiltration failure remain serious complications of chronic peritoneal dialysis (PD). Dysfunctional cellular stress responses aggravate peritoneal injury associated with PD fluid exposure, potentially due to peritoneal glutamine depletion. In this randomized cross-over phase I/II trial we investigated cytoprotective effects of alanyl-glutamine (AlaGln) addition to glucose-based PDF. Methods In a prospective randomized cross-over design, 20 stable PD outpatients underwent paired peritoneal equilibration tests 4 weeks apart, using conventional acidic, single chamber 3.86% glucose PD fluid, with and without 8 mM supplemental AlaGln. Heat-shock protein 72 expression was assessed in peritoneal effluent cells as surrogate parameter of cellular stress responses, complemented by metabolomics and functional immunocompetence assays. Results AlaGln restored peritoneal glutamine levels and increased the primary outcome heat-shock protein expression (effect 1.51-fold, CI 1.07–2.14; p = 0.022), without changes in peritoneal ultrafiltration, small solute transport, or biomarkers reflecting cell mass and inflammation. Further effects were glutamine-like metabolomic changes and increased ex-vivo LPS-stimulated cytokine release from healthy donor peripheral blood monocytes. In patients with a history of peritonitis (5 of 20), AlaGln supplementation decreased dialysate interleukin-8 levels. Supplemented PD fluid also attenuated inflammation and enhanced stimulated cytokine release in a mouse model of PD-associated peritonitis. Conclusion We conclude that AlaGln-supplemented, glucose-based PD fluid can restore peritoneal cellular stress responses with attenuation of sterile inflammation, and may improve peritoneal host-defense in the setting of PD. PMID:27768727

The AAA+ ATPase p97, a cellular multitool

PubMed Central

Stach, Lasse

2017-01-01

The AAA+ (ATPases associated with diverse cellular activities) ATPase p97 is essential to a wide range of cellular functions, including endoplasmic reticulum-associated degradation, membrane fusion, NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation and chromatin-associated processes, which are regulated by ubiquitination. p97 acts downstream from ubiquitin signaling events and utilizes the energy from ATP hydrolysis to extract its substrate proteins from cellular structures or multiprotein complexes. A multitude of p97 cofactors have evolved which are essential to p97 function. Ubiquitin-interacting domains and p97-binding domains combine to form bi-functional cofactors, whose complexes with p97 enable the enzyme to interact with a wide range of ubiquitinated substrates. A set of mutations in p97 have been shown to cause the multisystem proteinopathy inclusion body myopathy associated with Paget's disease of bone and frontotemporal dementia. In addition, p97 inhibition has been identified as a promising approach to provoke proteotoxic stress in tumors. In this review, we will describe the cellular processes governed by p97, how the cofactors interact with both p97 and its ubiquitinated substrates, p97 enzymology and the current status in developing p97 inhibitors for cancer therapy. PMID:28819009

Cellular and molecular mechanisms of HIV-1 integration targeting.

PubMed

Engelman, Alan N; Singh, Parmit K

2018-07-01

Integration is central to HIV-1 replication and helps mold the reservoir of cells that persists in AIDS patients. HIV-1 interacts with specific cellular factors to target integration to interior regions of transcriptionally active genes within gene-dense regions of chromatin. The viral capsid interacts with several proteins that are additionally implicated in virus nuclear import, including cleavage and polyadenylation specificity factor 6, to suppress integration into heterochromatin. The viral integrase protein interacts with transcriptional co-activator lens epithelium-derived growth factor p75 to principally position integration within gene bodies. The integrase additionally senses target DNA distortion and nucleotide sequence to help fine-tune the specific phosphodiester bonds that are cleaved at integration sites. Research into virus-host interactions that underlie HIV-1 integration targeting has aided the development of a novel class of integrase inhibitors and may help to improve the safety of viral-based gene therapy vectors.

Algorithm for cellular reprogramming.

PubMed

Ronquist, Scott; Patterson, Geoff; Muir, Lindsey A; Lindsly, Stephen; Chen, Haiming; Brown, Markus; Wicha, Max S; Bloch, Anthony; Brockett, Roger; Rajapakse, Indika

2017-11-07

The day we understand the time evolution of subcellular events at a level of detail comparable to physical systems governed by Newton's laws of motion seems far away. Even so, quantitative approaches to cellular dynamics add to our understanding of cell biology. With data-guided frameworks we can develop better predictions about, and methods for, control over specific biological processes and system-wide cell behavior. Here we describe an approach for optimizing the use of transcription factors (TFs) in cellular reprogramming, based on a device commonly used in optimal control. We construct an approximate model for the natural evolution of a cell-cycle-synchronized population of human fibroblasts, based on data obtained by sampling the expression of 22,083 genes at several time points during the cell cycle. To arrive at a model of moderate complexity, we cluster gene expression based on division of the genome into topologically associating domains (TADs) and then model the dynamics of TAD expression levels. Based on this dynamical model and additional data, such as known TF binding sites and activity, we develop a methodology for identifying the top TF candidates for a specific cellular reprogramming task. Our data-guided methodology identifies a number of TFs previously validated for reprogramming and/or natural differentiation and predicts some potentially useful combinations of TFs. Our findings highlight the immense potential of dynamical models, mathematics, and data-guided methodologies for improving strategies for control over biological processes. Copyright © 2017 the Author(s). Published by PNAS.

Glutamine's protection against cellular injury is dependent on heat shock factor-1.

PubMed

Morrison, Angela L; Dinges, Martin; Singleton, Kristen D; Odoms, Kelli; Wong, Hector R; Wischmeyer, Paul E

2006-06-01

Glutamine (GLN) has been shown to protect cells, tissues, and whole organisms from stress and injury. Enhanced expression of heat shock protein (HSP) has been hypothesized to be responsible for this protection. To date, there are no clear mechanistic data confirming this relationship. This study tested the hypothesis that GLN-mediated activation of the HSP pathway via heat shock factor-1 (HSF-1) is responsible for cellular protection. Wild-type HSF-1 (HSF-1(+/+)) and knockout (HSF-1(-/-)) mouse fibroblasts were used in all experiments. Cells were treated with GLN concentrations ranging from 0 to 16 mM and exposed to heat stress injury in a concurrent treatment model. Cell viability was assayed with phenazine methosulfate plus tetrazolium salt, HSP-70, HSP-25, and nuclear HSF-1 expression via Western blot analysis, and HSF-1/heat shock element (HSE) binding via EMSA. GLN significantly attenuated heat-stress induced cell death in HSF-1(+/+) cells in a dose-dependent manner; however, the survival benefit of GLN was lost in HSF-1(-/-) cells. GLN led to a dose-dependent increase in HSP-70 and HSP-25 expression after heat stress. No inducible HSP expression was observed in HSF-1(-/-) cells. GLN increased unphosphorylated HSF-1 in the nucleus before heat stress. This was accompanied by a GLN-mediated increase in HSF-1/HSE binding and nuclear content of phosphorylated HSF-1 after heat stress. This is the first demonstration that GLN-mediated cellular protection after heat-stress injury is related to HSF-1 expression and cellular capacity to activate an HSP response. Furthermore, the mechanism of GLN-mediated protection against injury appears to involve an increase in nuclear HSF-1 content before stress and increased HSF-1 promoter binding and phosphorylation.

Entry of Porphyromonas gingivalis outer membrane vesicles into epithelial cells causes cellular functional impairment.

PubMed

Furuta, Nobumichi; Takeuchi, Hiroki; Amano, Atsuo

2009-11-01

Porphyromonas gingivalis, a periodontal pathogen, secretes outer membrane vesicles (MVs) that contain major virulence factors, including proteases termed gingipains (Arg-gingipain [Rgp] and Lys-gingipain [Kgp]). We recently showed that P. gingivalis MVs swiftly enter host epithelial cells via an endocytosis pathway and are finally sorted to lytic compartments. However, it remains unknown whether MV entry impairs cellular function. Herein, we analyzed cellular functional impairment following entry of P. gingivalis into epithelial cells, including HeLa and immortalized human gingival epithelial (IHGE) cells. After being taken up by endocytic vacuoles, MVs degraded the cellular transferrin receptor (TfR) and integrin-related signaling molecules, such as paxillin and focal adhesion kinase (FAK), which resulted in depletion of intracellular transferrin and inhibition of cellular migration. Few Rgp-null MVs entered the cells, and these negligibly degraded TfR, whereas paxillin and FAK degradation was significant. In contrast, Kgp-null MVs clearly entered the cells and degraded TfR, while they scarcely degraded paxillin and FAK. In addition, both wild-type and Kgp-null MVs significantly impaired cellular migration, whereas the effect of Rgp-null MVs was limited. Our findings suggest that, following entry of P. gingivalis MVs into host cells, MV-associated gingipains degrade cellular functional molecules such as TfR and paxillin/FAK, resulting in cellular impairment, indicating that P. gingivalis MVs are potent vehicles for transmission of virulence factors into host cells and are involved in the etiology of periodontitis.

Entry of Porphyromonas gingivalis Outer Membrane Vesicles into Epithelial Cells Causes Cellular Functional Impairment▿

PubMed Central

Furuta, Nobumichi; Takeuchi, Hiroki; Amano, Atsuo

2009-01-01

Porphyromonas gingivalis, a periodontal pathogen, secretes outer membrane vesicles (MVs) that contain major virulence factors, including proteases termed gingipains (Arg-gingipain [Rgp] and Lys-gingipain [Kgp]). We recently showed that P. gingivalis MVs swiftly enter host epithelial cells via an endocytosis pathway and are finally sorted to lytic compartments. However, it remains unknown whether MV entry impairs cellular function. Herein, we analyzed cellular functional impairment following entry of P. gingivalis into epithelial cells, including HeLa and immortalized human gingival epithelial (IHGE) cells. After being taken up by endocytic vacuoles, MVs degraded the cellular transferrin receptor (TfR) and integrin-related signaling molecules, such as paxillin and focal adhesion kinase (FAK), which resulted in depletion of intracellular transferrin and inhibition of cellular migration. Few Rgp-null MVs entered the cells, and these negligibly degraded TfR, whereas paxillin and FAK degradation was significant. In contrast, Kgp-null MVs clearly entered the cells and degraded TfR, while they scarcely degraded paxillin and FAK. In addition, both wild-type and Kgp-null MVs significantly impaired cellular migration, whereas the effect of Rgp-null MVs was limited. Our findings suggest that, following entry of P. gingivalis MVs into host cells, MV-associated gingipains degrade cellular functional molecules such as TfR and paxillin/FAK, resulting in cellular impairment, indicating that P. gingivalis MVs are potent vehicles for transmission of virulence factors into host cells and are involved in the etiology of periodontitis. PMID:19737899

Microstructural architecture developed in the fabrication of solid and open-cellular copper components by additive manufacturing using electron beam melting

NASA Astrophysics Data System (ADS)

Ramirez, Diana Alejandra

The fabrication of Cu components were first built by additive manufacturing using electron beam melting (EBM) from low-purity, atomized Cu powder containing a high density of Cu2O precipitates leading to a novel example of precipitate-dislocation architecture. These microstructures exhibit cell-like arrays (1-3microm) in the horizontal reference plane perpendicular to the build direction with columnar-like arrays extending from ~12 to >60 microm in length and corresponding spatial dimensions of 1-3 microm. These observations were observed by the use of optical metallography, and scanning and transmission electron microscopy. The hardness measurements were taken both on the atomized powder and the Cu components. The hardness for these architectures ranged from ~HV 83 to 88, in contrast to the original Cu powder microindentation hardness of HV 72 and the commercial Cu base plate hardness of HV 57. These observations were utilized for the fabrication of open-cellular copper structures by additive manufacturing using EBM and illustrated the ability to fabricate some form of controlled microstructural architecture by EBM parameter alteration or optimizing. The fabrication of these structures ranged in densities from 0.73g/cm3 to 6.67g/cm3. These structures correspond to four different articulated mesh arrays. While these components contained some porosity as a consequence of some unmelted regions, the Cu2O precipitates also contributed to a reduced density. Using X-ray Diffraction showed the approximate volume fraction estimated to be ~2%. The addition of precipitates created in the EBM melt scan formed microstructural arrays which contributed to hardening contributing to the strength of mesh struts and foam ligaments. The measurements of relative stiffness versus relative density plots for Cu compared very closely with Ti-6Al-4V open cellular structures - both mesh and foams. The Cu reticulated mesh structures exhibit a slope of n = 2 in contrast to a slope of n = 2

Distinction of broken cellular wall Ganoderma lucidum spores and G. lucidum spores using FTIR microspectroscopy

NASA Astrophysics Data System (ADS)

Chen, Xianliang; Liu, Xingcun; Sheng, Daping; Huang, Dake; Li, Weizu; Wang, Xin

2012-11-01

In this paper, FTIR microspectroscopy was used to identify broken cellular wall Ganoderma lucidum spores and G. lucidum spores. For IR spectra, broken cellular wall G. lucidum spores and G. lucidum spores were mainly different in the regions of 3000-2800, 1660-1600, 1400-1200 and 1100-1000 cm-1. For curve fitting, the results showed the differences in the protein secondary structures and the polysaccharide structures/content between broken cellular wall G. lucidum spores and G. lucidum spores. Moreover, the value of A1078/A1741 might be a potentially useful factor to distinguish broken cellular wall G. lucidum spores from G. lucidum spores. Additionally, FTIR microspectroscopy could identify broken cellular wall G. lucidum spores and G. lucidum spores accurately when it was combined with hierarchical cluster analysis. The result suggests FTIR microspectroscopy is very simple and efficient for distinction of broken cellular wall G. lucidum spores and G. lucidum spores. The result also indicates FTIR microspectroscopy may be useful for TCM identification.

Cellular Homeostasis and Aging.

PubMed

Hartl, F Ulrich

2016-06-02

Aging and longevity are controlled by a multiplicity of molecular and cellular signaling events that interface with environmental factors to maintain cellular homeostasis. Modulation of these pathways to extend life span, including insulin-like signaling and the response to dietary restriction, identified the cellular machineries and networks of protein homeostasis (proteostasis) and stress resistance pathways as critical players in the aging process. A decline of proteostasis capacity during aging leads to dysfunction of specific cell types and tissues, rendering the organism susceptible to a range of chronic diseases. This volume of the Annual Review of Biochemistry contains a set of two reviews addressing our current understanding of the molecular mechanisms underlying aging in model organisms and humans.

Cellular senescence and organismal aging.

PubMed

Jeyapalan, Jessie C; Sedivy, John M

2008-01-01

Cellular senescence, first observed and defined using in vitro cell culture studies, is an irreversible cell cycle arrest which can be triggered by a variety of factors. Emerging evidence suggests that cellular senescence acts as an in vivo tumor suppression mechanism by limiting aberrant proliferation. It has also been postulated that cellular senescence can occur independently of cancer and contribute to the physiological processes of normal organismal aging. Recent data have demonstrated the in vivo accumulation of senescent cells with advancing age. Some characteristics of senescent cells, such as the ability to modify their extracellular environment, could play a role in aging and age-related pathology. In this review, we examine current evidence that links cellular senescence and organismal aging.

Cellular senescence and organismal aging

PubMed Central

Jeyapalan, Jessie C.; Sedivy, John M.

2012-01-01

Cellular senescence, first observed and defined using in vitro cell culture studies, is an irreversible cell cycle arrest which can be triggered by a variety of factors. Emerging evidence suggests that cellular senescence acts as an in vivo tumor suppression mechanism by limiting aberrant proliferation. It has also been postulated that cellular senescence can occur independently of cancer and contribute to the physiological processes of normal organismal aging. Recent data have demonstrated the in vivo accumulation of senescent cells with advancing age. Some characteristics of senescent cells, such as the ability to modify their extracellular environment, could play a role in aging and age related pathology. In this review, we examine current evidence that links cellular senescence and organismal aging. PMID:18502472

Cellular proliferation, cellular viability, and biocompatibility of HA-ZnO composites.

PubMed

Saha, Naresh; Dubey, Ashutosh K; Basu, Bikramjit

2012-01-01

One of the important issues in the development of hydroxyapatite (HA)-based biomaterials is the prosthetic infection, which limits wider use of monolithic HA despite superior cellular response. Recently, we reported that ZnO addition to HA can induce bactericidal property. It is therefore important to assess how ZnO addition influences the cytotoxicity property and cell adhesion/proliferation on HA-ZnO composite surfaces in vitro. In the above perspective, the objective of this study is to investigate the cell type and material composition dependent cellular proliferation and viability of pressureless sintered HA-ZnO composites. The combination of cell viability data as well as morphological observations of cultured human osteoblast-like SaOS2 cells and mouse fibroblast L929 cells suggests that HA-ZnO composites containing 10 Wt % or lower ZnO exhibit the ability to support cell adhesion and proliferation. Both SaOS2 and L929 cells exhibit extensive multidirectional network of actin cytoskeleton and cell flattening on the lower ZnO containing (≤10 Wt %) HA-ZnO composites. The in vitro results illustrate how variation in ZnO content can influence significantly the cell vitality, as evaluated using MTT biochemical assay. Also, the critical statistical analysis reveals that ZnO addition needs to be carefully tailored to ensure good in vitro cytocompatibility. The underlying reasons for difference in biological properties are analyzed. It is suggested that surface wettability as well as dissolution of ZnO, both contribute to the observed differences in cellular viability and proliferation. Copyright © 2011 Wiley Periodicals, Inc.

Origami interleaved tube cellular materials

NASA Astrophysics Data System (ADS)

Cheung, Kenneth C.; Tachi, Tomohiro; Calisch, Sam; Miura, Koryo

2014-09-01

A novel origami cellular material based on a deployable cellular origami structure is described. The structure is bi-directionally flat-foldable in two orthogonal (x and y) directions and is relatively stiff in the third orthogonal (z) direction. While such mechanical orthotropicity is well known in cellular materials with extruded two dimensional geometry, the interleaved tube geometry presented here consists of two orthogonal axes of interleaved tubes with high interfacial surface area and relative volume that changes with fold-state. In addition, the foldability still allows for fabrication by a flat lamination process, similar to methods used for conventional expanded two dimensional cellular materials. This article presents the geometric characteristics of the structure together with corresponding kinematic and mechanical modeling, explaining the orthotropic elastic behavior of the structure with classical dimensional scaling analysis.

Differences in primary cellular factors influencing the metabolism and distribution of 3,5,3′-L-triiodothyronine and L-thyroxine

PubMed Central

Oppenheimer, Jack H.; Schwartz, Harold L.; Shapiro, Harvey C.; Bernstein, Gerald; Surks, Martin I.

1970-01-01

Administration of phenobarbital, which acts exclusively on cellular sites, results in an augmentation of the liver/plasma concentration ratio of L-thyroxine (T4) in rats but no change in the liver/plasma concentration ratio of L-triiodothyronine (T3). Whereas phenobarbital stimulates the fecal clearance rate both of T3 and T4, it increases the deiodinative clearance rate of T4 only. These findings suggest basic differences in the cellular metabolism of T3 and T4. Further evidence pointing to cellular differences was obtained from a comparison of the distribution and metabolism of these hormones with appropriate corrections for the effect of differential plasma binding. The percentage of total exchangeable cellular T4 within the liver (28.5) is significantly greater than the corresponding percentage of exchangeable cellular T3 within this organ (12.3). Extrahepatic tissues bind T3 twice as firmly as T4. The cellular metabolic clearance rate (= free hormone clearance rate) of T3 exceeds that of T4 by a factor 1.8 in the rat. The corresponding ratio in man, 2.4, was determined by noncompartmental analysis of turnover studies in four individuals after the simultaneous injection of T4-125I and T3-131I. The greater cellular metabolic clearance rate of T3 both in rat and man may be related to the higher specific hormonal potency of this iodothyronine. PMID:5441537

Ebola virus modulates transforming growth factor β signaling and cellular markers of mesenchyme-like transition in hepatocytes.

PubMed

Kindrachuk, Jason; Wahl-Jensen, Victoria; Safronetz, David; Trost, Brett; Hoenen, Thomas; Arsenault, Ryan; Feldmann, Friederike; Traynor, Dawn; Postnikova, Elena; Kusalik, Anthony; Napper, Scott; Blaney, Joseph E; Feldmann, Heinz; Jahrling, Peter B

2014-09-01

Ebola virus (EBOV) causes a severe hemorrhagic disease in humans and nonhuman primates, with a median case fatality rate of 78.4%. Although EBOV is considered a public health concern, there is a relative paucity of information regarding the modulation of the functional host response during infection. We employed temporal kinome analysis to investigate the relative early, intermediate, and late host kinome responses to EBOV infection in human hepatocytes. Pathway overrepresentation analysis and functional network analysis of kinome data revealed that transforming growth factor (TGF-β)-mediated signaling responses were temporally modulated in response to EBOV infection. Upregulation of TGF-β signaling in the kinome data sets correlated with the upregulation of TGF-β secretion from EBOV-infected cells. Kinase inhibitors targeting TGF-β signaling, or additional cell receptors and downstream signaling pathway intermediates identified from our kinome analysis, also inhibited EBOV replication. Further, the inhibition of select cell signaling intermediates identified from our kinome analysis provided partial protection in a lethal model of EBOV infection. To gain perspective on the cellular consequence of TGF-β signaling modulation during EBOV infection, we assessed cellular markers associated with upregulation of TGF-β signaling. We observed upregulation of matrix metalloproteinase 9, N-cadherin, and fibronectin expression with concomitant reductions in the expression of E-cadherin and claudin-1, responses that are standard characteristics of an epithelium-to-mesenchyme-like transition. Additionally, we identified phosphorylation events downstream of TGF-β that may contribute to this process. From these observations, we propose a model for a broader role of TGF-β-mediated signaling responses in the pathogenesis of Ebola virus disease. Ebola virus (EBOV), formerly Zaire ebolavirus, causes a severe hemorrhagic disease in humans and nonhuman primates and is the most

Ebola Virus Modulates Transforming Growth Factor β Signaling and Cellular Markers of Mesenchyme-Like Transition in Hepatocytes

PubMed Central

Wahl-Jensen, Victoria; Safronetz, David; Trost, Brett; Hoenen, Thomas; Arsenault, Ryan; Feldmann, Friederike; Traynor, Dawn; Postnikova, Elena; Kusalik, Anthony; Napper, Scott; Blaney, Joseph E.; Feldmann, Heinz; Jahrling, Peter B.

2014-01-01

ABSTRACT Ebola virus (EBOV) causes a severe hemorrhagic disease in humans and nonhuman primates, with a median case fatality rate of 78.4%. Although EBOV is considered a public health concern, there is a relative paucity of information regarding the modulation of the functional host response during infection. We employed temporal kinome analysis to investigate the relative early, intermediate, and late host kinome responses to EBOV infection in human hepatocytes. Pathway overrepresentation analysis and functional network analysis of kinome data revealed that transforming growth factor (TGF-β)-mediated signaling responses were temporally modulated in response to EBOV infection. Upregulation of TGF-β signaling in the kinome data sets correlated with the upregulation of TGF-β secretion from EBOV-infected cells. Kinase inhibitors targeting TGF-β signaling, or additional cell receptors and downstream signaling pathway intermediates identified from our kinome analysis, also inhibited EBOV replication. Further, the inhibition of select cell signaling intermediates identified from our kinome analysis provided partial protection in a lethal model of EBOV infection. To gain perspective on the cellular consequence of TGF-β signaling modulation during EBOV infection, we assessed cellular markers associated with upregulation of TGF-β signaling. We observed upregulation of matrix metalloproteinase 9, N-cadherin, and fibronectin expression with concomitant reductions in the expression of E-cadherin and claudin-1, responses that are standard characteristics of an epithelium-to-mesenchyme-like transition. Additionally, we identified phosphorylation events downstream of TGF-β that may contribute to this process. From these observations, we propose a model for a broader role of TGF-β-mediated signaling responses in the pathogenesis of Ebola virus disease. IMPORTANCE Ebola virus (EBOV), formerly Zaire ebolavirus, causes a severe hemorrhagic disease in humans and nonhuman

Distinction of broken cellular wall Ganoderma lucidum spores and G. lucidum spores using FTIR microspectroscopy.

PubMed

Chen, Xianliang; Liu, Xingcun; Sheng, Daping; Huang, Dake; Li, Weizu; Wang, Xin

2012-11-01

In this paper, FTIR microspectroscopy was used to identify broken cellular wall Ganoderma lucidum spores and G. lucidum spores. For IR spectra, broken cellular wall G. lucidum spores and G. lucidum spores were mainly different in the regions of 3000-2800, 1660-1600, 1400-1200 and 1100-1000 cm(-1). For curve fitting, the results showed the differences in the protein secondary structures and the polysaccharide structures/content between broken cellular wall G. lucidum spores and G. lucidum spores. Moreover, the value of A1078/A1741 might be a potentially useful factor to distinguish broken cellular wall G. lucidum spores from G. lucidum spores. Additionally, FTIR microspectroscopy could identify broken cellular wall G. lucidum spores and G. lucidum spores accurately when it was combined with hierarchical cluster analysis. The result suggests FTIR microspectroscopy is very simple and efficient for distinction of broken cellular wall G. lucidum spores and G. lucidum spores. The result also indicates FTIR microspectroscopy may be useful for TCM identification. Copyright © 2012 Elsevier B.V. All rights reserved.

Modulation of Enhancer Looping and Differential Gene Targeting by Epstein-Barr Virus Transcription Factors Directs Cellular Reprogramming

PubMed Central

McClellan, Michael J.; Wood, C. David; Ojeniyi, Opeoluwa; Cooper, Tim J.; Kanhere, Aditi; Arvey, Aaron; Webb, Helen M.; Palermo, Richard D.; Harth-Hertle, Marie L.; Kempkes, Bettina; Jenner, Richard G.; West, Michelle J.

2013-01-01

Epstein-Barr virus (EBV) epigenetically reprogrammes B-lymphocytes to drive immortalization and facilitate viral persistence. Host-cell transcription is perturbed principally through the actions of EBV EBNA 2, 3A, 3B and 3C, with cellular genes deregulated by specific combinations of these EBNAs through unknown mechanisms. Comparing human genome binding by these viral transcription factors, we discovered that 25% of binding sites were shared by EBNA 2 and the EBNA 3s and were located predominantly in enhancers. Moreover, 80% of potential EBNA 3A, 3B or 3C target genes were also targeted by EBNA 2, implicating extensive interplay between EBNA 2 and 3 proteins in cellular reprogramming. Investigating shared enhancer sites neighbouring two new targets (WEE1 and CTBP2) we discovered that EBNA 3 proteins repress transcription by modulating enhancer-promoter loop formation to establish repressive chromatin hubs or prevent assembly of active hubs. Re-ChIP analysis revealed that EBNA 2 and 3 proteins do not bind simultaneously at shared sites but compete for binding thereby modulating enhancer-promoter interactions. At an EBNA 3-only intergenic enhancer site between ADAM28 and ADAMDEC1 EBNA 3C was also able to independently direct epigenetic repression of both genes through enhancer-promoter looping. Significantly, studying shared or unique EBNA 3 binding sites at WEE1, CTBP2, ITGAL (LFA-1 alpha chain), BCL2L11 (Bim) and the ADAMs, we also discovered that different sets of EBNA 3 proteins bind regulatory elements in a gene and cell-type specific manner. Binding profiles correlated with the effects of individual EBNA 3 proteins on the expression of these genes, providing a molecular basis for the targeting of different sets of cellular genes by the EBNA 3s. Our results therefore highlight the influence of the genomic and cellular context in determining the specificity of gene deregulation by EBV and provide a paradigm for host-cell reprogramming through modulation of

CNS autoimmune disease after Streptococcus pyogenes infections: animal models, cellular mechanisms and genetic factors

PubMed Central

Cutforth, Tyler; DeMille, Mellissa MC; Agalliu, Ilir; Agalliu, Dritan

2016-01-01

Streptococcus pyogenes infections have been associated with two autoimmune diseases of the CNS: Sydenham’s chorea (SC) and Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus infections (PANDAS). Despite the high frequency of pharyngeal streptococcus infections among children, only a small fraction develops SC or PANDAS. This suggests that several factors in combination are necessary to trigger autoimmune complications: specific S. pyogenes strains that induce a strong immune response toward the host nervous system; genetic susceptibility that predispose children toward an autoimmune response involving movement or tic symptoms; and multiple infections of the throat or tonsils that lead to a robust Th17 cellular and humoral immune response when untreated. In this review, we summarize the evidence for each factor and propose that all must be met for the requisite neurovascular pathology and behavioral deficits found in SC/PANDAS. PMID:27110222

Integrated cellular network of transcription regulations and protein-protein interactions.

PubMed

Wang, Yu-Chao; Chen, Bor-Sen

2010-03-08

With the accumulation of increasing omics data, a key goal of systems biology is to construct networks at different cellular levels to investigate cellular machinery of the cell. However, there is currently no satisfactory method to construct an integrated cellular network that combines the gene regulatory network and the signaling regulatory pathway. In this study, we integrated different kinds of omics data and developed a systematic method to construct the integrated cellular network based on coupling dynamic models and statistical assessments. The proposed method was applied to S. cerevisiae stress responses, elucidating the stress response mechanism of the yeast. From the resulting integrated cellular network under hyperosmotic stress, the highly connected hubs which are functionally relevant to the stress response were identified. Beyond hyperosmotic stress, the integrated network under heat shock and oxidative stress were also constructed and the crosstalks of these networks were analyzed, specifying the significance of some transcription factors to serve as the decision-making devices at the center of the bow-tie structure and the crucial role for rapid adaptation scheme to respond to stress. In addition, the predictive power of the proposed method was also demonstrated. We successfully construct the integrated cellular network which is validated by literature evidences. The integration of transcription regulations and protein-protein interactions gives more insight into the actual biological network and is more predictive than those without integration. The method is shown to be powerful and flexible and can be used under different conditions and for different species. The coupling dynamic models of the whole integrated cellular network are very useful for theoretical analyses and for further experiments in the fields of network biology and synthetic biology.

Cellular-based preemption system

NASA Technical Reports Server (NTRS)

Bachelder, Aaron D. (Inventor)

2011-01-01

A cellular-based preemption system that uses existing cellular infrastructure to transmit preemption related data to allow safe passage of emergency vehicles through one or more intersections. A cellular unit in an emergency vehicle is used to generate position reports that are transmitted to the one or more intersections during an emergency response. Based on this position data, the one or more intersections calculate an estimated time of arrival (ETA) of the emergency vehicle, and transmit preemption commands to traffic signals at the intersections based on the calculated ETA. Additional techniques may be used for refining the position reports, ETA calculations, and the like. Such techniques include, without limitation, statistical preemption, map-matching, dead-reckoning, augmented navigation, and/or preemption optimization techniques, all of which are described in further detail in the above-referenced patent applications.

[Discriminating power of socio-demographic and psychological variables on addictive use of cellular phones among middle school students].

PubMed

Lee, Haejung; Kim, Myoung Soo; Son, Hyun Kyung; Ahn, Sukhee; Kim, Jung Soon; Kim, Young Hae

2007-10-01

The purpose of this study was to examine the degrees of cellular phone usage among middle school students and to identify discriminating factors of addictive use of cellular phones among sociodemographic and psychological variables. From 123 middle schools in Busan, potential participants were identified through stratified random sampling and 747 middle school students participated in the study. The data was collected from December 1, 2004 to December 30, 2004. Descriptive and discriminant analyses were used. Fifty seven percent of the participants were male and 89.7% used cellular phones at school. The participants were grouped into three groups depending on the levels of the cellular phone usage: addicted (n=117), dependent (n=418), non-addicted (n=212). Within the three groups, two functions were produced and only one function was significant, discriminating the addiction group from non-addiction group. Additional discriminant analysis with only two groups produced one function that classified 81.2% of the participants correctly into the two groups. Impulsiveness, anxiety, and stress were significant discriminating factors. Based on the findings of this study, developing intervention programs focusing on impulsiveness, anxiety and stress to reduce the possible addictive use of cellular phones is suggested.

Role of Fatty Acid Kinase in Cellular Lipid Homeostasis and SaeRS-Dependent Virulence Factor Expression in Staphylococcus aureus

PubMed Central

Ericson, Megan E.; Subramanian, Chitra; Frank, Matthew W.

2017-01-01

ABSTRACT The SaeRS two-component system is a master activator of virulence factor transcription in Staphylococcus aureus, but the cellular factors that control its activity are unknown. Fatty acid (FA) kinase is a two-component enzyme system required for extracellular FA uptake and SaeRS activity. Here, we demonstrate the existence of an intracellular nonesterified FA pool in S. aureus that is elevated in strains lacking FA kinase activity. SaeRS-mediated transcription is restored in FA kinase-negative strains when the intracellular FA pool is reduced either by growth with FA-depleted bovine serum albumin to extract the FA into the medium or by the heterologous expression of Neisseria gonorrhoeae acyl-acyl carrier protein synthetase to activate FA for phospholipid synthesis. These data show that FAs act as negative regulators of SaeRS signaling, and FA kinase activates SaeRS-dependent virulence factor production by lowering inhibitory FA levels. Thus, FA kinase plays a role in cellular lipid homeostasis by activating FA for incorporation into phospholipid, and it indirectly regulates SaeRS signaling by maintaining a low intracellular FA pool. PMID:28765222

High-Concentrate Diet-Induced Change of Cellular Metabolism Leads to Decreases of Immunity and Imbalance of Cellular Activities in Rumen Epithelium.

PubMed

Lu, Zhongyan; Shen, Hong; Shen, Zanming

2018-01-01

In animals, the immune and cellular processes of tissue largely depend on the status of local metabolism. However, in the rumen epithelium, how the cellular metabolism affects epithelial immunity, and cellular processes, when the diet is switched from energy-rich to energy-excess status, with regard to animal production and health, have not as yet been reported. RNA-seq was applied to compare the biological processes altered by an increase of dietary concentration from 10% to 35% with those altered by an increase of dietary concentration from 35% to 65% (dietary concentrate: the non-grass component in diet, including corn, soya bean meal and additive. High concentrate diet composed of 35% grass, 55% corn, 8% soya bean meal and 2% additive). In addition to the functional analysis of enriched genes in terms of metabolism, the immune system, and cellular process, the highly correlated genes to the enriched metabolism genes were identified, and the function and signaling pathways related to the differentially expressed neighbors were compared among the groups. The variation trends of molar proportions of ruminal SCFAs and those of enriched pathways belonging to metabolism, immune system, and cellular process were altered with the change of diets. With regard to metabolism, lipid metabolism and amino acid metabolism were most affected. According to the correlation analysis, both innate and adaptive immune responses were promoted by the metabolism genes enriched under the 65% concentrate diet. However, the majority of immune responses were suppressed under the 35% concentrate diet. Moreover, the exclusive upregulation of cell growth and dysfunction of cellular transport and catabolism were induced by the metabolism genes enriched under the 65% concentrate diet. On the contrary, a balanced regulation of cellular processes was detected under the 35% concentrate diet. These results indicated that the alterations of cellular metabolism promote the alterations in cellular

Integrated cellular network of transcription regulations and protein-protein interactions

PubMed Central

2010-01-01

Background With the accumulation of increasing omics data, a key goal of systems biology is to construct networks at different cellular levels to investigate cellular machinery of the cell. However, there is currently no satisfactory method to construct an integrated cellular network that combines the gene regulatory network and the signaling regulatory pathway. Results In this study, we integrated different kinds of omics data and developed a systematic method to construct the integrated cellular network based on coupling dynamic models and statistical assessments. The proposed method was applied to S. cerevisiae stress responses, elucidating the stress response mechanism of the yeast. From the resulting integrated cellular network under hyperosmotic stress, the highly connected hubs which are functionally relevant to the stress response were identified. Beyond hyperosmotic stress, the integrated network under heat shock and oxidative stress were also constructed and the crosstalks of these networks were analyzed, specifying the significance of some transcription factors to serve as the decision-making devices at the center of the bow-tie structure and the crucial role for rapid adaptation scheme to respond to stress. In addition, the predictive power of the proposed method was also demonstrated. Conclusions We successfully construct the integrated cellular network which is validated by literature evidences. The integration of transcription regulations and protein-protein interactions gives more insight into the actual biological network and is more predictive than those without integration. The method is shown to be powerful and flexible and can be used under different conditions and for different species. The coupling dynamic models of the whole integrated cellular network are very useful for theoretical analyses and for further experiments in the fields of network biology and synthetic biology. PMID:20211003

Comprehensive Identification of Krüppel-Like Factor Family Members Contributing to the Self-Renewal of Mouse Embryonic Stem Cells and Cellular Reprogramming.

PubMed

Jeon, Hyojung; Waku, Tsuyoshi; Azami, Takuya; Khoa, Le Tran Phuc; Yanagisawa, Jun; Takahashi, Satoru; Ema, Masatsugu

2016-01-01

Pluripotency is maintained in mouse embryonic stem (ES) cells and is induced from somatic cells by the activation of appropriate transcriptional regulatory networks. Krüppel-like factor gene family members, such as Klf2, Klf4 and Klf5, have important roles in maintaining the undifferentiated state of mouse ES cells as well as in cellular reprogramming, yet it is not known whether other Klf family members exert self-renewal and reprogramming functions when overexpressed. In this study, we examined whether overexpression of any representative Klf family member, such as Klf1-Klf10, would be sufficient for the self-renewal of mouse ES cells. We found that only Klf2, Klf4, and Klf5 produced leukemia inhibitory factor (LIF)-independent self-renewal, although most KLF proteins, if not all, have the ability to occupy the regulatory regions of Nanog, a critical Klf target gene. We also examined whether overexpression of any of Klf1-Klf10 would be sufficient to convert epiblast stem cells into a naïve pluripotent state and found that Klf5 had such reprogramming ability, in addition to Klf2 and Klf4. We also delineated the functional domains of the Klf2 protein for LIF-independent self-renewal and reprogramming. Interestingly, we found that both the N-terminal transcriptional activation and C-terminal zinc finger domains were indispensable for this activity. Taken together, our comprehensive analysis provides new insight into the contribution of Klf family members to mouse ES self-renewal and cellular reprogramming.

Using exploratory regression to identify optimal driving factors for cellular automaton modeling of land use change.

PubMed

Feng, Yongjiu; Tong, Xiaohua

2017-09-22

Defining transition rules is an important issue in cellular automaton (CA)-based land use modeling because these models incorporate highly correlated driving factors. Multicollinearity among correlated driving factors may produce negative effects that must be eliminated from the modeling. Using exploratory regression under pre-defined criteria, we identified all possible combinations of factors from the candidate factors affecting land use change. Three combinations that incorporate five driving factors meeting pre-defined criteria were assessed. With the selected combinations of factors, three logistic regression-based CA models were built to simulate dynamic land use change in Shanghai, China, from 2000 to 2015. For comparative purposes, a CA model with all candidate factors was also applied to simulate the land use change. Simulations using three CA models with multicollinearity eliminated performed better (with accuracy improvements about 3.6%) than the model incorporating all candidate factors. Our results showed that not all candidate factors are necessary for accurate CA modeling and the simulations were not sensitive to changes in statistically non-significant driving factors. We conclude that exploratory regression is an effective method to search for the optimal combinations of driving factors, leading to better land use change models that are devoid of multicollinearity. We suggest identification of dominant factors and elimination of multicollinearity before building land change models, making it possible to simulate more realistic outcomes.

Identification of the cellular receptor for anthrax toxin

NASA Astrophysics Data System (ADS)

Bradley, Kenneth A.; Mogridge, Jeremy; Mourez, Michael; Collier, R. John; Young, John A. T.

2001-11-01

The tripartite toxin secreted by Bacillus anthracis, the causative agent of anthrax, helps the bacterium evade the immune system and can kill the host during a systemic infection. Two components of the toxin enzymatically modify substrates within the cytosol of mammalian cells: oedema factor (OF) is an adenylate cyclase that impairs host defences through a variety of mechanisms including inhibiting phagocytosis; lethal factor (LF) is a zinc-dependent protease that cleaves mitogen-activated protein kinase kinase and causes lysis of macrophages. Protective antigen (PA), the third component, binds to a cellular receptor and mediates delivery of the enzymatic components to the cytosol. Here we describe the cloning of the human PA receptor using a genetic complementation approach. The receptor, termed ATR (anthrax toxin receptor), is a type I membrane protein with an extracellular von Willebrand factor A domain that binds directly to PA. In addition, a soluble version of this domain can protect cells from the action of the toxin.

Nuclear factor erythroid-2-related factor regulates LRWD1 expression and cellular adaptation to oxidative stress in human embryonal carcinoma cells.

PubMed

Hung, Jui-Hsiang; Wee, Shi-Kae; Omar, Hany A; Su, Chia-Hui; Chen, Hsing-Yi; Chen, Pin-Shern; Chiu, Chien-Chih; Wu, Ming-Syuan; Teng, Yen-Ni

2018-05-01

Leucine-rich repeats and WD repeat domain-containing protein 1 (LRWD1) is implicated in the regulation of signal transduction, transcription, RNA processing and tumor development. However, LRWD1 transcriptional regulation is not fully understood. This study aimed to investigate the relationship between LRWD1 expression and reactive oxygen species (ROS) level in human embryonal carcinoma cell line, NT2/D1 cells, which will help in understanding the transcriptional regulatory role of ROS in cells. Results showed that the exposure of NT2/D1 cells to various concentrations of hydrogen peroxide (H 2 O 2 ) and the nitric oxide (NO) donor sodium nitroprusside (SNP) caused a significant increase in the mRNA and protein expression of LRWD1. In addition, LRWD1 promoter luciferase reporter assay, and Chromatin Immunoprecipitation assay (CHIP assay) showed that nuclear factor erythroid-2-related factor (Nrf2) was involved in the regulation of LRWD1 expression in response to oxidative stress. The involvement of Nrf2 was confirmed by shRNA-mediated knockdown of Nrf2 in NT2/D1 cells, which caused a significant decrease in LRWD1 expression in response to oxidative stress. Similarly, LRWD1 knockdown resulted in the accumulation of H 2 O 2 and superoxide anion radical (O2-). Blocking ROS production by N-acetyl cysteine (NAC) protected NT2/D1 shLRWD1cells from H 2 O 2 -induced cell death. Collectively, oxidative stress increased LRWD1 expression through a Nrf2-dependent mechanism, which plays an important role in cellular adaptation to oxidative stress. These results highlight an evidence, on the molecular level, about LRWD1 transcriptional regulation under oxidative stress. Copyright © 2018 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

Cellular Contraction and Polarization Drive Collective Cellular Motion.

PubMed

Notbohm, Jacob; Banerjee, Shiladitya; Utuje, Kazage J C; Gweon, Bomi; Jang, Hwanseok; Park, Yongdoo; Shin, Jennifer; Butler, James P; Fredberg, Jeffrey J; Marchetti, M Cristina

2016-06-21

Coordinated motions of close-packed multicellular systems typically generate cooperative packs, swirls, and clusters. These cooperative motions are driven by active cellular forces, but the physical nature of these forces and how they generate collective cellular motion remain poorly understood. Here, we study forces and motions in a confined epithelial monolayer and make two experimental observations: 1) the direction of local cellular motion deviates systematically from the direction of the local traction exerted by each cell upon its substrate; and 2) oscillating waves of cellular motion arise spontaneously. Based on these observations, we propose a theory that connects forces and motions using two internal state variables, one of which generates an effective cellular polarization, and the other, through contractile forces, an effective cellular inertia. In agreement with theoretical predictions, drugs that inhibit contractility reduce both the cellular effective elastic modulus and the frequency of oscillations. Together, theory and experiment provide evidence suggesting that collective cellular motion is driven by at least two internal variables that serve to sustain waves and to polarize local cellular traction in a direction that deviates systematically from local cellular velocity. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Hierarchy of cellular decisions in collective behavior: Implications for wound healing.

PubMed

Wickert, Lisa E; Pomerenke, Shaun; Mitchell, Isaiah; Masters, Kristyn S; Kreeger, Pamela K

2016-02-02

Collective processes such as wound re-epithelialization result from the integration of individual cellular decisions. To determine which individual cell behaviors represent the most promising targets to engineer re-epithelialization, we examined collective and individual responses of HaCaT keratinocytes seeded upon polyacrylamide gels of three stiffnesses (1, 30, and 100 kPa) and treated with a range of epidermal growth factor (EGF) doses. Wound closure was found to increase with substrate stiffness, but was responsive to EGF treatment only above a stiffness threshold. Individual cell behaviors were used to create a partial least squares regression model to predict the hierarchy of factors driving wound closure. Unexpectedly, cell area and persistence were found to have the strongest correlation to the observed differences in wound closure. Meanwhile, the model predicted a relatively weak correlation between wound closure with proliferation, and the unexpectedly minor input from proliferation was successfully tested with inhibition by aphidicolin. Combined, these results suggest that the poor clinical results for growth factor-based therapies for chronic wounds may result from a disconnect between the individual cellular behaviors targeted in these approaches and the resulting collective response. Additionally, the stiffness-dependency of EGF sensitivity suggests that therapies matched to microenvironmental characteristics will be more efficacious.

Translating neurotrophic and cellular plasticity: from pathophysiology to improved therapeutics for bipolar disorder.

PubMed

Soeiro-de-Souza, M G; Dias, V V; Figueira, M L; Forlenza, O V; Gattaz, W F; Zarate, C A; Machado-Vieira, R

2012-11-01

Bipolar disorder (BD) likely involves, at a molecular and cellular level, dysfunctions of critical neurotrophic, cellular plasticity and resilience pathways and neuroprotective processes. Therapeutic properties of mood stabilizers are presumed to result from a restoration of the function of these altered pathways and processes through a wide range of biochemical and molecular effects. We aimed to review the altered pathways and processes implicated in BD, such as neurotrophic factors, mitogen-activated protein kinases, Bcl-2, phosphoinositol signaling, intracellular calcium and glycogen synthase kinase-3. We undertook a literature search of recent relevant journal articles, book chapter and reviews on neurodegeneration and neuroprotection in BD. Search words entered were 'brain-derived neurotrophic factor,''Bcl-2,''mitogen-activated protein kinases,''neuroprotection,''calcium,''bipolar disorder,''mania,' and 'depression.' The most consistent and replicated findings in the pathophysiology of BD may be classified as follows: i) calcium dysregulation, ii) mitochondrial/endoplasmic reticulum dysfunction, iii) glial and neuronal death/atrophy and iv) loss of neurotrophic/plasticity effects in brain areas critically involved in mood regulation. In addition, the evidence supports that treatment with mood stabilizers; in particular, lithium restores these pathophysiological changes. Bipolar disorder is associated with impairments in neurotrophic, cellular plasticity and resilience pathways as well as in neuroprotective processes. The evidence supports that treatment with mood stabilizers, in particular lithium, restores these pathophysiological changes. Studies that attempt to prevent (intervene before the onset of the molecular and cellular changes), treat (minimize severity of these deficits over time), and rectify (reverse molecular and cellular deficits) are promising therapeutic strategies for developing improved treatments for bipolar disorder. © 2012 John Wiley

Differential cellular responses by oncogenic levels of c-Myc expression in long-term confluent retinal pigment epithelial cells.

PubMed

Wang, Yiping; Cheng, Xiangdong; Samma, Muhammad Kaleem; Kung, Sam K P; Lee, Clement M; Chiu, Sung Kay

2018-06-01

c-Myc is a highly pleiotropic transcription factor known to control cell cycle progression, apoptosis, and cellular transformation. Normally, ectopic expression of c-Myc is associated with promoting cell proliferation or triggering cell death via activating p53. However, it is not clear how the levels of c-Myc lead to different cellular responses. Here, we generated a series of stable RPE cell clones expressing c-Myc at different levels, and found that consistent low level of c-Myc induced cellular senescence by activating AP4 in post-confluent RPE cells, while the cells underwent cell death at high level of c-Myc. In addition, high level of c-Myc could override the effect of AP4 on cellular senescence. Further knockdown of AP4 abrogated senescence-like phenotype in cells expressing low level of c-Myc, and accelerated cell death in cells with medium level of c-Myc, indicating that AP4 was required for cellular senescence induced by low level of c-Myc.

Effect of crystals and fibrous network polymer additives on cellular morphology of microcellular foams

NASA Astrophysics Data System (ADS)

Miyamoto, Ryoma; Utano, Tatsumi; Yasuhara, Shunya; Ishihara, Shota; Ohshima, Masahiro

2015-05-01

In this study, the core-back foam injection molding was used for preparing microcelluar polypropylene (PP) foam with either a 1,3:2,4 bis-O-(4-methylbenzylidene)-D-sorbitol gelling agent (Gel-all MD) or a fibros network polymer additive (Metablen 3000). Both agent and addiive could effectively control the celluar morphology in foams but somehow different ways. In course of cooling the polymer with Gel-all MD in the mold caity, the agent enhanced the crystal nucleation and resulted in the large number of small crystals. The crystals acted as effective bubble nucleation agent in foaming process. Thus, the agent reduced the cell size and increased the cell density, drastically. Furthermore, the small crystals provided an inhomogenuity to the expanding cell wall and produced the high open cell content with nano-scale fibril structure. Gell-all as well as Metablene 3000 formed a gel-like fibrous network in melt. The network increased the elongational viscosity and tended to prevent the cell wall from breaking up. The foaming temperature window was widened by the presence of the network. Especially, the temperature window where the macro-fibrous structure was formed was expanded to the higher temperature. The effects of crystal nucleating agent and PTFE on crystals' size and number, viscoelsticity, rheological propreties of PP and cellular morphology were compared and thorougly investigated.

Cellular Strategies of Protein Quality Control

PubMed Central

Chen, Bryan; Retzlaff, Marco; Roos, Thomas; Frydman, Judith

2011-01-01

Eukaryotic cells must contend with a continuous stream of misfolded proteins that compromise the cellular protein homeostasis balance and jeopardize cell viability. An elaborate network of molecular chaperones and protein degradation factors continually monitor and maintain the integrity of the proteome. Cellular protein quality control relies on three distinct yet interconnected strategies whereby misfolded proteins can either be refolded, degraded, or delivered to distinct quality control compartments that sequester potentially harmful misfolded species. Molecular chaperones play a critical role in determining the fate of misfolded proteins in the cell. Here, we discuss the spatial and temporal organization of cellular quality control strategies and their implications for human diseases linked to protein misfolding and aggregation. PMID:21746797

Design, synthesis and cellular metabolism study of 4'-selenonucleosides.

PubMed

Yu, Jinha; Sahu, Pramod K; Kim, Gyudong; Qu, Shuhao; Choi, Yoojin; Song, Jayoung; Lee, Sang Kook; Noh, Minsoo; Park, Sunghyouk; Jeong, Lak Shin

2015-01-01

4'-seleno-homonucleosides were synthesized as next-generation nucleosides, and their cellular phosphorylation was studied to confirm the hypothesis that bulky selenium atom can sterically hinder the approach of cellular nucleoside kinase to the 5'-OH for phosphorylation. 4'-seleno-homonucleosides (n = 2), with one-carbon homologation, were synthesized through a tandem seleno-Michael addition-SN2 ring cyclization. LC-MS analysis demonstrated that they were phosphorylated by cellular nucleoside kinases, resulting in anticancer activity. The bulky selenium atom played a key role in deciding the phosphorylation by cellular nucleoside kinases. [Formula: see text].

Cellular Internalization of Fibroblast Growth Factor-12 Exerts Radioprotective Effects on Intestinal Radiation Damage Independently of FGFR Signaling

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

Nakayama, Fumiaki, E-mail: f_naka@nirs.go.jp; Umeda, Sachiko; Yasuda, Takeshi

2014-02-01

Purpose: Several fibroblast growth factors (FGFs) were shown to inhibit radiation-induced tissue damage through FGF receptor (FGFR) signaling; however, this signaling was also found to be involved in the pathogenesis of several malignant tumors. In contrast, FGF12 cannot activate any FGFRs. Instead, FGF12 can be internalized readily into cells using 2 cell-penetrating peptide domains (CPP-M, CPP-C). Therefore, this study focused on clarifying the role of FGF12 internalization in protection against radiation-induced intestinal injury. Methods and Materials: Each FGF or peptide was administered intraperitoneally to BALB/c mice in the absence of heparin 24 hours before or after total body irradiation withmore » γ rays at 9 to 12 Gy. Several radioprotective effects were examined in the jejunum. Results: Administration of FGF12 after radiation exposure was as effective as pretreatment in significantly promoting intestinal regeneration, proliferation of crypt cells, and epithelial differentiation. Two domains, comprising amino acid residues 80 to 109 and 140 to 169 of FGF12B, were identified as being responsible for the radioprotective activity, so that deletion of both domains from FGF12B resulted in a reduction in activity. Interestingly, these regions included the CPP-M and CPP-C domains, respectively; however, CPP-C by itself did not show an antiapoptotic effect. In addition, FGF1, prototypic FGF, possesses a domain corresponding to CPP-M, whereas it lacks CPP-C, so the fusion of FGF1 with CPP-C (FGF1/CPP-C) enhanced cellular internalization and increased radioprotective activity. However, FGF1/CPP-C reduced in vitro mitogenic activity through FGFRs compared with FGF1, implying that FGFR signaling might not be essential for promoting the radioprotective effect of FGF1/CPP-C. In addition, internalized FGF12 suppressed the activation of p38α after irradiation, resulting in reduced radiation-induced apoptosis. Conclusions: These findings indicate that FGF12 can

Transcriptional regulation of cellular ageing by the CCAAT box-binding factor CBF/NF-Y.

PubMed

Matuoka, Koozi; Chen, Kuang Yu

2002-09-01

Cellular ageing is a systematic process affecting the entirety of cell structure and function. Since changes in gene expression are extensive and global during ageing, involvement of general transcription regulators in the phenomenon is likely. Here, we focus on NF-Y, the major CCAAT box-binding factor, which exerts differential regulation on a wide variety of genes through its interaction with the CCAAT box present in as many as 25% of the eukaryotic genes. When a cell ages, senescing signals arise, typically through DNA damage due to oxidative stress or telomere shortening, and are transduced to proteins such as p53, retinoblastoma protein, and phosphatidylinositol 3-kinase. Among them, activated p53 family proteins suppress the function of NF-Y and thereby downregulate a set of cell cycle-related genes, including E2F1, which further leads to downregulation of E2F-regulated genes and cell cycle arrest. The p53 family also induces other ageing phenotypes such as morphological alterations and senescence-associated beta-galactosidase (SA-gal) presumably by upregulation of some genes through NF-Y suppression. In fact, the activities of NF-Y and E2F decrease during ageing and a dominant negative NF-YA induces SA-gal. Based on these observations, NF-Y appears to play an important role in the process of cellular ageing.

Cyclin A recruits p33cdk2 to the cellular transcription factor DRTF1.

PubMed

Bandara, L R; Adamczewski, J P; Zamanian, M; Poon, R Y; Hunt, T; Thangue, N B

1992-01-01

Cyclins are regulatory molecules that undergo periodic accumulation and destruction during each cell cycle. By activating p34cdc2 and related kinase subunits they control important events required for normal cell cycle progression. Cyclin A, for example, regulates at least two distinct kinase subunits, the mitotic kinase subunit p34cdc2 and related subunit p33cdk2, and is widely believed to be necessary for progression through S phase. However, cyclin A also forms a stable complex with the cellular transcription factor DRTF1 and thus may perform other functions during S phase. DRTF1, in addition, associates with the tumour suppressor retinoblastoma (Rb) gene product and the Rb-related protein p107. We now show, using biologically active fusion proteins, that cyclin A can direct the binding of the cdc2-like kinase subunit, p33cdk2, to complexed DRTF1, containing either Rb or p107, as well as activate its histone H1 kinase activity. Cyclin A cannot, however, direct p34cdc2 to the DRTF1 complex and we present evidence suggesting that the stability of the cyclin A-p33cdk2 complex is influenced by DRTF1 or an associated protein. Cyclin A, therefore, serves as an activating and targeting subunit of p33cdk2. The ability of cyclin A to activate and recruit p33cdk2 to DRTF1 may play an important role in regulating cell cycle progression and moreover defines a mechanism for coupling cell-cycle events to transcriptional initiation.

Lempel-Ziv complexity analysis of one dimensional cellular automata.

PubMed

Estevez-Rams, E; Lora-Serrano, R; Nunes, C A J; Aragón-Fernández, B

2015-12-01

Lempel-Ziv complexity measure has been used to estimate the entropy density of a string. It is defined as the number of factors in a production factorization of a string. In this contribution, we show that its use can be extended, by using the normalized information distance, to study the spatiotemporal evolution of random initial configurations under cellular automata rules. In particular, the transfer information from time consecutive configurations is studied, as well as the sensitivity to perturbed initial conditions. The behavior of the cellular automata rules can be grouped in different classes, but no single grouping captures the whole nature of the involved rules. The analysis carried out is particularly appropriate for studying the computational processing capabilities of cellular automata rules.

Lempel-Ziv complexity analysis of one dimensional cellular automata

NASA Astrophysics Data System (ADS)

Estevez-Rams, E.; Lora-Serrano, R.; Nunes, C. A. J.; Aragón-Fernández, B.

2015-12-01

Lempel-Ziv complexity measure has been used to estimate the entropy density of a string. It is defined as the number of factors in a production factorization of a string. In this contribution, we show that its use can be extended, by using the normalized information distance, to study the spatiotemporal evolution of random initial configurations under cellular automata rules. In particular, the transfer information from time consecutive configurations is studied, as well as the sensitivity to perturbed initial conditions. The behavior of the cellular automata rules can be grouped in different classes, but no single grouping captures the whole nature of the involved rules. The analysis carried out is particularly appropriate for studying the computational processing capabilities of cellular automata rules.

Translating neurotrophic and cellular plasticity: from pathophysiology to improved therapeutics for bipolar disorder

PubMed Central

Soeiro-de-Souza, M. G.; Dias, V. V.; Figueira, M. L.; Forlenza, O. V.; Gattaz, W. F.; Zarate, C. A.; Machado-Vieira, R.

2014-01-01

Objective Bipolar disorder (BD) likely involves, at a molecular and cellular level, dysfunctions of critical neurotrophic, cellular plasticity and resilience pathways and neuroprotective processes. Therapeutic properties of mood stabilizers are presumed to result from a restoration of the function of these altered pathways and processes through a wide range of biochemical and molecular effects. We aimed to review the altered pathways and processes implicated in BD, such as neurotrophic factors, mitogen-activated protein kinases, Bcl-2, phosphoinositol signaling, intracellular calcium and glycogen synthase kinase-3. Methods We undertook a literature search of recent relevant journal articles, book chapter and reviews on neurodegeneration and neuroprotection in BD. Search words entered were ‘brain-derived neurotrophic factor,’ ‘Bcl-2,’ ‘mitogen-activated protein kinases,’ ‘neuroprotection,’ ‘calcium,’ ‘bipolar disorder,’ ‘mania,’ and ‘depression.’ Results The most consistent and replicated findings in the pathophysiology of BD may be classified as follows: i) calcium dysregulation, ii) mitochondrial/endoplasmic reticulum dysfunction, iii) glial and neuronal death/atrophy and iv) loss of neurotrophic/plasticity effects in brain areas critically involved in mood regulation. In addition, the evidence supports that treatment with mood stabilizers; in particular, lithium restores these pathophysiological changes. Conclusion Bipolar disorder is associated with impairments in neurotrophic, cellular plasticity and resilience pathways as well as in neuroprotective processes. The evidence supports that treatment with mood stabilizers, in particular lithium, restores these pathophysiological changes. Studies that attempt to prevent (intervene before the onset of the molecular and cellular changes), treat (minimize severity of these deficits over time), and rectify (reverse molecular and cellular deficits) are promising therapeutic strategies for

Dicarbonyls stimulate cellular protection systems in primary rat hepatocytes and show anti-inflammatory properties.

PubMed

Buetler, Timo M; Latado, Hélia; Baumeyer, Alexandra; Delatour, Thierry

2008-04-01

Advanced glycation endproducts (AGEs) and their precursor dicarbonyls are generally perceived as having adverse health effects. They are also considered to be initiators and promoters of disease and aging. However, proof for a causal relationship is lacking. On the other hand, it is known that AGEs and melanoidins possess beneficial properties, such as antioxidant and metal-chelating activities. Furthermore, some AGEs may stimulate the cellular detoxification system, generally known as the phase II drug metabolizing system. We show here that several reactive dicarbonyl intermediates have the capability to stimulate the cellular phase II detoxification systems in both a reporter cell line and primary rat hepatocytes. In addition, we demonstrate that dicarbonyls can attenuate the inflammatory signaling induced by tumor necrosis factor-alpha in a reporter cell system.

Viral Activation of Cellular Metabolism

PubMed Central

Sanchez, Erica L.; Lagunoff, Michael

2015-01-01

To ensure optimal environments for their replication and spread, viruses have evolved to alter many host cell pathways. In the last decade, metabolomic studies have shown that eukaryotic viruses induce large-scale alterations in host cellular metabolism. Most viruses examined to date induce aerobic glycolysis also known as the Warburg effect. Many viruses tested also induce fatty acid synthesis as well as glutaminolysis. These modifications of carbon source utilization by infected cells can increase available energy for virus replication and virion production, provide specific cellular substrates for virus particles and create viral replication niches while increasing infected cell survival. Each virus species also likely requires unique metabolic changes for successful spread and recent research has identified additional virus-specific metabolic changes induced by many virus species. A better understanding of the metabolic alterations required for each virus may lead to novel therapeutic approaches through targeted inhibition of specific cellular metabolic pathways. PMID:25812764

Role of resveratrol in regulation of cellular defense systems against oxidative stress.

PubMed

Truong, Van-Long; Jun, Mira; Jeong, Woo-Sik

2018-01-01

Resveratrol, a natural polyphenolic compound, is found in various kinds of fruits, plants, and their commercial products such as red wine. It has been demonstrated to exhibit a variety of health-promoting effects including prevention and/or treatment of cardiovascular diseases, inflammation, diabetes, neurodegeneration, aging, and cancer. Cellular defensive properties of resveratrol can be explained through its ability of either directly neutralizing reactive oxygen species/reactive nitrogen species (ROS/RNS) or indirectly upregulating the expression of cellular defensive genes. As a direct antioxidant agent, resveratrol scavenges diverse ROS/RNS as well as secondary organic radicals with mechanisms of hydrogen atom transfer and sequential proton loss electron transfer, thereby protecting cellular biomolecules from oxidative damage. Resveratrol also enhances the expression of various antioxidant defensive enzymes such as heme oxygenase 1, catalase, glutathione peroxidase, and superoxide dismutase as well as the induction of glutathione level responsible for maintaining the cellular redox balance. Such defenses could be achieved by regulating various signaling pathways including sirtuin 1, nuclear factor-erythroid 2-related factor 2 and nuclear factor κB. This review provides current understanding and information on the role of resveratrol in cellular defense system against oxidative stress. © 2017 BioFactors, 44(1):36-49, 2018. © 2017 International Union of Biochemistry and Molecular Biology.

Matrix Metalloproteinase 3 Promotes Cellular Anti-Dengue Virus Response via Interaction with Transcription Factor NFκB in Cell Nucleus

PubMed Central

Zuo, Xiangyang; Pan, Wen; Feng, Tingting; Shi, Xiaohong; Dai, Jianfeng

2014-01-01

Dengue virus (DENV), the causative agent of human Dengue hemorrhagic fever, is a mosquito-borne virus of immense global health importance. Characterization of cellular factors promoting or inhibiting DENV infection is important for understanding the mechanism of DENV infection. In this report, MMP3 (stromelysin-1), a secretory endopeptidase that degrades extracellular matrices, has been shown promoting cellular antiviral response against DENV infection. Quantitative RT-PCR and Western Blot showed that the expression of MMP3 was upregulated in DENV-infected RAW264.7 cells. The intracellular viral loads were significantly higher in MMP3 silenced cells compared with controls. The expression level of selective anti-viral cytokines were decreased in MMP3 siRNA treated cells, and the transcription factor activity of NFκB was significantly impaired upon MMP3 silencing during DENV infection. Further, we found that MMP3 moved to cell nucleus upon DENV infection and colocalized with NFκB P65 in nucleus. Co-immunoprecipitation analysis suggested that MMP3 directly interacted with NFκB in nucleus during DENV infection and the C-terminal hemopexin-like domain of MMP3 was required for the interaction. This study suggested a novel role of MMP3 in nucleus during viral infection and provided new evidence for MMPs in immunomodulation. PMID:24416274

Matrix metalloproteinase 3 promotes cellular anti-dengue virus response via interaction with transcription factor NFκB in cell nucleus.

PubMed

Zuo, Xiangyang; Pan, Wen; Feng, Tingting; Shi, Xiaohong; Dai, Jianfeng

2014-01-01

Dengue virus (DENV), the causative agent of human Dengue hemorrhagic fever, is a mosquito-borne virus of immense global health importance. Characterization of cellular factors promoting or inhibiting DENV infection is important for understanding the mechanism of DENV infection. In this report, MMP3 (stromelysin-1), a secretory endopeptidase that degrades extracellular matrices, has been shown promoting cellular antiviral response against DENV infection. Quantitative RT-PCR and Western Blot showed that the expression of MMP3 was upregulated in DENV-infected RAW264.7 cells. The intracellular viral loads were significantly higher in MMP3 silenced cells compared with controls. The expression level of selective anti-viral cytokines were decreased in MMP3 siRNA treated cells, and the transcription factor activity of NFκB was significantly impaired upon MMP3 silencing during DENV infection. Further, we found that MMP3 moved to cell nucleus upon DENV infection and colocalized with NFκB P65 in nucleus. Co-immunoprecipitation analysis suggested that MMP3 directly interacted with NFκB in nucleus during DENV infection and the C-terminal hemopexin-like domain of MMP3 was required for the interaction. This study suggested a novel role of MMP3 in nucleus during viral infection and provided new evidence for MMPs in immunomodulation.

Cellular Automata

NASA Astrophysics Data System (ADS)

Gutowitz, Howard

1991-08-01

Cellular automata, dynamic systems in which space and time are discrete, are yielding interesting applications in both the physical and natural sciences. The thirty four contributions in this book cover many aspects of contemporary studies on cellular automata and include reviews, research reports, and guides to recent literature and available software. Chapters cover mathematical analysis, the structure of the space of cellular automata, learning rules with specified properties: cellular automata in biology, physics, chemistry, and computation theory; and generalizations of cellular automata in neural nets, Boolean nets, and coupled map lattices. Current work on cellular automata may be viewed as revolving around two central and closely related problems: the forward problem and the inverse problem. The forward problem concerns the description of properties of given cellular automata. Properties considered include reversibility, invariants, criticality, fractal dimension, and computational power. The role of cellular automata in computation theory is seen as a particularly exciting venue for exploring parallel computers as theoretical and practical tools in mathematical physics. The inverse problem, an area of study gaining prominence particularly in the natural sciences, involves designing rules that possess specified properties or perform specified task. A long-term goal is to develop a set of techniques that can find a rule or set of rules that can reproduce quantitative observations of a physical system. Studies of the inverse problem take up the organization and structure of the set of automata, in particular the parameterization of the space of cellular automata. Optimization and learning techniques, like the genetic algorithm and adaptive stochastic cellular automata are applied to find cellular automaton rules that model such physical phenomena as crystal growth or perform such adaptive-learning tasks as balancing an inverted pole. Howard Gutowitz is

Quantum cellular automata

NASA Astrophysics Data System (ADS)

Porod, Wolfgang; Lent, Craig S.; Bernstein, Gary H.

1994-06-01

The Notre Dame group has developed a new paradigm for ultra-dense and ultra-fast information processing in nanoelectronic systems. These Quantum Cellular Automata (QCA's) are the first concrete proposal for a technology based on arrays of coupled quantum dots. The basic building block of these cellular arrays is the Notre Dame Logic Cell, as it has been called in the literature. The phenomenon of Coulomb exclusion, which is a synergistic interplay of quantum confinement and Coulomb interaction, leads to a bistable behavior of each cell which makes possible their use in large-scale cellular arrays. The physical interaction between neighboring cells has been exploited to implement logic functions. New functionality may be achieved in this fashion, and the Notre Dame group invented a versatile majority logic gate. In a series of papers, the feasibility of QCA wires, wire crossing, inverters, and Boolean logic gates was demonstrated. A major finding is that all logic functions may be integrated in a hierarchial fashion which allows the design of complicated QCA structures. The most complicated system which was simulated to date is a one-bit full adder consisting of some 200 cells. In addition to exploring these new concepts, efforts are under way to physically realize such structures both in semiconductor and metal systems. Extensive modeling work of semiconductor quantum dot structures has helped identify optimum design parameters for QCA experimental implementations.

Euphorbia factor L1 inhibits osteoclastogenesis by regulating cellular redox status and induces Fas-mediated apoptosis in osteoclast.

PubMed

Hong, Seong-Eun; Lee, Jiae; Seo, Dong-Hyun; In Lee, Hye; Ri Park, Doo; Lee, Gong-Rak; Jo, You-Jin; Kim, Narae; Kwon, Minjung; Shon, Hansem; Kyoung Seo, Eun; Kim, Han-Sung; Young Lee, Soo; Jeong, Woojin

2017-11-01

Excessive bone resorption caused by increased osteoclast number or activity leads to a variety of bone diseases including osteoporosis, rheumatoid arthritis and periodontitis. Thus, the therapeutic strategy for these diseases has been focused primarily on the inhibition of osteoclast formation and function. This study shows that euphorbia factor L1 (EFL1), a diterpenoid isolated from Euphorbia lathyris, inhibited osteoclastogenesis and induced osteoclast apoptosis. EFL1 suppressed osteoclast formation and bone resorption at both initial and terminal differentiation stages. EFL1 inhibited receptor activator of NF-κB ligand (RANKL)-induced NFATc1 induction with attenuated NF-κB activation and c-Fos expression. EFL1 decreased the level of reactive oxygen species by scavenging them or activating Nrf2, and inhibited PGC-1β that regulates mitochondria biogenesis. In addition, EFL1 induced apoptosis in differentiated osteoclasts by increasing Fas ligand expression followed by caspase activation. Moreover, EFL1 inhibited inflammation-induced bone erosion and ovariectomy-induced bone loss in mice. These findings suggest that EFL1 inhibits osteoclast differentiation by regulating cellular redox status and induces Fas-mediated apoptosis in osteoclast, and may provide therapeutic potential for preventing or treating bone-related diseases caused by excessive osteoclast. Copyright © 2017 Elsevier Inc. All rights reserved.

34 CFR 477.22 - What additional factors does the Secretary consider?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION STATE PROGRAM ANALYSIS ASSISTANCE AND POLICY STUDIES PROGRAM How Does the Secretary Make an Award? § 477.22 What additional factors does the...

34 CFR 477.22 - What additional factors does the Secretary consider?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION STATE PROGRAM ANALYSIS ASSISTANCE AND POLICY STUDIES PROGRAM How Does the Secretary Make an Award? § 477.22 What additional factors does the...

Global functional analyses of cellular responses to pore-forming toxins.

PubMed

Kao, Cheng-Yuan; Los, Ferdinand C O; Huffman, Danielle L; Wachi, Shinichiro; Kloft, Nicole; Husmann, Matthias; Karabrahimi, Valbona; Schwartz, Jean-Louis; Bellier, Audrey; Ha, Christine; Sagong, Youn; Fan, Hui; Ghosh, Partho; Hsieh, Mindy; Hsu, Chih-Shen; Chen, Li; Aroian, Raffi V

2011-03-01

Here we present the first global functional analysis of cellular responses to pore-forming toxins (PFTs). PFTs are uniquely important bacterial virulence factors, comprising the single largest class of bacterial protein toxins and being important for the pathogenesis in humans of many Gram positive and Gram negative bacteria. Their mode of action is deceptively simple, poking holes in the plasma membrane of cells. The scattered studies to date of PFT-host cell interactions indicate a handful of genes are involved in cellular defenses to PFTs. How many genes are involved in cellular defenses against PFTs and how cellular defenses are coordinated are unknown. To address these questions, we performed the first genome-wide RNA interference (RNAi) screen for genes that, when knocked down, result in hypersensitivity to a PFT. This screen identifies 106 genes (∼0.5% of genome) in seven functional groups that protect Caenorhabditis elegans from PFT attack. Interactome analyses of these 106 genes suggest that two previously identified mitogen-activated protein kinase (MAPK) pathways, one (p38) studied in detail and the other (JNK) not, form a core PFT defense network. Additional microarray, real-time PCR, and functional studies reveal that the JNK MAPK pathway, but not the p38 MAPK pathway, is a key central regulator of PFT-induced transcriptional and functional responses. We find C. elegans activator protein 1 (AP-1; c-jun, c-fos) is a downstream target of the JNK-mediated PFT protection pathway, protects C. elegans against both small-pore and large-pore PFTs and protects human cells against a large-pore PFT. This in vivo RNAi genomic study of PFT responses proves that cellular commitment to PFT defenses is enormous, demonstrates the JNK MAPK pathway as a key regulator of transcriptionally-induced PFT defenses, and identifies AP-1 as the first cellular component broadly important for defense against large- and small-pore PFTs.

Mechanism of Diphtheria Toxin Catalytic Domain Delivery to the Eukaryotic Cell Cytosol and the Cellular Factors that Directly Participate in the Process

PubMed Central

Murphy, John R.

2011-01-01

Research on diphtheria and anthrax toxins over the past three decades has culminated in a detailed understanding of their structure function relationships (e.g., catalytic (C), transmembrane (T), and receptor binding (R) domains), as well as the identification of their eukaryotic cell surface receptor, an understanding of the molecular events leading to the receptor-mediated internalization of the toxin into an endosomal compartment, and the pH triggered conformational changes required for pore formation in the vesicle membrane. Recently, a major research effort has been focused on the development of a detailed understanding of the molecular interactions between each of these toxins and eukaryotic cell factors that play an essential role in the efficient translocation of their respective catalytic domains through the trans-endosomal vesicle membrane pore and delivery into the cell cytosol. In this review, I shall focus on recent findings that have led to a more detailed understanding of the mechanism by which the diphtheria toxin catalytic domain is delivered to the eukaryotic cell cytosol. While much work remains, it is becoming increasingly clear that the entry process is facilitated by specific interactions with a number of cellular factors in an ordered sequential fashion. In addition, since diphtheria, anthrax lethal factor and anthrax edema factor all carry multiple coatomer I complex binding motifs and COPI complex has been shown to play an essential role in entry process, it is likely that the initial steps in catalytic domain entry of these divergent toxins follow a common mechanism. PMID:22069710

Effects of fexofenadine and hydroxyzine on brake reaction time during car-driving with cellular phone use.

PubMed

Tashiro, Manabu; Horikawa, Etsuo; Mochizuki, Hideki; Sakurada, Yumiko; Kato, Motohisa; Inokuchi, Takatoshi; Ridout, Fran; Hindmarch, Ian; Yanai, Kazuhiko

2005-10-01

Antihistamines are a mainstay treatment for allergic rhinitis; however, many older agents cause adverse events, including sedation and central nervous system (CNS) impairment. Research has shown sedating effects of antihistamines on driving; currently, no known study has examined whether cellular phone usage while driving further compounds impairment in individuals administered antihistamines. The aim of this study was to examine this endpoint. In a randomized, double-blind, placebo-controlled, three-way crossover study, healthy volunteers received fexofenadine HCl 120 mg, hydroxyzine HCl 30 mg and placebo. Brake reaction time (BRT) was used to examine driving performance across four conditions: driving only; driving while completing simple calculations; complex calculations; and conversing on a cellular phone. Subjective sedation assessments were also conducted. Brake reaction time with and without cellular phone usage in fexofenadine-treated subjects did not differ significantly from placebo in any condition. In contrast, hydroxyzine-treated subjects were significantly more sedated and had slower BRTs, suggesting slower hazard recognition and brake application, compared with the fexofenadine and placebo groups in all conditions. Importantly, cellular phone operation was an additive factor, increasing BRTs in hydroxyzine-treated volunteers. Fexofenadine did not impair CNS function in subjects involved in a divided attention task of driving and cellular phone operation. Copyright (c) 2005 John Wiley & Sons, Ltd.

HSP90 Inhibition and Cellular Stress Elicits Phenotypic Plasticity in Hematopoietic Differentiation

PubMed Central

Lawag, Abdalla A.; Napper, Jennifer M.; Hunter, Caroline A.; Bacon, Nickolas A.; Deskins, Seth; El-hamdani, Manaf; Govender, Sarah-Leigh; Koc, Emine C.

2017-01-01

Abstract Cancer cells exist in a state of Darwinian selection using mechanisms that produce changes in gene expression through genetic and epigenetic alteration to facilitate their survival. Cellular plasticity, or the ability to alter cellular phenotype, can assist in survival of premalignant cells as they progress to full malignancy by providing another mechanism of adaptation. The connection between cellular stress and the progression of cancer has been established, although the details of the mechanisms have yet to be fully elucidated. The molecular chaperone HSP90 is often upregulated in cancers as they progress, presumably to allow cancer cells to deal with misfolded proteins and cellular stress associated with transformation. The objective of this work is to test the hypothesis that inhibition of HSP90 results in increased cell plasticity in mammalian systems that can confer a greater adaptability to selective pressures. The approach used is a murine in vitro model system of hematopoietic differentiation that utilizes a murine hematopoietic stem cell line, erythroid myeloid lymphoid (EML) clone 1, during their maturation from stem cells to granulocytic progenitors. During the differentiation protocol, 80%–90% of the cells die when placed in medium where the major growth factor is granulocyte–macrophage-colony stimulating factor. Using this selection point model, EML cells exhibit increases in cellular plasticity when they are better able to adapt to this medium and survive. Increases in cellular plasticity were found to occur upon exposure to geldanamycin to inhibit HSP90, when subjected to various forms of cellular stress, or inhibition of histone acetylation. Furthermore, we provide evidence that the cellular plasticity associated with inhibition of HSP90 in this model involves epigenetic mechanisms and is dependent upon high levels of stem cell factor signaling. This work provides evidence for a role of HSP90 and cellular stress in inducing phenotypic

HSP90 Inhibition and Cellular Stress Elicits Phenotypic Plasticity in Hematopoietic Differentiation.

PubMed

Lawag, Abdalla A; Napper, Jennifer M; Hunter, Caroline A; Bacon, Nickolas A; Deskins, Seth; El-Hamdani, Manaf; Govender, Sarah-Leigh; Koc, Emine C; Sollars, Vincent E

2017-10-01

Cancer cells exist in a state of Darwinian selection using mechanisms that produce changes in gene expression through genetic and epigenetic alteration to facilitate their survival. Cellular plasticity, or the ability to alter cellular phenotype, can assist in survival of premalignant cells as they progress to full malignancy by providing another mechanism of adaptation. The connection between cellular stress and the progression of cancer has been established, although the details of the mechanisms have yet to be fully elucidated. The molecular chaperone HSP90 is often upregulated in cancers as they progress, presumably to allow cancer cells to deal with misfolded proteins and cellular stress associated with transformation. The objective of this work is to test the hypothesis that inhibition of HSP90 results in increased cell plasticity in mammalian systems that can confer a greater adaptability to selective pressures. The approach used is a murine in vitro model system of hematopoietic differentiation that utilizes a murine hematopoietic stem cell line, erythroid myeloid lymphoid (EML) clone 1, during their maturation from stem cells to granulocytic progenitors. During the differentiation protocol, 80%-90% of the cells die when placed in medium where the major growth factor is granulocyte-macrophage-colony stimulating factor. Using this selection point model, EML cells exhibit increases in cellular plasticity when they are better able to adapt to this medium and survive. Increases in cellular plasticity were found to occur upon exposure to geldanamycin to inhibit HSP90, when subjected to various forms of cellular stress, or inhibition of histone acetylation. Furthermore, we provide evidence that the cellular plasticity associated with inhibition of HSP90 in this model involves epigenetic mechanisms and is dependent upon high levels of stem cell factor signaling. This work provides evidence for a role of HSP90 and cellular stress in inducing phenotypic plasticity

Zn2+ at a cellular crossroads

PubMed Central

Liang, Xiaomeng; Dempski, Robert E.; Burdette, Shawn C.

2016-01-01

Zinc is an essential micronutrient for cellular homeostasis. Initially proposed to only contribute to cellular viability through structural roles and non-redox catalysis, advances in quantifying changes in nM and pM quantities of Zn2+ have elucidated increasing functions as an important signaling molecule. This includes Zn2+-mediated regulation of transcription factors and subsequent protein expression, storage and release of intracellular compartments of zinc quanta into the extracellular space which modulates plasma membrane protein function, as well as intracellular signaling pathways which contribute to the immune response. This review highlights some recent advances in our understanding of zinc signaling. PMID:27010344

Achieving high energy absorption capacity in cellular bulk metallic glasses

PubMed Central

Chen, S. H.; Chan, K. C.; Wu, F. F.; Xia, L.

2015-01-01

Cellular bulk metallic glasses (BMGs) have exhibited excellent energy-absorption performance by inheriting superior strength from the parent BMGs. However, how to achieve high energy absorption capacity in cellular BMGs is vital but mysterious. In this work, using step-by-step observations of the deformation evolution of a series of cellular BMGs, the underlying mechanisms for the remarkable energy absorption capacity have been investigated by studying two influencing key factors: the peak stress and the decay of the peak stress during the plastic-flow plateau stages. An analytical model of the peak stress has been proposed, and the predicted results agree well with the experimental data. The decay of the peak stress has been attributed to the geometry change of the macroscopic cells, the formation of shear bands in the middle of the struts, and the “work-softening” nature of BMGs. The influencing factors such as the effect of the strut thickness and the number of unit cells have also been investigated and discussed. Strategies for achieving higher energy absorption capacity in cellular BMGs have been proposed. PMID:25973781

Genetically defined race, but not sex, is associated with higher humoral and cellular immune responses to measles vaccination

PubMed Central

Voigt, Emily A.; Ovsyannikova, Inna G.; Haralambieva, Iana H.; Kennedy, Richard B.; Larrabee, Beth R.; Schaid, Daniel J.; Poland, Gregory A.

2017-01-01

In addition to host genetic and environmental factors, variations in immune responses to vaccination are influenced by demographic variables, such as race and sex. The influence of genetic race and sex on measles vaccine responses is not well understood, yet important for the development of much-needed improved measles vaccines with lower failure rates. We assessed associations between genetically defined race and sex with measles humoral and cellular immunity after measles vaccination in three independent and geographically distinct cohorts totaling 2,872 healthy racially diverse children, older adolescents, and young adults. We found no associations between biological sex and either humoral or cellular immunity to measles vaccine, and no correlation between humoral and cellular immunity in these study subjects. Genetically defined race was, however, significantly associated with both measles vaccine-induced humoral and cellular immune responses, with subjects genetically classified as having African-American ancestry demonstrating significantly higher antibody and cell-mediated immune responses relative to subjects of Caucasian ancestry. This information may be useful in designing novel measles vaccines that are optimally effective across human genetic backgrounds. PMID:27591105

Long-duration effect of multi-factor stresses on the cellular biochemistry, oil-yielding performance and morphology of Nannochloropsis oculata

PubMed Central

Wei, Likun; Huang, Xuxiong

2017-01-01

Microalga Nannochloropsis oculata is a promising alternative feedstock for biodiesel. Elevating its oil-yielding capacity is conducive to cost-saving biodiesel production. However, the regulatory processes of multi-factor collaborative stresses (MFCS) on the oil-yielding performance of N. oculata are unclear. The duration effects of MFCS (high irradiation, nitrogen deficiency and elevated iron supplementation) on N. oculata were investigated in an 18-d batch culture. Despite the reduction in cell division, the biomass concentration increased, resulting from the large accumulation of the carbon/energy-reservoir. However, different storage forms were found in different cellular storage compounds, and both the protein content and pigment composition swiftly and drastically changed. The analysis of four biodiesel properties using pertinent empirical equations indicated their progressive effective improvement in lipid classes and fatty acid composition. The variation curve of neutral lipid productivity was monitored with fluorescent Nile red and was closely correlated to the results from conventional methods. In addition, a series of changes in the organelles (e.g., chloroplast, lipid body and vacuole) and cell shape, dependent on the stress duration, were observed by TEM and LSCM. These changes presumably played an important role in the acclimation of N. oculata to MFCS and accordingly improved its oil-yielding performance. PMID:28346505

Biomimetic hybrid porous scaffolds immobilized with platelet derived growth factor-BB promote cellularization and vascularization in tissue engineering.

PubMed

Murali, Ragothaman; Ponrasu, Thangavel; Cheirmadurai, Kalirajan; Thanikaivelan, Palanisamy

2016-02-01

Development of hybrid scaffolds with synergistic combination of growth factor is a promising approach to promote early in vivo wound repair and tissue regeneration. Here, we show the rapid wound healing in Wistar albino rats using biomimetic collagen-poly(dialdehyde) guar gum based hybrid porous scaffolds covalently immobilized with platelet derived growth factor-BB. The immobilized platelet derived growth factor in the hybrid scaffolds not only enhance the total protein, collagen, hexosamine, and uronic acid contents in the granulation tissue but also provide stronger tissues. The wound closure analysis reveal that the complete epithelialization period is 15.4 ± 0.9 days for collagen-poly(dialdehyde) guar gum-platelet derived growth factor hybrid scaffolds, whereas it is significantly higher for control, collagen, collagen- poly(dialdehyde) guar gum and povidine-iodine treated groups. Further, the histological evaluation shows that the immobilized platelet derived growth factor in the hybrid scaffolds induced a more robust cellular and vascular response in the implanted site. Hence, we demonstrate that the collagen-poly(dialdehyde) guar gum hybrid scaffolds loaded with platelet derived growth factor stimulates chemotactic effects in the implanted site to promote rapid tissue regeneration and wound repair without the assistance of antibacterial agents. © 2015 Wiley Periodicals, Inc.

At a glance: cellular biology for engineers.

PubMed

Khoshmanesh, K; Kouzani, A Z; Nahavandi, S; Baratchi, S; Kanwar, J R

2008-10-01

Engineering contributions have played an important role in the rise and evolution of cellular biology. Engineering technologies have helped biologists to explore the living organisms at cellular and molecular levels, and have created new opportunities to tackle the unsolved biological problems. There is now a growing demand to further expand the role of engineering in cellular biology research. For an engineer to play an effective role in cellular biology, the first essential step is to understand the cells and their components. However, the stumbling block of this step is to comprehend the information given in the cellular biology literature because it best suits the readers with a biological background. This paper aims to overcome this bottleneck by describing the human cell components as micro-plants that form cells as micro-bio-factories. This concept can accelerate the engineers' comprehension of the subject. In this paper, first the structure and function of different cell components are described. In addition, the engineering attempts to mimic various cell components through numerical modelling or physical implementation are highlighted. Next, the interaction of different cell components that facilitate complicated chemical processes, such as energy generation and protein synthesis, are described. These complex interactions are translated into simple flow diagrams, generally used by engineers to represent multi-component processes.

Lysosomal storage disorders: The cellular impact of lysosomal dysfunction

PubMed Central

2012-01-01

Lysosomal storage diseases (LSDs) are a family of disorders that result from inherited gene mutations that perturb lysosomal homeostasis. LSDs mainly stem from deficiencies in lysosomal enzymes, but also in some non-enzymatic lysosomal proteins, which lead to abnormal storage of macromolecular substrates. Valuable insights into lysosome functions have emerged from research into these diseases. In addition to primary lysosomal dysfunction, cellular pathways associated with other membrane-bound organelles are perturbed in these disorders. Through selective examples, we illustrate why the term “cellular storage disorders” may be a more appropriate description of these diseases and discuss therapies that can alleviate storage and restore normal cellular function. PMID:23185029

Endoplasmic Reticulum-Plasma Membrane Contacts Regulate Cellular Excitability.

PubMed

Dickson, Eamonn J

2017-01-01

Cells that have intrinsic electrical excitability utilize changes in membrane potential to communicate with neighboring cells and initiate cellular cascades. Excitable cells like neurons and myocytes have evolved highly specialized subcellular architectures to translate these electrical signals into cellular events. One such structural specialization is sarco-/endoplasmic reticulum-plasma membrane contact sites. These membrane contact sites are positioned by specific membrane-membrane tethering proteins and contain an ever-expanding list of additional proteins that organize information transfer across the junctional space (~ 15-25 nm distance) to shape membrane identity and control cellular excitability. In this chapter we discuss how contacts between the sarco-/endoplasmic reticulum and plasma membrane are essential for regulated excitation-contraction coupling in striated muscle and control of lipid-dependent ion channels.

34 CFR 472.23 - What additional factor does the Secretary consider?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false What additional factor does the Secretary consider? 472.23 Section 472.23 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION NATIONAL WORKPLACE LITERACY PROGRAM How...

34 CFR 648.32 - What additional factors does the Secretary consider?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false What additional factors does the Secretary consider? 648.32 Section 648.32 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION GRADUATE ASSISTANCE IN AREAS OF NATIONAL NEED...

Anaerobic sludge digestion with a biocatalytic additive

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

Ghosh, S.; Henry, M.P.; Fedde, P.A.

1982-01-01

The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. The experimental work consisted of several pairs of parallel mesophilic (35/sup 0/C) digestion runs (control and test) conducted in five experimental phases. Baseline runs without themore » additive showed that the two experimental digesters had the same methane content, gas production rate (GPR), and ethane yield. The effect of the additive was to increase methane yield and GPR by about 5% (which was statistically significant) during digester operation at a loading rate (LR) of 3.2 kg VS/m/sup 3/-day and a hydraulic retention time (HRT) of 14 days. Data collected from the various experimental phases showed that the biochemical additive increased methane yield, gas production rate, and VS reduction, and decreased volatile acids accumulation. In addition, it enhanced digester buffer capacity and improved the fertilizer value and dewatering characteristics of the digested residue.« less

The cellular response to vascular endothelial growth factors requires co-ordinated signal transduction, trafficking and proteolysis

PubMed Central

Smith, Gina A.; Fearnley, Gareth W.; Tomlinson, Darren C.; Harrison, Michael A.; Ponnambalam, Sreenivasan

2015-01-01

VEGFs (vascular endothelial growth factors) are a family of conserved disulfide-linked soluble secretory glycoproteins found in higher eukaryotes. VEGFs mediate a wide range of responses in different tissues including metabolic homoeostasis, cell proliferation, migration and tubulogenesis. Such responses are initiated by VEGF binding to soluble and membrane-bound VEGFRs (VEGF receptor tyrosine kinases) and co-receptors. VEGF and receptor splice isoform diversity further enhances complexity of membrane protein assembly and function in signal transduction pathways that control multiple cellular responses. Different signal transduction pathways are simultaneously activated by VEGFR–VEGF complexes with membrane trafficking along the endosome–lysosome network further modulating signal output from multiple enzymatic events associated with such pathways. Balancing VEGFR–VEGF signal transduction with trafficking and proteolysis is essential in controlling the intensity and duration of different intracellular signalling events. Dysfunction in VEGF-regulated signal transduction is important in chronic disease states including cancer, atherosclerosis and blindness. This family of growth factors and receptors is an important model system for understanding human disease pathology and developing new therapeutics for treating such ailments. PMID:26285805

Adenovirus E1a prevents the retinoblastoma gene product from repressing the activity of a cellular transcription factor.

PubMed Central

Zamanian, M; La Thangue, N B

1992-01-01

The retinoblastoma (Rb) gene product forms a complex with the cellular transcription factor DRTF1, a property assumed to be important for mediating negative growth control because certain viral oncogenes, such as adenovirus E1a, prevent this interaction and mutant Rb alleles, which have lost the capacity to regulate growth, encode proteins that fail to associate with DRTF1. In this study, we show that the wild-type Rb protein can specifically repress transcription from promoters driven by DRTF1 whereas a naturally occurring mutant Rb protein cannot. Furthermore, Rb-mediated transcriptional repression can be overridden by adenovirus E1a; this requires regions in E1a necessary for cellular transformation. The Rb protein therefore acts in trans to repress the transcriptional activity of DRTF1 whereas adenovirus E1a prevents this interaction and thus maintains DRTF1 in a constitutively active state. The Rb protein and adenovirus E1a therefore have opposite effects on the activity of a common molecular target. Transcriptional repression mediated by the Rb protein and inactivation of repression by the E1a protein are likely to play an important role in mediating their biological effects. Images PMID:1385776

Microfluidics-based in vivo mimetic systems for the study of cellular biology.

PubMed

Kim, Donghyuk; Wu, Xiaojie; Young, Ashlyn T; Haynes, Christy L

2014-04-15

The human body is a complex network of molecules, organelles, cells, tissues, and organs: an uncountable number of interactions and transformations interconnect all the system's components. In addition to these biochemical components, biophysical components, such as pressure, flow, and morphology, and the location of all of these interactions play an important role in the human body. Technical difficulties have frequently limited researchers from observing cellular biology as it occurs within the human body, but some state-of-the-art analytical techniques have revealed distinct cellular behaviors that occur only in the context of the interactions. These types of findings have inspired bioanalytical chemists to provide new tools to better understand these cellular behaviors and interactions. What blocks us from understanding critical biological interactions in the human body? Conventional approaches are often too naïve to provide realistic data and in vivo whole animal studies give complex results that may or may not be relevant for humans. Microfluidics offers an opportunity to bridge these two extremes: while these studies will not model the complexity of the in vivo human system, they can control the complexity so researchers can examine critical factors of interest carefully and quantitatively. In addition, the use of human cells, such as cells isolated from donated blood, captures human-relevant data and limits the use of animals in research. In addition, researchers can adapt these systems easily and cost-effectively to a variety of high-end signal transduction mechanisms, facilitating high-throughput studies that are also spatially, temporally, or chemically resolved. These strengths should allow microfluidic platforms to reveal critical parameters in the human body and provide insights that will help with the translation of pharmacological advances to clinical trials. In this Account, we describe selected microfluidic innovations within the last 5 years

34 CFR 490.22 - What additional factor does the Secretary consider?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false What additional factor does the Secretary consider? 490.22 Section 490.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION LIFE SKILLS FOR STATE AND LOCAL...

34 CFR 490.22 - What additional factor does the Secretary consider?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 34 Education 3 2011-07-01 2011-07-01 false What additional factor does the Secretary consider? 490.22 Section 490.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION LIFE SKILLS FOR STATE AND LOCAL...

Enhancing proliferation and optimizing the culture condition for human bone marrow stromal cells using hypoxia and fibroblast growth factor-2.

PubMed

Lee, Jung-Seok; Kim, Seul Ki; Jung, Byung-Joo; Choi, Seong-Bok; Choi, Eun-Young; Kim, Chang-Sung

2018-04-01

This study aimed to determine the cellular characteristics and behaviors of human bone marrow stromal cells (hBMSCs) expanded in media in a hypoxic or normoxic condition and with or without fibroblast growth factor-2 (FGF-2) treatment. hBMSCs isolated from the vertebral body and expanded in these four groups were evaluated for cellular proliferation/migration, colony-forming units, cell-surface characterization, in vitro differentiation, in vivo transplantation, and gene expression. Culturing hBMSCs using a particular environmental factor (hypoxia) and with the addition of FGF-2 increased the cellular proliferation rate while enhancing the regenerative potential, modulated the multipotency-related processes (enhanced chondrogenesis-related processes/osteogenesis, but reduced adipogenesis), and increased cellular migration and collagen formation. The gene expression levels in the experimental samples showed activation of the hypoxia-inducible factor-1 pathway and glycolysis in the hypoxic condition, with this not being affected by the addition of FGF-2. The concurrent application of hypoxia and FGF-2 could provide a favorable condition for culturing hBMSCs to be used in clinical applications associated with bone tissue engineering, due to the enhancement of cellular proliferation and regenerative potential. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Prostaglandin E₂ regulates cellular migration via induction of vascular endothelial growth factor receptor-1 in HCA-7 human colon cancer cells.

PubMed

Fujino, Hiromichi; Toyomura, Kaori; Chen, Xiao-bo; Regan, John W; Murayama, Toshihiko

2011-02-01

An important event in the development of tumors is angiogenesis, or the formation of new blood vessels. Angiogenesis is also known to be involved in tumor cell metastasis and is dependent upon the activity of the vascular endothelial growth factor (VEGF) signaling pathway. Studies of mice in which the EP3 prostanoid receptors have been genetically deleted have shown a role for these receptors in cancer growth and angiogenesis. In the present study, human colon cancer HCA-7 cells were used as a model system to understand the potential role of EP3 receptors in tumor cell migration. We now show that stimulation of HCA-7 cells with PGE₂ enhanced the up-regulation of VEGF receptor-1 (VEGFR-1) expression by a mechanism involving EP3 receptor-mediated activation of phosphatidylinositol 3-kinase and the extracellular signal-regulated kinases. Moreover, the PGE₂ stimulated increase in VEGFR-1 expression was accompanied by an increase in the cellular migration of HCA-7 cells. Given the known involvement of VEGFR-1 in cellular migration, our results suggest that EP3 receptors may contribute to tumor cell metastasis by increasing cellular migration through the up-regulation of VEGFR-1 signaling. Copyright © 2010 Elsevier Inc. All rights reserved.

Molecular and cellular mechanisms of aortic stenosis.

PubMed

Yetkin, Ertan; Waltenberger, Johannes

2009-06-12

Calcific aortic stenosis is the most common cause of aortic valve replacement in developed countries, and this condition increases in prevalence with advancing age. The fibrotic thickening and calcification are common eventual endpoint in both non-rheumatic calcific and rheumatic aortic stenoses. New observations in human aortic valves support the hypothesis that degenerative valvular aortic stenosis is the result of active bone formation in the aortic valve, which may be mediated through a process of osteoblast-like differentiation in these tissues. Additionally histopathologic evidence suggests that early lesions in aortic valves are not just a disease process secondary to aging, but an active cellular process that follows the classical "response to injury hypothesis" similar to the situation in atherosclerosis. Although there are similarities with the risk factor and as well as with the process of atherogenesis, not all the patients with coronary artery disease or atherosclerosis have calcific aortic stenosis. This review mainly focuses on the potential vascular and molecular mechanisms involved in the pathogenesis of aortic valve stenosis. Namely extracellular matrix remodeling, angiogenesis, inflammation, and eventually osteoblast-like differentiation resulting in bone formation have been shown to play a role in the pathogenesis of calcific aortic stenosis. Several mediators related to underlying mechanisms, including growth factors especially transforming growth factor-beta1 and vascular endothelial growth factors, angiogenesis, cathepsin enzymes, adhesion molecules, bone regulatory proteins and matrix metalloproteinases have been demonstrated, however the target to be attacked is not defined yet.

Modulation of Cellular Stress Response via the Erythropoietin/CD131 Heteroreceptor Complex in Mouse Mesenchymal-Derived Cells

PubMed Central

Bohr, Stefan; Patel, Suraj J; Vasko, Radovan; Shen, Keyue; Iracheta-Vellve, Arvin; Lee, Jungwoo; Bale, Shyam Sundhar; Chakraborty, Nilay; Brines, Michael; Cerami, Anthony; Berthiaume, Francois; Yarmush, Martin L

2014-01-01

Tissue protective properties of erythropoietin (EPO) have let to the discovery of an alternative EPO-signaling via an EPO-R/CD131 receptor complex which can now be specifically targeted through pharmaceutically designed short sequence peptides such as ARA290. However, little is still known about specific functions of alternative EPO-signaling in defined cell populations. In this study we investigated effects of signaling through EPO-R/CD131 complex on cellular stress responses and pro-inflammatory activation in different mesenchymal-derived phenotypes. We show that anti-apoptotic, anti-inflammatory effects of ARA290 and EPO coincide with the externalization of CD131 receptor component as an immediate response to cellular stress. In addition, alternative EPO-signaling strongly modulated transcriptional, translational or metabolic responses after stressor removal. Specifically, we saw that ARA290 was able overcome a TNFα-mediated inhibition of transcription factor activation related to cell stress responses, most notably of serum response factor (SRF), heat shock transcription factor protein 1 (HSF1) and activator protein 1 (AP1). We conclude that alternative EPO-signaling acts as a modulator of pro-inflammatory signaling pathways and likely plays a role in restoring tissue homeostasis. PMID:25373867

Additive Factors Analysis of Inhibitory Processing in the Stop-Signal Paradigm

ERIC Educational Resources Information Center

van den Wildenberg, W.P.M.; van der Molen, M.W.

2004-01-01

This article reports an additive factors analysis of choice reaction and selective stop processes manipulated in a stop-signal paradigm. Three experiments were performed in which stimulus discriminability (SD) and stimulus-response compatibility (SRC) were manipulated in a factorial fashion. In each experiment, the effects of SD and SRC were…

Cellular solidification of transparent monotectics

NASA Technical Reports Server (NTRS)

Kaulker, W. F.

1986-01-01

Understanding how liquid phase particles are engulfed or pushed during freezing of a monotectic is addressed. The additional complication is that the solid-liquid interface is nonplanar due to constitutional undercooling. Some evidence of particle pushing where the particles are the liquid phase of the montectic was already observed. Cellular freezing of the succinonitrile-glycerol system also occurred. Only a few compositions were tested at that time. The starting materials were not especially pure so that cellular interface observed was likely due to the presence of unkown impurities, the major portion of which was water. Topics addressed include: the effort of modeling the particle pushing process using the computer, establishing an apparatus for the determination of phase diagrams, and the measurement of the temperature gradients with a specimen which will solidify on the temperature gradient microscope stage.

PDGF-AA-induced filamentous mitochondria benefit dermal papilla cells in cellular migration.

PubMed

Mifude, C; Kaseda, K

2015-06-01

Human dermal papilla cells (HDPCs) play essential roles in hair follicular morphogenesis and postnatal hair growth cycles. Previous reports demonstrated that platelet-derived growth factor-AA (PDGF-AA) enhanced the formation of dermal condensates in hair follicular development. Additionally, PDGF-AA induces/maintains the anagen phase of the hair cycle. It is likely that mitochondrial morphology and functions are tightly coupled with maintenance of these energy-demanding activities. However, little is known about the mitochondrial regulation in HDPCs. Thus, we investigated the PDGF-involved mitochondrial regulation in HDPCs. The mitochondrial morphologies of HDPCs were examined in the presence or absence of PDGF-AA under a fluorescent microscope. ATP production and cellular motility were investigated. The relationship between mitochondrial morphology and the cellular functions was discussed. We observed that primary HDPCs contained mitochondria with filamentous and/or rounded morphologies. Both types of mitochondria showed similar membrane potentials. Interestingly, in the presence of PDGF-AA, but not PDGF-BB, the balance between the two morphologies shifted towards the filamentous form. Concomitantly, both mitochondrial enzymatic activity and total cellular ATP level were augmented by PDGF-AA. These two parameters were closely correlated, suggesting the mitochondrial involvement in the PDGF-augmented ATP production. Moreover, PDGF-AA accelerated the migration of HDPCs in a gap-filling assay, but did not change the rate of cellular proliferation. Notably, filamentous mitochondria dominated migrating HDPCs. PDGF-AA benefits HDPCs in the process of migration, by increasing the number of filamentous mitochondria. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Humoral and Cellular Immune Response in Canine Hypothyroidism.

PubMed

Miller, J; Popiel, J; Chełmońska-Soyta, A

2015-07-01

Hypothyroidism is one of the most common endocrine diseases in dogs and is generally considered to be autoimmune in nature. In human hypothyroidism, the thyroid gland is destroyed by both cellular (i.e. autoreactive helper and cytotoxic T lymphocytes) and humoral (i.e. autoantibodies specific for thyroglobulin, thyroxine and triiodothyronine) effector mechanisms. Other suggested factors include impaired peripheral immune suppression (i.e. the malfunction of regulatory T cells) or an additional pro-inflammatory effect of T helper 17 lymphocytes. The aim of this study was to evaluate immunological changes in canine hypothyroidism. Twenty-eight clinically healthy dogs, 25 hypothyroid dogs without thyroglobulin antibodies and eight hypothyroid dogs with these autoantibodies were enrolled into the study. There were alterations in serum proteins in hypothyroid dogs compared with healthy controls (i.e. raised concentrations of α-globulins, β2- and γ-globulins) as well as higher concentration of acute phase proteins and circulating immune complexes. Hypothyroid animals had a lower CD4:CD8 ratio in peripheral blood compared with control dogs and diseased dogs also had higher expression of interferon γ (gene and protein expression) and CD28 (gene expression). Similar findings were found in both groups of hypothyroid dogs. Canine hypothyroidism is therefore characterized by systemic inflammation with dominance of a cellular immune response. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cellular and molecular perspectives in rheumatoid arthritis.

PubMed

Veale, Douglas J; Orr, Carl; Fearon, Ursula

2017-06-01

Synovial immunopathology in rheumatoid arthritis is complex involving both resident and infiltrating cells. The synovial tissue undergoes significant neovascularization, facilitating an influx of lymphocytes and monocytes that transform a typically acellular loose areolar membrane into an invasive tumour-like pannus. The microvasculature proliferates to form straight regularly-branching vessels; however, they are highly dysfunctional resulting in reduced oxygen supply and a hypoxic microenvironment. Autoantibodies such as rheumatoid factor and anti-citrullinated protein antibodies are found at an early stage, often before arthritis has developed, and they have been implicated in the pathogenesis of RA. Abnormal cellular metabolism and mitochondrial dysfunction thus ensue and, in turn, through the increased production of reactive oxygen species actively induce inflammation. Key pro-inflammatory cytokines, chemokines and growth factors and their signalling pathways, including nuclear factor κB, Janus kinase-signal transducer, are highly activated when immune cells are exposed to hypoxia in the inflamed rheumatoid joint show adaptive survival reactions by activating. This review attempts to highlight those aberrations in the innate and adaptive immune systems including the role of genetic and environmental factors, autoantibodies, cellular alterations, signalling pathways and metabolism that are implicated in the pathogenesis of RA and may therefore provide an opportunity for therapeutic intervention.

Role of cellular adhesions in tissue dynamics spectroscopy

NASA Astrophysics Data System (ADS)

Merrill, Daniel A.; An, Ran; Turek, John; Nolte, David

2014-02-01

Cellular adhesions play a critical role in cell behavior, and modified expression of cellular adhesion compounds has been linked to various cancers. We tested the role of cellular adhesions in drug response by studying three cellular culture models: three-dimensional tumor spheroids with well-developed cellular adhesions and extracellular matrix (ECM), dense three-dimensional cell pellets with moderate numbers of adhesions, and dilute three-dimensional cell suspensions in agarose having few adhesions. Our technique for measuring the drug response for the spheroids and cell pellets was biodynamic imaging (BDI), and for the suspensions was quasi-elastic light scattering (QELS). We tested several cytoskeletal chemotherapeutic drugs (nocodazole, cytochalasin-D, paclitaxel, and colchicine) on three cancer cell lines chosen from human colorectal adenocarcinoma (HT-29), human pancreatic carcinoma (MIA PaCa-2), and rat osteosarcoma (UMR-106) to exhibit differences in adhesion strength. Comparing tumor spheroid behavior to that of cell suspensions showed shifts in the spectral motion of the cancer tissues that match predictions based on different degrees of cell-cell contacts. The HT-29 cell line, which has the strongest adhesions in the spheroid model, exhibits anomalous behavior in some cases. These results highlight the importance of using three-dimensional tissue models in drug screening with cellular adhesions being a contributory factor in phenotypic differences between the drug responses of tissue and cells.

Growth factor withdrawal in combination with sodium butyrate addition extends culture longevity and enhances antibody production in CHO cells.

PubMed

Hong, Jong Kwang; Lee, Gyun Min; Yoon, Sung Kwan

2011-09-10

The effect of growth factor (GF) and sodium butyrate (NaBu) on Chinese hamster ovary (CHO) cell growth, cell viability and antibody production was investigated using shaking flasks in GF-containing and GF-deficient medium containing 0, 1 and 3mM NaBu. The withdrawal of GF and the addition of NaBu suppressed cell growth, but they significantly increased specific antibody productivity, q(Ab). Interestingly, the withdrawal of GF in combination with the addition of NaBu markedly retarded cell death, leading to extended culture longevity. For instance, at 3mM NaBu, cell viability fell below 80% after day 4 in GF-containing medium, but it remained over 80% until day 18 in GF-deficient medium. Due to the enhanced q(Ab) and the extended culture longevity, approximately 2-fold increase in total antibody production was achieved in pseudo-perfusion culture with 1mM NaBu in GF-deficient medium, compared to the culture in GF-containing medium. The effect of GF and NaBu on the change in the expression and activity of cellular proteins, c-Myc, Bcl-2 and pyruvate dehydrogenase (PDH), was also investigated. Both the withdrawal of GF and the addition of NaBu decreased the expression of c-Myc. The expression of Bcl-2 was enhanced by the addition of NaBu in a dose-dependent manner while it was not affected by the withdrawal of GF. In addition, both the withdrawal of GF and the addition of NaBu reduced metabolic rates, q(Glc), q(Lac) and Y(Lac/Glc), and increased PDH activity while not affecting PDH expression, suggesting that they may reduce the glycolytic rates, but enhance the conversion rates of pyruvate to TCA intermediates. Taken together, the withdrawal of GF in combination with the addition of NaBu can be considered as a relevant strategy for alleviating NaBu-induced cell apoptosis and enhancing antibody production since it can be easily implemented as well as enhance q(Ab) and extend culture longevity. Copyright © 2011 Elsevier B.V. All rights reserved.

Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling.

PubMed

Lovelace, Erica S; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard P; Zink, Erika M; Kim, Young-Mo; Kyle, Jennifer E; Webb-Robertson, Bobbie-Jo M; Waters, Katrina M; Metz, Thomas O; Farin, Federico; Oberlies, Nicholas H; Polyak, Stephen J

2015-08-28

Silymarin, a characterized extract of the seeds of milk thistle (Silybum marianum), suppresses cellular inflammation. To define how this occurs, transcriptional profiling, metabolomics, and signaling studies were performed in human liver and T cell lines. Cellular stress and metabolic pathways were modulated within 4 h of silymarin treatment: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed silymarin suppression of glycolytic, tricarboxylic acid (TCA) cycle, and amino acid metabolism. Anti-inflammatory effects arose with prolonged (i.e., 24 h) silymarin exposure, with suppression of multiple pro-inflammatory mRNAs and signaling pathways including nuclear factor kappa B (NF-κB) and forkhead box O (FOXO). Studies with murine knock out cells revealed that silymarin inhibition of both mTOR and NF-κB was partially AMPK dependent, whereas silymarin inhibition of mTOR required DDIT4. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Thus, natural products activate stress and repair responses that culminate in an anti-inflammatory cellular phenotype. Natural products like silymarin may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation.

Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling

PubMed Central

Lovelace, Erica S.; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard; Zink, Erika M.; Kim, Young-Mo; Kyle, Jennifer E.; Webb-Robertson, Bobbie-Jo; Waters, Katrina M.; Metz, Thomas O.; Farin, Federico; Oberlies, Nicholas H.; Polyak, Stephen J.

2016-01-01

Silymarin, a characterized extract of the seeds of milk thistle (Silybum marianum), suppresses cellular inflammation. To define how this occurs, transcriptional profiling, metabolomics, and signaling studies were performed in human liver and T cell lines. Cellular stress and metabolic pathways were modulated within 4 h of silymarin treatment: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed silymarin suppression of glycolytic, tricarboxylic acid (TCA) cycle, and amino acid metabolism. Anti-inflammatory effects arose with prolonged (i.e. 24 h) silymarin exposure, with suppression of multiple pro-inflammatory mRNAs and signaling pathways including nuclear factor kappa B (NF-κB) and forkhead box O (FOXO). Studies with murine knock out cells revealed that silymarin inhibition of both mTOR and NF-κB was partially AMPK dependent, while silymarin inhibition of mTOR required DDIT4. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Thus, natural products activate stress and repair responses that culminate in an anti-inflammatory cellular phenotype. Natural products like silymarin may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation. PMID:26186142

A Herpesvirus Protein Selectively Inhibits Cellular mRNA Nuclear Export.

PubMed

Gong, Danyang; Kim, Yong Hoon; Xiao, Yuchen; Du, Yushen; Xie, Yafang; Lee, Kevin K; Feng, Jun; Farhat, Nisar; Zhao, Dawei; Shu, Sara; Dai, Xinghong; Chanda, Sumit K; Rana, Tariq M; Krogan, Nevan J; Sun, Ren; Wu, Ting-Ting

2016-11-09

Nuclear mRNA export is highly regulated to ensure accurate cellular gene expression. Viral inhibition of cellular mRNA export can enhance viral access to the cellular translation machinery and prevent anti-viral protein production but is generally thought to be nonselective. We report that ORF10 of Kaposi's sarcoma-associated herpesvirus (KSHV), a nuclear DNA virus, inhibits mRNA export in a transcript-selective manner to control cellular gene expression. Nuclear export inhibition by ORF10 requires an interaction with an RNA export factor, Rae1. Genome-wide analysis reveals a subset of cellular mRNAs whose nuclear export is blocked by ORF10 with the 3' UTRs of ORF10-targeted transcripts conferring sensitivity to export inhibition. The ORF10-Rae1 interaction is important for the virus to express viral genes and produce infectious virions. These results suggest that a nuclear DNA virus can selectively interfere with RNA export to restrict host gene expression for optimal replication. Published by Elsevier Inc.

ORF phage display to identify cellular proteins with different functions.

PubMed

Li, Wei

2012-09-01

Open reading frame (ORF) phage display is a new branch of phage display aimed at improving its efficiency to identify cellular proteins with specific binding or functional activities. Despite the success of phage display with antibody libraries and random peptide libraries, phage display with cDNA libraries of cellular proteins identifies a high percentage of non-ORF clones encoding unnatural short peptides with minimal biological implications. This is mainly because of the uncontrollable reading frames of cellular proteins in conventional cDNA libraries. ORF phage display solves this problem by eliminating non-ORF clones to generate ORF cDNA libraries. Here I summarize the procedures of ORF phage display, discuss the factors influencing its efficiency, present examples of its versatile applications, and highlight evidence of its capability of identifying biologically relevant cellular proteins. ORF phage display coupled with different selection strategies is capable of delineating diverse functions of cellular proteins with unique advantages. Copyright © 2012 Elsevier Inc. All rights reserved.

Regulatory Nexus of Synthesis and Degradation Deciphers Cellular Nrf2 Expression Levels

PubMed Central

Suzuki, Takafumi; Shibata, Tatsuhiro; Takaya, Kai; Shiraishi, Kouya; Kohno, Takashi; Kunitoh, Hideo; Tsuta, Koji; Furuta, Koh; Goto, Koichi; Hosoda, Fumie; Sakamoto, Hiromi; Motohashi, Hozumi

2013-01-01

Transcription factor Nrf2 (NF-E2-related factor 2) is essential for oxidative and electrophilic stress responses. While it has been well characterized that Nrf2 activity is tightly regulated at the protein level through proteasomal degradation via Keap1 (Kelch-like ECH-associated protein 1)-mediated ubiquitination, not much attention has been paid to the supply side of Nrf2, especially regulation of Nrf2 gene transcription. Here we report that manipulation of Nrf2 transcription is effective in changing the final Nrf2 protein level and activity of cellular defense against oxidative stress even in the presence of Keap1 and under efficient Nrf2 degradation, determined using genetically engineered mouse models. In excellent agreement with this finding, we found that minor A/A homozygotes of a single nucleotide polymorphism (SNP) in the human NRF2 upstream promoter region (rs6721961) exhibited significantly diminished NRF2 gene expression and, consequently, an increased risk of lung cancer, especially those who had ever smoked. Our results support the notion that in addition to control over proteasomal degradation and derepression from degradation/repression, the transcriptional level of the Nrf2 gene acts as another important regulatory point to define cellular Nrf2 levels. These results thus verify the critical importance of human SNPs that influence the levels of transcription of the NRF2 gene for future personalized medicine. PMID:23572560

The SEB-1 Transcription Factor Binds to the STRE Motif in Neurospora crassa and Regulates a Variety of Cellular Processes Including the Stress Response and Reserve Carbohydrate Metabolism.

PubMed

Freitas, Fernanda Zanolli; Virgilio, Stela; Cupertino, Fernanda Barbosa; Kowbel, David John; Fioramonte, Mariana; Gozzo, Fabio Cesar; Glass, N Louise; Bertolini, Maria Célia

2016-05-03

When exposed to stress conditions, all cells induce mechanisms resulting in an attempt to adapt to stress that involve proteins which, once activated, trigger cell responses by modulating specific signaling pathways. In this work, using a combination of pulldown assays and mass spectrometry analyses, we identified the Neurospora crassa SEB-1 transcription factor that binds to the Stress Response Element (STRE) under heat stress. Orthologs of SEB-1 have been functionally characterized in a few filamentous fungi as being involved in stress responses; however, the molecular mechanisms mediated by this transcription factor may not be conserved. Here, we provide evidences for the involvement of N. crassa SEB-1 in multiple cellular processes, including response to heat, as well as osmotic and oxidative stress. The Δseb-1 strain displayed reduced growth under these conditions, and genes encoding stress-responsive proteins were differentially regulated in the Δseb-1 strain grown under the same conditions. In addition, the SEB-1-GFP protein translocated from the cytosol to the nucleus under heat, osmotic, and oxidative stress conditions. SEB-1 also regulates the metabolism of the reserve carbohydrates glycogen and trehalose under heat stress, suggesting an interconnection between metabolism control and this environmental condition. We demonstrated that SEB-1 binds in vivo to the promoters of genes encoding glycogen metabolism enzymes and regulates their expression. A genome-wide transcriptional profile of the Δseb-1 strain under heat stress was determined by RNA-seq, and a broad range of cellular processes was identified that suggests a role for SEB-1 as a protein interconnecting these mechanisms. Copyright © 2016 Freitas et al.

Cellular studies and interaction mechanisms of extremely low frequency fields

NASA Astrophysics Data System (ADS)

Liburdy, Robert P.

1995-01-01

) or the magnetic (B) field, or if combinations of static B and time-varying B fields represent an exposure metric for the cell. This question relates directly to understanding fundamental interaction mechanisms and to the development of a rationale for ELF dose threshold guidelines. The weight of experimental evidence indicates that an induced E field according to Faraday's law of induction during magnetic field exposures elicits cellular effects. An E-field-mediated interaction has interesting consequences for microdosimetry at the cellular level and is mechanistically consistent with an interaction at the cell surface, since the E field does not penetrate beyond the cell membrane. Recently, several studies have suggested that an ELF B field by itself or in combination with a static B field may elicit cellular effects. Thus in addition to E-field-mediated effects, other interaction mechanisms as yet not fully understood may operate at the cellular level; this complexity is in contrast to the case for ionizing radiation. In addition to the question of an exposure field metric, the biological state of the target cell is important in ELF interactions. Biological factors such as cell type, cell cycle, cell activation, age of donor animal, passage number of cell line, presence of specific growth/mitogenic factors, temperature, shape, and cell density/packing during exposures have been shown to play a role in mediating ELF interactions with cells. Most recently, reports of single-cell studies usher in a new direction for research that can be termed microbioelectromagnetics. Single-cell digital microscopy introduces a new approach to answer the above questions with potential for real-time microdosimetry and bioeffects limited only by the spatial resolution of state-of-the-art microscopy, which is approximately 0.1 /μm. Digital imaging microscopy should therefore permit the quantitative assessment of spatial and temporal features of ELF field interactions within living

A Major Binding Protein for Leukemia Inhibitory Factor in Normal Mouse Serum: Identification as a Soluble Form of the Cellular Receptor

NASA Astrophysics Data System (ADS)

Layton, Meredith J.; Cross, Bronwyn A.; Metcalf, Donald; Ward, Larry D.; Simpson, Richard J.; Nicola, Nicos A.

1992-09-01

A protein that specifically binds leukemia inhibitory factor (LIF) has been isolated from normal mouse serum by using four successive fractionation steps: chromatography on a LIF affinity matrix, anion-exchange chromatography, size-exclusion chromatography, and preparative native gel electrophoresis. The purified LIF-binding protein (LBP) is a glycoprotein with an apparent molecular mass of 90 kDa that specifically binds 125I-labeled murine LIF with an affinity comparable to that of the low-affinity cellular LIF receptor (K_d = 600 pM). N-terminal sequencing has identified this protein as a soluble truncated form of the α chain of the cellular LIF receptor. LBP is present in normal mouse serum at high levels (1 μg/ml) and these levels are elevated in pregnant mice and reduced in neonatal mice. Since normal serum concentrations of LBP can block the biological actions of LIF in culture, LBP may serve as an inhibitor of the systemic effects of locally produced LIF.

Growth factors and myometrium: biological effects in uterine fibroid and possible clinical implications

PubMed Central

Ciarmela, Pasquapina; Islam, Md. Soriful; Reis, Fernando M.; Gray, Peter C.; Bloise, Enrrico; Petraglia, Felice; Vale, Wylie; Castellucci, Mario

2011-01-01

BACKGROUND Growth factors are proteins secreted by a number of cell types that are capable of modulating cellular growth, proliferation and cellular differentiation. It is well accepted that uterine cellular events such as proliferation and differentiation are regulated by sex steroids and their actions in target tissues are mediated by local production of growth factors acting through paracrine and/or autocrine mechanisms. Myometrial mass is ultimately modified in pregnancy as well as in tumour conditions such as leiomyoma and leiomyosarcoma. Leiomyomas, also known as fibroids, are benign tumours of the uterus, considered to be one of the most frequent causes of infertility in reproductive years in women. METHODS For this review, we searched the database MEDLINE and Google Scholar for articles with content related to growth factors acting on myometrium; the findings are hereby reviewed and discussed. RESULTS Different growth factors such as epidermal growth factor (EGF), transforming growth factor-α (TGF-α), heparin-binding EGF (HB-EGF), acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), platelet-derived growth factor (PDGF) and TGF-β perform actions in myometrium and in leiomyomas. In addition to these growth factors, activin and myostatin have been recently identified in myometrium and leiomyoma. CONCLUSIONS Growth factors play an important role in the mechanisms involved in myometrial patho-physiology. PMID:21788281

Feline leukemia virus infection requires a post-receptor binding envelope-dependent cellular component.

PubMed

Hussain, Naveen; Thickett, Kelly R; Na, Hong; Leung, Cherry; Tailor, Chetankumar S

2011-12-01

Gammaretrovirus receptors have been suggested to contain the necessary determinants to mediate virus binding and entry. Here, we show that murine NIH 3T3 and baby hamster kidney (BHK) cells overexpressing receptors for subgroup A, B, and C feline leukemia viruses (FeLVs) are weakly susceptible (10(1) to 10(2) CFU/ml) to FeLV pseudotype viruses containing murine leukemia virus (MLV) core (Gag-Pol) proteins, whereas FeLV receptor-expressing murine Mus dunni tail fibroblast (MDTF) cells are highly susceptible (10(4) to 10(6) CFU/ml). However, NIH 3T3 cells expressing the FeLV subgroup B receptor PiT1 are highly susceptible to gibbon ape leukemia virus pseudotype virus, which differs from the FeLV pseudotype viruses only in the envelope protein. FeLV resistance is not caused by a defect in envelope binding, low receptor expression levels, or N-linked glycosylation. Resistance is not alleviated by substitution of the MLV core in the FeLV pseudotype virus with FeLV core proteins. Interestingly, FeLV resistance is alleviated by fusion of receptor-expressing NIH 3T3 and BHK cells with MDTF or human TE671 cells, suggesting the absence of an additional cellular component in NIH 3T3 and BHK cells that is required for FeLV infection. The putative FeLV-specific cellular component is not a secreted factor, as MDTF conditioned medium does not alleviate the block to FeLV infection. Together, our findings suggest that FeLV infection requires an additional envelope-dependent cellular component that is absent in NIH 3T3 and BHK cells but that is present in MDTF and TE671 cells.

Cell Motility Dynamics: A Novel Segmentation Algorithm to Quantify Multi-Cellular Bright Field Microscopy Images

PubMed Central

Zaritsky, Assaf; Natan, Sari; Horev, Judith; Hecht, Inbal; Wolf, Lior; Ben-Jacob, Eshel; Tsarfaty, Ilan

2011-01-01

Confocal microscopy analysis of fluorescence and morphology is becoming the standard tool in cell biology and molecular imaging. Accurate quantification algorithms are required to enhance the understanding of different biological phenomena. We present a novel approach based on image-segmentation of multi-cellular regions in bright field images demonstrating enhanced quantitative analyses and better understanding of cell motility. We present MultiCellSeg, a segmentation algorithm to separate between multi-cellular and background regions for bright field images, which is based on classification of local patches within an image: a cascade of Support Vector Machines (SVMs) is applied using basic image features. Post processing includes additional classification and graph-cut segmentation to reclassify erroneous regions and refine the segmentation. This approach leads to a parameter-free and robust algorithm. Comparison to an alternative algorithm on wound healing assay images demonstrates its superiority. The proposed approach was used to evaluate common cell migration models such as wound healing and scatter assay. It was applied to quantify the acceleration effect of Hepatocyte growth factor/scatter factor (HGF/SF) on healing rate in a time lapse confocal microscopy wound healing assay and demonstrated that the healing rate is linear in both treated and untreated cells, and that HGF/SF accelerates the healing rate by approximately two-fold. A novel fully automated, accurate, zero-parameters method to classify and score scatter-assay images was developed and demonstrated that multi-cellular texture is an excellent descriptor to measure HGF/SF-induced cell scattering. We show that exploitation of textural information from differential interference contrast (DIC) images on the multi-cellular level can prove beneficial for the analyses of wound healing and scatter assays. The proposed approach is generic and can be used alone or alongside traditional fluorescence single

Cell motility dynamics: a novel segmentation algorithm to quantify multi-cellular bright field microscopy images.

PubMed

Zaritsky, Assaf; Natan, Sari; Horev, Judith; Hecht, Inbal; Wolf, Lior; Ben-Jacob, Eshel; Tsarfaty, Ilan

2011-01-01

Confocal microscopy analysis of fluorescence and morphology is becoming the standard tool in cell biology and molecular imaging. Accurate quantification algorithms are required to enhance the understanding of different biological phenomena. We present a novel approach based on image-segmentation of multi-cellular regions in bright field images demonstrating enhanced quantitative analyses and better understanding of cell motility. We present MultiCellSeg, a segmentation algorithm to separate between multi-cellular and background regions for bright field images, which is based on classification of local patches within an image: a cascade of Support Vector Machines (SVMs) is applied using basic image features. Post processing includes additional classification and graph-cut segmentation to reclassify erroneous regions and refine the segmentation. This approach leads to a parameter-free and robust algorithm. Comparison to an alternative algorithm on wound healing assay images demonstrates its superiority. The proposed approach was used to evaluate common cell migration models such as wound healing and scatter assay. It was applied to quantify the acceleration effect of Hepatocyte growth factor/scatter factor (HGF/SF) on healing rate in a time lapse confocal microscopy wound healing assay and demonstrated that the healing rate is linear in both treated and untreated cells, and that HGF/SF accelerates the healing rate by approximately two-fold. A novel fully automated, accurate, zero-parameters method to classify and score scatter-assay images was developed and demonstrated that multi-cellular texture is an excellent descriptor to measure HGF/SF-induced cell scattering. We show that exploitation of textural information from differential interference contrast (DIC) images on the multi-cellular level can prove beneficial for the analyses of wound healing and scatter assays. The proposed approach is generic and can be used alone or alongside traditional fluorescence single

Cellular structure of lean hydrogen flames in microgravity

NASA Technical Reports Server (NTRS)

Patnaik, G.; Kailasanath, K.

1990-01-01

Detailed, time-dependent, two-dimensional numerical simulations of premixed laminar flames have been used to study the initiation and subsequent development of cellular structures in lean hydrogen-air flames. The model includes detailed hydrogen-oxygen combustion with 24 elementary reactions of eight reactive species and a nitrogen diluent, molecular diffusion of all species, thermal conduction, viscosity, and convection. This model has been used to study the nonlinear evolution of cellular flame structure and shows that cell splitting, as observed in experiments, can be predicted numerically for sufficiently reactive mixtures. The structures that evolved also resembled the cellular structures observed in experiments. The present study shows that the 'cell-split limit' postulated from experimental observations is an intrinsic property of the mixture and that external factors such as heat losses are not necessary to cause this limit.

Retinoblastoma-binding Protein 4-regulated Classical Nuclear Transport Is Involved in Cellular Senescence*

PubMed Central

Tsujii, Akira; Miyamoto, Yoichi; Moriyama, Tetsuji; Tsuchiya, Yuko; Obuse, Chikashi; Mizuguchi, Kenji; Oka, Masahiro; Yoneda, Yoshihiro

2015-01-01

Nucleocytoplasmic trafficking is a fundamental cellular process in eukaryotic cells. Here, we demonstrated that retinoblastoma-binding protein 4 (RBBP4) functions as a novel regulatory factor to increase the efficiency of importin α/β-mediated nuclear import. RBBP4 accelerates the release of importin β1 from importin α via competitive binding to the importin β-binding domain of importin α in the presence of RanGTP. Therefore, it facilitates importin α/β-mediated nuclear import. We showed that the importin α/β pathway is down-regulated in replicative senescent cells, concomitant with a decrease in RBBP4 level. Knockdown of RBBP4 caused both suppression of nuclear transport and induction of cellular senescence. This is the first report to identify a factor that competes with importin β1 to bind to importin α, and it demonstrates that the loss of this factor can trigger cellular senescence. PMID:26491019

Cellular Therapies Clinical Research Roadmap: lessons learned on how to move a cellular therapy into a clinical trial.

PubMed

Ouseph, Stacy; Tappitake, Darah; Armant, Myriam; Wesselschmidt, Robin; Derecho, Ivy; Draxler, Rebecca; Wood, Deborah; Centanni, John M

2015-04-01

A clinical research roadmap has been developed as a resource for researchers to identify critical areas and potential pitfalls when transitioning a cellular therapy product from the research laboratory, by means of an Investigational New Drug (IND) application, into early-phase clinical trials. The roadmap describes four key areas: basic and preclinical research, resource development, translational research and Good Manufacturing Practice (GMP) and IND assembly and submission. Basic and preclinical research identifies a new therapeutic concept and demonstrates its potential value with the use of a model of the relevant disease. During resource development, the appropriate specialists and the required expertise to bring this product into the clinic are identified (eg, researchers, regulatory specialists, GMP manufacturing staff, clinicians and clinical trials staff, etc). Additionally, the funds required to achieve this goal (or a plan to procure them) are identified. In the next phase, the plan to translate the research product into a clinical-grade therapeutic is developed. Finally regulatory approval to start the trial must be obtained. In the United States, this is done by filing an IND application with the Food and Drug Administration. The National Heart, Lung and Blood Institute-funded Production Assistance for Cellular Therapies program has facilitated the transition of a variety of cellular therapy products from the laboratory into Phase1/2 trials. The five Production Assistance for Cellular Therapies facilities have assisted investigators by performing translational studies and GMP manufacturing to ensure that cellular products met release specifications and were manufactured safely, reproducibly and at the appropriate scale. The roadmap resulting from this experience is the focus of this article. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Composite alginate gels for tunable cellular microenvironment mechanics

NASA Astrophysics Data System (ADS)

Khavari, Adele; Nydén, Magnus; Weitz, David A.; Ehrlicher, Allen J.

2016-08-01

The mechanics of the cellular microenvironment can be as critical as biochemistry in directing cell behavior. Many commonly utilized materials derived from extra-cellular-matrix create excellent scaffolds for cell growth, however, evaluating the relative mechanical and biochemical effects independently in 3D environments has been difficult in frequently used biopolymer matrices. Here we present 3D sodium alginate hydrogel microenvironments over a physiological range of stiffness (E = 1.85 to 5.29 kPa), with and without RGD binding sites or collagen fibers. We use confocal microscopy to measure the growth of multi-cellular aggregates (MCAs), of increasing metastatic potential in different elastic moduli of hydrogels, with and without binding factors. We find that the hydrogel stiffness regulates the growth and morphology of these cell clusters; MCAs grow larger and faster in the more rigid environments similar to cancerous breast tissue (E = 4-12 kPa) as compared to healthy tissue (E = 0.4-2 kpa). Adding binding factors from collagen and RGD peptides increases growth rates, and change maximum MCA sizes. These findings demonstrate the utility of these independently tunable mechanical/biochemistry gels, and that mechanical confinement in stiffer microenvironments may increase cell proliferation.

Cellular response of preosteoblasts to nanograined/ultrafine-grained structures.

PubMed

Misra, R D K; Thein-Han, W W; Pesacreta, T C; Hasenstein, K H; Somani, M C; Karjalainen, L P

2009-06-01

Metallic materials with submicron- to nanometer-sized grains provide surfaces that are different from conventional polycrystalline materials because of the large proportion of grain boundaries with high free energy. In the study described here, the combination of cellular and molecular biology, materials science and engineering advances our understanding of cell-substrate interactions, especially the cellular activity between preosteoblasts and nanostructured metallic surfaces. Experiments on the effect of nano-/ultrafine grains have shown that cell attachment, proliferation, viability, morphology and spread are favorably modulated and significantly different from conventional coarse-grained structures. Additionally, immunofluorescence studies demonstrated stronger vinculin signals associated with actin stress fibers in the outer regions of the cells and cellular extensions on nanograined/ultrafine-grained substrate. These observations suggest enhanced cell-substrate interaction and activity. The differences in the cellular response on nanograined/ultrafine-grained and coarse-grained substrates are attributed to grain size and degree of hydrophilicity. The outcomes of the study are expected to reduce challenges to engineer bulk nanostructured materials with specific physical and surface properties for medical devices with improved cellular attachment and response. The data lay the foundation for a new branch of nanostructured materials for biomedical applications.

Anaerobic sludge digestion with a biocatalytic additive. [Lactobacillus acidophilus

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

Ghosh, S.; Henry, M.P.; Fedde, P.A.

1982-01-01

Aimed at improving the process operating characteristics of anaerobic digestion for sludge stabilization and SNG production, this study evaluates the effects of a lactobacillus additive under normal, variable, and overload conditions. This whey fermentation product of an acid-tolerant strain of L. acidophilus fortified with CoCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. Data indicate that the biochemical additive increases methane yield, gas production rate, and volatile solids reduction; decreases volatile acids accumulation; enhances the digester buffer capacity; and improves the fertilizer value andmore » dewatering characteristics of the digested residue. Digester capacities could be potentially doubled when the feed is so treated. Results of field tests with six full-scale digesters confirm observations made with bench-scale digesters.« less

RRM2 induces NF-{kappa}B-dependent MMP-9 activation and enhances cellular invasiveness

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

Duxbury, Mark S.; Whang, Edward E.

2007-03-02

Ribonucleotide reductase is a dimeric enzyme that catalyzes conversion of ribonucleotide 5'-diphosphates to their 2'-deoxynucleotide forms, a rate-limiting step in the production of 2'-deoxyribonucleoside 5'-triphosphates required for DNA synthesis. The ribonucleotide reductase M2 subunit (RRM2) is a determinant of malignant cellular behavior in a range of human cancers. We examined the effect of RRM2 overexpression on pancreatic adenocarcinoma cellular invasiveness and nuclear factor-{kappa}B (NF-{kappa}B) transcription factor activity. RRM2 overexpression increases pancreatic adenocarcinoma cellular invasiveness and MMP-9 expression in a NF-{kappa}B-dependent manner. RNA interference (RNAi)-mediated silencing of RRM2 expression attenuates cellular invasiveness and NF-{kappa}B activity. NF-{kappa}B is a key mediator ofmore » the invasive phenotypic changes induced by RRM2 overexpression.« less

Enhanced transfection by antioxidative polymeric gene carrier that reduces polyplex-mediated cellular oxidative stress.

PubMed

Lee, Min Sang; Kim, Nak Won; Lee, Kyuri; Kim, Hongtae; Jeong, Ji Hoon

2013-06-01

To test the hypothesis in which polyplex-induced oxidative stress may affect overall transfection efficiency, an antioxidative transfection system minimizing cellular oxidative stress was designed for enhanced transfection. An amphiphilic copolymer (PEI-PLGA) was synthesized and used as a micelle-type gene carrier containing hydrophobic antioxidant, α-tocopherol. Cellular oxidative stress and the change of mitochondrial membrane potential after transfection was measured by using a fluorescent probe (H₂DCFDA) and lipophilic cationic probe (JC-1), respectively. Transfection efficiency was determined by measuring a reporter gene (luciferase) expression level. The initial transfection study with conventional PEI/plasmid DNA polyplex showed significant generation of reactive oxygen species (ROS). The PEI-PLGA copolymer successfully carried out the simultaneous delivery of α-tocopherol and plasmid DNA (PEI-PLGA/Toco/pDNA polyplex) into cells, resulting in a significant reduction in cellular ROS generation after transfection and helped to maintain the mitochondrial membrane potential (ΔΨ). In addition, the transfection efficiency was dramatically increased using the antioxidative transfection system. This work showed that oxidative stress would be one of the important factors that should be considered in designing non-viral gene carriers and suggested a possible way to reduce the carrier-mediated oxidative stress, which consequently leads to enhanced transfection.

Cellular and multicellular form and function.

PubMed

Liu, Wendy F; Chen, Christopher S

2007-11-10

Engineering artificial tissue constructs requires the appropriate spatial arrangement of cells within scaffolds. The introduction of microengineering tools to the biological community has provided a valuable set of techniques to manipulate the cellular environment, and to examine how cell structure affects cellular function. Using micropatterning techniques, investigators have found that the geometric presentation of cell-matrix adhesions are important regulators of various cell behaviors including cell growth, proliferation, differentiation, polarity and migration. Furthermore, the presence of neighboring cells in multicellular aggregates has a significant impact on the proliferative and differentiated state of cells. Using microengineering tools, it will now be possible to manipulate the various environmental factors for practical applications such as engineering tissue constructs with greater control over the physical structure and spatial arrangement of cells within their surrounding microenvironment.

Microfluidics-Based in Vivo Mimetic Systems for the Study of Cellular Biology

PubMed Central

2015-01-01

Conspectus The human body is a complex network of molecules, organelles, cells, tissues, and organs: an uncountable number of interactions and transformations interconnect all the system’s components. In addition to these biochemical components, biophysical components, such as pressure, flow, and morphology, and the location of all of these interactions play an important role in the human body. Technical difficulties have frequently limited researchers from observing cellular biology as it occurs within the human body, but some state-of-the-art analytical techniques have revealed distinct cellular behaviors that occur only in the context of the interactions. These types of findings have inspired bioanalytical chemists to provide new tools to better understand these cellular behaviors and interactions. What blocks us from understanding critical biological interactions in the human body? Conventional approaches are often too naïve to provide realistic data and in vivo whole animal studies give complex results that may or may not be relevant for humans. Microfluidics offers an opportunity to bridge these two extremes: while these studies will not model the complexity of the in vivo human system, they can control the complexity so researchers can examine critical factors of interest carefully and quantitatively. In addition, the use of human cells, such as cells isolated from donated blood, captures human-relevant data and limits the use of animals in research. In addition, researchers can adapt these systems easily and cost-effectively to a variety of high-end signal transduction mechanisms, facilitating high-throughput studies that are also spatially, temporally, or chemically resolved. These strengths should allow microfluidic platforms to reveal critical parameters in the human body and provide insights that will help with the translation of pharmacological advances to clinical trials. In this Account, we describe selected microfluidic innovations within the

A biphasic endothelial stress-survival mechanism regulates the cellular response to vascular endothelial growth factor A

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

Latham, Antony M.; Odell, Adam F.; Mughal, Nadeem A.

2012-11-01

Vascular endothelial growth factor A (VEGF-A) is an essential cytokine that regulates endothelial function and angiogenesis. VEGF-A binding to endothelial receptor tyrosine kinases such as VEGFR1 and VEGFR2 triggers cellular responses including survival, proliferation and new blood vessel sprouting. Increased levels of a soluble VEGFR1 splice variant (sFlt-1) correlate with endothelial dysfunction in pathologies such as pre-eclampsia; however the cellular mechanism(s) underlying the regulation and function of sFlt-1 are unclear. Here, we demonstrate the existence of a biphasic stress response in endothelial cells, using serum deprivation as a model of endothelial dysfunction. The early phase is characterized by a highmore » VEGFR2:sFlt-1 ratio, which is reversed in the late phase. A functional consequence is a short-term increase in VEGF-A-stimulated intracellular signaling. In the late phase, sFlt-1 is secreted and deposited at the extracellular matrix. We hypothesized that under stress, increased endothelial sFlt-1 levels reduce VEGF-A bioavailability: VEGF-A treatment induces sFlt-1 expression at the cell surface and VEGF-A silencing inhibits sFlt-1 anchorage to the extracellular matrix. Treatment with recombinant sFlt-1 inhibits VEGF-A-stimulated in vitro angiogenesis and sFlt-1 silencing enhances this process. In this response, increased VEGFR2 levels are regulated by the phosphatidylinositol-3-kinase and PKB/Akt signaling pathways and increased sFlt-1 levels by the ERK1/2 signaling pathway. We conclude that during serum withdrawal, cellular sensing of environmental stress modulates sFlt-1 and VEGFR2 levels, regulating VEGF-A bioavailability and ensuring cell survival takes precedence over cell proliferation and migration. These findings may underpin an important mechanism contributing to endothelial dysfunction in pathological states. -- Highlights: Black-Right-Pointing-Pointer Endothelial cells mount a stress response under conditions of low serum. Black

Vitamin D deficiency may be a risk factor for recurrent pregnancy losses by increasing cellular immunity and autoimmunity.

PubMed

Ota, Kuniaki; Dambaeva, Svetlana; Han, Ae-Ra; Beaman, Kenneth; Gilman-Sachs, Alice; Kwak-Kim, Joanne

2014-02-01

.5 mg/dl) was significantly lower in VDlow than those of VDnl (P < 0.05, P < 0.01, respectively). There were no differences in Th1/Th2 ratios between VDlow and VDnl. When vitamin D3 was added in NK cytotoxicity assay in vitro, NK cytotoxicity at E:T ratio of 50:1 was significantly suppressed with 10 nMol/L (nM) (11.9 ± 3.3%) and 100 nM (10.9 ± 3.7%) of vitamin D3 when compared with controls (15.3 ± 4.7%) (P < 0.01 each). TNF-α/IL-10 expressing CD3(+)/4(+) cell ratios were significantly decreased with 100 nM of vitamin D3 (31.3 ± 9.4, P < 0.05) when compared with controls (40.4 ± 11.3) in vitro. Additionally, INF-γ/IL-10 expressing CD3(+)/4(+) cell ratio was significantly decreased with 100 nM of vitamin D3 (12.1 ± 4.0, P < 0.05) when compared with controls (14.8 ± 4.6). IFN-γ and TNF-α secretion from NK cells were significantly decreased (P < 0.01 each), and IL-10, IL-1β, vascular endothelial growth factor and granulocyte colony stimulating factor levels were significantly increased (P < 0.01 each) with vitamin D3 100 nM when compared with those of controls. The prevalence of vitamin D deficiency in women with RPL in this study is open to a possible type I error since women with vitamin D supplementation were excluded from this study. Assessment of vitamin D level is recommended in women with RPL. Vitamin D supplementation should be explored further as a possible therapeutic option for RPL. This work was supported by the intramural funding from Department of Microbiology and Immunology, Chicago Medical School at Rosalind Franklin University of Medicine and Science. None of the authors has any conflict of interest to declare. N/A.

Small molecule-induced cellular fate reprogramming: promising road leading to Rome.

PubMed

Li, Xiang; Xu, Jun; Deng, Hongkui

2018-05-29

Cellular fate reprogramming holds great promise to generate functional cell types for replenishing new cells and restoring functional loss. Inspired by transcription factor-induced reprogramming, the field of cellular reprogramming has greatly advanced and developed into divergent streams of reprogramming approaches. Remarkably, increasing studies have shown the power and advantages of small molecule-based approaches for cellular fate reprogramming, which could overcome the limitations of conventional transgenic-based reprogramming. In this concise review, we discuss these findings and highlight the future potentiality with particular focus on this new trend of chemical reprogramming. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sleep deprivation and activation of morning levels of cellular and genomic markers of inflammation.

PubMed

Irwin, Michael R; Wang, Minge; Campomayor, Capella O; Collado-Hidalgo, Alicia; Cole, Steve

2006-09-18

Inflammation is associated with increased risk of cardiovascular disorders, arthritis, diabetes mellitus, and mortality. The effects of sleep loss on the cellular and genomic mechanisms that contribute to inflammatory cytokine activity are not known. In 30 healthy adults, monocyte intracellular proinflammatory cytokine production was repeatedly assessed during the day across 3 baseline periods and after partial sleep deprivation (awake from 11 pm to 3 am). We analyzed the impact of sleep loss on transcription of proinflammatory cytokine genes and used DNA microarray analyses to characterize candidate transcription-control pathways that might mediate the effects of sleep loss on leukocyte gene expression. In the morning after a night of sleep loss, monocyte production of interleukin 6 and tumor necrosis factor alpha was significantly greater compared with morning levels following uninterrupted sleep. In addition, sleep loss induced a more than 3-fold increase in transcription of interleukin 6 messenger RNA and a 2-fold increase in tumor necrosis factor alpha messenger RNA. Bioinformatics analyses suggested that the inflammatory response was mediated by the nuclear factor kappaB inflammatory signaling system as well as through classic hormone and growth factor response pathways. Sleep loss induces a functional alteration of the monocyte proinflammatory cytokine response. A modest amount of sleep loss also alters molecular processes that drive cellular immune activation and induce inflammatory cytokines; mapping the dynamics of sleep loss on molecular signaling pathways has implications for understanding the role of sleep in altering immune cell physiologic characteristics. Interventions that target sleep might constitute new strategies to constrain inflammation with effects on inflammatory disease risk.

Genetic Algorithm Calibration of Probabilistic Cellular Automata for Modeling Mining Permit Activity

USGS Publications Warehouse

Louis, S.J.; Raines, G.L.

2003-01-01

We use a genetic algorithm to calibrate a spatially and temporally resolved cellular automata to model mining activity on public land in Idaho and western Montana. The genetic algorithm searches through a space of transition rule parameters of a two dimensional cellular automata model to find rule parameters that fit observed mining activity data. Previous work by one of the authors in calibrating the cellular automaton took weeks - the genetic algorithm takes a day and produces rules leading to about the same (or better) fit to observed data. These preliminary results indicate that genetic algorithms are a viable tool in calibrating cellular automata for this application. Experience gained during the calibration of this cellular automata suggests that mineral resource information is a critical factor in the quality of the results. With automated calibration, further refinements of how the mineral-resource information is provided to the cellular automaton will probably improve our model.

Unbiased compound screening with a reporter gene assay highlights the role of p13 in the cardiac cellular stress response.

PubMed

Inoue, Naoki; Hirouchi, Taisei; Kasai, Atsushi; Higashi, Shintaro; Hiraki, Natsumi; Tanaka, Shota; Nakazawa, Takanobu; Nunomura, Kazuto; Lin, Bangzhong; Omori, Akiko; Hayata-Takano, Atsuko; Kim, Yoon-Jeong; Doi, Takefumi; Baba, Akemichi; Hashimoto, Hitoshi; Shintani, Norihito

2018-01-08

We recently showed that a 13-kDa protein (p13), the homolog protein of formation of mitochondrial complex V assembly factor 1 in yeast, acts as a potential protective factor in pancreatic islets under diabetes. Here, we aimed to identify known compounds regulating p13 mRNA expression to obtain therapeutic insight into the cellular stress response. A luciferase reporter system was developed using the putative promoter region of the human p13 gene. Overexpression of peroxisome proliferator-activated receptor gamma coactivator 1α, a master player regulating mitochondrial metabolism, increased both reporter activity and p13 expression. Following unbiased screening with 2320 known compounds in HeLa cells, 12 pharmacological agents (including 8 cardiotonics and 2 anthracyclines) that elicited >2-fold changes in p13 mRNA expression were identified. Among them, four cardiac glycosides decreased p13 expression and concomitantly elevated cellular oxidative stress. Additional database analyses showed highest p13 expression in heart, with typically decreased expression in cardiac disease. Accordingly, our results illustrate the usefulness of unbiased compound screening as a method for identifying novel functional roles of unfamiliar genes. Our findings also highlight the importance of p13 in the cellular stress response in heart. Copyright © 2017. Published by Elsevier Inc.

Cellular fatty acids and aldehydes of oral Eubacterium.

PubMed

Itoh, U; Sato, M; Tsuchiya, H; Namikawa, I

1995-02-01

The cellular fatty acids and aldehydes of oral Eubacterium species were determined by gas chromatography-mass spectrometry. E. brachy and E. lentum contained mainly branched-chain fatty acids, whereas the others contained straight-chain acids. E. brachy, E. lentum, E. yurii ssp. yurii, E. yurii spp. margaretiae, E. limosum, E. plauti and E. aerofaciens also contained aldehydes with even carbon numbers. In addition to species-specific components, the compositional ratios of fatty acids and aldehydes characterized each individual species. The 10 species tested were divided into 5 groups by the principal component analysis. Cellular fatty acids and aldehydes would be chemical markers for interspecies differentiation of oral Eubacterium.

The Novel Mechanisms Concerning the Inhibitions of Palmitate-Induced Proinflammatory Factor Releases and Endogenous Cellular Stress with Astaxanthin on MIN6 β-Cells.

PubMed

Kitahara, Atsuko; Takahashi, Kazuto; Morita, Naru; Murashima, Toshitaka; Onuma, Hirohisa; Sumitani, Yoshikazu; Tanaka, Toshiaki; Kondo, Takuma; Hosaka, Toshio; Ishida, Hitoshi

2017-06-20

Astaxanthin, an antioxidant agent, can protect pancreatic β-cells of db/db mice from glucotoxicity and resolve chronic inflammation in adipose tissue. Nonetheless, the effects of astaxanthin on free-fatty-acid-induced inflammation and cellular stress in β-cells remain to be demonstrated. Meanwhile, palmitate enhances the secretion of pro-inflammatory adipokines monocyte chemoattractant protein-1 (MCP-1) and VEGF 120 (vascular endothelial growth factor). We therefore investigated the influence of astaxanthin on palmitate-stimulated MCP-1 and VEGF 120 secretion in mouse insulinoma (MIN6) pancreatic β-cells. Furthermore, whether astaxanthin prevents cellular stress in MIN6 cells was also assessed. Pre-treatment with astaxanthin or with N -acetyl-cysteine (NAC) which is an antioxidant drug, significantly attenuated the palmitate-induced MCP-1 release through downregulation of phosphorylated c-Jun NH₂-terminal protein kinase (JNK) pathways, and suppressed VEGF 120 through the PI3K/Akt pathways relative to the cells stimulated with palmitate alone. In addition, palmitate significantly upregulated homologous protein (CHOP) and anti-glucose-regulated protein (GRP78), which are endoplasmic reticulum (ER) stress markers, in MIN6 cells. On the other hand, astaxanthin attenuated the increased CHOP content, but further up-regulated palmitate-stimulated GRP78 protein expression. By contrast, NAC had no effects on either CHOP or GRP78 enhancement induced by palmitate in MIN6 cells. In conclusion, astaxanthin diminishes the palmitate-stimulated increase in MCP-1 secretion via the downregulation of JNK pathways in MIN6 cells, and affects VEGF 120 secretion through PI3K/Akt pathways. Moreover, astaxanthin can prevent not only oxidative stress caused endogenously by palmitate but also ER stress, which NAC fails to attenuate, via upregulation of GRP78, an ER chaperon.

The Novel Mechanisms Concerning the Inhibitions of Palmitate-Induced Proinflammatory Factor Releases and Endogenous Cellular Stress with Astaxanthin on MIN6 β-Cells

PubMed Central

Kitahara, Atsuko; Takahashi, Kazuto; Morita, Naru; Murashima, Toshitaka; Onuma, Hirohisa; Sumitani, Yoshikazu; Tanaka, Toshiaki; Kondo, Takuma; Hosaka, Toshio; Ishida, Hitoshi

2017-01-01

Astaxanthin, an antioxidant agent, can protect pancreatic β-cells of db/db mice from glucotoxicity and resolve chronic inflammation in adipose tissue. Nonetheless, the effects of astaxanthin on free-fatty-acid-induced inflammation and cellular stress in β-cells remain to be demonstrated. Meanwhile, palmitate enhances the secretion of pro-inflammatory adipokines monocyte chemoattractant protein-1 (MCP-1) and vascular endothelial growth factor (VEGF120). We therefore investigated the influence of astaxanthin on palmitate-stimulated MCP-1 and VEGF120 secretion in mouse insulinoma (MIN6) pancreatic β-cells. Furthermore, whether astaxanthin prevents cellular stress in MIN6 cells was also assessed. Pre-treatment with astaxanthin or with N-acetyl-cysteine (NAC) which is an antioxidant drug, significantly attenuated the palmitate-induced MCP-1 release through downregulation of phosphorylated c-Jun NH2-terminal protein kinase (JNK) pathways, and suppressed VEGF120 through the PI3K/Akt pathways relative to the cells stimulated with palmitate alone. In addition, palmitate significantly upregulated homologous protein (CHOP) and anti-glucose-regulated protein (GRP78), which are endoplasmic reticulum (ER) stress markers, in MIN6 cells. On the other hand, astaxanthin attenuated the increased CHOP content, but further up-regulated palmitate-stimulated GRP78 protein expression. By contrast, NAC had no effects on either CHOP or GRP78 enhancement induced by palmitate in MIN6 cells. In conclusion, astaxanthin diminishes the palmitate-stimulated increase in MCP-1 secretion via the downregulation of JNK pathways in MIN6 cells, and affects VEGF120 secretion through PI3K/Akt pathways. Moreover, astaxanthin can prevent not only oxidative stress caused endogenously by palmitate but also ER stress, which NAC fails to attenuate, via upregulation of GRP78, an ER chaperon. PMID:28632169

Parasitoid wasp venom SERCA regulates Drosophila calcium levels and inhibits cellular immunity.

PubMed

Mortimer, Nathan T; Goecks, Jeremy; Kacsoh, Balint Z; Mobley, James A; Bowersock, Gregory J; Taylor, James; Schlenke, Todd A

2013-06-04

Because parasite virulence factors target host immune responses, identification and functional characterization of these factors can provide insight into poorly understood host immune mechanisms. The fruit fly Drosophila melanogaster is a model system for understanding humoral innate immunity, but Drosophila cellular innate immune responses remain incompletely characterized. Fruit flies are regularly infected by parasitoid wasps in nature and, following infection, flies mount a cellular immune response culminating in the cellular encapsulation of the wasp egg. The mechanistic basis of this response is largely unknown, but wasps use a mixture of virulence proteins derived from the venom gland to suppress cellular encapsulation. To gain insight into the mechanisms underlying wasp virulence and fly cellular immunity, we used a joint transcriptomic/proteomic approach to identify venom genes from Ganaspis sp.1 (G1), a previously uncharacterized Drosophila parasitoid species, and found that G1 venom contains a highly abundant sarco/endoplasmic reticulum calcium ATPase (SERCA) pump. Accordingly, we found that fly immune cells termed plasmatocytes normally undergo a cytoplasmic calcium burst following infection, and that this calcium burst is required for activation of the cellular immune response. We further found that the plasmatocyte calcium burst is suppressed by G1 venom in a SERCA-dependent manner, leading to the failure of plasmatocytes to become activated and migrate toward G1 eggs. Finally, by genetically manipulating plasmatocyte calcium levels, we were able to alter fly immune success against G1 and other parasitoid species. Our characterization of parasitoid wasp venom proteins led us to identify plasmatocyte cytoplasmic calcium bursts as an important aspect of fly cellular immunity.

Cell-Nonautonomous Mechanisms Underlying Cellular and Organismal Aging.

PubMed

Medkour, Younes; Svistkova, Veronika; Titorenko, Vladimir I

2016-01-01

Cell-autonomous mechanisms underlying cellular and organismal aging in evolutionarily distant eukaryotes have been established; these mechanisms regulate longevity-defining processes within a single eukaryotic cell. Recent findings have provided valuable insight into cell-nonautonomous mechanisms modulating cellular and organismal aging in eukaryotes across phyla; these mechanisms involve a transmission of various longevity factors between different cells, tissues, and organisms. Herein, we review such cell-nonautonomous mechanisms of aging in eukaryotes. We discuss the following: (1) how low molecular weight transmissible longevity factors modulate aging and define longevity of cells in yeast populations cultured in liquid media or on solid surfaces, (2) how communications between proteostasis stress networks operating in neurons and nonneuronal somatic tissues define longevity of the nematode Caenorhabditis elegans by modulating the rates of aging in different tissues, and (3) how different bacterial species colonizing the gut lumen of C. elegans define nematode longevity by modulating the rate of organismal aging. Copyright © 2016. Published by Elsevier Inc.

Parasitism and venom of ectoparasitoid Scleroderma guani impairs host cellular immunity.

PubMed

Li, Li-Fang; Xu, Zhi-Wen; Liu, Nai-Yong; Wu, Guo-Xing; Ren, Xue-Min; Zhu, Jia-Ying

2018-06-01

Venom is a prominently maternal virulent factor utilized by parasitoids to overcome hosts immune defense. With respect to roles of this toxic mixture involved in manipulating hosts immunity, great interest has been mostly restricted to Ichneumonoidea parasitoids associated with polydnavirus (PDV), of which venom is usually considered as a helper component to enhance the role of PDV, and limited Chalcidoidea species. In contrast, little information is available in other parasitoids, especially ectoparasitic species not carrying PDV. The ectoparasitoid Scleroderma guani injects venom into its host, Tenebrio molitor, implying its venom was involved in suppression of hosts immune response for successful parasitism. Thus, we investigated the effects of parasitism and venom of this parasitoid on counteracting the cellular immunity of its host by examining changes of hemocyte counts, and hemocyte spreading and encapsulation ability. Total hemocyte counts were elevated in parasitized and venom-injected pupae. The spreading behavior of both granulocytes and plasmatocytes was impaired by parasitization and venom. High concentration of venom led to more severely increased hemocyte counts and suppression of hemocyte spreading. The ability of hemocyte encapsulation was inhibited by venom in vitro. In addition to immediate effects observed, venom showed persistent interference in hosts cellular immunity. These results indicate that venom alone from S. guani plays a pivotal role in blocking hosts cellular immune response, serving as a regulator that guarantees the successful development of its progenies. The findings provide a foundation for further investigation of the underlying mechanisms in immune inhibitory action of S. guani venom. © 2018 Wiley Periodicals, Inc.

Cellular senescence and autophagy in the pathogenesis of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF).

PubMed

Kuwano, Kazuyoshi; Araya, Jun; Hara, Hiromichi; Minagawa, Shunsuke; Takasaka, Naoki; Ito, Saburo; Kobayashi, Kenji; Nakayama, Katsutoshi

2016-11-01

Aging is associated with impairments in homeostasis. Although aging and senescence are not equivalent, the number of senescent cells increases with aging. Cellular senescence plays important roles in tissue repair or remodeling, as well as embryonic development. Autophagy is a process of lysosomal self-degradation that maintains a homeostatic balance between the synthesis, degradation, and recycling of cellular proteins. Autophagy diminishes with aging; additionally, accelerated aging can be attributed to reduced autophagy. Cellular senescence has been widely implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD), a disease of accelerated lung aging, presumably by impairing cell repopulation and by aberrant cytokine secretion in the senescence-associated secretory phenotype. The possible participation of autophagy in the pathogenic sequence of COPD has been extensively explored. Although it has been reported that increased autophagy may induce epithelial cell death, an insufficient reserve of autophagy can induce cellular senescence in bronchial epithelial cells of COPD. Furthermore, advanced age is one of the most important risk factors for the development of idiopathic pulmonary fibrosis (IPF). Telomere shortening is found in blood leukocytes and alveolar epithelial cells from patients with IPF. Accelerated senescence of epithelial cells plays a role in IPF pathogenesis by perpetuating abnormal epithelial-mesenchymal interactions. Insufficient autophagy may be an underlying mechanism of accelerated epithelial cell senescence and myofibroblast differentiation in IPF. Herein, we review the molecular mechanisms of cellular senescence and autophagy and summarize the role of cellular senescence and autophagy in both COPD and IPF. Copyright © 2016 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

Plant Nucleolar Stress Response, a New Face in the NAC-Dependent Cellular Stress Responses.

PubMed

Ohbayashi, Iwai; Sugiyama, Munetaka

2017-01-01

The nucleolus is the most prominent nuclear domain, where the core processes of ribosome biogenesis occur vigorously. All these processes are finely orchestrated by many nucleolar factors to build precisely ribosome particles. In animal cells, perturbations of ribosome biogenesis, mostly accompanied by structural disorders of the nucleolus, cause a kind of cellular stress to induce cell cycle arrest, senescence, or apoptosis, which is called nucleolar stress response. The best-characterized pathway of this stress response involves p53 and MDM2 as key players. p53 is a crucial transcription factor that functions in response to not only nucleolar stress but also other cellular stresses such as DNA damage stress. These cellular stresses release p53 from the inhibition by MDM2, an E3 ubiquitin ligase targeting p53, in various ways, which leads to p53-dependent activation of a set of genes. In plants, genetic impairments of ribosome biogenesis factors or ribosome components have been shown to cause characteristic phenotypes, including a narrow and pointed leaf shape, implying a common signaling pathway connecting ribosomal perturbations and certain aspects of growth and development. Unlike animals, however, plants have neither p53 nor MDM2 family proteins. Then the question arises whether plant cells have a nucleolar stress response pathway. In recent years, it has been reported that several members of the plant-specific transcription factor family NAC play critical roles in the pathways responsive to various cellular stresses. In this mini review, we outline the plant cellular stress response pathways involving NAC transcription factors with reference to the p53-MDM2-dependent pathways of animal cells, and discuss the possible involvement of a plant-unique, NAC-mediated pathway in the nucleolar stress response in plants.

Discovery of a proteinaceous cellular receptor for a norovirus

PubMed Central

Orchard, Robert C.; Wilen, Craig B.; Doench, John G.; Baldridge, Megan T.; McCune, Broc T.; Lee, Ying-Chiang J.; Lee, Sanghyun; Pruett-Miller, Shondra M.; Nelson, Christopher A.; Fremont, Daved H.; Virgin, Herbert W.

2017-01-01

Human noroviruses (NoV) are a leading cause of gastroenteritis globally, yet host factors required for NoV infection are poorly understood. We identified host molecules essential for murine NoV (MNoV) induced cell death including CD300lf as a proteinaceous receptor. CD300lf is essential for MNoV binding and replication in cell lines and primary cells. Additionally, Cd300lf−/− mice are resistant to MNoV infection. Expression of CD300lf in human cells breaks the species barrier restricting MNoV replication. The crystal structure of the CD300lf ectodomain revealed a potential ligand binding cleft composed of residues critical for MNoV infection. Therefore, the presence of a proteinaceous receptor is the primary determinant of MNoV species tropism while other components of cellular machinery required for NoV replication are conserved between humans and mice. PMID:27540007

Rapid detection of biothreat agents based on cellular machinery.

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

Lane, Todd W.; Gantt, Richard W.

This research addresses rapid and sensitive identification of biological agents in a complex background. We attempted to devise a method by which the specificity of the cellular transcriptional machinery could be used to detect and identify bacterial bio-terror agents in a background of other organisms. Bacterial cells contain RNA polymerases and transcription factors that transcribe genes into mRNA for translation into proteins. RNA polymerases in conjunction with transcription factors recognize regulatory elements (promoters) upstream of the gene. These promoters are, in many cases, recognized by the polymerase and transcription factor combinations of one species only. We have engineered a plasmid,more » for Escherichia coli, containing the virA promoter from the target species Shigella flexneri. This promoter was fused to a reporter gene Green Fluorescent Protein (GFP). In theory the indicator strain (carrying the plasmid) is mixed with the target strain and the two are lysed. The cellular machinery from both cells mixes and the GFP is produced. This report details the results of testing this system.« less

Regulation of the mammalian heat shock factor 1.

PubMed

Dayalan Naidu, Sharadha; Dinkova-Kostova, Albena T

2017-06-01

Living organisms are endowed with the capability to tackle various forms of cellular stress due to the presence of molecular chaperone machinery complexes that are ubiquitous throughout the cell. During conditions of proteotoxic stress, the transcription factor heat shock factor 1 (HSF1) mediates the elevation of heat shock proteins, which are crucial components of the chaperone complex machinery and function to ameliorate protein misfolding and aggregation and restore protein homeostasis. In addition, HSF1 orchestrates a versatile transcriptional programme that includes genes involved in repair and clearance of damaged macromolecules and maintenance of cell structure and metabolism, and provides protection against a broad range of cellular stress mediators, beyond heat shock. Here, we discuss the structure and function of the mammalian HSF1 and its regulation by post-translational modifications (phosphorylation, sumoylation and acetylation), proteasomal degradation, and small-molecule activators and inhibitors. © 2017 Federation of European Biochemical Societies.

Cellular density-dependent down-regulation of EP4 prostanoid receptors via the up-regulation of hypoxia-inducible factor-1α in HCA-7 human colon cancer cells.

PubMed

Otake, Sho; Yoshida, Kenji; Seira, Naofumi; Sanchez, Christopher M; Regan, John W; Fujino, Hiromichi; Murayama, Toshihiko

2015-02-01

Increases in prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2) levels are features of colon cancer. Among the different E-type prostanoid receptor subtypes, EP4 receptors are considered to play a crucial role in carcinogenesis by, for example, inducing COX-2 when stimulated with PGE2. However, EP4 receptor levels and PGE2-induced cellular responses are inconsistent among the cellular conditions. Therefore, the connections responsible for the expression of EP4 receptors were investigated in the present study by focusing on cell density-induced hypoxia-inducible factor-1α (HIF-1α). The expression of EP4 receptors was examined using immunoblot analysis, quantitative polymerase chain reaction, and reporter gene assays in HCA-7 human colon cancer cells with different cellular densities. The involvement of HIF-1α and its signaling pathways were also examined by immunoblot analysis, reporter gene assays, and with siRNA. We here demonstrated that EP4 receptors as well as EP4 receptor-mediated COX-2 expression levels decreased with an increase in cellular density. In contrast, HIF-1α levels increased in a cellular density-dependent manner. The knockdown of HIF-1α by siRNA restored the expression of EP4 receptors and EP4 receptor-mediated COX-2 in cells at a high density. Thus, the cellular density-dependent increase observed in HIF-1α expression levels reduced the expression of COX-2 by decreasing EP4 receptor levels. This novel regulation mechanism for the expression of EP4 receptors by HIF-1α may provide an explanation for the inconsistent actions of PGE2. The expression levels of EP4 receptors may vary depending on cellular density, which may lead to the differential activation of their signaling pathways by PGE2. Thus, cellular density-dependent PGE2-mediated signaling may determine the fate/stage of cancer cells, i.e., the surrounding environments could define the fate/stage of malignancies associated with colon cancer.

Cellular density-dependent down-regulation of EP4 prostanoid receptors via the up-regulation of hypoxia-inducible factor-1α in HCA-7 human colon cancer cells

PubMed Central

Otake, Sho; Yoshida, Kenji; Seira, Naofumi; Sanchez, Christopher M; Regan, John W; Fujino, Hiromichi; Murayama, Toshihiko

2015-01-01

Increases in prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2) levels are features of colon cancer. Among the different E-type prostanoid receptor subtypes, EP4 receptors are considered to play a crucial role in carcinogenesis by, for example, inducing COX-2 when stimulated with PGE2. However, EP4 receptor levels and PGE2-induced cellular responses are inconsistent among the cellular conditions. Therefore, the connections responsible for the expression of EP4 receptors were investigated in the present study by focusing on cell density-induced hypoxia-inducible factor-1α (HIF-1α). The expression of EP4 receptors was examined using immunoblot analysis, quantitative polymerase chain reaction, and reporter gene assays in HCA-7 human colon cancer cells with different cellular densities. The involvement of HIF-1α and its signaling pathways were also examined by immunoblot analysis, reporter gene assays, and with siRNA. We here demonstrated that EP4 receptors as well as EP4 receptor-mediated COX-2 expression levels decreased with an increase in cellular density. In contrast, HIF-1α levels increased in a cellular density-dependent manner. The knockdown of HIF-1α by siRNA restored the expression of EP4 receptors and EP4 receptor-mediated COX-2 in cells at a high density. Thus, the cellular density-dependent increase observed in HIF-1α expression levels reduced the expression of COX-2 by decreasing EP4 receptor levels. This novel regulation mechanism for the expression of EP4 receptors by HIF-1α may provide an explanation for the inconsistent actions of PGE2. The expression levels of EP4 receptors may vary depending on cellular density, which may lead to the differential activation of their signaling pathways by PGE2. Thus, cellular density-dependent PGE2-mediated signaling may determine the fate/stage of cancer cells, i.e., the surrounding environments could define the fate/stage of malignancies associated with colon cancer. PMID:25692008

Sub-cellular force microscopy in single normal and cancer cells.

PubMed

Babahosseini, H; Carmichael, B; Strobl, J S; Mahmoodi, S N; Agah, M

2015-08-07

This work investigates the biomechanical properties of sub-cellular structures of breast cells using atomic force microscopy (AFM). The cells are modeled as a triple-layered structure where the Generalized Maxwell model is applied to experimental data from AFM stress-relaxation tests to extract the elastic modulus, the apparent viscosity, and the relaxation time of sub-cellular structures. The triple-layered modeling results allow for determination and comparison of the biomechanical properties of the three major sub-cellular structures between normal and cancerous cells: the up plasma membrane/actin cortex, the mid cytoplasm/nucleus, and the low nuclear/integrin sub-domains. The results reveal that the sub-domains become stiffer and significantly more viscous with depth, regardless of cell type. In addition, there is a decreasing trend in the average elastic modulus and apparent viscosity of the all corresponding sub-cellular structures from normal to cancerous cells, which becomes most remarkable in the deeper sub-domain. The presented modeling in this work constitutes a unique AFM-based experimental framework to study the biomechanics of sub-cellular structures. Copyright © 2015 Elsevier Inc. All rights reserved.

The cellular transcription factor CREB corresponds to activating transcription factor 47 (ATF-47) and forms complexes with a group of polypeptides related to ATF-43.

PubMed

Hurst, H C; Masson, N; Jones, N C; Lee, K A

1990-12-01

Promoter elements containing the sequence motif CGTCA are important for a variety of inducible responses at the transcriptional level. Multiple cellular factors specifically bind to these elements and are encoded by a multigene family. Among these factors, polypeptides termed activating transcription factor 43 (ATF-43) and ATF-47 have been purified from HeLa cells and a factor referred to as cyclic AMP response element-binding protein (CREB) has been isolated from PC12 cells and rat brain. We demonstrated that CREB and ATF-47 are identical and that CREB and ATF-43 form protein-protein complexes. We also found that the cis requirements for stable DNA binding by ATF-43 and CREB are different. Using antibodies to ATF-43 we have identified a group of polypeptides (ATF-43) in the size range from 40 to 43 kDa. ATF-43 polypeptides are related by their reactivity with anti-ATF-43, DNA-binding specificity, complex formation with CREB, heat stability, and phosphorylation by protein kinase A. Certain cell types vary in their ATF-43 complement, suggesting that CREB activity is modulated in a cell-type-specific manner through interaction with ATF-43. ATF-43 polypeptides do not appear simply to correspond to the gene products of the ATF multigene family, suggesting that the size of the ATF family at the protein level is even larger than predicted from cDNA-cloning studies.

47 CFR 22.970 - Unacceptable interference to part 90 non-cellular 800 MHz licensees from cellular radiotelephone...

Code of Federal Regulations, 2011 CFR

2011-10-01

...-cellular 800 MHz licensees from cellular radiotelephone or part 90-800 MHz cellular systems. 22.970 Section... MOBILE SERVICES Cellular Radiotelephone Service § 22.970 Unacceptable interference to part 90 non-cellular 800 MHz licensees from cellular radiotelephone or part 90-800 MHz cellular systems. (a) Definition...

Antihypertensive methyldopa, labetalol, hydralazine, and clonidine reversed tumour necrosis factor-α inhibited endothelial nitric oxide synthase expression in endothelial-trophoblast cellular networks.

PubMed

Xu, Bei; Bobek, Gabriele; Makris, Angela; Hennessy, Annemarie

2017-03-01

Medications used to control hypertension in pregnancy also improve trophoblast and endothelial cellular interaction in vitro. Tumour necrosis factor-α (TNF-α) inhibits trophoblast and endothelial cellular interactions and simultaneously decreases endothelial nitric oxide synthase (eNOS) expression. This study investigated whether antihypertensive medications improved these cellular interactions by modulating eNOS and inducible nitric oxide synthase (iNOS) expression. Human uterine myometrial microvascular endothelial cells (UtMVECs) were pre-incubated with (or without) low dose TNF-α (0.5 ng/mL) or TNF-α plus soluble fms-like tyrosine kinase-1 (sFlt-1) (100 ng/mL). The endothelial cells were cultured on Matrigel. After endothelial cellular networks appeared, trophoblast derived HTR-8/SVneo cells were co-cultured in the presence of clinically relevant doses of methyldopa, labetalol, hydralazine or clonidine for 24 hours. Cells were retrieved from the Matrigel to extract mRNA and eNOS and iNOS expression were examined by quantitative PCR. Methyldopa, labetalol, hydralazine and clonidine reversed the inhibitory effect of TNF-α on eNOS mRNA expression. After pre-incubating endothelial cells with TNF-α and sFlt-1, all the medications except methyldopa lost their effect on eNOS mRNA expression. In the absence of TNF-α, antihypertensive medications did not change eNOS expression. The mRNA expression of iNOS was not affected by TNF-α or any medications. This study shows that selected antihypertensive medications used in the treatment of hypertension in pregnancy increase eNOS expression in vitro when induced by the inflammatory TNF-α. The anti-angiogenic molecule sFlt-1 may antagonise the potential benefit of these medications by interfering with the NOS pathway. © 2016 John Wiley & Sons Australia, Ltd.

Biosynthesis and maturation of cellular membrane glycoproteins.

PubMed

Hunt, L A

1979-01-01

The biosynthesis and the processing of asparagine-linked oligosaccharides of cellular membrane glycoproteins were examined in monolayer cultures of BHK21 cells and human diploid fibroblasts after pulse- and pulse-chase labeling with [2-3H]mannose. After pronase digestion, radiolabeled glycopeptides were characterized by high-resolution gel filtration, with or without additional digestion with various exoglycosidases and endoglycosidases. Pulse-labeled glycoproteins contained a relatively homogenous population of neutral oligosaccharides (major species: Man9GlcNAc2ASN). The vast majority of these asparagine-linked oligosaccharides was smaller than the major fraction of lipid-linked oligosaccharides from the cell and was apparently devoid of terminal glucose. After pulse-chase or long labeling periods, a significant fraction of the large oligomannosyl cores was processed by removal of mannose units and addition of branch sugars (NeuNAc-Gal-GlcNAc), resulting in complex acidic structures containing three and possibly five mannoses. In addition, some of the large oligomannosyl cores were processed by the removal of only several mannoses, resulting in a mixture of neutral structures with 5-9 mannoses. This oligomannosyl core heterogeneity in both neutral and acidic oligosaccharides linked to asparagine in cellular membrane glycoproteins was analogous to the heterogeneity reported for the oligosaccharides of avian RNA tumor virus glycoproteins (Hunt LA, Wright SE, Etchison JR, Summers DF: J Virol 29:336, 1979).

Cellular automata in photonic cavity arrays.

PubMed

Li, Jing; Liew, T C H

2016-10-31

We propose theoretically a photonic Turing machine based on cellular automata in arrays of nonlinear cavities coupled with artificial gauge fields. The state of the system is recorded making use of the bistability of driven cavities, in which losses are fully compensated by an external continuous drive. The sequential update of the automaton layers is achieved automatically, by the local switching of bistable states, without requiring any additional synchronization or temporal control.

Comprehensive finite element modeling of Ti-6Al-4V cellular solids fabricated by electron beam melting

NASA Astrophysics Data System (ADS)

Arrieta, Edel

Additive manufacturing permits the fabrication of cellular metals which are materials that can be highly customizable and possess multiple and extraordinary properties such as damage tolerance, metamorphic and auxetic behaviors, and high specific stiffness. This makes them the subject of interest for innovative applications. With interest in these materials for energy absorption applications, this work presents the development of nonlinear finite element models in commercial software platforms (MSC Patran/Nastran) that permit the analysis of the deformation mechanisms of these materials under compressive loads. In the development of these models, a detailed multiscale study on the different factors affecting the response of cellular metals was conducted with the objective to understanding the physics with the objective of selecting the most appropriate experiments. In that manner, a series of experiments were conducted on Ti-6Al-4V specimens fabricated by electron beam melting at different manufacturing orientations. Digital image correlation was presented as a vital tool for the measurement of strains in specimens with complex shapes; the experiments contemplated compression and tension tests of Ti-6Al-4V solid components, as well as compression tests on cellular lattices of the same alloy. FEMs were developed from the same CAD file utilized for the fabrication of the lattices; in addition, different meshing approaches and mesh convergence analysis were discussed. The mesh density showed convergence in models with over 70,000 elements, permitting the evaluation of the stress/strain-distribution mechanisms in the lattices. However, because of the considerable variability of the experimental material properties, some numerical results showed significant errors in predicting the compressive force applied to the lattices during the experiments; thus suggesting the need to improve the quality control in the manufacturing process and develop better technologies in

Cellular Imaging With MRI.

PubMed

Makela, Ashley V; Murrell, Donna H; Parkins, Katie M; Kara, Jenna; Gaudet, Jeffrey M; Foster, Paula J

2016-10-01

Cellular magnetic resonance imaging (MRI) is an evolving field of imaging with strong translational and research potential. The ability to detect, track, and quantify cells in vivo and over time allows for studying cellular events related to disease processes and may be used as a biomarker for decisions about treatments and for monitoring responses to treatments. In this review, we discuss methods for labeling cells, various applications for cellular MRI, the existing limitations, strategies to address these shortcomings, and clinical cellular MRI.

Cell-Specific Establishment of Poliovirus Resistance to an Inhibitor Targeting a Cellular Protein

PubMed Central

Viktorova, Ekaterina G.; Nchoutmboube, Jules; Ford-Siltz, Lauren A.

2015-01-01

ABSTRACT It is hypothesized that targeting stable cellular factors involved in viral replication instead of virus-specific proteins may raise the barrier for development of resistant mutants, which is especially important for highly adaptable small (+)RNA viruses. However, contrary to this assumption, the accumulated evidence shows that these viruses easily generate mutants resistant to the inhibitors of cellular proteins at least in some systems. We investigated here the development of poliovirus resistance to brefeldin A (BFA), an inhibitor of the cellular protein GBF1, a guanine nucleotide exchange factor for the small cellular GTPase Arf1. We found that while resistant viruses can be easily selected in HeLa cells, they do not emerge in Vero cells, in spite that in the absence of the drug both cultures support robust virus replication. Our data show that the viral replication is much more resilient to BFA than functioning of the cellular secretory pathway, suggesting that the role of GBF1 in the viral replication is independent of its Arf activating function. We demonstrate that the level of recruitment of GBF1 to the replication complexes limits the establishment and expression of a BFA resistance phenotype in both HeLa and Vero cells. Moreover, the BFA resistance phenotype of poliovirus mutants is also cell type dependent in different cells of human origin and results in a fitness loss in the form of reduced efficiency of RNA replication in the absence of the drug. Thus, a rational approach to the development of host-targeting antivirals may overcome the superior adaptability of (+)RNA viruses. IMPORTANCE Compared to the number of viral diseases, the number of available vaccines is miniscule. For some viruses vaccine development has not been successful after multiple attempts, and for many others vaccination is not a viable option. Antiviral drugs are needed for clinical practice and public health emergencies. However, viruses are highly adaptable and can

Regulation of cellular growth by the Drosophila target of rapamycin dTOR

PubMed Central

Zhang, Hongbing; Stallock, James P.; Ng, Joyce C.; Reinhard, Christoph; Neufeld, Thomas P.

2000-01-01

The TOR protein kinases (TOR1 and TOR2 in yeast; mTOR/FRAP/RAFT1 in mammals) promote cellular proliferation in response to nutrients and growth factors, but their role in development is poorly understood. Here, we show that the Drosophila TOR homolog dTOR is required cell autonomously for normal growth and proliferation during larval development, and for increases in cellular growth caused by activation of the phosphoinositide 3-kinase (PI3K) signaling pathway. As in mammalian cells, the kinase activity of dTOR is required for growth factor-dependent phosphorylation of p70 S6 kinase (p70S6K) in vitro, and we demonstrate that overexpression of p70S6K in vivo can rescue dTOR mutant animals to viability. Loss of dTOR also results in cellular phenotypes characteristic of amino acid deprivation, including reduced nucleolar size, lipid vesicle aggregation in the larval fat body, and a cell type-specific pattern of cell cycle arrest that can be bypassed by overexpression of the S-phase regulator cyclin E. Our results suggest that dTOR regulates growth during animal development by coupling growth factor signaling to nutrient availability. PMID:11069888

Role of Nuclear Factor Erythroid 2-Related Factor 2 in Diabetic Nephropathy

PubMed Central

Min, Xu; Xu, Xiaohong

2017-01-01

Diabetic nephropathy (DN) is manifested as increased urinary protein level, decreased glomerular filtration rate, and final renal dysfunction. DN is the leading cause of end-stage renal disease worldwide and causes a huge societal healthcare burden. Since satisfied treatments are still limited, exploring new strategies for the treatment of this disease is urgently needed. Oxidative stress takes part in the initiation and development of DN. In addition, nuclear factor erythroid 2-related factor 2 (Nrf2) plays a key role in the cellular response to oxidative stress. Thus, activation of Nrf2 seems to be a new choice for the treatment of DN. In current review, we discussed and summarized the therapeutic effects of Nrf2 activation on DN from both basic and clinical studies. PMID:28512642

Cellular and Physiological Effects of Anthrax Exotoxin and Its Relevance to Disease

PubMed Central

Lowe, David E.; Glomski, Ian J.

2012-01-01

Bacillus anthracis, the causative agent of anthrax, secretes a tri-partite exotoxin that exerts pleiotropic effects on the host. The purification of the exotoxin components, protective antigen, lethal factor, and edema factor allowed the rapid characterization of their physiologic effects on the host. As molecular biology matured, interest focused on the molecular mechanisms and cellular alterations induced by intoxication. Only recently have researchers begun to connect molecular and cellular knowledge back to the broader physiological effects of the exotoxin. This review focuses on the progress that has been made bridging molecular knowledge back to the exotoxin’s physiological effects on the host. PMID:22919667

KDM5 Interacts with Foxo to Modulate Cellular Levels of Oxidative Stress

PubMed Central

Liu, Xingyin; Greer, Christina; Secombe, Julie

2014-01-01

Increased cellular levels of oxidative stress are implicated in a large number of human diseases. Here we describe the transcription co-factor KDM5 (also known as Lid) as a new critical regulator of cellular redox state. Moreover, this occurs through a novel KDM5 activity whereby it alters the ability of the transcription factor Foxo to bind to DNA. Our microarray analyses of kdm5 mutants revealed a striking enrichment for genes required to regulate cellular levels of oxidative stress. Consistent with this, loss of kdm5 results in increased sensitivity to treatment with oxidizers, elevated levels of oxidized proteins, and increased mutation load. KDM5 activates oxidative stress resistance genes by interacting with Foxo to facilitate its recruitment to KDM5-Foxo co-regulated genes. Significantly, this occurs independently of KDM5's well-characterized demethylase activity. Instead, KDM5 interacts with the lysine deacetylase HDAC4 to promote Foxo deacetylation, which affects Foxo DNA binding. PMID:25329053

Control of human adenovirus type 5 gene expression by cellular Daxx/ATRX chromatin-associated complexes

PubMed Central

Schreiner, Sabrina; Bürck, Carolin; Glass, Mandy; Groitl, Peter; Wimmer, Peter; Kinkley, Sarah; Mund, Andreas; Everett, Roger D.; Dobner, Thomas

2013-01-01

Death domain–associated protein (Daxx) cooperates with X-linked α-thalassaemia retardation syndrome protein (ATRX), a putative member of the sucrose non-fermentable 2 family of ATP-dependent chromatin-remodelling proteins, acting as the core ATPase subunit in this complex, whereas Daxx is the targeting factor, leading to histone deacetylase recruitment, H3.3 deposition and transcriptional repression of cellular promoters. Despite recent findings on the fundamental importance of chromatin modification in host-cell gene regulation, it remains unclear whether adenovirus type 5 (Ad5) transcription is regulated by cellular chromatin remodelling to allow efficient virus gene expression. Here, we focus on the repressive role of the Daxx/ATRX complex during Ad5 replication, which depends on intact protein–protein interaction, as negative regulation could be relieved with a Daxx mutant that is unable to interact with ATRX. To ensure efficient viral replication, Ad5 E1B-55K protein inhibits Daxx and targets ATRX for proteasomal degradation in cooperation with early region 4 open reading frame protein 6 and cellular components of a cullin-dependent E3-ubiquitin ligase. Our studies illustrate the importance and diversity of viral factors antagonizing Daxx/ATRX-mediated repression of viral gene expression and shed new light on the modulation of cellular chromatin remodelling factors by Ad5. We show for the first time that cellular Daxx/ATRX chromatin remodelling complexes play essential roles in Ad gene expression and illustrate the importance of early viral proteins to counteract cellular chromatin remodelling. PMID:23396441

Zinc Finger-Containing Cellular Transcription Corepressor ZBTB25 Promotes Influenza Virus RNA Transcription and Is a Target for Zinc Ejector Drugs.

PubMed

Chen, Shu-Chuan; Jeng, King-Song; Lai, Michael M C

2017-10-15

Influenza A virus (IAV) replication relies on an intricate interaction between virus and host cells. How the cellular proteins are usurped for IAV replication remains largely obscure. The aim of this study was to search for novel and potential cellular factors that participate in IAV replication. ZBTB25, a transcription repressor of a variety of cellular genes, was identified by an RNA interference (RNAi) genomic library screen. Depletion of ZBTB25 significantly reduced IAV production. Conversely, overexpression of ZBTB25 enhanced it. ZBTB25 interacted with the viral RNA-dependent RNA polymerase (RdRp) protein and modulated its transcription activity. In addition, ZBTB25 also functioned as a viral RNA (vRNA)-binding protein, binding preferentially to the U-rich sequence within the 5' untranslated region (UTR) of vRNA. Both protein-protein and protein-RNA interactions involving ZBTB25 facilitated viral RNA transcription and replication. In addition, ZBTB25 suppressed interferon production, further enhancing viral replication. ZBTB25-associated functions required an intact zinc finger domain and posttranslational SUMO-1 modification of ZBTB25. Furthermore, treatment with disulfiram (a zinc ejector) of ZBTB25-overexpressing cells showed significantly reduced IAV production as a result of reduced RNA synthesis. Our findings indicate that IAV usurps ZBTB25 for IAV RNA synthesis and serves as a novel and potential therapeutic antiviral target. IMPORTANCE IAV-induced seasonal influenza causes severe illness and death in high-risk populations. However, IAV has developed resistance to current antiviral drugs due to its high mutation rate. Therefore, development of drugs targeting cellular factors required for IAV replication is an attractive alternative for IAV therapy. Here, we discovered a cellular protein, ZBTB25, that enhances viral RdRp activity by binding to both viral RdRp and viral RNA to stimulate viral RNA synthesis. A unique feature of ZBTB25 in the regulation of

Zinc Finger-Containing Cellular Transcription Corepressor ZBTB25 Promotes Influenza Virus RNA Transcription and Is a Target for Zinc Ejector Drugs

PubMed Central

Chen, Shu-Chuan; Jeng, King-Song

2017-01-01

ABSTRACT Influenza A virus (IAV) replication relies on an intricate interaction between virus and host cells. How the cellular proteins are usurped for IAV replication remains largely obscure. The aim of this study was to search for novel and potential cellular factors that participate in IAV replication. ZBTB25, a transcription repressor of a variety of cellular genes, was identified by an RNA interference (RNAi) genomic library screen. Depletion of ZBTB25 significantly reduced IAV production. Conversely, overexpression of ZBTB25 enhanced it. ZBTB25 interacted with the viral RNA-dependent RNA polymerase (RdRp) protein and modulated its transcription activity. In addition, ZBTB25 also functioned as a viral RNA (vRNA)-binding protein, binding preferentially to the U-rich sequence within the 5′ untranslated region (UTR) of vRNA. Both protein-protein and protein-RNA interactions involving ZBTB25 facilitated viral RNA transcription and replication. In addition, ZBTB25 suppressed interferon production, further enhancing viral replication. ZBTB25-associated functions required an intact zinc finger domain and posttranslational SUMO-1 modification of ZBTB25. Furthermore, treatment with disulfiram (a zinc ejector) of ZBTB25-overexpressing cells showed significantly reduced IAV production as a result of reduced RNA synthesis. Our findings indicate that IAV usurps ZBTB25 for IAV RNA synthesis and serves as a novel and potential therapeutic antiviral target. IMPORTANCE IAV-induced seasonal influenza causes severe illness and death in high-risk populations. However, IAV has developed resistance to current antiviral drugs due to its high mutation rate. Therefore, development of drugs targeting cellular factors required for IAV replication is an attractive alternative for IAV therapy. Here, we discovered a cellular protein, ZBTB25, that enhances viral RdRp activity by binding to both viral RdRp and viral RNA to stimulate viral RNA synthesis. A unique feature of ZBTB25 in the

Regulating cellular trace metal economy in algae

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

Blaby-Haas, Crysten E.; Merchant, Sabeeha S.

As indispensable protein cofactors, Fe, Mn, Cu and Zn are at the center of multifaceted acclimation mechanisms that have evolved to ensure extracellular supply meets intracellular demand. In starting with selective transport at the plasma membrane and ending in protein metalation, metal homeostasis in algae involves regulated trafficking of metal ions across membranes, intracellular compartmentalization by proteins and organelles, and metal-sparing/recycling mechanisms to optimize metal-use efficiency. Overlaid on these processes are additional circuits that respond to the metabolic state as well as to the prior metal status of the cell. Here, we focus on recent progress made toward understanding themore » pathways by which the single-celled, green alga Chlamydomonas reinhardtii controls its cellular trace metal economy. We also compare these mechanisms to characterized and putative processes in other algal lineages. Photosynthetic microbes continue to provide insight into cellular regulation and handling of Cu, Fe, Zn and Mn as a function of the nutritional supply and cellular demand for metal cofactors. We found that new experimental tools such as RNA-Seq and subcellular metal imaging are bringing us closer to a molecular understanding of acclimation to supply dynamics in algae and beyond.« less

Regulating cellular trace metal economy in algae

DOE PAGES

Blaby-Haas, Crysten E.; Merchant, Sabeeha S.

2017-06-30

As indispensable protein cofactors, Fe, Mn, Cu and Zn are at the center of multifaceted acclimation mechanisms that have evolved to ensure extracellular supply meets intracellular demand. In starting with selective transport at the plasma membrane and ending in protein metalation, metal homeostasis in algae involves regulated trafficking of metal ions across membranes, intracellular compartmentalization by proteins and organelles, and metal-sparing/recycling mechanisms to optimize metal-use efficiency. Overlaid on these processes are additional circuits that respond to the metabolic state as well as to the prior metal status of the cell. Here, we focus on recent progress made toward understanding themore » pathways by which the single-celled, green alga Chlamydomonas reinhardtii controls its cellular trace metal economy. We also compare these mechanisms to characterized and putative processes in other algal lineages. Photosynthetic microbes continue to provide insight into cellular regulation and handling of Cu, Fe, Zn and Mn as a function of the nutritional supply and cellular demand for metal cofactors. We found that new experimental tools such as RNA-Seq and subcellular metal imaging are bringing us closer to a molecular understanding of acclimation to supply dynamics in algae and beyond.« less

Regulation of cellular senescence by the essential caveolar component PTRF/Cavin-1

PubMed Central

Bai, Lin; Deng, Xiaoli; Li, Juanjuan; Wang, Miao; Li, Qian; An, Wei; A, Deli; Cong, Yu-Sheng

2011-01-01

Polymerase I and transcript release factor (PTRF, also known as Cavin-1) is an essential component in the biogenesis and function of caveolae. Here, we show that PTRF expression is increased in senescent human fibroblasts. Importantly, overexpression of PTRF induced features characteristic of cellular senescence, whereas reduced PTRF expression extended the cellular replicative lifespan. Interestingly, we found that PTRF localized primarily to the nuclei of young and quiescent WI-38 human fibroblasts, but translocated to the cytosol and plasma membrane during cellular senescence. Furthermore, electron microscopic analysis demonstrated an increased number of caveolar structures in senescent and PTRF-transfected WI-38 cells. Our data suggest that the role of PTRF in cellular senescence is dependent on its targeting to caveolae and its interaction with caveolin-1, which appeared to be regulated by the phosphorylation of PTRF. Taken together, our findings identify PTRF as a novel regulator of cellular senescence that acts through the p53/p21 and caveolar pathways. PMID:21445100

Cellular Instabilities and Self-Acceleration of Expanding Spherical Flames

NASA Technical Reports Server (NTRS)

Law, C. K.; Kwon, O. C.

2003-01-01

In the present investigation we aim to provide experimental information on and thereby understanding of the generation and propagation of spark-ignited, outwardly propagating cellular flames, with three major focuses. The first is to unambiguously demonstrate the influence of the four most important parameters in inducing hydrodynamic and diffusional-thermal cellularities, namely thermal expansion, flame thickness, non-unity Lewis number, and global activation energy. The second is to investigate the critical state for the onset of cellularity for the stretch-affected, expanding flame. The third is to identify and consequently quantify the phenomena of self-acceleration and possibly auto-turbulization of cellular flames. Due to space limitation the effects of activation energy and the critical state for the onset of cellularity will not be discussed herein. Experiments were conducted using C3H8-air and H2-O2-N2 mixtures for their opposite influences of non-equidiffusivity. The additional system parameters varied were the chamber pressure (p) and the mixture composition including the equivalence ratio (phi). From a sequence of the flame images we can assess the propensity of cell formation, and determine the instantaneous flame radius (R), the flame propagation rate, the global stretch rate experienced by the flame, the critical flame radius at which cells start to grow, and the average cell size.

Risk factors for an additional port in single-incision laparoscopic cholecystectomy in patients with cholecystitis.

PubMed

Araki, Kenichiro; Shirabe, Ken; Watanabe, Akira; Kubo, Norio; Sasaki, Shigeru; Suzuki, Hideki; Asao, Takayuki; Kuwano, Hiroyuki

2017-01-01

Although single-incision laparoscopic cholecystectomy is now widely performed in patients with cholecystitis, some cases require an additional port to complete the procedure. In this study, we focused on risk factor of additional port in this surgery. We performed single-incision cholecystectomy in 75 patients with acute cholecystitis or after cholecystitis between 2010 and 2014 at Gunma University Hospital. Surgical indications followed the TG13 guidelines. Our standard procedure for single-incision cholecystectomy routinely uses two needlescopic devices. We used logistic regression analysis to identify the risk factors associated with use of an additional full-size port (5 or 10 mm). Surgical outcome was acceptable without biliary injury. Nine patients (12.0%) required an additional port, and one patient (1.3%) required conversion to open cholecystectomy because of severe adhesions around the cystic duct and common bile duct. In multivariate analysis, high C-reactive protein (CRP) values (>7.0 mg/dl) during cholecystitis attacks were significantly correlated with the need for an additional port (P = 0.009), with a sensitivity of 55.6%, specificity of 98.5%, and accuracy of 93.3%. This study indicated that the severe inflammation indicated by high CRP values during cholecystitis attacks predicts the need for an additional port. J. Med. Invest. 64: 245-249, August, 2017.

Evaluation of microbiological, cellular and risk factors associated with subclinical mastitis in female buffaloes

PubMed Central

de Oliveira Moura, Emmanuella; do Nascimento Rangel, Adriano Henrique; de Melo, Maria Celeste Nunes; Borba, Luiz Henrique Fernandes; de Lima Júnior, Dorgival Morais; Novaes, Luciano Patto; Urbano, Stela Antas; de Andrade Neto, Júlio César

2017-01-01

Objective This study aimed to evaluate the microbiological and cellular milk profile for the diagnosis of subclinical mastitis in female buffaloes and to assess risk factors for predisposition of the disease. Methods Analyses were carried out by standard plate count (SPC), identification of species and antibiotic resistance, somatic cell count (SCC), electrical electrical conductivity of milk (ECM), and lactoferrin content in milk. Teat cups were swabbed to evaluate risk factors, observing hyperkeratosis, milking vacuum pressure and cleanliness of the site. Hence, 30 female buffaloes were randomly selected (15 from a group in early lactation and 15 in late lactation). Results The most common bacteria in the microbiological examination were Staphylococcus spp., Streptococcus spp. and Corynebacterium sp. In the antibiotic sensitivity test, 10 (58.82%) of the 17 antibiotics tested were sensitive to all isolates, and resistant bacteria were Streptococcus uberis, Streptococcus dysgalactiae, Streptococcus haemolyticus, and Escherichia coli. It was observed that positive samples in the microbiological examination showed total bacterial count between 9.10×103 to 6.94×106 colony forming units/mL, SCC between 42,000 to 4,320,000 cells/mL and ECM ranging from 1.85 to 7.40 mS/cm. It was also found that the teat cups had high microbial counts indicating poor hygiene, and even faults in the cleanliness of the animals’ waiting room were observed. It is concluded that values of SCC above 537,000 cells/mL and ECM above 3.0 mS/mL are indications of mammary gland infection for this herd; however, the association of these values with a microbiological analysis is necessary to more accurately evaluate the health status of mammary glands with subclinical mastitis. Conclusion Through phenotypic characterization of bacteria involved in the samples, the genera Staphylococcus spp., Streptococcus spp., and Corynebacterimum bovis were the most prevalent in this study. Faults in

Prenatal alcohol exposure and cellular differentiation: a role for Polycomb and Trithorax group proteins in FAS phenotypes?

PubMed

Veazey, Kylee J; Muller, Daria; Golding, Michael C

2013-01-01

Exposure to alcohol significantly alters the developmental trajectory of progenitor cells and fundamentally compromises tissue formation (i.e., histogenesis). Emerging research suggests that ethanol can impair mammalian development by interfering with the execution of molecular programs governing differentiation. For example, ethanol exposure disrupts cellular migration, changes cell-cell interactions, and alters growth factor signaling pathways. Additionally, ethanol can alter epigenetic mechanisms controlling gene expression. Normally, lineage-specific regulatory factors (i.e., transcription factors) establish the transcriptional networks of each new cell type; the cell's identity then is maintained through epigenetic alterations in the way in which the DNA encoding each gene becomes packaged within the chromatin. Ethanol exposure can induce epigenetic changes that do not induce genetic mutations but nonetheless alter the course of fetal development and result in a large array of patterning defects. Two crucial enzyme complexes--the Polycomb and Trithorax proteins--are central to the epigenetic programs controlling the intricate balance between self-renewal and the execution of cellular differentiation, with diametrically opposed functions. Prenatal ethanol exposure may disrupt the functions of these two enzyme complexes, altering a crucial aspect of mammalian differentiation. Characterizing the involvement of Polycomb and Trithorax group complexes in the etiology of fetal alcohol spectrum disorders will undoubtedly enhance understanding of the role that epigenetic programming plays in this complex disorder.

Additional risk factors for lethal hypothermia.

PubMed

Bright, Fiona; Gilbert, John D; Winskog, Calle; Byard, Roger W

2013-08-01

An 86-year-old woman was found dead lying on her back on the floor of an unkempt kitchen. She had last been seen four days before. Her dress was pulled up and she was not wearing underpants. The house was noted to be in "disarray" with papers covering most surfaces and the floor. Rubbish was piled up against one of the doors. At autopsy the major findings were of a fractured left neck of femur, fresh pressure areas over her right buttock, Wischnewski spots of the stomach and foci of pancreatic necrosis, in keeping with hypothermia. No significant underlying organic diseases were identified and there was no other evidence of trauma. Death was due to hypothermia complicating immobility from a fractured neck of femur. This case confirms the vulnerability of frail, elderly and socially-isolated individuals to death from hypothermia if a significant illness or injury occurs. Additional risk factors for hypothermia are also illustrated in this case that involve inadequate housing construction with absent insulation and window double glazing. The approach to hypothermic deaths should, therefore, include checking for these features as well as measuring room and environmental temperatures, evaluating the type and quality of heating and the nature of the floor and its coverings, Given the ageing population in many Western countries, increasing social isolation of the elderly, cost of fuel and electricity, and lack of energy efficient housing, this type of death may become an increasingly witnessed occurrence during the colder months of the year. Copyright © 2012 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Coordination of Cellular Dynamics Contributes to Tooth Epithelium Deformations

PubMed Central

Morita, Ritsuko; Kihira, Miho; Nakatsu, Yousuke; Nomoto, Yohei; Ogawa, Miho; Ohashi, Kazumasa; Mizuno, Kensaku; Tachikawa, Tetsuhiko; Ishimoto, Yukitaka; Morishita, Yoshihiro; Tsuji, Takashi

2016-01-01

The morphologies of ectodermal organs are shaped by appropriate combinations of several deformation modes, such as invagination and anisotropic tissue elongation. However, how multicellular dynamics are coordinated during deformation processes remains to be elucidated. Here, we developed a four-dimensional (4D) analysis system for tracking cell movement and division at a single-cell resolution in developing tooth epithelium. The expression patterns of a Fucci probe clarified the region- and stage-specific cell cycle patterns within the tooth germ, which were in good agreement with the pattern of the volume growth rate estimated from tissue-level deformation analysis. Cellular motility was higher in the regions with higher growth rates, while the mitotic orientation was significantly biased along the direction of tissue elongation in the epithelium. Further, these spatio-temporal patterns of cellular dynamics and tissue-level deformation were highly correlated with that of the activity of cofilin, which is an actin depolymerization factor, suggesting that the coordination of cellular dynamics via actin remodeling plays an important role in tooth epithelial morphogenesis. Our system enhances the understanding of how cellular behaviors are coordinated during ectodermal organogenesis, which cannot be observed from histological analyses. PMID:27588418

Species as Stressors: Heterospecific Interactions and the Cellular Stress Response under Global Change.

PubMed

Gunderson, Alex R; King, Emily E; Boyer, Kirsten; Tsukimura, Brian; Stillman, Jonathon H

2017-07-01

Anthropogenic global change is predicted to increase the physiological stress of organisms through changes in abiotic conditions such as temperature, pH, and pollution. However, organisms can also experience physiological stress through interactions with other species, especially parasites, predators, and competitors. The stress of species interactions could be an important driver of species' responses to global change as the composition of biological communities change through factors such as distributional and phenological shifts. Interactions between biotic and abiotic stressors could also induce non-linear physiological stress responses under global change. One of the primary means by which organisms deal with physiological stress is through the cellular stress response (CSR), which is broadly the upregulation of a conserved set of genes that facilitate the removal and repair of damaged macromolecules. Here, we present data on behavioral interactions and CSR gene expression for two competing species of intertidal zone porcelain crab (Petrolisthes cinctipes and Petrolisthes manimaculis). We found that P. cinctipes and P. manimaculis engage in more agonistic behaviors when interacting with heterospecifics than conspecifics; however, we found no evidence that heterospecific interactions induced a CSR in these species. In addition to our new data, we review the literature with respect to CSR induction via species interactions, focusing on predator-prey systems and heterospecific competition. We find extensive evidence for predators to induce cellular stress and aspects of the CSR in prey, even in the absence of direct physical contact between species. Effects of heterospecific competition on the CSR have been studied far less, but we do find evidence that agonistic interactions with heterospecifics can induce components of the CSR. Across all published studies, there is clear evidence that species interactions can lead to cellular stress and induction of the CSR

NUCLEAR FACTOR Y Transcription Factors Have Both Opposing and Additive Roles in ABA-Mediated Seed Germination

PubMed Central

Kumimoto, Roderick W.; Siriwardana, Chamindika L.; Gayler, Krystal K.; Risinger, Jan R.; Siefers, Nicholas; Holt, Ben F.

2013-01-01

In the model organism Arabidopsis thaliana the heterotrimeric transcription factor NUCLEAR FACTOR Y (NF-Y) has been shown to play multiple roles in facilitating plant growth and development. Although NF-Y itself represents a multi-protein transcriptional complex, recent studies have shown important interactions with other transcription factors, especially those in the bZIP family. Here we add to the growing evidence that NF-Y and bZIP form common complexes to affect many processes. We carried out transcriptional profiling on nf-yc mutants and through subsequent analyses found an enrichment of bZIP binding sites in the promoter elements of misregulated genes. Using NF-Y as bait, yeast two hybrid assays yielded interactions with bZIP proteins that are known to control ABA signaling. Accordingly, we find that plants mutant for several NF-Y subunits show characteristic phenotypes associated with the disruption of ABA signaling. While previous reports have shown additive roles for NF-YC family members in photoperiodic flowering, we found that they can have opposing roles in ABA signaling. Collectively, these results demonstrated the importance and complexity of NF-Y in the integration of environmental and hormone signals. PMID:23527203

Molecular and cellular biology of cerebral arteriovenous malformations: a review of current concepts and future trends in treatment.

PubMed

Rangel-Castilla, Leonardo; Russin, Jonathan J; Martinez-Del-Campo, Eduardo; Soriano-Baron, Hector; Spetzler, Robert F; Nakaji, Peter

2014-09-01

Arteriovenous malformations (AVMs) are classically described as congenital static lesions. However, in addition to rupturing, AVMs can undergo growth, remodeling, and regression. These phenomena are directly related to cellular, molecular, and physiological processes. Understanding these relationships is essential to direct future diagnostic and therapeutic strategies. The authors performed a search of the contemporary literature to review current information regarding the molecular and cellular biology of AVMs and how this biology will impact their potential future management. A PubMed search was performed using the key words "genetic," "molecular," "brain," "cerebral," "arteriovenous," "malformation," "rupture," "management," "embolization," and "radiosurgery." Only English-language papers were considered. The reference lists of all papers selected for full-text assessment were reviewed. Current concepts in genetic polymorphisms, growth factors, angiopoietins, apoptosis, endothelial cells, pathophysiology, clinical syndromes, medical treatment (including tetracycline and microRNA-18a), radiation therapy, endovascular embolization, and surgical treatment as they apply to AVMs are discussed. Understanding the complex cellular biology, physiology, hemodynamics, and flow-related phenomena of AVMs is critical for defining and predicting their behavior, developing novel drug treatments, and improving endovascular and surgical therapies.

In vitro cellular uptake of evodiamine and rutaecarpine using a microemulsion

PubMed Central

Zhang, Yong-Tai; Huang, Zhe-Bin; Zhang, Su-Juan; Zhao, Ji-Hui; Wang, Zhi; Liu, Ying; Feng, Nian-Ping

2012-01-01

Objective To investigate the cellular uptake of evodiamine and rutaecarpine in a microemulsion in comparison with aqueous suspensions and tinctures. Materials and methods A microemulsion was prepared using the dropwise addition method. Mouse skin fibroblasts were cultured in vitro to investigate the optimal conditions for evodiamine and rutaecarpine uptake with different drug concentrations and administration times. Under optimal conditions, the cellular uptake of microemulsified drugs was assayed and compared to tinctures and aqueous suspensions. Rhodamine B labeling and laser scanning confocal microscopy (LSCM) were used to explore the distribution of fluorochrome transferred with the microemulsion in fibroblasts. Cellular morphology was also investigated, using optical microscopy to evaluate microemulsion-induced cellular toxicity. Results The maximum cellular drug uptake amounts were obtained with a 20% concentration (v/v) of microemulsion and an 8 hour administration time. Drug uptake by mouse skin fibroblasts was lowest when the drugs were loaded in microemulsion. After incubation with rhodamine B-labeled microemulsion for 8 hours, the highest fluorescence intensity was achieved, and the fluorochrome was primarily distributed in the cytochylema. No obvious cellular morphologic changes were observed with the administration of either the microemulsion or the aqueous suspension; for the tincture group, however, massive cellular necrocytosis was observed. Conclusion The lower cellular uptake with microemulsion may be due to the fact that most of the drug loaded in the microemulsion vehicle was transported via the intercellular space, while a small quantity of free drug (released from the vehicle) was ingested through transmembrane transport. Mouse skin fibroblasts rarely endocytosed evodiamine and rutaecarpine with a microemulsion as the vehicle. The microemulsion had no obvious effect on cellular morphology, suggesting there is little or no cellular toxicity

In vitro cellular uptake of evodiamine and rutaecarpine using a microemulsion.

PubMed

Zhang, Yong-Tai; Huang, Zhe-Bin; Zhang, Su-Juan; Zhao, Ji-Hui; Wang, Zhi; Liu, Ying; Feng, Nian-Ping

2012-01-01

To investigate the cellular uptake of evodiamine and rutaecarpine in a microemulsion in comparison with aqueous suspensions and tinctures. A microemulsion was prepared using the dropwise addition method. Mouse skin fibroblasts were cultured in vitro to investigate the optimal conditions for evodiamine and rutaecarpine uptake with different drug concentrations and administration times. Under optimal conditions, the cellular uptake of microemulsified drugs was assayed and compared to tinctures and aqueous suspensions. Rhodamine B labeling and laser scanning confocal microscopy (LSCM) were used to explore the distribution of fluorochrome transferred with the microemulsion in fibroblasts. Cellular morphology was also investigated, using optical microscopy to evaluate microemulsion-induced cellular toxicity. The maximum cellular drug uptake amounts were obtained with a 20% concentration (v/v) of microemulsion and an 8 hour administration time. Drug uptake by mouse skin fibroblasts was lowest when the drugs were loaded in microemulsion. After incubation with rhodamine B-labeled microemulsion for 8 hours, the highest fluorescence intensity was achieved, and the fluorochrome was primarily distributed in the cytochylema. No obvious cellular morphologic changes were observed with the administration of either the microemulsion or the aqueous suspension; for the tincture group, however, massive cellular necrocytosis was observed. The lower cellular uptake with microemulsion may be due to the fact that most of the drug loaded in the microemulsion vehicle was transported via the intercellular space, while a small quantity of free drug (released from the vehicle) was ingested through transmembrane transport. Mouse skin fibroblasts rarely endocytosed evodiamine and rutaecarpine with a microemulsion as the vehicle. The microemulsion had no obvious effect on cellular morphology, suggesting there is little or no cellular toxicity associated with the administration of microemulsion on

A search for structurally similar cellular internal ribosome entry sites

PubMed Central

Baird, Stephen D.; Lewis, Stephen M.; Turcotte, Marcel; Holcik, Martin

2007-01-01

Internal ribosome entry sites (IRES) allow ribosomes to be recruited to mRNA in a cap-independent manner. Some viruses that impair cap-dependent translation initiation utilize IRES to ensure that the viral RNA will efficiently compete for the translation machinery. IRES are also employed for the translation of a subset of cellular messages during conditions that inhibit cap-dependent translation initiation. IRES from viruses like Hepatitis C and Classical Swine Fever virus share a similar structure/function without sharing primary sequence similarity. Of the cellular IRES structures derived so far, none were shown to share an overall structural similarity. Therefore, we undertook a genome-wide search of human 5′UTRs (untranslated regions) with an empirically derived structure of the IRES from the key inhibitor of apoptosis, X-linked inhibitor of apoptosis protein (XIAP), to identify novel IRES that share structure/function similarity. Three of the top matches identified by this search that exhibit IRES activity are the 5′UTRs of Aquaporin 4, ELG1 and NF-kappaB repressing factor (NRF). The structures of AQP4 and ELG1 IRES have limited similarity to the XIAP IRES; however, they share trans-acting factors that bind the XIAP IRES. We therefore propose that cellular IRES are not defined by overall structure, as viral IRES, but are instead dependent upon short motifs and trans-acting factors for their function. PMID:17591613

Cellular metabolic rates from primary dermal fibroblast cells isolated from birds of different body masses.

PubMed

Jimenez, Ana Gabriela; Williams, Joseph B

2014-10-01

The rate of metabolism is the speed at which organisms use energy, an integration of energy transformations within the body; it governs biological processes that influence rates of growth and reproduction. Progress at understanding functional linkages between whole organism metabolic rate and underlying mechanisms that influence its magnitude has been slow despite the central role this issue plays in evolutionary and physiological ecology. Previous studies that have attempted to relate how cellular processes translate into whole-organism physiology have done so over a range of body masses of subjects. However, the data still remains controversial when observing metabolic rates at the cellular level. To bridge the gap between these ideas, we examined cellular metabolic rate of primary dermal fibroblasts isolated from 49 species of birds representing a 32,000-fold range in body masses to test the hypothesis that metabolic rate of cultured cells scales with body size. We used a Seahorse XF-96 Extracellular flux analyzer to measure cellular respiration in fibroblasts. Additionally, we measured fibroblast size and mitochondrial content. We found no significant correlation between cellular metabolic rate, cell size, or mitochondrial content and body mass. Additionally, there was a significant relationship between cellular basal metabolic rate and proton leak in these cells. We conclude that metabolic rate of cells isolated in culture does not scale with body mass, but cellular metabolic rate is correlated to growth rate in birds. Copyright © 2014 Elsevier Inc. All rights reserved.

Cellular Therapies Clinical Research Roadmap: Lessons learned on how to move a cellular therapy into a clinical trial

PubMed Central

Ouseph, Stacy; Tappitake, Darah; Armant, Myriam; Wesselschmidt, Robin; Derecho, Ivy; Draxler, Rebecca; Wood, Deborah; Centanni, John M.

2014-01-01

A clinical research roadmap has been developed as a resource for researchers to identify critical areas and potential pitfalls when transitioning a cellular therapy product from the research laboratory, via and Investigational New Drug (IND) application, into early phase clinical trials. The roadmap describes four key areas; basic and preclinical research, resource development, translational research and good manufacturing practice (GMP), and IND assembly and submission. Basic and preclinical research identifies a new therapeutic concept and demonstrates its potential value using a model of the relevant disease. During resource development the appropriate specialists and the required expertise to bring this product into the clinic are identified (e.g., researchers, regulatory specialists, GMP manufacturing staff, clinicians, and clinical trials staff, etc.). Additionally, the funds required to achieve this goal (or a plan to procure them) are identified. In the next phase the plan to translate the research product into a clinical grade therapeutic is developed. Finally regulatory approval to start the trial must be obtained. In the United States this is done by filing an IND application with the Food and Drug Administration. The NHLBI-funded Production Assistance for Cellular Therapies (PACT) program has facilitated the transition of a variety of cellular therapy products from the laboratory into Phase1/2 trials. The five PACT facilities have assisted investigators by performing translational studies and GMP manufacturing to ensure that cellular products met release specifications and were manufactured safely, reproducibly, and at the appropriate scale. The roadmap resulting from this experience is the focus of this article. PMID:25484311

Sensing the Environment Through Sestrins: Implications for Cellular Metabolism.

PubMed

Parmigiani, A; Budanov, A V

2016-01-01

Sestrins are a family of stress-responsive genes that have evolved to attenuate damage induced by stress caused to the cell. By virtue of their antioxidant activity, protein products of Sestrin genes prevent the accumulation of reactive oxygen species within the cell, thereby attenuating the detrimental effects of oxidative stress. In parallel, Sestrins participate in several signaling pathways that control the activity of the target of rapamycin protein kinase (TOR). TOR is a crucial sensor of intracellular and extracellular conditions that promotes cell growth and anabolism when nutrients and growth factors are abundant. In addition to reacting to stress-inducing insults, Sestrins also monitor the changes in the availability of nutrients, which allows them to serve as a key checkpoint for the TOR-regulated signaling pathways. In this review, we will discuss how Sestrins integrate signals from numerous stress- and nutrient-responsive signaling pathways to orchestrate cellular metabolism and support cell viability. Copyright © 2016 Elsevier Inc. All rights reserved.

Biomechanics of cellular solids.

PubMed

Gibson, Lorna J

2005-03-01

Materials with a cellular structure are widespread in nature and include wood, cork, plant parenchyma and trabecular bone. Natural cellular materials are often mechanically efficient: the honeycomb-like microstructure of wood, for instance, gives it an exceptionally high performance index for resisting bending and buckling. Here we review the mechanics of a wide range of natural cellular materials and examine their role in lightweight natural sandwich structures (e.g. iris leaves) and natural tubular structures (e.g. plant stems or animal quills). We also describe two examples of engineered biomaterials with a cellular structure, designed to replace or regenerate tissue in the body.

Phenylbutyric acid induces the cellular senescence through an Akt/p21{sup WAF1} signaling pathway

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

Kim, Hag Dong; Jang, Chang-Young; Choe, Jeong Min

2012-06-01

Highlights: Black-Right-Pointing-Pointer Phenylbutyric acid induces cellular senescence. Black-Right-Pointing-Pointer Phenylbutyric acid activates Akt kinase. Black-Right-Pointing-Pointer The knockdown of PERK also can induce cellular senescence. Black-Right-Pointing-Pointer Akt/p21{sup WAF1} pathway activates in PERK knockdown induced cellular senescence. -- Abstract: It has been well known that three sentinel proteins - PERK, ATF6 and IRE1 - initiate the unfolded protein response (UPR) in the presence of misfolded or unfolded proteins in the ER. Recent studies have demonstrated that upregulation of UPR in cancer cells is required to survive and proliferate. Here, we showed that long exposure to 4-phenylbutyric acid (PBA), a chemical chaperone that canmore » reduce retention of unfolded and misfolded proteins in ER, induced cellular senescence in cancer cells such as MCF7 and HT1080. In addition, we found that treatment with PBA activates Akt, which results in p21{sup WAF1} induction. Interestingly, the depletion of PERK but not ATF6 and IRE1 also induces cellular senescence, which was rescued by additional depletion of Akt. This suggests that Akt pathway is downstream of PERK in PBA induced cellular senescence. Taken together, these results show that PBA induces cellular senescence via activation of the Akt/p21{sup WAF1} pathway by PERK inhibition.« less

Using semipermeable membrane devices (SPMDs) to estimate bioconcentration potential of petroleum additives

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

Crecelius, E.A.; Rausina, G.A.; Biggs, W.R.

1995-12-31

Lubricant additives can be released into the environment during transport, usage, or improper disposal. Therefore, it is necessary to evaluate these substances for their potential to cause adverse environmental effects. Because lubricant additives tend to be large molecular size hydrophobic substances with very limited water solubility, they could possibly bioconcentrate if released into the environment. A test was developed using SPMD technology to assess the bioconcentration potential of lubricant additives. SPMDs are low-density polyethylene tubing with an effective pore size of 600 daltons, similar to that of cellular membranes. SPMDs filled with triolein, the predominant lipid in fish, function asmore » model fish or mollusks, with selective membranes and lipid reservoirs to concentrate organic compounds from water. Using the SPMD test system, bioconcentration factors were determined for a poly alpha olefin (PAO) base stock and lubricant additive compounds that represent three additive use categories. The SPMD test system was validated using a radiocarbon-labeled calcium detergent lubricant additive in side-by-side exposures to SPMDs and aquatic organisms. Radiocarbon-labeled pyrene was used as a reference compound in the tests.« less

Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death

PubMed Central

Narayanan, Kannan Badri; Ali, Manaf; Barclay, Barry J.; Cheng, Qiang (Shawn); D’Abronzo, Leandro; Dornetshuber-Fleiss, Rita; Ghosh, Paramita M.; Gonzalez Guzman, Michael J.; Lee, Tae-Jin; Leung, Po Sing; Li, Lin; Luanpitpong, Suidjit; Ratovitski, Edward; Rojanasakul, Yon; Romano, Maria Fiammetta; Romano, Simona; Sinha, Ranjeet K.; Yedjou, Clement; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Brown, Dustin G.; Ryan, Elizabeth P.; Colacci, Anna Maria; Hamid, Roslida A.; Mondello, Chiara; Raju, Jayadev; Salem, Hosni K.; Woodrick, Jordan; Scovassi, A.Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Kim, Seo Yun; Bisson, William H.; Lowe, Leroy; Park, Hyun Ho

2015-01-01

Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis. PMID:26106145

Cellular Reflectarray Antenna

NASA Technical Reports Server (NTRS)

Romanofsky, Robert R.

2010-01-01

The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

Electromagnetic cellular interactions.

PubMed

Cifra, Michal; Fields, Jeremy Z; Farhadi, Ashkan

2011-05-01

Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating. Copyright © 2010 Elsevier Ltd. All rights reserved.

Molecular and cellular alterations in Down syndrome: toward the identification of targets for therapeutics.

PubMed

Créau, Nicole

2012-01-01

Down syndrome is a complex disease that has challenged molecular and cellular research for more than 50 years. Understanding the molecular bases of morphological, cellular, and functional alterations resulting from the presence of an additional complete chromosome 21 would aid in targeting specific genes and pathways for rescuing some phenotypes. Recently, progress has been made by characterization of brain alterations in mouse models of Down syndrome. This review will highlight the main molecular and cellular findings recently described for these models, particularly with respect to their relationship to Down syndrome phenotypes.

Multiple-channel detection of cellular activities by ion-sensitive transistors

NASA Astrophysics Data System (ADS)

Machida, Satoru; Shimada, Hideto; Motoyama, Yumi

2018-04-01

An ion-sensitive field-effect transistor to record cellular activities was demonstrated. This field-effect transistor (bio transistor) includes cultured cells on the gate insulator instead of gate electrode. The bio transistor converts a change in potential underneath the cells into variation of the drain current when ion channels open. The bio transistor has high detection sensitivity to even minute variations in potential utilizing a subthreshold swing region. To open ion channels, a reagent solution (acetylcholine) was added to a human-originating cell cultured on the bio transistor. The drain current was successfully decreased with the addition of acetylcholine. Moreover, we attempted to detect the opening of ion channels using a multiple-channel measurement circuit containing several bio transistors. As a consequence, the drain current distinctly decreased only after the addition of acetylcholine. We confirmed that this measurement system including bio transistors enables to observation of cellular activities sensitively and simultaneously.

TFEB and TFE3: Linking Lysosomes to Cellular Adaptation to Stress.

PubMed

Raben, Nina; Puertollano, Rosa

2016-10-06

In recent years, our vision of lysosomes has drastically changed. Formerly considered to be mere degradative compartments, they are now recognized as key players in many cellular processes. The ability of lysosomes to respond to different stimuli revealed a complex and coordinated regulation of lysosomal gene expression. This review discusses the participation of the transcription factors TFEB and TFE3 in the regulation of lysosomal function and biogenesis, as well as the role of the lysosomal pathway in cellular adaptation to a variety of stress conditions, including nutrient deprivation, mitochondrial dysfunction, protein misfolding, and pathogen infection. We also describe how cancer cells make use of TFEB and TFE3 to promote their own survival and highlight the potential of these transcription factors as therapeutic targets for the treatment of neurological and lysosomal diseases.

Huntingtin-interacting protein 1 is overexpressed in prostate and colon cancer and is critical for cellular survival.

PubMed

Rao, Dinesh S; Hyun, Teresa S; Kumar, Priti D; Mizukami, Ikuko F; Rubin, Mark A; Lucas, Peter C; Sanda, Martin G; Ross, Theodora S

2002-08-01

Huntingtin-interacting protein 1 (HIP1) is a cofactor in clathrin-mediated vesicle trafficking. It was first implicated in cancer biology as part of a chromosomal translocation in leukemia. Here we report that HIP1 is expressed in prostate and colon tumor cells, but not in corresponding benign epithelia. The relationship between HIP1 expression in primary prostate cancer and clinical outcomes was evaluated with tissue microarrays. HIP1 expression was significantly associated with prostate cancer progression and metastasis. Conversely, primary prostate cancers lacking HIP1 expression consistently showed no progression after radical prostatectomy. In addition, the expression of HIP1 was elevated in prostate tumors from the transgenic mouse model of prostate cancer (TRAMP). At the molecular level, expression of a dominant negative mutant of HIP1 led to caspase-9-dependent apoptosis, suggesting that HIP1 is a cellular survival factor. Thus, HIP1 may play a role in tumorigenesis by allowing the survival of precancerous or cancerous cells. HIP1 might accomplish this via regulation of clathrin-mediated trafficking, a fundamental cellular pathway that has not previously been associated with tumorigenesis. HIP1 represents a putative prognostic factor for prostate cancer and a potential therapy target in prostate as well as colon cancers.

Huntingtin-interacting protein 1 is overexpressed in prostate and colon cancer and is critical for cellular survival

PubMed Central

Rao, Dinesh S.; Hyun, Teresa S.; Kumar, Priti D.; Mizukami, Ikuko F.; Rubin, Mark A.; Lucas, Peter C.; Sanda, Martin G.; Ross, Theodora S.

2002-01-01

Huntingtin-interacting protein 1 (HIP1) is a cofactor in clathrin-mediated vesicle trafficking. It was first implicated in cancer biology as part of a chromosomal translocation in leukemia. Here we report that HIP1 is expressed in prostate and colon tumor cells, but not in corresponding benign epithelia. The relationship between HIP1 expression in primary prostate cancer and clinical outcomes was evaluated with tissue microarrays. HIP1 expression was significantly associated with prostate cancer progression and metastasis. Conversely, primary prostate cancers lacking HIP1 expression consistently showed no progression after radical prostatectomy. In addition, the expression of HIP1 was elevated in prostate tumors from the transgenic mouse model of prostate cancer (TRAMP). At the molecular level, expression of a dominant negative mutant of HIP1 led to caspase-9–dependent apoptosis, suggesting that HIP1 is a cellular survival factor. Thus, HIP1 may play a role in tumorigenesis by allowing the survival of precancerous or cancerous cells. HIP1 might accomplish this via regulation of clathrin-mediated trafficking, a fundamental cellular pathway that has not previously been associated with tumorigenesis. HIP1 represents a putative prognostic factor for prostate cancer and a potential therapy target in prostate as well as colon cancers. PMID:12163454

Additive Manufacturing of Vascular Grafts and Vascularized Tissue Constructs.

PubMed

Elomaa, Laura; Yang, Yunzhi Peter

2017-10-01

There is a great need for engineered vascular grafts among patients with cardiovascular diseases who are in need of bypass therapy and lack autologous healthy blood vessels. In addition, because of the severe worldwide shortage of organ donors, there is an increasing need for engineered vascularized tissue constructs as an alternative to organ transplants. Additive manufacturing (AM) offers great advantages and flexibility of fabrication of cell-laden, multimaterial, and anatomically shaped vascular grafts and vascularized tissue constructs. Various inkjet-, extrusion-, and photocrosslinking-based AM techniques have been applied to the fabrication of both self-standing vascular grafts and porous, vascularized tissue constructs. This review discusses the state-of-the-art research on the use of AM for vascular applications and the key criteria for biomaterials in the AM of both acellular and cellular constructs. We envision that new smart printing materials that can adapt to their environment and encourage rapid endothelialization and remodeling will be the key factor in the future for the successful AM of personalized and dynamic vascular tissue applications.

Predisposing factors for atrial fibrillation in the elderly

PubMed Central

Wasmer, Kristina; Eckardt, Lars; Breithardt, Günter

2017-01-01

Atrial fibrillation (AF) in the elderly occurs as a consequence of cardiovascular aging and an age related increase of comorbidity. Several predisposing factors for AF have been identified for the overall AF population. Most of them, cardiovascular disease in particular, play a role in younger and older patients. The longer time period during which these risk factors can cause structural changes that ultimately lead to AF may, at least in part, explain the association between age and AF. In addition, less well defined age-related changes in cellular electrophysiologic properties and structure predispose to AF in the elderly. PMID:28592961

Identification of regulatory targets for the bacterial Nus factor complex.

PubMed

Baniulyte, Gabriele; Singh, Navjot; Benoit, Courtney; Johnson, Richard; Ferguson, Robert; Paramo, Mauricio; Stringer, Anne M; Scott, Ashley; Lapierre, Pascal; Wade, Joseph T

2017-12-11

Nus factors are broadly conserved across bacterial species, and are often essential for viability. A complex of five Nus factors (NusB, NusE, NusA, NusG and SuhB) is considered to be a dedicated regulator of ribosomal RNA folding, and has been shown to prevent Rho-dependent transcription termination. Here, we identify an additional cellular function for the Nus factor complex in Escherichia coli: repression of the Nus factor-encoding gene, suhB. This repression occurs primarily by translation inhibition, followed by Rho-dependent transcription termination. Thus, the Nus factor complex can prevent or promote Rho activity depending on the gene context. Conservation of putative NusB/E binding sites upstream of Nus factor genes suggests that Nus factor autoregulation occurs in many bacterial species. Additionally, many putative NusB/E binding sites are also found upstream of other genes in diverse species, and we demonstrate Nus factor regulation of one such gene in Citrobacter koseri. We conclude that Nus factors have an evolutionarily widespread regulatory function beyond ribosomal RNA, and that they are often autoregulatory.

Genome-wide siRNA screen identifies the retromer as a cellular entry factor for human papillomavirus

PubMed Central

Lipovsky, Alex; Popa, Andreea; Pimienta, Genaro; Wyler, Michael; Bhan, Ashima; Kuruvilla, Leena; Guie, Marie-Aude; Poffenberger, Adrian C.; Nelson, Christian D. S.; Atwood, Walter J.; DiMaio, Daniel

2013-01-01

Despite major advances in our understanding of many aspects of human papillomavirus (HPV) biology, HPV entry is poorly understood. To identify cellular genes required for HPV entry, we conducted a genome-wide screen for siRNAs that inhibited infection of HeLa cells by HPV16 pseudovirus. Many retrograde transport factors were required for efficient infection, including multiple subunits of the retromer, which initiates retrograde transport from the endosome to the trans-Golgi network (TGN). The retromer has not been previously implicated in virus entry. Furthermore, HPV16 capsid proteins arrive in the TGN/Golgi in a retromer-dependent fashion during entry, and incoming HPV proteins form a stable complex with retromer subunits. We propose that HPV16 directly engages the retromer at the early or late endosome and traffics to the TGN/Golgi via the retrograde pathway during cell entry. These results provide important insights into HPV entry, identify numerous potential antiviral targets, and suggest that the role of the retromer in infection by other viruses should be assessed. PMID:23569269

Cellular Particle Dynamics simulation of biomechanical relaxation processes of multi-cellular systems

NASA Astrophysics Data System (ADS)

McCune, Matthew; Kosztin, Ioan

2013-03-01

Cellular Particle Dynamics (CPD) is a theoretical-computational-experimental framework for describing and predicting the time evolution of biomechanical relaxation processes of multi-cellular systems, such as fusion, sorting and compression. In CPD, cells are modeled as an ensemble of cellular particles (CPs) that interact via short range contact interactions, characterized by an attractive (adhesive interaction) and a repulsive (excluded volume interaction) component. The time evolution of the spatial conformation of the multicellular system is determined by following the trajectories of all CPs through numerical integration of their equations of motion. Here we present CPD simulation results for the fusion of both spherical and cylindrical multi-cellular aggregates. First, we calibrate the relevant CPD model parameters for a given cell type by comparing the CPD simulation results for the fusion of two spherical aggregates to the corresponding experimental results. Next, CPD simulations are used to predict the time evolution of the fusion of cylindrical aggregates. The latter is relevant for the formation of tubular multi-cellular structures (i.e., primitive blood vessels) created by the novel bioprinting technology. Work supported by NSF [PHY-0957914]. Computer time provided by the University of Missouri Bioinformatics Consortium.

Cellular Viscosity in Prokaryotes and Thermal Stability of Low Molecular Weight Biomolecules.

PubMed

Cuecas, Alba; Cruces, Jorge; Galisteo-López, Juan F; Peng, Xiaojun; Gonzalez, Juan M

2016-08-23

Some low molecular weight biomolecules, i.e., NAD(P)H, are unstable at high temperatures. The use of these biomolecules by thermophilic microorganisms has been scarcely analyzed. Herein, NADH stability has been studied at different temperatures and viscosities. NADH decay increased at increasing temperatures. At increasing viscosities, NADH decay rates decreased. Thus, maintaining relatively high cellular viscosity in cells could result in increased stability of low molecular weight biomolecules (i.e., NADH) at high temperatures, unlike what was previously deduced from studies in diluted water solutions. Cellular viscosity was determined using a fluorescent molecular rotor in various prokaryotes covering the range from 10 to 100°C. Some mesophiles showed the capability of changing cellular viscosity depending on growth temperature. Thermophiles and extreme thermophiles presented a relatively high cellular viscosity, suggesting this strategy as a reasonable mechanism to thrive under these high temperatures. Results substantiate the capability of thermophiles and extreme thermophiles (growth range 50-80°C) to stabilize and use generally considered unstable, universal low molecular weight biomolecules. In addition, this study represents a first report, to our knowledge, on cellular viscosity measurements in prokaryotes and it shows the dependency of prokaryotic cellular viscosity on species and growth temperature. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Hydrogels in acellular and cellular strategies for intervertebral disc regeneration.

PubMed

Pereira, D R; Silva-Correia, J; Oliveira, J M; Reis, R L

2013-02-01

Low back pain is an extremely common illness syndrome that causes patient suffering and disability and requires urgent solutions to improve the quality of life of these patients. Treatment options aimed to regenerate the intervertebral disc (IVD) are still under development. The cellular complexity of IVD, and consequently its fine regulatory system, makes it a challenge to the scientific community. Biomaterials-based therapies are the most interesting solutions to date, whereby tissue engineering and regenerative medicine (TE&RM) strategies are included. By using such strategies, i.e., combining biomaterials, cells, and biomolecules, the ultimate goal of reaching a complete integration between native and neo-tissue can be achieved. Hydrogels are promising materials for restoring IVD, mainly nucleus pulposus (NP). This study presents an overview of the use of hydrogels in acellular and cellular strategies for intervertebral disc regeneration. To better understand IVD and its functioning, this study will focus on several aspects: anatomy, pathophysiology, cellular and biomolecular performance, intrinsic healing processes, and current therapies. In addition, the application of hydrogels as NP substitutes will be addressed due to their similarities to NP mechanical properties and extracellular matrix. These hydrogels can be used in cellular strategies when combined with cells from different sources, or in acellular strategies by performing the functionalization of the hydrogels with biomolecules. In addition, a brief summary of therapies based on simple injection for primary biological repair will be examined. Finally, special emphasis will focus on reviewing original studies reporting on the use of autologous cells and biomolecules such as platelet-rich plasma and their potential clinical applications. Copyright © 2011 John Wiley & Sons, Ltd.

Dynamic cellular uptake of mixed-monolayer protected nanoparticles.

PubMed

Carney, Randy P; Carney, Tamara M; Mueller, Marie; Stellacci, Francesco

2012-12-01

Nanoparticles (NPs) are gaining increasing attention for potential application in medicine; consequently, studying their interaction with cells is of central importance. We found that both ligand arrangement and composition on gold nanoparticles play a crucial role in their cellular internalization. In our previous investigation, we showed that 66-34OT nanoparticles coated with stripe-like domains of hydrophobic (octanethiol, OT, 34%) and hydrophilic (11-mercaptoundecane sulfonate, MUS, 66%) ligands permeated through the cellular lipid bilayer via passive diffusion, in addition to endo-/pino-cytosis. Here, we show an analysis of NP internalization by DC2.4, 3T3, and HeLa cells at two temperatures and multiple time points. We study four NPs that differ in their surface structures and ligand compositions and report on their cellular internalization by intracellular fluorescence quantification. Using confocal laser scanning microscopy we have found that all three cell types internalize the 66-34OT NPs more than particles coated only with MUS, or particles coated with a very similar coating but lacking any detectable ligand shell structure, or 'striped' particles but with a different composition (34-66OT) at multiple data points.

Dynamic behavior of cellular materials and cellular structures: Experiments and modeling

NASA Astrophysics Data System (ADS)

Gao, Ziyang

Cellular solids, including cellular materials and cellular structures (CMS), have attracted people's great interests because of their low densities and novel physical, mechanical, thermal, electrical and acoustic properties. They offer potential for lightweight structures, energy absorption, thermal management, etc. Therefore, the studies of cellular solids have become one of the hottest research fields nowadays. From energy absorption point of view, any plastically deformed structures can be divided into two types (called type I and type II), and the basic cells of the CMS may take the configurations of these two types of structures. Accordingly, separated discussions are presented in this thesis. First, a modified 1-D model is proposed and numerically solved for a typical type II structure. Good agreement is achieved with the previous experimental data, hence is used to simulate the dynamic behavior of a type II chain. Resulted from different load speeds, interesting collapse modes are observed, and the parameters which govern the cell's post-collapse behavior are identified through a comprehensive non-dimensional analysis on general cellular chains. Secondly, the MHS specimens are chosen as an example of type I foam materials because of their good uniformity of the cell geometry. An extensive experimental study was carried out, where more attention was paid to their responses to dynamic loadings. Great enhancement of the stress-strain curve was observed in dynamic cases, and the energy absorption capacity is found to be several times higher than that of the commercial metal foams. Based on the experimental study, finite elemental simulations and theoretical modeling are also conducted, achieving good agreements and demonstrating the validities of those models. It is believed that the experimental, numerical and analytical results obtained in the present study will certainly deepen the understanding of the unsolved fundamental issues on the mechanical behavior of

Multifunctional Cellular Materials Based on 2D Nanomaterials: Prospects and Challenges.

PubMed

Qiu, Ling; He, Zijun; Li, Dan

2018-01-01

Recent advances in emerging 2D nanomaterial-based cellular materials (2D-CMs) open up new opportunities for the development of next generation cellular solids with exceptional properties. Herein, an overview of the current research status of 2D-CMs is provided and their future opportunities are highlighted. First, the unique features of 2D nanomaterials are introduced to illustrate why these nanoscale building blocks are promising for the development of novel cellular materials and what the new features of 2D nanoscale building blocks can offer when compared to their 0D and 1D counterparts. An in-depth discussion on the structure-property relationships of 2D-CMs is then provided, and the remarkable functions that can be achieved by engineering their cellular architecture are highlighted. Additionally, the use of 2D-CMs to tackle key challenges in different practical applications is demonstrated. In conclusion, a personal perspective on the challenges and future research directions of 2D-CMs is given. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Typhoid fever as cellular microbiological model.

PubMed

de Andrade, Dahir Ramos; de Andrade Júnior, Dahir Ramos

2003-01-01

The knowledge about typhoid fever pathogenesis is growing in the last years, mainly about the cellular and molecular phenomena that are responsible by clinical manifestations of this disease. In this article are discussed several recent discoveries, as follows: a) Bacterial type III protein secretion system; b) The five virulence genes of Salmonella spp. that encoding Sips (Salmonella invasion protein) A, B, C, D and E, which are capable of induce apoptosis in macrophages; c) The function of Toll R2 and Toll R4 receptors present in the macrophage surface (discovered in the Drosophila). The Toll family receptors are critical in the signalizing mediated by LPS in macrophages in association with LBP and CD14; d) The lines of immune defense between intestinal lumen and internal organs; e) The fundamental role of the endothelial cells in the inflammatory deviation from bloodstream into infected tissues by bacteria. In addition to above subjects, the authors comment the correlation between the clinical features of typhoid fever and the cellular and molecular phenomena of this disease, as well as the therapeutic consequences of this knowledge.

Astrobiological complexity with probabilistic cellular automata.

PubMed

Vukotić, Branislav; Ćirković, Milan M

2012-08-01

The search for extraterrestrial life and intelligence constitutes one of the major endeavors in science, but has yet been quantitatively modeled only rarely and in a cursory and superficial fashion. We argue that probabilistic cellular automata (PCA) represent the best quantitative framework for modeling the astrobiological history of the Milky Way and its Galactic Habitable Zone. The relevant astrobiological parameters are to be modeled as the elements of the input probability matrix for the PCA kernel. With the underlying simplicity of the cellular automata constructs, this approach enables a quick analysis of large and ambiguous space of the input parameters. We perform a simple clustering analysis of typical astrobiological histories with "Copernican" choice of input parameters and discuss the relevant boundary conditions of practical importance for planning and guiding empirical astrobiological and SETI projects. In addition to showing how the present framework is adaptable to more complex situations and updated observational databases from current and near-future space missions, we demonstrate how numerical results could offer a cautious rationale for continuation of practical SETI searches.

Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death.

PubMed

Narayanan, Kannan Badri; Ali, Manaf; Barclay, Barry J; Cheng, Qiang Shawn; D'Abronzo, Leandro; Dornetshuber-Fleiss, Rita; Ghosh, Paramita M; Gonzalez Guzman, Michael J; Lee, Tae-Jin; Leung, Po Sing; Li, Lin; Luanpitpong, Suidjit; Ratovitski, Edward; Rojanasakul, Yon; Romano, Maria Fiammetta; Romano, Simona; Sinha, Ranjeet K; Yedjou, Clement; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Brown, Dustin G; Ryan, Elizabeth P; Colacci, Annamaria; Hamid, Roslida A; Mondello, Chiara; Raju, Jayadev; Salem, Hosni K; Woodrick, Jordan; Scovassi, A Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Kim, Seo Yun; Bisson, William H; Lowe, Leroy; Park, Hyun Ho

2015-06-01

Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Expression and cellular localization of the transcription factor NeuroD1 in the developing and adult rat pineal gland.

PubMed

Castro, Analía E; Benitez, Sergio G; Farias Altamirano, Luz E; Savastano, Luis E; Patterson, Sean I; Muñoz, Estela M

2015-05-01

Circadian rhythms govern many aspects of mammalian physiology. The daily pattern of melatonin synthesis and secretion is one of the classic examples of circadian oscillations. It is mediated by a class of neuroendocrine cells known as pinealocytes which are not yet fully defined. An established method to evaluate functional and cytological characters is through the expression of lineage-specific transcriptional regulators. NeuroD1 is a basic helix-loop-helix transcription factor involved in the specification and maintenance of both endocrine and neuronal phenotypes. We have previously described developmental and adult regulation of NeuroD1 mRNA in the rodent pineal gland. However, the transcript levels were not influenced by the elimination of sympathetic input, suggesting that any rhythmicity of NeuroD1 might be found downstream of transcription. Here, we describe NeuroD1 protein expression and cellular localization in the rat pineal gland during development and the daily cycle. In embryonic and perinatal stages, protein expression follows the mRNA pattern and is predominantly nuclear. Thereafter, NeuroD1 is mostly found in pinealocyte nuclei in the early part of the night and in cytoplasm during the day, a rhythm maintained into adulthood. Additionally, nocturnal nuclear NeuroD1 levels are reduced after sympathetic disruption, an effect mimicked by the in vivo administration of α- and β-adrenoceptor blockers. NeuroD1 phosphorylation at two sites, Ser(274) and Ser(336) , associates with nuclear localization in pinealocytes. These data suggest that NeuroD1 influences pineal phenotype both during development and adulthood, in an autonomic and phosphorylation-dependent manner. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Digital Cellular Solid Pressure Vessels: A Novel Approach for Human Habitation in Space

NASA Technical Reports Server (NTRS)

Cellucci, Daniel; Jenett, Benjamin; Cheung, Kenneth C.

2017-01-01

It is widely assumed that human exploration beyond Earth's orbit will require vehicles capable of providing long duration habitats that simulate an Earth-like environment - consistent artificial gravity, breathable atmosphere, and sufficient living space- while requiring the minimum possible launch mass. This paper examines how the qualities of digital cellular solids - high-performance, repairability, reconfigurability, tunable mechanical response - allow the accomplishment of long-duration habitat objectives at a fraction of the mass required for traditional structural technologies. To illustrate the impact digital cellular solids could make as a replacement to conventional habitat subsystems, we compare recent proposed deep space habitat structural systems with a digital cellular solids pressure vessel design that consists of a carbon fiber reinforced polymer (CFRP) digital cellular solid cylindrical framework that is lined with an ultra-high molecular weight polyethylene (UHMWPE) skin. We use the analytical treatment of a linear specific modulus scaling cellular solid to find the minimum mass pressure vessel for a structure and find that, for equivalent habitable volume and appropriate safety factors, the use of digital cellular solids provides clear methods for producing structures that are not only repairable and reconfigurable, but also higher performance than their conventionally manufactured counterparts.

Cellular signaling by fibroblast growth factors (FGFs) and their receptors (FGFRs) in male reproduction.

PubMed

Cotton, Leanne M; O'Bryan, Moira K; Hinton, Barry T

2008-04-01

The major function of the reproductive system is to ensure the survival of the species by passing on hereditary traits from one generation to the next. This is accomplished through the production of gametes and the generation of hormones that function in the maturation and regulation of the reproductive system. It is well established that normal development and function of the male reproductive system is mediated by endocrine and paracrine signaling pathways. Fibroblast growth factors (FGFs), their receptors (FGFRs), and signaling cascades have been implicated in a diverse range of cellular processes including: proliferation, apoptosis, cell survival, chemotaxis, cell adhesion, motility, and differentiation. The maintenance and regulation of correct FGF signaling is evident from human and mouse genetic studies which demonstrate that mutations leading to disruption of FGF signaling cause a variety of developmental disorders including dominant skeletal diseases, infertility, and cancer. Over the course of this review, we will provide evidence for differential expression of FGFs/FGFRs in the testis, male germ cells, the epididymis, the seminal vesicle, and the prostate. We will show that this signaling cascade has an important role in sperm development and maturation. Furthermore, we will demonstrate that FGF/FGFR signaling is essential for normal epididymal function and prostate development. To this end, we will provide evidence for the involvement of the FGF signaling system in the regulation and maintenance of the male reproductive system.

MSAT and cellular hybrid networking

NASA Astrophysics Data System (ADS)

Baranowsky, Patrick W., II

Westinghouse Electric Corporation is developing both the Communications Ground Segment and the Series 1000 Mobile Phone for American Mobile Satellite Corporation's (AMSC's) Mobile Satellite (MSAT) system. The success of the voice services portion of this system depends, to some extent, upon the interoperability of the cellular network and the satellite communication circuit switched communication channels. This paper will describe the set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone and described how they are implemented with the ground segment. Topics including roaming registration and cellular-to-satellite 'seamless' call handoff will be discussed, along with the relevant Interim Standard IS-41 Revision B Cellular Radiotelecommunications Intersystem Operations and IOS-553 Mobile Station - Land Station Compatibility Specification.

Shock enhancement of cellular materials subjected to intensive pulse loading

NASA Astrophysics Data System (ADS)

Zhang, J.; Fan, J.; Wang, Z.; Zhao, L.; Li, Z.

2018-03-01

Cellular materials can dissipate a large amount of energy due to their considerable stress plateau, which contributes to their extensive applications in structural design for crashworthiness. However, in some experiments with specimens subjected to intense impact loads, transmitted stress enhancement has been observed, leading to severe damage to the objects protected. Transmitted stress through two-dimensional Voronoi cellular materials as a protective device is qualitatively studied in this paper. Dimensionless parameters of material properties and loading parameters are defined to give critical conditions for shock enhancement and clarify the correlation between the deformations and stress enhancement. The effect of relative density on this amplifying phenomenon is investigated as well. In addition, local strain fields are calculated by using the optimal local deformation gradient, which gives a clear presentation of deformations and possible local non-uniformity in the crushing process. This research provides valuable insight into the reliability of cellular materials as protective structures.

Enhanced cellular uptake of maleimide-modified liposomes via thiol-mediated transport

PubMed Central

Li, Tianshu; Takeoka, Shinji

2014-01-01

With a small amount of maleimide modification on the liposome surface, enhanced cellular uptake of liposomes and drug-delivery efficiency can be obtained both in vitro and in vivo. Herein, we describe the mechanisms underlying this enhanced cellular uptake. Suppression of the cellular uptake of maleimide-modified liposomes (M-GGLG, composed of 1,5-dihexadecyl N,N-diglutamyl-lysyl-L-glutamate [GGLG]/cholesterol/poly(ethylene glycol) – 1,2-distearoyl-sn-glycero-3-phosphoethanolamine [PEG5000-DSPE]/maleimide [M]-PEG5000-Glu2C18 at a molar ratio of 5:5:0.03:0.03) caused by temperature block and addition of serum was alleviated compared with that of liposomes without maleimide modification (GGLG liposomes, composed of GGLG/cholesterol/PEG5000-DSPE/PEG5000-Glu2C18 at a molar ratio of 5:5:0.03:0.03). When 0.01 nM N-ethylmaleimide was used to pre-block cellular thiols, the cellular uptake of M-GGLG liposomes was decreased to approximately 70% in HeLa, HCC1954, MDA-MB-468, and COS-7 cell lines. Moreover, inhibition of a thiol-related reductase such as protein disulfide isomerase resulted in a 15%–45% inhibition of the cellular uptake of M-GGLG liposomes, whereas GGLG liposomes were not influenced. Further, single and mixed inhibitors of clathrin-mediated endocytosis, caveolae-mediated endocytosis, and macropinocytosis did not efficiently inhibit the cellular uptake of M-GGLG liposomes. Using confocal microscopy, we verified that M-GGLG liposomes were localized partially in lysosomes after inhibition of the mentioned conventional endocytic pathways. Therefore, it was hypothesized that the mechanisms underlying the enhanced cellular uptake of liposomes by maleimide modification was thiol-mediated membrane trafficking, including endocytosis and energy-independent transport. PMID:24940060

Enhanced cellular uptake of maleimide-modified liposomes via thiol-mediated transport.

PubMed

Li, Tianshu; Takeoka, Shinji

2014-01-01

With a small amount of maleimide modification on the liposome surface, enhanced cellular uptake of liposomes and drug-delivery efficiency can be obtained both in vitro and in vivo. Herein, we describe the mechanisms underlying this enhanced cellular uptake. Suppression of the cellular uptake of maleimide-modified liposomes (M-GGLG, composed of 1,5-dihexadecyl N,N-diglutamyl-lysyl-L-glutamate [GGLG]/cholesterol/poly(ethylene glycol) - 1,2-distearoyl-sn-glycero-3-phosphoethanolamine [PEG₅₀₀₀-DSPE]/maleimide [M]-PEG₅₀₀₀-Glu2C18 at a molar ratio of 5:5:0.03:0.03) caused by temperature block and addition of serum was alleviated compared with that of liposomes without maleimide modification (GGLG liposomes, composed of GGLG/cholesterol/PEG₅₀₀₀-DSPE/PEG₅₀₀₀-Glu2C₁₈ at a molar ratio of 5:5:0.03:0.03). When 0.01 nM N-ethylmaleimide was used to pre-block cellular thiols, the cellular uptake of M-GGLG liposomes was decreased to approximately 70% in HeLa, HCC1954, MDA-MB-468, and COS-7 cell lines. Moreover, inhibition of a thiol-related reductase such as protein disulfide isomerase resulted in a 15%-45% inhibition of the cellular uptake of M-GGLG liposomes, whereas GGLG liposomes were not influenced. Further, single and mixed inhibitors of clathrin-mediated endocytosis, caveolae-mediated endocytosis, and macropinocytosis did not efficiently inhibit the cellular uptake of M-GGLG liposomes. Using confocal microscopy, we verified that M-GGLG liposomes were localized partially in lysosomes after inhibition of the mentioned conventional endocytic pathways. Therefore, it was hypothesized that the mechanisms underlying the enhanced cellular uptake of liposomes by maleimide modification was thiol-mediated membrane trafficking, including endocytosis and energy-independent transport.

Quantifying time-varying cellular secretions with local linear models.

PubMed

Byers, Jeff M; Christodoulides, Joseph A; Delehanty, James B; Raghu, Deepa; Raphael, Marc P

2017-07-01

Extracellular protein concentrations and gradients initiate a wide range of cellular responses, such as cell motility, growth, proliferation and death. Understanding inter-cellular communication requires spatio-temporal knowledge of these secreted factors and their causal relationship with cell phenotype. Techniques which can detect cellular secretions in real time are becoming more common but generalizable data analysis methodologies which can quantify concentration from these measurements are still lacking. Here we introduce a probabilistic approach in which local-linear models and the law of mass action are applied to obtain time-varying secreted concentrations from affinity-based biosensor data. We first highlight the general features of this approach using simulated data which contains both static and time-varying concentration profiles. Next we apply the technique to determine concentration of secreted antibodies from 9E10 hybridoma cells as detected using nanoplasmonic biosensors. A broad range of time-dependent concentrations was observed: from steady-state secretions of 230 pM near the cell surface to large transients which reached as high as 56 nM over several minutes and then dissipated.

FAD-dependent lysine-specific demethylase-1 regulates cellular energy expenditure

PubMed Central

Hino, Shinjiro; Sakamoto, Akihisa; Nagaoka, Katsuya; Anan, Kotaro; Wang, Yuqing; Mimasu, Shinya; Umehara, Takashi; Yokoyama, Shigeyuki; Kosai, Ken-ichiro; Nakao, Mitsuyoshi

2012-01-01

Environmental factors such as nutritional state may act on the epigenome that consequently contributes to the metabolic adaptation of cells and the organisms. The lysine-specific demethylase-1 (LSD1) is a unique nuclear protein that utilizes flavin adenosine dinucleotide (FAD) as a cofactor. Here we show that LSD1 epigenetically regulates energy-expenditure genes in adipocytes depending on the cellular FAD availability. We find that the loss of LSD1 function, either by short interfering RNA or by selective inhibitors in adipocytes, induces a number of regulators of energy expenditure and mitochondrial metabolism such as PPARγ coactivator-1α resulting in the activation of mitochondrial respiration. In the adipose tissues from mice on a high-fat diet, expression of LSD1-target genes is reduced, compared with that in tissues from mice on a normal diet, which can be reverted by suppressing LSD1 function. Our data suggest a novel mechanism where LSD1 regulates cellular energy balance through coupling with cellular FAD biosynthesis. PMID:22453831

FAD-dependent lysine-specific demethylase-1 regulates cellular energy expenditure.

PubMed

Hino, Shinjiro; Sakamoto, Akihisa; Nagaoka, Katsuya; Anan, Kotaro; Wang, Yuqing; Mimasu, Shinya; Umehara, Takashi; Yokoyama, Shigeyuki; Kosai, Ken-Ichiro; Nakao, Mitsuyoshi

2012-03-27

Environmental factors such as nutritional state may act on the epigenome that consequently contributes to the metabolic adaptation of cells and the organisms. The lysine-specific demethylase-1 (LSD1) is a unique nuclear protein that utilizes flavin adenosine dinucleotide (FAD) as a cofactor. Here we show that LSD1 epigenetically regulates energy-expenditure genes in adipocytes depending on the cellular FAD availability. We find that the loss of LSD1 function, either by short interfering RNA or by selective inhibitors in adipocytes, induces a number of regulators of energy expenditure and mitochondrial metabolism such as PPARγ coactivator-1α resulting in the activation of mitochondrial respiration. In the adipose tissues from mice on a high-fat diet, expression of LSD1-target genes is reduced, compared with that in tissues from mice on a normal diet, which can be reverted by suppressing LSD1 function. Our data suggest a novel mechanism where LSD1 regulates cellular energy balance through coupling with cellular FAD biosynthesis.

Infectious and dietary risk factors of oral cancer.

PubMed

Meurman, Jukka H

2010-06-01

In addition to the classic risk factors of oral cancer, namely alcohol and tobacco, other factors both infectious and environmental are thought to be associated with the development of oral malignancy. Infections in the oral cavity may be an important preventable cause of cancer. Poor oral hygiene, periodontal disease, chronic candidiasis, human papilloma virus (HPV) and herpesvirus infections link statistically with cancer but the mechanisms involved are largely unknown. Infections may trigger cell proliferation, inhibit apoptosis, interfere with cellular signaling mechanisms and up-regulate tumor promoters. In addition, several oral micro-organisms metabolize alcohol to carcinogenic acetaldehyde thus explaining the association between poor oral hygiene, alcohol consumption and carcinogenesis. With regards to dietary factors the Mediterranean-type fruit and vegetable rich diet has been shown to reduce the risk of oral cancer but the evidence is weak, the effect of individual food components and trace elements on carcinogenesis remains unclear at present. Copyright 2010 Elsevier Ltd. All rights reserved.

Operating principles of tristable circuits regulating cellular differentiation

NASA Astrophysics Data System (ADS)

Jia, Dongya; Jolly, Mohit Kumar; Harrison, William; Boareto, Marcelo; Ben-Jacob, Eshel; Levine, Herbert

2017-06-01

Many cell-fate decisions during embryonic development are governed by a motif comprised of two transcription factors (TFs) A and B that mutually inhibit each other and may self-activate. This motif, called as a self-activating toggle switch (SATS), can typically have three stable states (phenotypes)—two corresponding to differentiated cell fates, each of which has a much higher level of one TF than the other—≤ft(A,~B\\right)=≤ft(1,~0\\right) or ≤ft(0,~1\\right) —and the third state corresponding to an ‘undecided’ stem-like state with similar levels of both A and B—≤ft(A,~B\\right)=≤ft(1/2,1/2\\right) . Furthermore, two or more SATSes can be coupled together in various topologies in different contexts, thereby affecting the coordination between multiple cellular decisions. However, two questions remain largely unanswered: (a) what governs the co-existence and relative stability of these three stable states? (b) What orchestrates the decision-making of coupled SATSes? Here, we first demonstrate that the co-existence and relative stability of the three stable states in an individual SATS can be governed by the relative strength of self-activation, external signals activating and/or inhibiting A and B, and mutual degradation between A and B. Simultaneously, we investigate the effects of these factors on the decision-making of two coupled SATSes. Our results offer novel understanding into the operating principles of individual and coupled tristable self-activating toggle switches (SATSes) regulating cellular differentiation and can yield insights into synthesizing three-way genetic circuits and understanding of cellular reprogramming.

Regulation of Cellular Communication by Signaling Microdomains in the Blood Vessel Wall

PubMed Central

Billaud, Marie; Lohman, Alexander W.; Johnstone, Scott R.; Biwer, Lauren A.; Mutchler, Stephanie; Isakson, Brant E.

2014-01-01

It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function. PMID:24671377

Regulation of cellular communication by signaling microdomains in the blood vessel wall.

PubMed

Billaud, Marie; Lohman, Alexander W; Johnstone, Scott R; Biwer, Lauren A; Mutchler, Stephanie; Isakson, Brant E

2014-01-01

It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function.

Mechanisms of Oxygen Toxicity at the Cellular Level.

DTIC Science & Technology

1982-06-30

exposed and measured using glucose as the sole carbon source. Addition of SH containing reducing agents (cysteine, lipoic acid or dithiothreitol) before...of a Few Seconds. Biotechnology and Bioengineering 16:1645-1657 (1974). (28) Brown, O.R. Failure of Lipoic Acid to Protect Against Cellular Oxygen...respiration, and fatty acid synthesis. The interruption of fatty acid synthesis is not the result of inactivation of the fatty acid synthetase enzyme complex

Modeling of Ti-W Solidification Microstructures Under Additive Manufacturing Conditions

NASA Astrophysics Data System (ADS)

Rolchigo, Matthew R.; Mendoza, Michael Y.; Samimi, Peyman; Brice, David A.; Martin, Brian; Collins, Peter C.; LeSar, Richard

2017-07-01

Additive manufacturing (AM) processes have many benefits for the fabrication of alloy parts, including the potential for greater microstructural control and targeted properties than traditional metallurgy processes. To accelerate utilization of this process to produce such parts, an effective computational modeling approach to identify the relationships between material and process parameters, microstructure, and part properties is essential. Development of such a model requires accounting for the many factors in play during this process, including laser absorption, material addition and melting, fluid flow, various modes of heat transport, and solidification. In this paper, we start with a more modest goal, to create a multiscale model for a specific AM process, Laser Engineered Net Shaping (LENS™), which couples a continuum-level description of a simplified beam melting problem (coupling heat absorption, heat transport, and fluid flow) with a Lattice Boltzmann-cellular automata (LB-CA) microscale model of combined fluid flow, solute transport, and solidification. We apply this model to a binary Ti-5.5 wt pct W alloy and compare calculated quantities, such as dendrite arm spacing, with experimental results reported in a companion paper.

Tribological behavior of Ti6Al4V cellular structures produced by Selective Laser Melting.

PubMed

Bartolomeu, F; Sampaio, M; Carvalho, O; Pinto, E; Alves, N; Gomes, J R; Silva, F S; Miranda, G

2017-05-01

Additive manufacturing (AM) technologies enable the fabrication of innovative structures with complex geometries not easily manufactured by traditional processes. Regarding metallic cellular structures with tailored/customized mechanical and wear performance aiming to biomedical applications, Selective Laser Melting (SLM) is a remarkable solution for their production. Focusing on prosthesis and implants, in addition to a suitable Young's modulus it is important to assess the friction response and wear resistance of these cellular structures in a natural environment. In this sense, five cellular Ti6Al4V structures with different open-cell sizes (100-500µm) were designed and produced by SLM. These structures were tribologicaly tested against alumina using a reciprocating sliding ball-on-plate tribometer. Samples were submerged in Phosphate Buffered Saline (PBS) fluid at 37°C, in order to mimic in some extent the human body environment. The results showed that friction and wear performance of Ti6Al4V cellular structures is influenced by the structure open-cell size. The higher wear resistance was obtained for structures with 100µm designed open-cell size due to the higher apparent area of contact to support tribological loading. Copyright © 2017 Elsevier Ltd. All rights reserved.

Critical Behavior in Cellular Automata Animal Disease Transmission Model

NASA Astrophysics Data System (ADS)

Morley, P. D.; Chang, Julius

Using cellular automata model, we simulate the British Government Policy (BGP) in the 2001 foot and mouth epidemic in Great Britain. When clinical symptoms of the disease appeared in a farm, there is mandatory slaughter (culling) of all livestock in an infected premise (IP). Those farms in the neighboring of an IP (contiguous premise, CP), are also culled, aka nearest neighbor interaction. Farms where the disease may be prevalent from animal, human, vehicle or airborne transmission (dangerous contact, DC), are additionally culled, aka next-to-nearest neighbor interactions and lightning factor. The resulting mathematical model possesses a phase transition, whereupon if the physical disease transmission kernel exceeds a critical value, catastrophic loss of animals ensues. The nonlocal disease transport probability can be as low as 0.01% per day and the disease can still be in the high mortality phase. We show that the fundamental equation for sustainable disease transport is the criticality equation for neutron fission cascade. Finally, we calculate that the percentage of culled animals that are actually healthy is ≈30%.

Diagnosis of stinging insect allergy: utility of cellular in-vitro tests.

PubMed

Scherer, Kathrin; Bircher, Andreas J; Heijnen, Ingmar Afm

2009-08-01

Diagnosis of stinging insect allergy is based on a detailed history, venom skin tests, and detection of venom-specific IgE. As an additional diagnostic tool, basophil responsiveness to venom allergens has been shown to be helpful in selected patients. This review summarizes the current diagnostic procedures for stinging insect allergy and discusses the latest developments in cellular in-vitro tests. Cellular assays have been evaluated in patients with Hymenoptera venom allergy. The diagnostic performance of the cellular mediator release test is similar to that of the flow cytometric basophil activation test (BAT), but the BAT has been the most intensively studied. BAT offers the possibility to assess basophil reactivity to allergens in their natural environment and to simultaneously analyze surface marker expression and intracellular signaling. It has been demonstrated that BAT represents a valuable additional diagnostic tool in selected patients when used in combination with other well established tests. A major limitation is the current lack of unified, standardized protocols. Flow cytometry offers huge possibilities to enhance knowledge of basophil functions. The BAT may be used as an additional test to confirm the diagnosis of stinging insect allergy in selected patients, provided that it is performed by an experienced laboratory using a validated assay. Test results have to be interpreted by clinicians familiar with the methodological aspects. The utility of the BAT to confirm allergy diagnosis and to predict the risk of subsequent systemic reactions may be improved by combined analysis of multiple surface markers and intracellular signaling pathways.

The role of actin networks in cellular mechanosensing

NASA Astrophysics Data System (ADS)

Azatov, Mikheil

behavior as in cancer metastasis. In addition to stiffness, the local geometry or topography of the surface has been shown to modulate the movement, morphology, and cytoskeletal organization of cells. However, the effect of topography on fluctuations of intracellular structures, which arise from motor driven activity on a viscoelastic actin network are not known. I have used nanofabricated substrates with parallel ridges to show that the cell shape, the actin cytoskeleton and focal adhesions all align along the direction of the ridges, exhibiting a biphasic dependence on the spacing between ridges. I further demonstrated that palladin bands along actin stress fibers undergo a complex diffusive motion with velocities aligned along the direction of ridges. These results provide insight into the mechanisms of cellular mechanosensing of the environment, suggesting a complex interplay between the actin cytoskeleton and cellular adhesions in coordinating cellular response to surface topography. Overall, this work has advanced our understanding of mechanisms that govern cellular responses to their physical environment.

76 FR 82308 - Guidance for Industry: Current Good Tissue Practice and Additional Requirements for Manufacturers...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-30

... Cells, Tissues, and Cellular and Tissue-Based Products; Availability AGENCY: Food and Drug... Requirements for Manufacturers of Human Cells, Tissues, and Cellular and Tissue-Based Products (HCT/Ps)'' dated... Tissue Practice (CGTP) and Additional Requirements for Manufacturers of Human Cells, Tissues, and...

Navigating novel mechanisms of cellular plasticity with the NAD+ precursor and nutrient nicotinamide.

PubMed

Li, Faqi; Chong, Zhao Zhong; Maiese, Kenneth

2004-09-01

Interest in neuroprotectants for the central nervous system continues to garner significant attention. Nicotinamide, the amide form of niacin (vitamin B3), is the precursor for the coenzyme beta-nicotinamide adenine dinucleotide (NAD+) and is considered to be necessary for cellular function and metabolism. However, recent work has focused on the development of nicotinamide as a novel agent that is critical for modulating cellular plasticity, longevity, and inflammatory microglial function. The ability of nicotinamide to preserve both neuronal and vascular cell populations in the brain during injury is intriguing, but further knowledge of the specific cellular mechanisms that determine protection by this agent is required. The capacity of nicotinamide to govern not only intrinsic cellular integrity, but also extrinsic cellular inflammation rests with the modulation of a host of cellular targets that involve protein kinase B, glycogen synthase kinase-3 beta (GSK-3 beta), Forkhead transcription factors, mitochondrial dysfunction, poly(ADP-ribose) polymerase, cysteine proteases, and microglial activation. Intimately tied to the cytoprotection of nicotinamide is the modulation of an early and late phase of apoptotic injury that is triggered by the loss of membrane asymmetry. Identifying robust cytoprotective agents as nicotinamide in conjunction with the elucidation of the cellular mechanisms responsible for cell survival will continue to solidify the development of therapeutic strategies against neurodegenerative diseases

Anodic Aluminum Oxide (AAO) Membranes for Cellular Devices

NASA Astrophysics Data System (ADS)

Ventura, Anthony P.

Anodic Aluminum Oxide (AAO) membranes can be fabricated with a highly tunable pore structure making them a suitable candidate for cellular hybrid devices with single-molecule selectivity. The objective of this study was to characterize the cellular response of AAO membranes with varying pore sizes to serve as a proof-of-concept for an artificial material/cell synapse system. AAO membranes with pore diameters ranging from 34-117 nm were achieved via anodization at a temperature of -1°C in a 2.7% oxalic acid electrolyte. An operating window was established for this setup to create membranes with through-pore and disordered pore morphologies. C17.2 neural stem cells were seeded onto the membranes and differentiated via serum withdrawal. The data suggests a highly tunable correlation between AAO pore diameter and differentiated cell populations. Analysis of membranes before and after cell culture indicated no breakdown of the through-pore structure. Immunocytochemistry (ICC) showed that AAO membranes had increased neurite outgrowth when compared to tissue culture treated (TCT) glass, and neurite outgrowth varied with pore diameter. Additionally, lower neuronal percentages were found on AAO as compared to TCT glass; however, neuronal population was also found to vary with pore diameter. Scanning electron microscopy (SEM) and ICC images suggested the presence of a tissue-like layer with a mixed-phenotype population. AAO membranes appear to be an excellent candidate for cellular devices, but more work must be completed to understand the surface chemistry of the AAO membranes as it relates to cellular response.

Receptor-mediated endocytosis generates nanomechanical force reflective of ligand identity and cellular property.

PubMed

Zhang, Xiao; Ren, Juan; Wang, Jingren; Li, Shixie; Zou, Qingze; Gao, Nan

2018-08-01

Whether environmental (thermal, chemical, and nutrient) signals generate quantifiable, nanoscale, mechanophysical changes in the cellular plasma membrane has not been well elucidated. Assessment of such mechanophysical properties of plasma membrane may shed lights on fundamental cellular process. Atomic force microscopic (AFM) measurement of the mechanical properties of live cells was hampered by the difficulty in accounting for the effects of the cantilever motion and the associated hydrodynamic force on the mechanical measurement. These challenges have been addressed in our recently developed control-based AFM nanomechanical measurement protocol, which enables a fast, noninvasive, broadband measurement of the real-time changes in plasma membrane elasticity in live cells. Here we show using this newly developed AFM platform that the plasma membrane of live mammalian cells exhibits a constant and quantifiable nanomechanical property, the membrane elasticity. This mechanical property sensitively changes in response to environmental factors, such as the thermal, chemical, and growth factor stimuli. We demonstrate that different chemical inhibitors of endocytosis elicit distinct changes in plasma membrane elastic modulus reflecting their specific molecular actions on the lipid configuration or the endocytic machinery. Interestingly, two different growth factors, EGF and Wnt3a, elicited distinct elastic force profiles revealed by AFM at the plasma membrane during receptor-mediated endocytosis. By applying this platform to genetically modified cells, we uncovered a previously unknown contribution of Cdc42, a key component of the cellular trafficking network, to EGF-stimulated endocytosis at plasma membrane. Together, this nanomechanical AFM study establishes an important foundation that is expandable and adaptable for investigation of cellular membrane evolution in response to various key extracellular signals. © 2017 Wiley Periodicals, Inc.

Cellular dysfunction in the diabetic fibroblast: impairment in migration, vascular endothelial growth factor production, and response to hypoxia.

PubMed

Lerman, Oren Z; Galiano, Robert D; Armour, Mary; Levine, Jamie P; Gurtner, Geoffrey C

2003-01-01

Although it is known that systemic diseases such as diabetes result in impaired wound healing, the mechanism for this impairment is not understood. Because fibroblasts are essential for wound repair, we compared the in vitro behavior of fibroblasts cultured from diabetic, leptin receptor-deficient (db/db) mice with wild-type fibroblasts from mice of the same genetic background in processes important during tissue repair. Adult diabetic mouse fibroblast migration exhibited a 75% reduction in migration compared to normal fibroblasts (P < 0.001) and was not significantly stimulated by hypoxia (1% O(2)), whereas wild-type fibroblast migration was up-regulated nearly twofold in hypoxic conditions (P < 0.05). Diabetic fibroblasts produced twice the amount of pro-matrix metalloproteinase-9 as normal fibroblasts, as measured by both gelatin zymography and enzyme-linked immunosorbent assay (P < 0.05). Adult diabetic fibroblasts exhibited a sevenfold impairment in vascular endothelial growth factor (VEGF) production (4.5 +/- 1.3 pg/ml versus 34.8 +/- 3.3 pg/ml, P < 0.001) compared to wild-type fibroblasts. Moreover, wild-type fibroblast production of VEGF increased threefold in response to hypoxia, whereas diabetic fibroblast production of VEGF was not up-regulated in hypoxic conditions (P < 0.001). To address the question whether these differences resulted from chronic hyperglycemia or absence of the leptin receptor, fibroblasts were harvested from newborn db/db mice before the onset of diabetes (4 to 5 weeks old). These fibroblasts showed no impairments in VEGF production under basal or hypoxic conditions, confirming that the results from db/db fibroblasts in mature mice resulted from the diabetic state and were not because of alterations in the leptin-leptin receptor axis. Markers of cellular viability including proliferation and senescence were not significantly different between diabetic and wild-type fibroblasts. We conclude that, in vitro, diabetic fibroblasts show

Cellular genetic therapy.

PubMed

Del Vecchio, F; Filareto, A; Spitalieri, P; Sangiuolo, F; Novelli, G

2005-01-01

Cellular genetic therapy is the ultimate frontier for those pathologies that are consequent to a specific nonfunctional cellular type. A viable cure for there kinds of diseases is the replacement of sick cells with healthy ones, which can be obtained from the same patient or a different donor. In fact, structures can be corrected and strengthened with the introduction of undifferentiated cells within specific target tissues, where they will specialize into the desired cellular types. Furthermore, consequent to the recent results obtained with the transdifferentiation experiments, a process that allows the in vitro differentiation of embryonic and adult stem cells, it has also became clear that many advantages may be obtained from the use of stem cells to produce drugs, vaccines, and therapeutic molecules. Since stem cells can sustain lineage potentials, the capacity for differentiation, and better tolerance for the introduction of exogenous genes, they are also considered as feasible therapeutic vehicles for gene therapy. In fact, it is strongly believed that the combination of cellular genetic and gene therapy approaches will definitely allow the development of new therapeutic strategies as well as the production of totipotent cell lines to be used as experimental models for the cure of genetic disorders.

Additively manufactured hierarchical stainless steels with high strength and ductility.

PubMed

Wang, Y Morris; Voisin, Thomas; McKeown, Joseph T; Ye, Jianchao; Calta, Nicholas P; Li, Zan; Zeng, Zhi; Zhang, Yin; Chen, Wen; Roehling, Tien Tran; Ott, Ryan T; Santala, Melissa K; Depond, Philip J; Matthews, Manyalibo J; Hamza, Alex V; Zhu, Ting

2018-01-01

Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.

Additively manufactured hierarchical stainless steels with high strength and ductility

NASA Astrophysics Data System (ADS)

Wang, Y. Morris; Voisin, Thomas; McKeown, Joseph T.; Ye, Jianchao; Calta, Nicholas P.; Li, Zan; Zeng, Zhi; Zhang, Yin; Chen, Wen; Roehling, Tien Tran; Ott, Ryan T.; Santala, Melissa K.; Depond, Philip J.; Matthews, Manyalibo J.; Hamza, Alex V.; Zhu, Ting

2018-01-01

Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.

Additively manufactured hierarchical stainless steels with high strength and ductility

DOE PAGES

Wang, Y. Morris; Voisin, Thomas; McKeown, Joseph T.; ...

2017-10-30

Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength–ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearlymore » six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.« less

Additively manufactured hierarchical stainless steels with high strength and ductility

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

Wang, Y. Morris; Voisin, Thomas; McKeown, Joseph T.

Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength–ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearlymore » six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.« less

Cellular telephone interference with medical equipment.

PubMed

Tri, Jeffrey L; Severson, Rodney P; Firl, Allen R; Hayes, David L; Abenstein, John P

2005-10-01

To assess the potential electromagnetic interference (EMI) effects that new or current-generation cellular telephones have on medical devices. For this study, performed at the Mayo Clinic in Rochester, Minn, between March 9, 2004, and April 24, 2004, we tested 16 different medical devices with 6 cellular telephones to assess the potential for EMI. Two of the medical devices were tested with both new and old interface modules. The 6 cellular telephones chosen represent the different cellular technology protocols in use: Code Division Multiple Access (2 models), Global System for Mobile communications, Integrated Digital Enhanced Network, Time Division Multiple Access, and analog. The cellular telephones were tested when operating at or near their maximum power output. The medical devices, connected to clinical simulators during testing, were monitored by observing the device displays and alarms. Of 510 tests performed, the incidence of clinically important interference was 1.2%; EMI was Induced in 108 tests (21.2%). Interference occurred in 7 (44%) of the 16 devices tested. Cellular telephones can interfere with medical equipment. Technology changes in both cellular telephones and medical equipment may continue to mitigate or may worsen clinically relevant interference. Compared with cellular telephones tested in previous studies, those currently in use must be closer to medical devices before any interference is noticed. However, periodic testing of cellular telephones to determine their effects on medical equipment will be required.

Effects of the breed, sex and age on cellular content and growth factor release from equine pure-platelet rich plasma and pure-platelet rich gel.

PubMed

Giraldo, Carlos E; López, Catalina; Álvarez, María E; Samudio, Ismael J; Prades, Marta; Carmona, Jorge U

2013-02-12

There is no information on the effects of the breed, gender and age on the cellular content and growth factor (GF) release from equine pure-platelet rich plasma (P-PRP) and pure-platelet rich gel (P-PRG). The objectives of this study were: 1) to compare the cellular composition of P-PRP with whole blood and platelet poor plasma (PPP); 2) to compare the concentration of transforming GF beta 1 (TGF-β1) and platelet derived GF isoform BB (PDGF-BB) between P-PRP treated with non-ionic detergent (P-PRP+NID), P-PRG (activated with calcium gluconate -CG-), PPP+NID, PPP gel (PPG), and plasma and; 3) to evaluate and to correlate the effect of the breed, gender and age on the cellular and GF concentration for each blood component. Forty adult horses, 20 Argentinean Creole Horses (ACH) and, 20 Colombian Creole Horses (CCH) were included. Data were analyzed by parametric (i.e.: t-test, one way ANOVA) and non parametric (Kruskal-Wallis test, Wilcoxon test) tests. Correlation analysis was also performed by using the Spearman and Pearson tests. A p ≤ 0.05 was set as significant for all tests. All the blood components were compared for platelet (PLT), leukocyte (WBC), TGF-β1 and PDGF-BB concentrations. The effect of the breed, gender and age on these variables was analyzed. A P ≤ 0.05 was accepted as significant for all the tests. PLT counts were 1.8 and 0.6 times higher in P-PRP than in whole blood and PPP, respectively; WBC counts were 0.5 and 0.1 times lower in P-PRP, in comparison with whole blood and PPP, respectively. TGF-β1 and PDGF-BB concentrations were 2.3 and 262 times higher, respectively, in P-PRG than in plasma, and 0.59 and 0.48 times higher, respectively, in P-PRG than in PPG. P-PRG derived from CCH females or young horses presented significantly (P < 0.001) higher PDGF-BB concentrations than P-PRG derived from ACH males or older horses. Our results indicated that P-PRP obtained by a manual method was affected by intrinsic factors such as the breed

Mathematical Modeling of Cellular Metabolism.

PubMed

Berndt, Nikolaus; Holzhütter, Hermann-Georg

Cellular metabolism basically consists of the conversion of chemical compounds taken up from the extracellular environment into energy (conserved in energy-rich bonds of organic phosphates) and a wide array of organic molecules serving as catalysts (enzymes), information carriers (nucleic acids), and building blocks for cellular structures such as membranes or ribosomes. Metabolic modeling aims at the construction of mathematical representations of the cellular metabolism that can be used to calculate the concentration of cellular molecules and the rates of their mutual chemical interconversion in response to varying external conditions as, for example, hormonal stimuli or supply of essential nutrients. Based on such calculations, it is possible to quantify complex cellular functions as cellular growth, detoxification of drugs and xenobiotic compounds or synthesis of exported molecules. Depending on the specific questions to metabolism addressed, the methodological expertise of the researcher, and available experimental information, different conceptual frameworks have been established, allowing the usage of computational methods to condense experimental information from various layers of organization into (self-) consistent models. Here, we briefly outline the main conceptual frameworks that are currently exploited in metabolism research.

Towards the prediction of essential genes by integration of network topology, cellular localization and biological process information

PubMed Central

2009-01-01

Background The identification of essential genes is important for the understanding of the minimal requirements for cellular life and for practical purposes, such as drug design. However, the experimental techniques for essential genes discovery are labor-intensive and time-consuming. Considering these experimental constraints, a computational approach capable of accurately predicting essential genes would be of great value. We therefore present here a machine learning-based computational approach relying on network topological features, cellular localization and biological process information for prediction of essential genes. Results We constructed a decision tree-based meta-classifier and trained it on datasets with individual and grouped attributes-network topological features, cellular compartments and biological processes-to generate various predictors of essential genes. We showed that the predictors with better performances are those generated by datasets with integrated attributes. Using the predictor with all attributes, i.e., network topological features, cellular compartments and biological processes, we obtained the best predictor of essential genes that was then used to classify yeast genes with unknown essentiality status. Finally, we generated decision trees by training the J48 algorithm on datasets with all network topological features, cellular localization and biological process information to discover cellular rules for essentiality. We found that the number of protein physical interactions, the nuclear localization of proteins and the number of regulating transcription factors are the most important factors determining gene essentiality. Conclusion We were able to demonstrate that network topological features, cellular localization and biological process information are reliable predictors of essential genes. Moreover, by constructing decision trees based on these data, we could discover cellular rules governing essentiality. PMID:19758426

Cellular stress induces a protective sleep-like state in C. elegans.

PubMed

Hill, Andrew J; Mansfield, Richard; Lopez, Jessie M N G; Raizen, David M; Van Buskirk, Cheryl

2014-10-20

Sleep is recognized to be ancient in origin, with vertebrates and invertebrates experiencing behaviorally quiescent states that are regulated by conserved genetic mechanisms. Despite its conservation throughout phylogeny, the function of sleep remains debated. Hypotheses for the purpose of sleep include nervous-system-specific functions such as modulation of synaptic strength and clearance of metabolites from the brain, as well as more generalized cellular functions such as energy conservation and macromolecule biosynthesis. These models are supported by the identification of synaptic and metabolic processes that are perturbed during prolonged wakefulness. It remains to be seen whether perturbations of cellular homeostasis in turn drive sleep. Here we show that under conditions of cellular stress, including noxious heat, cold, hypertonicity, and tissue damage, the nematode Caenorhabditis elegans engages a behavioral quiescence program. The stress-induced quiescent state displays properties of sleep and is dependent on the ALA neuron, which mediates the conserved soporific effect of epidermal growth factor (EGF) ligand overexpression. We characterize heat-induced quiescence in detail and show that it is indeed dependent on components of EGF signaling, providing physiological relevance to the behavioral effects of EGF family ligands. We find that after noxious heat exposure, quiescence-defective animals show elevated expression of cellular stress reporter genes and are impaired for survival, demonstrating the benefit of stress-induced behavioral quiescence. These data provide evidence that cellular stress can induce a protective sleep-like state in C. elegans and suggest that a deeply conserved function of sleep is to mitigate disruptions of cellular homeostasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Signals for the lysosome: a control center for cellular clearance and energy metabolism

PubMed Central

Settembre, Carmine; Fraldi, Alessandro; Medina, Diego L.

2015-01-01

Preface For a long time lysosomes were considered merely to be cellular “incinerators” involved in the degradation and recycling of cellular waste. However, there is now compelling evidence indicating that lysosomes have a much broader function and that they are involved in fundamental processes such as secretion, plasma membrane repair, signaling and energy metabolism. Furthermore, the essential role of lysosomes in the autophagic pathway puts these organelles at the crossroads of several cellular processes, with significant implications for health and disease. The identification of a master gene, transcription factor EB (TFEB), that regulates lysosomal biogenesis and autophagy, has revealed how the lysosome adapts to environmental cues, such as starvation, and suggests novel therapeutic strategies for modulating lysosomal function in human disease. PMID:23609508

Cellular Signaling by Fibroblast Growth Factors (FGFs) and Their Receptors (FGFRs) in Male Reproduction

PubMed Central

Cotton, Leanne M.; O’Bryan, Moira K.; Hinton, Barry T.

2008-01-01

The major function of the reproductive system is to ensure the survival of the species by passing on hereditary traits from one generation to the next. This is accomplished through the production of gametes and the generation of hormones that function in the maturation and regulation of the reproductive system. It is well established that normal development and function of the male reproductive system is mediated by endocrine and paracrine signaling pathways. Fibroblast growth factors (FGFs), their receptors (FGFRs), and signaling cascades have been implicated in a diverse range of cellular processes including: proliferation, apoptosis, cell survival, chemotaxis, cell adhesion, motility, and differentiation. The maintenance and regulation of correct FGF signaling is evident from human and mouse genetic studies which demonstrate that mutations leading to disruption of FGF signaling cause a variety of developmental disorders including dominant skeletal diseases, infertility, and cancer. Over the course of this review, we will provide evidence for differential expression of FGFs/FGFRs in the testis, male germ cells, the epididymis, the seminal vesicle, and the prostate. We will show that this signaling cascade has an important role in sperm development and maturation. Furthermore, we will demonstrate that FGF/FGFR signaling is essential for normal epididymal function and prostate development. To this end, we will provide evidence for the involvement of the FGF signaling system in the regulation and maintenance of the male reproductive system. PMID:18216218

Involvement of Cellular Prion Protein in α-Synuclein Transport in Neurons.

PubMed

Urrea, Laura; Segura-Feliu, Miriam; Masuda-Suzukake, Masami; Hervera, Arnau; Pedraz, Lucas; García Aznar, José Manuel; Vila, Miquel; Samitier, Josep; Torrents, Eduard; Ferrer, Isidro; Gavín, Rosalina; Hagesawa, Masato; Del Río, José Antonio

2018-03-01

The cellular prion protein, encoded by the gene Prnp, has been reported to be a receptor of β-amyloid. Their interaction is mandatory for neurotoxic effects of β-amyloid oligomers. In this study, we aimed to explore whether the cellular prion protein participates in the spreading of α-synuclein. Results demonstrate that Prnp expression is not mandatory for α-synuclein spreading. However, although the pathological spreading of α-synuclein can take place in the absence of Prnp, α-synuclein expanded faster in PrP C -overexpressing mice. In addition, α-synuclein binds strongly on PrP C -expressing cells, suggesting a role in modulating the effect of α-synuclein fibrils.

Total cellular glycomics allows characterizing cells and streamlining the discovery process for cellular biomarkers.

PubMed

Fujitani, Naoki; Furukawa, Jun-ichi; Araki, Kayo; Fujioka, Tsuyoshi; Takegawa, Yasuhiro; Piao, Jinhua; Nishioka, Taiki; Tamura, Tomohiro; Nikaido, Toshio; Ito, Makoto; Nakamura, Yukio; Shinohara, Yasuro

2013-02-05

Although many of the frequently used pluripotency biomarkers are glycoconjugates, a glycoconjugate-based exploration of novel cellular biomarkers has proven difficult due to technical difficulties. This study reports a unique approach for the systematic overview of all major classes of oligosaccharides in the cellular glycome. The proposed method enabled mass spectrometry-based structurally intensive analyses, both qualitatively and quantitatively, of cellular N- and O-linked glycans derived from glycoproteins, glycosaminoglycans, and glycosphingolipids, as well as free oligosaccharides of human embryonic stem cells (hESCs), induced pluripotent stem cells (hiPSCs), and various human cells derived from normal and carcinoma cells. Cellular total glycomes were found to be highly cell specific, demonstrating their utility as unique cellular descriptors. Structures of glycans of all classes specifically observed in hESCs and hiPSCs tended to be immature in general, suggesting the presence of stem cell-specific glycosylation spectra. The current analysis revealed the high similarity of the total cellular glycome between hESCs and hiPSCs, although it was suggested that hESCs are more homogeneous than hiPSCs from a glycomic standpoint. Notably, this study enabled a priori identification of known pluripotency biomarkers such as SSEA-3, -4, and -5 and Tra-1-60/81, as well as a panel of glycans specifically expressed by hESCs and hiPSCs.

Dynamic interactions between 14-3-3 proteins and phosphoproteins regulate diverse cellular processes

PubMed Central

2004-01-01

14-3-3 proteins exert an extraordinarily widespread influence on cellular processes in all eukaryotes. They operate by binding to specific phosphorylated sites on diverse target proteins, thereby forcing conformational changes or influencing interactions between their targets and other molecules. In these ways, 14-3-3s ‘finish the job’ when phosphorylation alone lacks the power to drive changes in the activities of intracellular proteins. By interacting dynamically with phosphorylated proteins, 14-3-3s often trigger events that promote cell survival – in situations from preventing metabolic imbalances caused by sudden darkness in leaves to mammalian cell-survival responses to growth factors. Recent work linking specific 14-3-3 isoforms to genetic disorders and cancers, and the cellular effects of 14-3-3 agonists and antagonists, indicate that the cellular complement of 14-3-3 proteins may integrate the specificity and strength of signalling through to different cellular responses. PMID:15167810

Long-distance communication by specialized cellular projections during pigment pattern development and evolution

PubMed Central

Eom, Dae Seok; Bain, Emily J; Patterson, Larissa B; Grout, Megan E; Parichy, David M

2015-01-01

Changes in gene activity are essential for evolutionary diversification. Yet, elucidating the cellular behaviors that underlie modifications to adult form remains a profound challenge. We use neural crest-derived adult pigmentation of zebrafish and pearl danio to uncover cellular bases for alternative pattern states. We show that stripes in zebrafish require a novel class of thin, fast cellular projection to promote Delta-Notch signaling over long distances from cells of the xanthophore lineage to melanophores. Projections depended on microfilaments and microtubules, exhibited meandering trajectories, and stabilized on target cells to which they delivered membraneous vesicles. By contrast, the uniformly patterned pearl danio lacked such projections, concomitant with Colony stimulating factor 1-dependent changes in xanthophore differentiation that likely curtail signaling available to melanophores. Our study reveals a novel mechanism of cellular communication, roles for differentiation state heterogeneity in pigment cell interactions, and an unanticipated morphogenetic behavior contributing to a striking difference in adult form. DOI: http://dx.doi.org/10.7554/eLife.12401.001 PMID:26701906

Single-cell topological RNA-Seq analysis reveals insights into cellular differentiation and development

PubMed Central

Rizvi, Abbas H.; Camara, Pablo G.; Kandror, Elena K.; Roberts, Thomas J.; Schieren, Ira; Maniatis, Tom; Rabadan, Raul

2017-01-01

Transcriptional programs control cellular lineage commitment and differentiation during development. Understanding cell fate has been advanced by studying single-cell RNA-seq, but is limited by the assumptions of current analytic methods regarding the structure of data. We present single-cell topological data analysis (scTDA), an algorithm for topology-based computational analyses to study temporal, unbiased transcriptional regulation. Compared to other methods, scTDA is a non-linear, model-independent, unsupervised statistical framework that can characterize transient cellular states. We applied scTDA to the analysis of murine embryonic stem cell (mESC) differentiation in vitro in response to inducers of motor neuron differentiation. scTDA resolved asynchrony and continuity in cellular identity over time, and identified four transient states (pluripotent, precursor, progenitor, and fully differentiated cells) based on changes in stage-dependent combinations of transcription factors, RNA-binding proteins and long non-coding RNAs. scTDA can be applied to study asynchronous cellular responses to either developmental cues or environmental perturbations. PMID:28459448

Risk perception and public concerns of electromagnetic waves from cellular phones in Korea.

PubMed

Kim, Kyunghee; Kim, Hae-Joon; Song, Dae Jong; Cho, Yong Min; Choi, Jae Wook

2014-05-01

In this study, the difference between the risk perception of electromagnetic waves from cellular phones and the risk perception of other factors such as environment and food was analyzed. The cause of the difference in the psychological and social factors that affect the group with high risk perception of electromagnetic waves was also analyzed. A questionnaire survey on the risk perception of electromagnetic waves from cellular phones was carried out on 1001 subjects (men and women) over the age of 20. In the group with high risk perception of electromagnetic waves from cellular phones, women had higher risk perception than men. Logistic regression analysis, where the group with high risk perception of electromagnetic waves and the group with low risk perception were used as dependent variables, indicated that the risk perception of electromagnetic waves in women was 1.815 times statistically significantly higher than the risk perception of men (95% CI: 1.340-2.457). Also, high risk perception of electromagnetic waves from cellular phones was observed when the subjects considered that they had more personal knowledge (OR: 1.416, 95% CI: 1.216-1.648), that the seriousness of the risk to future generations was high (OR: 1.410, 95% CI: 1.234-1.611), and their outrage for the occurrence of accidents related to electromagnetic waves was high (OR: 1.460, 95% CI: 1.264-1.686). The results of this study need to be sufficiently considered and reflected in designing the risk communication strategies and communication methods for the preventive measures and advice on electromagnetic waves from cellular phones. © 2014 Wiley Periodicals, Inc.

The similia principle: results obtained in a cellular model system.

PubMed

Wiegant, Fred; Van Wijk, Roeland

2010-01-01

This paper describes the results of a research program focused on the beneficial effect of low dose stress conditions that were applied according to the similia principle to cells previously disturbed by more severe stress conditions. In first instance, we discuss criteria for research on the similia principle at the cellular level. Then, the homologous ('isopathic') approach is reviewed, in which the initial (high dose) stress used to disturb cellular physiology and the subsequent (low dose) stress are identical. Beneficial effects of low dose stress are described in terms of increased cellular survival capacity and at the molecular level as an increase in the synthesis of heat shock proteins (hsps). Both phenomena reflect a stimulation of the endogenous cellular self-recovery capacity. Low dose stress conditions applied in a homologous approach stimulate the synthesis of hsps and enhance survival in comparison with stressed cells that were incubated in the absence of low dose stress conditions. Thirdly, the specificity of the low dose stress condition is described where the initial (high dose) stress is different in nature from the subsequently applied (low dose) stress; the heterologous or 'heteropathic' approach. The results support the similia principle at the cellular level and add to understanding of how low dose stress conditions influence the regulatory processes underlying self-recovery. In addition, the phenomenon of 'symptom aggravation' which is also observed at the cellular level, is discussed in the context of self-recovery. Finally, the difference in efficiency between the homologous and the heterologous approach is discussed; a perspective is indicated for further research; and the relationship between studies on the similia principle and the recently introduced concept of 'postconditioning hormesis' is emphasized. Copyright 2009 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Are cellular phone blocking applications effective for novice teen drivers?

PubMed

Creaser, Janet I; Edwards, Christopher J; Morris, Nichole L; Donath, Max

2015-09-01

Distracted driving is a significant concern for novice teen drivers. Although cellular phone bans are applied in many jurisdictions to restrict cellular phone use, teen drivers often report making calls and texts while driving. The Minnesota Teen Driver Study incorporated cellular phone blocking functions via a software application for 182 novice teen drivers in two treatment conditions. The first condition included 92 teens who ran a driver support application on a smartphone that also blocked phone usage. The second condition included 90 teens who ran the same application with phone blocking but which also reported back to parents about monitored risky behaviors (e.g., speeding). A third control group consisting of 92 novice teen drivers had the application and phone-based software installed on the phones to record cellular phone (but not block it) use while driving. The two treatment groups made significantly fewer calls and texts per mile driven compared to the control group. The control group data also demonstrated a higher propensity to text while driving rather than making calls. Software that blocks cellular phone use (except 911) while driving can be effective at mitigating calling and texting for novice teen drivers. However, subjective data indicates that some teens were motivated to find ways around the software, as well as to use another teen's phone while driving when they were unable to use theirs. Cellular phone bans for calling and texting are the first step to changing behaviors associated with texting and driving, particularly among novice teen drivers. Blocking software has the additional potential to reduce impulsive calling and texting while driving among novice teen drivers who might logically know the risks, but for whom it is difficult to ignore calling or texting while driving. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

Domain 4 (D4) of Perfringolysin O to Visualize Cholesterol in Cellular Membranes-The Update.

PubMed

Maekawa, Masashi

2017-03-03

The cellular membrane of eukaryotes consists of phospholipids, sphingolipids, cholesterol and membrane proteins. Among them, cholesterol is crucial for various cellular events (e.g., signaling, viral/bacterial infection, and membrane trafficking) in addition to its essential role as an ingredient of steroid hormones, vitamin D, and bile acids. From a micro-perspective, at the plasma membrane, recent emerging evidence strongly suggests the existence of lipid nanodomains formed with cholesterol and phospholipids (e.g., sphingomyelin, phosphatidylserine). Thus, it is important to elucidate how cholesterol behaves in membranes and how the behavior of cholesterol is regulated at the molecular level. To elucidate the complexed characteristics of cholesterol in cellular membranes, a couple of useful biosensors that enable us to visualize cholesterol in cellular membranes have been recently developed by utilizing domain 4 (D4) of Perfringolysin O (PFO, theta toxin), a cholesterol-binding toxin. This review highlights the current progress on development of novel cholesterol biosensors that uncover new insights of cholesterol in cellular membranes.

Preparation of BFV Gag antiserum and preliminary study on cellular distribution of BFV.

PubMed

Wang, Jian; Guo, Hong-yan; Jia, Rui; Xu, Xuan; Tan, Juan; Geng, Yun-qi; Qiao, Wen-tao

2010-04-01

Viruses (e.g. Human immunodeficiency virus, Human simplex virus and Prototype foamy virus) are obligate intracellular parasites and therefore depend on the cellular machinery for cellular trafficking. Bovine foamy virus (BFV) is a member of the Spumaretrovirinae subfamily of Retroviruses, however, details of its cellular trafficking remain unknown. In this study, we cloned the BFV gag gene into prokaryotic expression vector pET28a and purified the denaturalized Gag protein. The protein was used to immunize BALB/c mouse to produce antiserum, which could specifically recognize the BFV Gag protein in BFV-infected cells through western blot assay. Additionally, these results demonstrated that both the optimal and suboptimal cleavage of Gag protein occur in BFV-infected cells. Subsequently, the Gag antiserum was used to investigate subcellular localization of BFV. In immunofluorescence microscopy assays, colocalization microtubules (MTs) and assembling viral particles were clearly observed, which implied that BFV may transport along cellular MTs in host cells. Furthermore, MTs-depolymerizing assay indicated MTs were required for the efficient replication of BFV. In conclusion, our study suggests that BFV has evolved the mechanism to hijack the cellular cytoskeleton for its replication.

Cellular Angiofibroma of the Nasopharynx.

PubMed

Erdur, Zülküf Burak; Yener, Haydar Murat; Yilmaz, Mehmet; Karaaltin, Ayşegül Batioğlu; Inan, Hakki Caner; Alaskarov, Elvin; Gozen, Emine Deniz

2017-11-01

Angiofibroma is a common tumor of the nasopharynx region but cellular type is extremely rare in head and neck. A 13-year-old boy presented with frequent epistaxis and nasal obstruction persisting for 6 months. According to the clinical symptoms and imaging studies juvenile angiofibroma was suspected. Following angiographic embolization total excision of the lesion by midfacial degloving approach was performed. Histological examination revealed that the tumor consisted of staghorn blood vessels and irregular fibrous stroma. Stellate fibroblasts with small pyknotic to large vesicular nuclei were seen in a highly cellular stroma. These findings identified cellular angiofibroma mimicking juvenile angiofibroma. This article is about a very rare patient of cellular angiofibroma of nasopharynx.

Sub-cellular force microscopy in single normal and cancer cells

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

Babahosseini, H.; Carmichael, B.; Strobl, J.S.

2015-08-07

This work investigates the biomechanical properties of sub-cellular structures of breast cells using atomic force microscopy (AFM). The cells are modeled as a triple-layered structure where the Generalized Maxwell model is applied to experimental data from AFM stress-relaxation tests to extract the elastic modulus, the apparent viscosity, and the relaxation time of sub-cellular structures. The triple-layered modeling results allow for determination and comparison of the biomechanical properties of the three major sub-cellular structures between normal and cancerous cells: the up plasma membrane/actin cortex, the mid cytoplasm/nucleus, and the low nuclear/integrin sub-domains. The results reveal that the sub-domains become stiffer andmore » significantly more viscous with depth, regardless of cell type. In addition, there is a decreasing trend in the average elastic modulus and apparent viscosity of the all corresponding sub-cellular structures from normal to cancerous cells, which becomes most remarkable in the deeper sub-domain. The presented modeling in this work constitutes a unique AFM-based experimental framework to study the biomechanics of sub-cellular structures. - Highlights: • The cells are modeled as a triple-layered structure using Generalized Maxwell model. • The sub-domains include membrane/cortex, cytoplasm/nucleus, and nuclear/integrin. • Biomechanics of corresponding sub-domains are compared among normal and cancer cells. • Viscoelasticity of sub-domains show a decreasing trend from normal to cancer cells. • The decreasing trend becomes most significant in the deeper sub-domain.« less

Transient inter-cellular polymeric linker.

PubMed

Ong, Siew-Min; He, Lijuan; Thuy Linh, Nguyen Thi; Tee, Yee-Han; Arooz, Talha; Tang, Guping; Tan, Choon-Hong; Yu, Hanry

2007-09-01

Three-dimensional (3D) tissue-engineered constructs with bio-mimicry cell-cell and cell-matrix interactions are useful in regenerative medicine. In cell-dense and matrix-poor tissues of the internal organs, cells support one another via cell-cell interactions, supplemented by small amount of the extra-cellular matrices (ECM) secreted by the cells. Here we connect HepG2 cells directly but transiently with inter-cellular polymeric linker to facilitate cell-cell interaction and aggregation. The linker consists of a non-toxic low molecular-weight polyethyleneimine (PEI) backbone conjugated with multiple hydrazide groups that can aggregate cells within 30 min by reacting with the aldehyde handles on the chemically modified cell-surface glycoproteins. The cells in the cellular aggregates proliferated; and maintained the cortical actin distribution of the 3D cell morphology while non-aggregated cells died over 7 days of suspension culture. The aggregates lost distinguishable cell-cell boundaries within 3 days; and the ECM fibers became visible around cells from day 3 onwards while the inter-cellular polymeric linker disappeared from the cell surfaces over time. The transient inter-cellular polymeric linker can be useful for forming 3D cellular and tissue constructs without bulk biomaterials or extensive network of engineered ECM for various applications.

Literature Review on Dynamic Cellular Manufacturing System

NASA Astrophysics Data System (ADS)

Nouri Houshyar, A.; Leman, Z.; Pakzad Moghadam, H.; Ariffin, M. K. A. M.; Ismail, N.; Iranmanesh, H.

2014-06-01

In previous decades, manufacturers faced a lot of challenges because of globalization and high competition in markets. These problems arise from shortening product life cycle, rapid variation in demand of products, and also rapid changes in manufcaturing technologies. Nowadays most manufacturing companies expend considerable attention for improving flexibility and responsiveness in order to overcome these kinds of problems and also meet customer's needs. By considering the trend toward the shorter product life cycle, the manufacturing environment is towards manufacturing a wide variety of parts in small batches [1]. One of the major techniques which are applied for improving manufacturing competitiveness is Cellular Manufacturing System (CMS). CMS is type of manufacturing system which tries to combine flexibility of job shop and also productivity of flow shop. In addition, Dynamic cellular manufacturing system which considers different time periods for the manufacturing system becomes an important topic and attracts a lot of attention to itself. Therefore, this paper made attempt to have a brief review on this issue and focused on all published paper on this subject. Although, this topic gains a lot of attention to itself during these years, none of previous researchers focused on reviewing the literature of that which can be helpful and useful for other researchers who intend to do the research on this topic. Therefore, this paper is the first study which has focused and reviewed the literature of dynamic cellular manufacturing system.

Genetic podocyte lineage reveals progressive podocytopenia with parietal cell hyperplasia in a murine model of cellular/collapsing focal segmental glomerulosclerosis.

PubMed

Suzuki, Taisei; Matsusaka, Taiji; Nakayama, Makiko; Asano, Takako; Watanabe, Teruo; Ichikawa, Iekuni; Nagata, Michio

2009-05-01

Focal segmental glomerulosclerosis (FSGS) is a progressive renal disease, and the glomerular visceral cell hyperplasia typically observed in cellular/collapsing FSGS is an important pathological factor in disease progression. However, the cellular features that promote FSGS currently remain obscure. To determine both the origin and phenotypic alterations in hyperplastic cells in cellular/collapsing FSGS, the present study used a previously described FSGS model in p21-deficient mice with visceral cell hyperplasia and identified the podocyte lineage by genetic tagging. The p21-deficient mice with nephropathy showed significantly higher urinary protein levels, extracapillary hyperplastic indices on day 5, and glomerular sclerosis indices on day 14 than wild-type controls. X-gal staining and immunohistochemistry for podocyte and parietal epithelial cell (PEC) markers revealed progressive podocytopenia with capillary collapse accompanied by PEC hyperplasia leading to FSGS. In our investigation, non-tagged cells expressed neither WT1 nor nestin. Ki-67, a proliferation marker, was rarely associated with podocytes but was expressed at high levels in PECs. Both terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and electron microscopy failed to show evidence of significant podocyte apoptosis on days 5 and 14. These findings suggest that extensive podocyte loss and simultaneous PEC hyperplasia is an actual pathology that may contribute to the progression of cellular/collapsing FSGS in this mouse model. Additionally, this is the first study to demonstrate the regulatory role of p21 in the PEC cell cycle.

Cellular Basis for Learning Impairment in Fragile X Syndrome

DTIC Science & Technology

2014-08-01

oxygen is restored. Induction of the heat shock proteins (HSPs) is one of the first lines of defense against physiological stress , shifting cellular...Haddad, 2001), and aid resistance to glutamate and hypoxic stress in mammals (Zhang et al., 2000). AMPA receptor currents, meanwhile, are also...level in anoxic turtle brain. These include increases in heat shock proteins, anti-apoptotic factors, the MAP kinases, antioxidants and modulation of

34 CFR 658.34 - What additional factors does the Secretary consider in selecting grant recipients?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false What additional factors does the Secretary consider in selecting grant recipients? 658.34 Section 658.34 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION UNDERGRADUATE INTERNATIONAL...

Oscillatory cellular patterns in three-dimensional directional solidification

NASA Astrophysics Data System (ADS)

Tourret, D.; Debierre, J.-M.; Song, Y.; Mota, F. L.; Bergeon, N.; Guérin, R.; Trivedi, R.; Billia, B.; Karma, A.

2015-10-01

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in microgravity. Directional solidification experiments conducted onboard the International Space Station have allowed us to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 min. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelated at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (i.e., low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exists, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is observed in both

IGF-I enhances cellular senescence via the reactive oxygen species-p53 pathway

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

Handayaningsih, Anastasia-Evi; Takahashi, Michiko; Fukuoka, Hidenori

2012-08-24

Highlights: Black-Right-Pointing-Pointer Cellular senescence plays an important role in tumorigenesis and aging process. Black-Right-Pointing-Pointer We demonstrated IGF-I enhanced cellular senescence in primary confluent cells. Black-Right-Pointing-Pointer IGF-I enhanced cellular senescence in the ROS and p53-dependent manner. Black-Right-Pointing-Pointer These results may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging. -- Abstract: Cellular senescence is characterized by growth arrest, enlarged and flattened cell morphology, the expression of senescence-associated {beta}-galactosidase (SA-{beta}-gal), and by activation of tumor suppressor networks. Insulin-like growth factor-I (IGF-I) plays a critical role in cellular growth, proliferation, tumorigenesis, and regulation of aging. In the presentmore » study, we show that IGF-I enhances cellular senescence in mouse, rat, and human primary cells in the confluent state. IGF-I induced expression of a DNA damage marker, {gamma}H2AX, the increased levels of p53 and p21 proteins, and activated SA-{beta}-gal. In the confluent state, an altered downstream signaling of IGF-I receptor was observed. Treatment with a reactive oxygen species (ROS) scavenger, N-acetylcystein (NAC) significantly suppressed induction of these markers, indicating that ROS are involved in the induction of cellular senescence by IGF-I. In p53-null mouse embryonic fibroblasts, the IGF-I-induced augmentation of SA-{beta}-gal and p21 was inhibited, demonstrating that p53 is required for cellular senescence induced by IGF-I. Thus, these data reveal a novel pathway whereby IGF-I enhances cellular senescence in the ROS and p53-dependent manner and may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging.« less

Distinguishing between biochemical and cellular function: Are there peptide signatures for cellular function of proteins?

PubMed

Jain, Shruti; Bhattacharyya, Kausik; Bakshi, Rachit; Narang, Ankita; Brahmachari, Vani

2017-04-01

The genome annotation and identification of gene function depends on conserved biochemical activity. However, in the cell, proteins with the same biochemical function can participate in different cellular pathways and cannot complement one another. Similarly, two proteins of very different biochemical functions are put in the same class of cellular function; for example, the classification of a gene as an oncogene or a tumour suppressor gene is not related to its biochemical function, but is related to its cellular function. We have taken an approach to identify peptide signatures for cellular function in proteins with known biochemical function. ATPases as a test case, we classified ATPases (2360 proteins) and kinases (517 proteins) from the human genome into different cellular function categories such as transcriptional, replicative, and chromatin remodelling proteins. Using publicly available tool, MEME, we identify peptide signatures shared among the members of a given category but not between cellular functional categories; for example, no motif sharing is seen between chromatin remodelling and transporter ATPases, similarly between receptor Serine/Threonine Kinase and Receptor Tyrosine Kinase. There are motifs shared within each category with significant E value and high occurrence. This concept of signature for cellular function was applied to developmental regulators, the polycomb and trithorax proteins which led to the prediction of the role of INO80, a chromatin remodelling protein, in development. This has been experimentally validated earlier for its role in homeotic gene regulation and its interaction with regulatory complexes like the Polycomb and Trithorax complex. Proteins 2017; 85:682-693. © 2016 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Binding affinity of amyloid oligomers to cellular membranes is a generic indicator of cellular dysfunction in protein misfolding diseases

PubMed Central

Evangelisti, Elisa; Cascella, Roberta; Becatti, Matteo; Marrazza, Giovanna; Dobson, Christopher M.; Chiti, Fabrizio; Stefani, Massimo; Cecchi, Cristina

2016-01-01

The conversion of peptides or proteins from their soluble native states into intractable amyloid deposits is associated with a wide range of human disorders. Misfolded protein oligomers formed during the process of aggregation have been identified as the primary pathogenic agents in many such conditions. Here, we show the existence of a quantitative relationship between the degree of binding to neuronal cells of different types of oligomers formed from a model protein, HypF-N, and the GM1 content of the plasma membranes. In addition, remarkably similar behavior is observed for oligomers of the Aβ42 peptide associated with Alzheimer’s disease. Further analysis has revealed the existence of a linear correlation between the level of the influx of Ca2+ across neuronal membranes that triggers cellular damage, and the fraction of oligomeric species bound to the membrane. Our findings indicate that the susceptibility of neuronal cells to different types of misfolded oligomeric assemblies is directly related to the extent of binding of such oligomers to the cellular membrane. PMID:27619987

47 CFR 90.672 - Unacceptable interference to non-cellular 800 MHz licensees from 800 MHz cellular systems or part...

Code of Federal Regulations, 2011 CFR

2011-10-01

... MHz licensees from 800 MHz cellular systems or part 22 Cellular Radiotelephone systems, and within the... COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES... licensees from 800 MHz cellular systems or part 22 Cellular Radiotelephone systems, and within the 900 MHz...

Cellular reflectarray antenna and method of making same

NASA Technical Reports Server (NTRS)

Romanofsky, Robert R (Inventor)

2011-01-01

A method of manufacturing a cellular reflectarray antenna arranged in an m by n matrix of radiating elements for communication with a satellite includes steps of determining a delay .phi.m,n for each of said m by n matrix of elements of said cellular reflectarray antenna using sub-steps of: determining the longitude and latitude of operation, determining elevation and azimuth angles of the reflectarray with respect to the satellite and converting theta.sub.0 (.theta..sub.0) and phi.sub.0 (.phi..sub.0), determining .DELTA..beta..sub.m,n, the pointing vector correction, for a given inter-element spacing and wavelength, determining .DELTA..phi..sub.m,n, the spherical wave front correction factor, for a given radius from the central element and/or from measured data from the feed horn; and, determining a delay .phi.m,n for each of said m by n matrix of elements as a function of .DELTA..beta..sub.m,n and .DELTA..phi..sub.m,n.

Cellular reflectarray antenna and method of making same

NASA Technical Reports Server (NTRS)

Romanofsky, Robert R (Inventor)

2010-01-01

A method of manufacturing a cellular reflectarray antenna arranged in an m by n matrix of radiating elements for communication with a satellite includes steps of determining a delay .phi.m,n for each of said m by n matrix of elements of said cellular reflectarray antenna using sub-steps of: determining the longitude and latitude of operation, determining elevation and azimuth angles of the reflectarray with respect to the satellite and converting theta.sub.0 (.theta..sub.0) and phi.sub.0 (.phi..sub.0), determining .DELTA..beta..sub.m,n, the pointing vector correction, for a given inter-element spacing and wavelength, determining .DELTA..phi..sub.m,n, the spherical wave front correction factor, for a given radius from the central element and/or from measured data from the feed horn; and, determining a delay .phi.m,n for each of said m by n matrix of elements as a function of .DELTA..beta..sub.m,n and .DELTA..phi..sub.m,n..

Cellular and molecular mechanisms of tooth root development

PubMed Central

Li, Jingyuan; Parada, Carolina

2017-01-01

ABSTRACT The tooth root is an integral, functionally important part of our dentition. The formation of a functional root depends on epithelial-mesenchymal interactions and integration of the root with the jaw bone, blood supply and nerve innervations. The root development process therefore offers an attractive model for investigating organogenesis. Understanding how roots develop and how they can be bioengineered is also of great interest in the field of regenerative medicine. Here, we discuss recent advances in understanding the cellular and molecular mechanisms underlying tooth root formation. We review the function of cellular structure and components such as Hertwig's epithelial root sheath, cranial neural crest cells and stem cells residing in developing and adult teeth. We also highlight how complex signaling networks together with multiple transcription factors mediate tissue-tissue interactions that guide root development. Finally, we discuss the possible role of stem cells in establishing the crown-to-root transition, and provide an overview of root malformations and diseases in humans. PMID:28143844

Cognitive Cellular Systems: A New Challenge on the RF Analog Frontend

NASA Astrophysics Data System (ADS)

Varga, Gabor; Schrey, Moritz; Subbiah, Iyappan; Ashok, Arun; Heinen, Stefan

2016-07-01

Cognitive Cellular Systems are seen today as one of the most promising ways of moving forward solving or at least easing the still worsening situation of congested spectrum caused by the growing number of users and the expectation of higher data transfer rates. As the intelligence of a Cognitive Radio system is located in the digital domain - the Cognitive Engine and associated layers - extensive research has been ongoing in that domain since Mitola published his idea in 1999. Since, a big progress has been made in the domain of architectures and algorithms making systems more efficient and highly flexible. The pace of this progress, however, is going to be impeded by hard requirements on the received and transmitted signal quality, introducing ultimate challenges on the performance of the RF analog frontend, such as in-band local oscillator harmonics, ultra low sensitivity and ultra high linearity. The RF frontend is thus likely to become the limiting technical factor in the true realization of a Cognitive Cellular System. Based on short recapitulations of the most crucial issues in RF analog design for Cognitive Systems, this article will point out why those mechanisms become responsible for the limitation of the overall performance particularly in a broadband Cognitive Cellular System. Furthermore, as part of a possible solution to ease the situation, system design of a high intermediate frequency (IF) to UHF frequency converter for cognitive radios is discussed and the performance of such a converter analyzed as a proof of concept. In addition to successfully tackling some of the challenges, such a high-IF converter enables white space operation for existing commercial devices by acting as frequency converter. From detailed measurements, the capabilities in both physical layer and application layer performance of a high-IF frontend developed out of off-the-shelf components is explained and is shown to provide negligible degradation to the commercial device

Polymeric biomaterials for nerve regeneration applications: From promoting cellular organization to the delivery of bioactive molecules

NASA Astrophysics Data System (ADS)

Delgado-Rivera, Roberto L.

Thousands of new cases of injury to the central nervous system (CNS) occur each year in the USA and all over the world. However, despite recent advances, at present there is no cure for the resulting paraplegia or quadriplegia. This research is directed towards engineering biomaterial platforms to promote cellular organization at the surface of polymer scaffolds that will be conducive to proper regeneration of injured CNS. In addition, the formulation of a delivery system for neuroactive molecules using polymer-based materials will be evaluated to establish its potential to treat CNS disorders. Initial studies involved the chemical modification of an electrospun nonwoven matrix of nanofibers with fibroblast growth factor 2 (FGF-2). Nanofibers alone up-regulated FGF-2, albeit to a lesser extent than nanofibers covalently modified with FGF-2. These results underscore the importance of both surface topography and growth factor presentation on cellular function. Moreover, that FGF-2 modified nanofibrillar scaffolds may demonstrate utility in tissue engineering applications for replacement and regeneration of damaged tissue following CNS injury or disease. Subsequent research efforts focused on a novel micropatterning technique called microscale plasma-initiated patterning (microPIP). This patterning method uses a polydimethylsiloxane (PDMS) stamp to selectively protect regions of an underlying substrate from oxygen plasma treatment resulting in hydrophobic and hydrophilic regions. FGF-2 and laminin-1 were applied to an electrospun polyamide nanofibrillar matrix following plasma treatment. In this work it, was possible to demonstrate that textured surfaces, such as nanofibrillar scaffolds, can be micropatterned to provide external chemical cues for cellular organization. Finally, a microsphere system capable of encapsulating proteins while minimizing the mechanisms of protein degradation and providing a controlled release was investigated. Microspheres were comprised of

Glutathione transferases, regulators of cellular metabolism and physiology.

PubMed

Board, Philip G; Menon, Deepthi

2013-05-01

The cytosolic glutathione transferases (GSTs) comprise a super family of proteins that can be categorized into multiple classes with a mixture of highly specific and overlapping functions. The review covers the genetics, structure and function of the human cytosolic GSTs with particular attention to their emerging roles in cellular metabolism. All the catalytically active GSTs contribute to the glutathione conjugation or glutathione dependant-biotransformation of xenobiotics and many catalyze glutathione peroxidase or thiol transferase reactions. GSTs also catalyze glutathione dependent isomerization reactions required for the synthesis of several prostaglandins and steroid hormones and the catabolism of tyrosine. An increasing body of work has implicated several GSTs in the regulation of cell signaling pathways mediated by stress-activated kinases like Jun N-terminal kinase. In addition, some members of the cytosolic GST family have been shown to form ion channels in intracellular membranes and to modulate ryanodine receptor Ca(2+) channels in skeletal and cardiac muscle. In addition to their well established roles in the conjugation and biotransformation of xenobiotics, GSTs have emerged as significant regulators of pathways determining cell proliferation and survival and as regulators of ryanodine receptors that are essential for muscle function. This article is part of a Special Issue entitled Cellular functions of glutathione. Copyright © 2012 Elsevier B.V. All rights reserved.

Cementocyte cell death occurs in rat cellular cementum during orthodontic tooth movement.

PubMed

Matsuzawa, Humihiro; Toriya, Naoko; Nakao, Yuya; Konno-Nagasaka, Moe; Arakawa, Toshiya; Okayama, Miki; Mizoguchi, Itaru

2017-05-01

To clarify the mechanism of root resorption during orthodontic treatment, we examined cementocyte cell death and root resorption in the cellular cementum on the pressure side during experimental tooth movement. Using 8-week-old male Wistar rats, the right first molar was pushed mesiobuccally with a force of 40 g by a Ni-Ti alloy wire while the contralateral first molar was used as a control. Localization and number of cleaved caspase-3-positive and single-stranded DNA (ssDNA) - positive cells were evaluated using dual-label immunohistochemistry with anticleaved caspase-3 and anti-ssDNA antibodies. In addition, tartrate-resistant acid phosphatase (TRAP)-positive cells in the cellular cementum were evaluated using TRAP histochemical staining. Caspase-3- and ssDNA-positive cells appeared at 12 hours, but were restricted to the compressed periodontal ligament (PDL) and not the cellular cementum. Cleaved caspase-3-positive cementocytes were observed in the cellular cementum adjacent to the compressed PDL on day 1. From days 2 to 4, the number of caspase-3- and ssDNA-positive cementocytes increased. TRAP-positive cells appeared on the cellular cementum at the periphery of the hyalinized tissue on day 7, and resorption progressed into the broad surface of the cementum by day 14. Cementocytes adjacent to the hyalinized tissue underwent apoptotic cell death during orthodontic tooth movement, which might have been associated with subsequent root resorption.

Combined RAF1 protein expression and p53 mutational status provides a strong predictor of cellular radiosensitivity

PubMed Central

Warenius, H M; Jones, M; Gorman, T; McLeish, R; Seabra, L; Barraclough, R; Rudland, P

2000-01-01

The tumour suppressor gene, p53, and genes coding for positive signal transduction factors can influence transit through cell-cycle checkpoints and modulate radiosensitivity. Here we examine the effects of RAF1 protein on the rate of exit from a G2/M block induced by γ-irradiation in relation to intrinsic cellular radiosensitivity in human cell lines expressing wild-type p53 (wtp53) protein as compared to mutant p53 (mutp53) protein. Cell lines which expressed mutp53 protein were all relatively radioresistant and exhibited no relationship between RAF1 protein and cellular radiosensitivity. Cell lines expressing wtp53 protein, however, showed a strong relationship between RAF1 protein levels and the radiosensitivity parameter SF2. In addition, when post-irradiation perturbation of G2/M transit was compared using the parameter T50 (time after the peak of G2/M delay at which 50% of the cells had exited from a block induced by 2 Gy of irradiation), RAF1 was related to T50 in wtp53, but not mutp53, cell lines. Cell lines which expressed wtp53 protein and high levels of RAF1 had shorter T50s and were also more radiosensitive. These results suggest a cooperative role for wtp53 and RAF1 protein in determining cellular radiosensitivity in human cells, which involves control of the G2/M checkpoint. © 2000 Cancer Research Campaign PMID:10993658

Postischemic revascularization: from cellular and molecular mechanisms to clinical applications.

PubMed

Silvestre, Jean-Sébastien; Smadja, David M; Lévy, Bernard I

2013-10-01

After the onset of ischemia, cardiac or skeletal muscle undergoes a continuum of molecular, cellular, and extracellular responses that determine the function and the remodeling of the ischemic tissue. Hypoxia-related pathways, immunoinflammatory balance, circulating or local vascular progenitor cells, as well as changes in hemodynamical forces within vascular wall trigger all the processes regulating vascular homeostasis, including vasculogenesis, angiogenesis, arteriogenesis, and collateral growth, which act in concert to establish a functional vascular network in ischemic zones. In patients with ischemic diseases, most of the cellular (mainly those involving bone marrow-derived cells and local stem/progenitor cells) and molecular mechanisms involved in the activation of vessel growth and vascular remodeling are markedly impaired by the deleterious microenvironment characterized by fibrosis, inflammation, hypoperfusion, and inhibition of endogenous angiogenic and regenerative programs. Furthermore, cardiovascular risk factors, including diabetes, hypercholesterolemia, hypertension, diabetes, and aging, constitute a deleterious macroenvironment that participates to the abrogation of postischemic revascularization and tissue regeneration observed in these patient populations. Thus stimulation of vessel growth and/or remodeling has emerged as a new therapeutic option in patients with ischemic diseases. Many strategies of therapeutic revascularization, based on the administration of growth factors or stem/progenitor cells from diverse sources, have been proposed and are currently tested in patients with peripheral arterial disease or cardiac diseases. This review provides an overview from our current knowledge regarding molecular and cellular mechanisms involved in postischemic revascularization, as well as advances in the clinical application of such strategies of therapeutic revascularization.

Studying Nuclear Receptor Complexes in the Cellular Environment.

PubMed

Schaufele, Fred

2016-01-01

The ligand-regulated structure and biochemistry of nuclear receptor complexes are commonly determined by in vitro studies of isolated receptors, cofactors, and their fragments. However, in the living cell, the complexes that form are governed not just by the relative affinities of isolated cofactors for the receptor but also by the cell-specific sequestration or concentration of subsets of competing or cooperating cofactors, receptors, and other effectors into distinct subcellular domains and/or their temporary diversion into other cellular activities. Most methods developed to understand nuclear receptor function in the cellular environment involve the direct tagging of the nuclear receptor or its cofactors with fluorescent proteins (FPs) and the tracking of those FP-tagged factors by fluorescence microscopy. One of those approaches, Förster resonance energy transfer (FRET) microscopy, quantifies the transfer of energy from a higher energy "donor" FP to a lower energy "acceptor" FP attached to a single protein or to interacting proteins. The amount of FRET is influenced by the ligand-induced changes in the proximities and orientations of the FPs within the tagged nuclear receptor complexes, which is an indicator of the structure of the complexes, and by the kinetics of the interaction between FP-tagged factors. Here, we provide a guide for parsing information about the structure and biochemistry of nuclear receptor complexes from FRET measurements in living cells.

Cellular context-dependent consequences of Apc mutations on gene regulation and cellular behavior.

PubMed

Hashimoto, Kyoichi; Yamada, Yosuke; Semi, Katsunori; Yagi, Masaki; Tanaka, Akito; Itakura, Fumiaki; Aoki, Hitomi; Kunisada, Takahiro; Woltjen, Knut; Haga, Hironori; Sakai, Yoshiharu; Yamamoto, Takuya; Yamada, Yasuhiro

2017-01-24

The spectrum of genetic mutations differs among cancers in different organs, implying a cellular context-dependent effect for genetic aberrations. However, the extent to which the cellular context affects the consequences of oncogenic mutations remains to be fully elucidated. We reprogrammed colon tumor cells in an Apc Min/+ (adenomatous polyposis coli) mouse model, in which the loss of the Apc gene plays a critical role in tumor development and subsequently, established reprogrammed tumor cells (RTCs) that exhibit pluripotent stem cell (PSC)-like signatures of gene expression. We show that the majority of the genes in RTCs that were affected by Apc mutations did not overlap with the genes affected in the intestine. RTCs lacked pluripotency but exhibited an increased expression of Cdx2 and a differentiation propensity that was biased toward the trophectoderm cell lineage. Genetic rescue of the mutated Apc allele conferred pluripotency on RTCs and enabled their differentiation into various cell types in vivo. The redisruption of Apc in RTC-derived differentiated cells resulted in neoplastic growth that was exclusive to the intestine, but the majority of the intestinal lesions remained as pretumoral microadenomas. These results highlight the significant influence of cellular context on gene regulation, cellular plasticity, and cellular behavior in response to the loss of the Apc function. Our results also imply that the transition from microadenomas to macroscopic tumors is reprogrammable, which underscores the importance of epigenetic regulation on tumor promotion.

Cellular context-dependent consequences of Apc mutations on gene regulation and cellular behavior

PubMed Central

Hashimoto, Kyoichi; Yamada, Yosuke; Semi, Katsunori; Yagi, Masaki; Tanaka, Akito; Itakura, Fumiaki; Aoki, Hitomi; Kunisada, Takahiro; Woltjen, Knut; Haga, Hironori; Sakai, Yoshiharu; Yamamoto, Takuya; Yamada, Yasuhiro

2017-01-01

The spectrum of genetic mutations differs among cancers in different organs, implying a cellular context-dependent effect for genetic aberrations. However, the extent to which the cellular context affects the consequences of oncogenic mutations remains to be fully elucidated. We reprogrammed colon tumor cells in an ApcMin/+ (adenomatous polyposis coli) mouse model, in which the loss of the Apc gene plays a critical role in tumor development and subsequently, established reprogrammed tumor cells (RTCs) that exhibit pluripotent stem cell (PSC)-like signatures of gene expression. We show that the majority of the genes in RTCs that were affected by Apc mutations did not overlap with the genes affected in the intestine. RTCs lacked pluripotency but exhibited an increased expression of Cdx2 and a differentiation propensity that was biased toward the trophectoderm cell lineage. Genetic rescue of the mutated Apc allele conferred pluripotency on RTCs and enabled their differentiation into various cell types in vivo. The redisruption of Apc in RTC-derived differentiated cells resulted in neoplastic growth that was exclusive to the intestine, but the majority of the intestinal lesions remained as pretumoral microadenomas. These results highlight the significant influence of cellular context on gene regulation, cellular plasticity, and cellular behavior in response to the loss of the Apc function. Our results also imply that the transition from microadenomas to macroscopic tumors is reprogrammable, which underscores the importance of epigenetic regulation on tumor promotion. PMID:28057861

Genome-Wide RNAi Screen Identifies Broadly-Acting Host Factors That Inhibit Arbovirus Infection

PubMed Central

Yasunaga, Ari; Hanna, Sheri L.; Li, Jianqing; Cho, Hyelim; Rose, Patrick P.; Spiridigliozzi, Anna; Gold, Beth; Diamond, Michael S.; Cherry, Sara

2014-01-01

Vector-borne viruses are an important class of emerging and re-emerging pathogens; thus, an improved understanding of the cellular factors that modulate infection in their respective vertebrate and insect hosts may aid control efforts. In particular, cell-intrinsic antiviral pathways restrict vector-borne viruses including the type I interferon response in vertebrates and the RNA interference (RNAi) pathway in insects. However, it is likely that additional cell-intrinsic mechanisms exist to limit these viruses. Since insects rely on innate immune mechanisms to inhibit virus infections, we used Drosophila as a model insect to identify cellular factors that restrict West Nile virus (WNV), a flavivirus with a broad and expanding geographical host range. Our genome-wide RNAi screen identified 50 genes that inhibited WNV infection. Further screening revealed that 17 of these genes were antiviral against additional flaviviruses, and seven of these were antiviral against other vector-borne viruses, expanding our knowledge of invertebrate cell-intrinsic immunity. Investigation of two newly identified factors that restrict diverse viruses, dXPO1 and dRUVBL1, in the Tip60 complex, demonstrated they contributed to antiviral defense at the organismal level in adult flies, in mosquito cells, and in mammalian cells. These data suggest the existence of broadly acting and functionally conserved antiviral genes and pathways that restrict virus infections in evolutionarily divergent hosts. PMID:24550726

Cellular and Tumor Radiosensitivity is Correlated to Epidermal Growth Factor Receptor Protein Expression Level in Tumors Without EGFR Amplification;Epidermal growth factor receptor; Radiotherapy; Squamous cell carcinoma; Biomarker; Local tumor control

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

Kasten-Pisula, Ulla; Saker, Jarob; Eicheler, Wolfgang

2011-07-15

Purpose: There is conflicting evidence for whether the expression of epidermal growth factor receptor in human tumors can be used as a marker of radioresponse. Therefore, this association was studied in a systematic manner using squamous cell carcinoma (SCC) cell lines grown as cell cultures and xenografts. Methods and Materials: The study was performed with 24 tumor cell lines of different tumor types, including 10 SCC lines, which were also investigated as xenografts on nude mice. Egfr gene dose and the length of CA-repeats in intron 1 were determined by polymerase chain reaction, protein expression in vitro by Western blotmore » and in vivo by enzyme-linked immunosorbent assay, and radiosensitivity in vitro by colony formation. Data were correlated with previously published tumor control dose 50% data after fractionated irradiation of xenografts of the 10 SCC. Results: EGFR protein expression varies considerably, with most tumor cell lines showing moderate and only few showing pronounced upregulation. EGFR upregulation could only be attributed to massive gene amplification in the latter. In the case of little or no amplification, in vitro EGFR expression correlated with both cellular and tumor radioresponse. In vivo EGFR expression did not show this correlation. Conclusions: Local tumor control after the fractionated irradiation of tumors with little or no gene amplification seems to be dependent on in vitro EGFR via its effect on cellular radiosensitivity.« less

Mesenchymal Stem Cell-Derived Factors Restore Function to Human Frataxin-Deficient Cells.

PubMed

Kemp, Kevin; Dey, Rimi; Cook, Amelia; Scolding, Neil; Wilkins, Alastair

2017-08-01

Friedreich's ataxia is an inherited neurological disorder characterised by mitochondrial dysfunction and increased susceptibility to oxidative stress. At present, no therapy has been shown to reduce disease progression. Strategies being trialled to treat Friedreich's ataxia include drugs that improve mitochondrial function and reduce oxidative injury. In addition, stem cells have been investigated as a potential therapeutic approach. We have used siRNA-induced knockdown of frataxin in SH-SY5Y cells as an in vitro cellular model for Friedreich's ataxia. Knockdown of frataxin protein expression to levels detected in patients with the disorder was achieved, leading to decreased cellular viability, increased susceptibility to hydrogen peroxide-induced oxidative stress, dysregulation of key anti-oxidant molecules and deficiencies in both cell proliferation and differentiation. Bone marrow stem cells are being investigated extensively as potential treatments for a wide range of neurological disorders, including Friedreich's ataxia. The potential neuroprotective effects of bone marrow-derived mesenchymal stem cells were therefore studied using our frataxin-deficient cell model. Soluble factors secreted by mesenchymal stem cells protected against cellular changes induced by frataxin deficiency, leading to restoration in frataxin levels and anti-oxidant defences, improved survival against oxidative stress and stimulated both cell proliferation and differentiation down the Schwann cell lineage. The demonstration that mesenchymal stem cell-derived factors can restore cellular homeostasis and function to frataxin-deficient cells further suggests that they may have potential therapeutic benefits for patients with Friedreich's ataxia.

Effects of sodium fluoride on blood cellular and humoral immunity in mice.

PubMed

Guo, Hongrui; Kuang, Ping; Luo, Qin; Cui, Hengmin; Deng, Huidan; Liu, Huan; Lu, Yujiao; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Li, Yinglun; Wang, Xun; Zhao, Ling

2017-10-17

Exposure to high fluorine can cause toxicity in human and animals. Currently, there are no systematic studies on effects of high fluorine on blood cellular immunity and humoral immunity in mice. We evaluated the alterations of blood cellular immunity and humoral immunity in mice by using flow cytometry and ELISA. In the cellular immunity, we found that sodium fluoride (NaF) in excess of 12 mg/Kg resulted in a significant decrease in the percentages of CD3 + , CD3 + CD4 + , CD3 + CD8 + T lymphocytes in the peripheral blood. Meanwhile, serum T helper type 1 (Th1) cytokines including interleukin (IL)-2, interferon (IFN)-γ, tumor necrosis factor (TNF), and Th2 cytokines including IL-4, IL-6, IL-10, and Th17 cytokine (IL-17A) contents were decreased. In the humoral immunity, NaF reduced the peripheral blood percentages of CD19 + B lymphocytes and serum immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM). The above results show that NaF can reduce blood cellular and humoral immune function in mice, providing an excellent animal model for clinical studies on immunotoxicity-related fluorosis.

The vacuolar-ATPase complex and assembly factors, TMEM199 and CCDC115, control HIF1α prolyl hydroxylation by regulating cellular iron levels.

PubMed

Miles, Anna L; Burr, Stephen P; Grice, Guinevere L; Nathan, James A

2017-03-15

Hypoxia Inducible transcription Factors (HIFs) are principally regulated by the 2-oxoglutarate and Iron(II) prolyl hydroxylase (PHD) enzymes, which hydroxylate the HIFα subunit, facilitating its proteasome-mediated degradation. Observations that HIFα hydroxylation can be impaired even when oxygen is sufficient emphasise the importance of understanding the complex nature of PHD regulation. Here, we use an unbiased genome-wide genetic screen in near-haploid human cells to uncover cellular processes that regulate HIF1α. We identify that genetic disruption of the Vacuolar H+ ATPase (V-ATPase), the key proton pump for endo-lysosomal acidification, and two previously uncharacterised V-ATPase assembly factors, TMEM199 and CCDC115, stabilise HIF1α in aerobic conditions. Rather than preventing the lysosomal degradation of HIF1α, disrupting the V-ATPase results in intracellular iron depletion, thereby impairing PHD activity and leading to HIF activation. Iron supplementation directly restores PHD catalytic activity following V-ATPase inhibition, revealing important links between the V-ATPase, iron metabolism and HIFs.

Aquatide Activation of SIRT1 Reduces Cellular Senescence through a SIRT1-FOXO1-Autophagy Axis.

PubMed

Lim, Chae Jin; Lee, Yong-Moon; Kang, Seung Goo; Lim, Hyung W; Shin, Kyong-Oh; Jeong, Se Kyoo; Huh, Yang Hoon; Choi, Suin; Kor, Myungho; Seo, Ho Seong; Park, Byeong Deog; Park, Keedon; Ahn, Jeong Keun; Uchida, Yoshikazu; Park, Kyungho

2017-09-01

Ultraviolet (UV) irradiation is a relevant environment factor to induce cellular senescence and photoaging. Both autophagy- and silent information regulator T1 (SIRT1)-dependent pathways are critical cellular processes of not only maintaining normal cellular functions, but also protecting cellular senescence in skin exposed to UV irradiation. In the present studies, we investigated whether modulation of autophagy induction using a novel synthetic SIRT1 activator, heptasodium hexacarboxymethyl dipeptide-12 (named as Aquatide), suppresses the UVB irradiation-induced skin aging. Treatment with Aquatide directly activates SIRT1 and stimulates autophagy induction in cultured human dermal fibroblasts. Next, we found that Aquatide-mediated activation of SIRT1 increases autophagy induction via deacetylation of forkhead box class O (FOXO) 1. Finally, UVB irradiation-induced cellular senescence measured by SA-β-gal staining was significantly decreased in cells treated with Aquatide in parallel to occurring SIRT1 activation-dependent autophagy. Together, Aquatide modulates autophagy through SIRT1 activation, contributing to suppression of skin aging caused by UV irradiation.

Cellular reprogramming through mitogen-activated protein kinases.

PubMed

Lee, Justin; Eschen-Lippold, Lennart; Lassowskat, Ines; Böttcher, Christoph; Scheel, Dierk

2015-01-01

Mitogen-activated protein kinase (MAPK) cascades are conserved eukaryote signaling modules where MAPKs, as the final kinases in the cascade, phosphorylate protein substrates to regulate cellular processes. While some progress in the identification of MAPK substrates has been made in plants, the knowledge on the spectrum of substrates and their mechanistic action is still fragmentary. In this focused review, we discuss the biological implications of the data in our original paper (Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana; Frontiers in Plant Science 5: 554) in the context of related research. In our work, we mimicked in vivo activation of two stress-activated MAPKs, MPK3 and MPK6, through transgenic manipulation of Arabidopsis thaliana and used phosphoproteomics analysis to identify potential novel MAPK substrates. Here, we plotted the identified putative MAPK substrates (and downstream phosphoproteins) as a global protein clustering network. Based on a highly stringent selection confidence level, the core networks highlighted a MAPK-induced cellular reprogramming at multiple levels of gene and protein expression-including transcriptional, post-transcriptional, translational, post-translational (such as protein modification, folding, and degradation) steps, and also protein re-compartmentalization. Additionally, the increase in putative substrates/phosphoproteins of energy metabolism and various secondary metabolite biosynthesis pathways coincides with the observed accumulation of defense antimicrobial substances as detected by metabolome analysis. Furthermore, detection of protein networks in phospholipid or redox elements suggests activation of downstream signaling events. Taken in context with other studies, MAPKs are key regulators that reprogram cellular events to orchestrate defense signaling in eukaryotes.

Consolidation & Factors Influencing Sintering Process in Polymer Powder Based Additive Manufacturing

NASA Astrophysics Data System (ADS)

Sagar, M. B.; Elangovan, K.

2017-08-01

Additive Manufacturing (AM) is two decade old technology; where parts are build layer manufacturing method directly from a CAD template. Over the years, AM techniques changes the future way of part fabrication with enhanced intricacy and custom-made features are aimed. Commercially polymers, metals, ceramic and metal-polymer composites are in practice where polymers enhanced the expectations in AM and are considered as a kind of next industrial revolution. Growing trend in polymer application motivated to study their feasibility and properties. Laser sintering, Heat sintering and Inhibition sintering are the most successful AM techniques for polymers but having least application. The presentation gives up selective sintering of powder polymers and listed commercially available polymer materials. Important significant factors for effective processing and analytical approaches to access them are discussed.

Cellular mechanisms of estradiol-mediated sexual differentiation of the brain.

PubMed

Wright, Christopher L; Schwarz, Jaclyn S; Dean, Shannon L; McCarthy, Margaret M

2010-09-01

Gonadal steroids organize the developing brain during a perinatal sensitive period and have enduring consequences for adult behavior. In male rodents testicular androgens are aromatized in neurons to estrogens and initiate multiple distinct cellular processes that ultimately determine the masculine phenotype. Within specific brain regions, overall cell number and dendritic morphology are the principal targets for hormonal organization. Recent advances have been made in elucidating the cellular mechanisms by which the neurological underpinnings of sexually dimorphic physiology and behavior are determined. These include estradiol-mediated prostaglandin synthesis, presynaptic release of glutamate, postsynaptic changes in glutamate receptors and changes in cell adhesion molecules. Sex differences in cell death are mediated by hormonal modulation of survival and death factors such as TNFalpha and Bcl-2/BAX. Copyright 2010 Elsevier Ltd. All rights reserved.

Protein accounting in the cellular economy.

PubMed

Vázquez-Laslop, Nora; Mankin, Alexander S

2014-04-24

Knowing the copy number of cellular proteins is critical for understanding cell physiology. By being able to measure the absolute synthesis rates of the majority of cellular proteins, Li et al. gain insights into key aspects of translation regulation and fundamental principles of cellular strategies to adjust protein synthesis according to the functional needs. Copyright © 2014 Elsevier Inc. All rights reserved.

Origins of cellular geometry

PubMed Central

2011-01-01

Cells are highly complex and orderly machines, with defined shapes and a startling variety of internal organizations. Complex geometry is a feature of both free-living unicellular organisms and cells inside multicellular animals. Where does the geometry of a cell come from? Many of the same questions that arise in developmental biology can also be asked of cells, but in most cases we do not know the answers. How much of cellular organization is dictated by global cell polarity cues as opposed to local interactions between cellular components? Does cellular structure persist across cell generations? What is the relationship between cell geometry and tissue organization? What ensures that intracellular structures are scaled to the overall size of the cell? Cell biology is only now beginning to come to grips with these questions. PMID:21880160

Epigenetics and Cellular Metabolism

PubMed Central

Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao

2016-01-01

Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well. PMID:27695375

Methylene Blue Protects Astrocytes against Glucose Oxygen Deprivation by Improving Cellular Respiration

PubMed Central

Roy Choudhury, Gourav; Winters, Ali; Rich, Ryan M.; Ryou, Myoung-Gwi; Gryczynski, Zygmunt; Yuan, Fang; Yang, Shao-Hua; Liu, Ran

2015-01-01

Astrocytes outnumber neurons and serve many metabolic and trophic functions in the mammalian brain. Preserving astrocytes is critical for normal brain function as well as for protecting the brain against various insults. Our previous studies have indicated that methylene blue (MB) functions as an alternative electron carrier and enhances brain metabolism. In addition, MB has been shown to be protective against neurodegeneration and brain injury. In the current study, we investigated the protective role of MB in astrocytes. Cell viability assays showed that MB treatment significantly protected primary astrocytes from oxygen-glucose deprivation (OGD) & reoxygenation induced cell death. We also studied the effect of MB on cellular oxygen and glucose metabolism in primary astrocytes following OGD-reoxygenation injury. MB treatment significantly increased cellular oxygen consumption, glucose uptake and ATP production in primary astrocytes. In conclusion our study demonstrated that MB protects astrocytes against OGD-reoxygenation injury by improving astrocyte cellular respiration. PMID:25848957

Modeling the mechanics of cancer: effect of changes in cellular and extra-cellular mechanical properties.

PubMed

Katira, Parag; Bonnecaze, Roger T; Zaman, Muhammad H

2013-01-01

Malignant transformation, though primarily driven by genetic mutations in cells, is also accompanied by specific changes in cellular and extra-cellular mechanical properties such as stiffness and adhesivity. As the transformed cells grow into tumors, they interact with their surroundings via physical contacts and the application of forces. These forces can lead to changes in the mechanical regulation of cell fate based on the mechanical properties of the cells and their surrounding environment. A comprehensive understanding of cancer progression requires the study of how specific changes in mechanical properties influences collective cell behavior during tumor growth and metastasis. Here we review some key results from computational models describing the effect of changes in cellular and extra-cellular mechanical properties and identify mechanistic pathways for cancer progression that can be targeted for the prediction, treatment, and prevention of cancer.

Compact Biocompatible Quantum Dots Functionalized for Cellular Imaging

PubMed Central

Liu, Wenhao; Howarth, Mark; Greytak, Andrew B.; Zheng, Yi; Nocera, Daniel G.; Ting, Alice Y.; Bawendi, Moungi G.

2009-01-01

We present a family of water-soluble quantum dots (QDs) that exhibit low nonspecific binding to cells, small hydrodynamic diameter, tunable surface charge, high quantum yield, and good solution stability across a wide pH range. These QDs are amenable to covalent modification via simple carbodiimide coupling chemistry, which is achieved by functionalizing the surface of QDs with a new class of heterobifunctional ligands incorporating dihydrolipoic acid, a short poly(ethylene glycol) (PEG) spacer, and an amine or carboxylate terminus. The covalent attachment of molecules is demonstrated by appending a rhodamine dye to form a QD-dye conjugate exhibiting fluorescence resonance energy transfer (FRET). High-affinity labeling is demonstrated by covalent attachment of streptavidin, thus enabling the tracking of biotinylated epidermal growth factor (EGF) bound to EGF receptor on live cells. In addition, QDs solubilized with the heterobifunctional ligands retain their metal-affinity driven conjugation chemistry with polyhistidine-tagged proteins. This dual functionality is demonstrated by simultaneous covalent attachment of a rhodamine FRET acceptor and binding of polyhistidine-tagged streptavidin on the same nanocrystal to create a targeted QD, which exhibits dual-wavelength emission. Such emission properties could serve as the basis for ratiometric sensing of the cellular receptor’s local chemical environment. PMID:18177042

Optimizing neurotrophic factor combinations for neurite outgrowth

NASA Astrophysics Data System (ADS)

Deister, C.; Schmidt, C. E.

2006-06-01

Most neurotrophic factors are members of one of three families: the neurotrophins, the glial cell-line derived neurotrophic factor family ligands (GFLs) and the neuropoietic cytokines. Each family activates distinct but overlapping cellular pathways. Several studies have shown additive or synergistic interactions between neurotrophic factors from different families, though generally only a single combination has been studied. Because of possible interactions between the neurotrophic factors, the optimum concentration of a factor in a mixture may differ from the optimum when applied individually. Additionally, the effect of combinations of neurotrophic factors from each of the three families on neurite extension is unclear. This study examines the effects of several combinations of the neurotrophin nerve growth factor (NGF), the GFL glial cell-line derived neurotrophic factor (GDNF) and the neuropoietic cytokine ciliary neurotrophic factor (CNTF) on neurite outgrowth from young rat dorsal root ganglion (DRG) explants. The combination of 50 ng ml-1 NGF and 10 ng ml-1 of each GDNF and CNTF induced the highest level of neurite outgrowth at a 752 ± 53% increase over untreated DRGs and increased the longest neurite length to 2031 ± 97 µm compared to 916 ± 64 µm for untreated DRGs. The optimum concentrations of the three factors applied in combination corresponded to the optimum concentration of each factor when applied individually. These results indicate that the efficacy of future therapies for nerve repair would be enhanced by the controlled release of a combination of neurotrophins, GFLs and neuropoietic cytokines at higher concentrations than used in previous conduit designs.

The Epidermis of Grhl3-Null Mice Displays Altered Lipid Processing and Cellular Hyperproliferation

PubMed Central

Ting, Stephen B; Caddy, Jacinta; Wilanowski, Tomasz; Auden, Alana; Cunningham, John M; Elias, Peter M; Holleran, Walter M

2005-01-01

The presence of an impermeable surface barrier is an essential homeostatic mechanism in almost all living organisms. We have recently described a novel gene that is critical for the developmental instruction and repair of the integument in mammals. This gene, Grainy head-like 3 (Grhl3) is a member of a large family of transcription factors that are homologs of the Drosophila developmental gene grainy head (grh). Mice lacking Grhl3 fail to form an adequate skin barrier, and die at birth due to dehydration. These animals are also unable to repair the epidermis, exhibiting failed wound healing in both fetal and adult stages of development. These defects are due, in part, to diminished expression of a Grhl3 target gene, Transglutaminase 1 (TGase 1), which encodes a key enzyme involved in cross-linking of epidermal structural proteins and lipids into the cornified envelope (CE). Remarkably, the Drosophila grh gene plays an analogous role, regulating enzymes involved in the generation of quinones, which are essential for cross-linking structural components of the fly epidermis. In an extension of our initial analyses, we focus this report on additional defects observed in the Grhl3-null epidermis, namely defective extra-cellular lipid processing, altered lamellar lipid architecture and cellular hyperproliferation. These abnormalities suggest that Grhl3 plays diverse mechanistic roles in maintaining homeostasis in the skin. PMID:19521564

The epidermis of grhl3-null mice displays altered lipid processing and cellular hyperproliferation.

PubMed

Ting, Stephen B; Caddy, Jacinta; Wilanowski, Tomasz; Auden, Alana; Cunningham, John M; Elias, Peter M; Holleran, Walter M; Jane, Stephen M

2005-04-01

The presence of an impermeable surface barrier is an essential homeostatic mechanism in almost all living organisms. We have recently described a novel gene that is critical for the developmental instruction and repair of the integument in mammals. This gene, Grainy head-like 3 (Grhl3) is a member of a large family of transcription factors that are homologs of the Drosophila developmental gene grainy head (grh). Mice lacking Grhl3 fail to form an adequate skin barrier, and die at birth due to dehydration. These animals are also unable to repair the epidermis, exhibiting failed wound healing in both fetal and adult stages of development. These defects are due, in part, to diminished expression of a Grhl3 target gene, Transglutaminase 1 (TGase 1), which encodes a key enzyme involved in cross-linking of epidermal structural proteins and lipids into the cornified envelope (CE). Remarkably, the Drosophila grh gene plays an analogous role, regulating enzymes involved in the generation of quinones, which are essential for cross-linking structural components of the fly epidermis. In an extension of our initial analyses, we focus this report on additional defects observed in the Grhl3-null epidermis, namely defective extra-cellular lipid processing, altered lamellar lipid architecture and cellular hyperproliferation. These abnormalities suggest that Grhl3 plays diverse mechanistic roles in maintaining homeostasis in the skin.

Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

EPA Science Inventory

CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...

Winding through the WNT pathway during cellular development and demise.

PubMed

Li, F; Chong, Z Z; Maiese, K

2006-01-01

In slightly over a period of twenty years, our comprehension of the cellular and molecular mechanisms that govern the Wnt signaling pathway continue to unfold. The Wnt proteins were initially implicated in viral carcinogenesis experiments associated with mammary tumors, but since this period investigations focusing on the Wnt pathways and their transmembrane receptors termed Frizzled have been advanced to demonstrate the critical nature of Wnt for the development of a variety of cell populations as well as the potential of the Wnt pathway to avert apoptotic injury. In particular, Wnt signaling plays a significant role in both the cardiovascular and nervous systems during embryonic cell patterning, proliferation, differentiation, and orientation. Furthermore, modulation of Wnt signaling under specific cellular influences can either promote or prevent the early and late stages of apoptotic cellular injury in neurons, endothelial cells, vascular smooth muscle cells, and cardiomyocytes. A number of downstream signal transduction pathways can mediate the biological response of the Wnt proteins that include Dishevelled, beta-catenin, intracellular calcium, protein kinase C, Akt, and glycogen synthase kinase-3beta. Interestingly, these cellular cascades of the Wnt-Frizzled pathways can participate in several neurodegenerative, vascular, and cardiac disorders and may be closely integrated with the function of trophic factors. Identification of the critical elements that modulate the Wnt-Frizzled signaling pathway should continue to unlock the potential of Wnt pathway for the development of new therapeutic options against neurodegenerative and vascular diseases.

Evolution of Cellular Inclusions in Bietti's Crystalline Dystrophy.

PubMed

Furusato, Emiko; Cameron, J Douglas; Chan, Chi-Chao

2010-03-09

Bietti's crystalline dystrophy (BCD) consists of small, yellow-white, glistening intraretinal crystals in the posterior pole, tapetoretinal degeneration with atrophy of the retinal pigment epithelium (RPE) and "sclerosis" of the choroid; in addition, sparking yellow crystals in the superficial marginal cornea are also found in many patients. BCD is inherited as an autosomal-recessive trait (4q35-tel) and usually has its onset in the third decade of life. This review focuses on the ultrastructure of cellular crystals and lipid inclusions of BCD.

Delivery of growth factors for tissue regeneration and wound healing.

PubMed

Koria, Piyush

2012-06-01

Growth factors are soluble secreted proteins capable of affecting a variety of cellular processes important for tissue regeneration. Consequently, the self-healing capacity of patients can be augmented by artificially enhancing one or more processes important for healing through the application of growth factors. However, their application in clinics remains limited due to lack of robust delivery systems and biomaterial carriers. Interestingly, all clinically approved therapies involving growth factors utilize some sort of a biomaterial carrier for growth factor delivery. This suggests that biomaterial delivery systems are extremely important for successful usage of growth factors in regenerative medicine. This review outlines the role of growth factors in tissue regeneration, and their application in both pre-clinical animal models of regeneration and clinical trials is discussed. Additionally, current status of biomaterial substrates and sophisticated delivery systems such as nanoparticles for delivery of exogenous growth factors and peptides in humans are reviewed. Finally, issues and possible future research directions for growth factor therapy in regenerative medicine are discussed.

Molecular and cellular aspects of rhabdovirus entry.

PubMed

Albertini, Aurélie A V; Baquero, Eduard; Ferlin, Anna; Gaudin, Yves

2012-01-01

Rhabdoviruses enter the cell via the endocytic pathway and subsequently fuse with a cellular membrane within the acidic environment of the endosome. Both receptor recognition and membrane fusion are mediated by a single transmembrane viral glycoprotein (G). Fusion is triggered via a low-pH induced structural rearrangement. G is an atypical fusion protein as there is a pH-dependent equilibrium between its pre- and post-fusion conformations. The elucidation of the atomic structures of these two conformations for the vesicular stomatitis virus (VSV) G has revealed that it is different from the previously characterized class I and class II fusion proteins. In this review, the pre- and post-fusion VSV G structures are presented in detail demonstrating that G combines the features of the class I and class II fusion proteins. In addition to these similarities, these G structures also reveal some particularities that expand our understanding of the working of fusion machineries. Combined with data from recent studies that revealed the cellular aspects of the initial stages of rhabdovirus infection, all these data give an integrated view of the entry pathway of rhabdoviruses into their host cell.

Molecular and Cellular Aspects of Rhabdovirus Entry

PubMed Central

Albertini, Aurélie A. V.; Baquero, Eduard; Ferlin, Anna; Gaudin, Yves

2012-01-01

Rhabdoviruses enter the cell via the endocytic pathway and subsequently fuse with a cellular membrane within the acidic environment of the endosome. Both receptor recognition and membrane fusion are mediated by a single transmembrane viral glycoprotein (G). Fusion is triggered via a low-pH induced structural rearrangement. G is an atypical fusion protein as there is a pH-dependent equilibrium between its pre- and post-fusion conformations. The elucidation of the atomic structures of these two conformations for the vesicular stomatitis virus (VSV) G has revealed that it is different from the previously characterized class I and class II fusion proteins. In this review, the pre- and post-fusion VSV G structures are presented in detail demonstrating that G combines the features of the class I and class II fusion proteins. In addition to these similarities, these G structures also reveal some particularities that expand our understanding of the working of fusion machineries. Combined with data from recent studies that revealed the cellular aspects of the initial stages of rhabdovirus infection, all these data give an integrated view of the entry pathway of rhabdoviruses into their host cell. PMID:22355455

Effect of living cellular sheets on the angiogenic potential of human microvascular endothelial cells.

PubMed

Villar, Cristina C; Zhao, Xiang R; Livi, Carolina B; Cochran, David L

2015-05-01

A fundamental issue limiting the efficacy of surgical approaches designed to correct periodontal mucogingival defects is that new tissues rely on limited sources of blood supply from the adjacent recipient bed. Accordingly, therapies based on tissue engineering that leverage local self-healing potential may represent promising alternatives for the treatment of mucogingival defects by inducing local vascularization. The aim of this study is to evaluate the effect of commercially available living cellular sheets (LCS) on the angiogenic potential of neonatal dermal human microvascular endothelial cells (HMVEC-dNeo). The effect of LCS on HMVEC-dNeo proliferation, migration, capillary tube formation, gene expression, and production of angiogenic factors was evaluated over time. LCS positively influenced HMVEC-dNeo proliferation and migration. Moreover, HMVEC-dNeo incubated with LCS showed transcriptional profiles different from those of untreated cells. Whereas increased expression of angiogenic genes predominated early on in response to LCS, late-phase responses were characterized by up- and downregulation of angiostatic and angiogenic genes. However, this trend was not confirmed at the protein level, as LCS induced increased production of most of the angiogenic factors tested (i.e., epidermal growth factor [EGF], heparin-binding EGF-like growth factor, interleukin 6, angiopoietin, platelet-derived growth factor-BB, placental growth factor, and vascular endothelial growth factor) throughout the investigational period. Finally, although LCS induced HMVEC-dNeo proliferation, migration, and expression of angiogenic factors, additional factors and environmental pressures are likely to be required to promote the development of complex, mesh-like vascular structures. LCS favor initial mechanisms that govern angiogenesis but failed to enhance or accelerate HMVEC-dNeo morphologic transition to complex vascular structures.

DNA Polymerase κ Is a Key Cellular Factor for the Formation of Covalently Closed Circular DNA of Hepatitis B Virus.

PubMed

Qi, Yonghe; Gao, Zhenchao; Xu, Guangwei; Peng, Bo; Liu, Chenxuan; Yan, Huan; Yao, Qiyan; Sun, Guoliang; Liu, Yang; Tang, Dingbin; Song, Zilin; He, Wenhui; Sun, Yinyan; Guo, Ju-Tao; Li, Wenhui

2016-10-01

Hepatitis B virus (HBV) infection of hepatocytes begins by binding to its cellular receptor sodium taurocholate cotransporting polypeptide (NTCP), followed by the internalization of viral nucleocapsid into the cytoplasm. The viral relaxed circular (rc) DNA genome in nucleocapsid is transported into the nucleus and converted into covalently closed circular (ccc) DNA to serve as a viral persistence reservoir that is refractory to current antiviral therapies. Host DNA repair enzymes have been speculated to catalyze the conversion of rcDNA to cccDNA, however, the DNA polymerase(s) that fills the gap in the plus strand of rcDNA remains to be determined. Here we conducted targeted genetic screening in combination with chemical inhibition to identify the cellular DNA polymerase(s) responsible for cccDNA formation, and exploited recombinant HBV with capsid coding deficiency which infects HepG2-NTCP cells with similar efficiency of wild-type HBV to assure cccDNA synthesis is exclusively from de novo HBV infection. We found that DNA polymerase κ (POLK), a Y-family DNA polymerase with maximum activity in non-dividing cells, substantially contributes to cccDNA formation during de novo HBV infection. Depleting gene expression of POLK in HepG2-NTCP cells by either siRNA knockdown or CRISPR/Cas9 knockout inhibited the conversion of rcDNA into cccDNA, while the diminished cccDNA formation in, and hence the viral infection of, the knockout cells could be effectively rescued by ectopic expression of POLK. These studies revealed that POLK is a crucial host factor required for cccDNA formation during a de novo HBV infection and suggest that POLK may be a potential target for developing antivirals against HBV.

BTK suppresses myeloma cellular senescence through activating AKT/P27/Rb signaling.

PubMed

Gu, Chunyan; Peng, Hailin; Lu, Yue; Yang, Hongbao; Tian, Zhidan; Yin, Gang; Zhang, Wen; Lu, Sicheng; Zhang, Yi; Yang, Ye

2017-08-22

We previously explored the role of BTK in maintaining multiple myeloma stem cells (MMSCs) self-renewal and drug-resistance. Here we investigated the elevation of BTK suppressing MM cellular senescence, a state of irreversible cellular growth arrest. We firstly discovered that an increased expression of BTK in MM samples compared to normal controls by immunohistochemistry (IHC), and significant chromosomal gain in primary samples. In addition, BTK high-expressing MM patients are associated with poor outcome in both Total Therapy 2 (TT2) and TT3 cohorts. Knockdown BTK expression by shRNA induced MM cellular senescence using β-galactosidase (SA-b-gal) staining, cell growth arrest by cell cycle staining and decreased clonogenicity while forcing BTK expression in MM cells abrogated these characteristics. We also validated this feature in mouse embryonic fibroblast cells (MEFs), which showed that elevated BTK expression was resistant to MEF senescence after serial cultivation in vitro . Further mechanism study revealed that BTK activated AKT signaling leading to down-regulation of P27 expression and hindered RB activity while AKT inhibitor, LY294002, overcame BTK-overexpression induced cellular senescence resistance. Eventually we demonstrated that BTK inhibitor, CGI-1746, induced MM cellular senescence, colony reduction and tumorigenecity inhibition in vivo . Summarily, we designate a novel mechanism of BTK in mediating MM growth, and BTK inhibitor is of great potential in vivo and in vitro suggesting BTK is a promising therapeutic target for MM.

BTK suppresses myeloma cellular senescence through activating AKT/P27/Rb signaling

PubMed Central

Lu, Yue; Yang, Hongbao; Tian, Zhidan; Yin, Gang; Zhang, Wen; Lu, Sicheng; Zhang, Yi; Yang, Ye

2017-01-01

We previously explored the role of BTK in maintaining multiple myeloma stem cells (MMSCs) self-renewal and drug-resistance. Here we investigated the elevation of BTK suppressing MM cellular senescence, a state of irreversible cellular growth arrest. We firstly discovered that an increased expression of BTK in MM samples compared to normal controls by immunohistochemistry (IHC), and significant chromosomal gain in primary samples. In addition, BTK high-expressing MM patients are associated with poor outcome in both Total Therapy 2 (TT2) and TT3 cohorts. Knockdown BTK expression by shRNA induced MM cellular senescence using β-galactosidase (SA-b-gal) staining, cell growth arrest by cell cycle staining and decreased clonogenicity while forcing BTK expression in MM cells abrogated these characteristics. We also validated this feature in mouse embryonic fibroblast cells (MEFs), which showed that elevated BTK expression was resistant to MEF senescence after serial cultivation in vitro. Further mechanism study revealed that BTK activated AKT signaling leading to down-regulation of P27 expression and hindered RB activity while AKT inhibitor, LY294002, overcame BTK-overexpression induced cellular senescence resistance. Eventually we demonstrated that BTK inhibitor, CGI-1746, induced MM cellular senescence, colony reduction and tumorigenecity inhibition in vivo. Summarily, we designate a novel mechanism of BTK in mediating MM growth, and BTK inhibitor is of great potential in vivo and in vitro suggesting BTK is a promising therapeutic target for MM. PMID:28915637

Next Generation Orthopaedic Implants by Additive Manufacturing Using Electron Beam Melting

PubMed Central

Murr, Lawrence E.; Gaytan, Sara M.; Martinez, Edwin; Medina, Frank; Wicker, Ryan B.

2012-01-01

This paper presents some examples of knee and hip implant components containing porous structures and fabricated in monolithic forms utilizing electron beam melting (EBM). In addition, utilizing stiffness or relative stiffness versus relative density design plots for open-cellular structures (mesh and foam components) of Ti-6Al-4V and Co-29Cr-6Mo alloy fabricated by EBM, it is demonstrated that stiffness-compatible implants can be fabricated for optimal stress shielding for bone regimes as well as bone cell ingrowth. Implications for the fabrication of patient-specific, monolithic, multifunctional orthopaedic implants using EBM are described along with microstructures and mechanical properties characteristic of both Ti-6Al-4V and Co-29Cr-6Mo alloy prototypes, including both solid and open-cellular prototypes manufactured by additive manufacturing (AM) using EBM. PMID:22956957

Cellular Scale Anisotropic Topography Guides Schwann Cell Motility

PubMed Central

Mitchel, Jennifer A.; Hoffman-Kim, Diane

2011-01-01

Directed migration of Schwann cells (SC) is critical for development and repair of the peripheral nervous system. Understanding aspects of motility specific to SC, along with SC response to engineered biomaterials, may inform strategies to enhance nerve regeneration. Rat SC were cultured on laminin-coated microgrooved poly(dimethyl siloxane) platforms that were flat or presented repeating cellular scale anisotropic topographical cues, 30 or 60 µm in width, and observed with timelapse microscopy. SC motion was directed parallel to the long axis of the topography on both the groove floor and the plateau, with accompanying differences in velocity and directional persistence in comparison to SC motion on flat substrates. In addition, feature dimension affected SC morphology, alignment, and directional persistence. Plateaus and groove floors presented distinct cues which promoted differential motility and variable interaction with the topographical features. SC on the plateau surfaces tended to have persistent interactions with the edge topography, while SC on the groove floors tended to have infrequent contact with the corners and walls. Our observations suggest the capacity of SC to be guided without continuous contact with a topographical cue. SC exhibited a range of distinct motile morphologies, characterized by their symmetry and number of extensions. Across all conditions, SC with a single extension traveled significantly faster than cells with more or no extensions. We conclude that SC motility is complex, where persistent motion requires cellular asymmetry, and that anisotropic topography with cellular scale features can direct SC motility. PMID:21949703

FishFace: interactive atlas of zebrafish craniofacial development at cellular resolution

PubMed Central

2013-01-01

Background The vertebrate craniofacial skeleton may exhibit anatomical complexity and diversity, but its genesis and evolution can be understood through careful dissection of developmental programs at cellular resolution. Resources are lacking that include introductory overviews of skeletal anatomy coupled with descriptions of craniofacial development at cellular resolution. In addition to providing analytical guidelines for other studies, such an atlas would suggest cellular mechanisms underlying development. Description We present the Fish Face Atlas, an online, 3D-interactive atlas of craniofacial development in the zebrafish Danio rerio. Alizarin red-stained skulls scanned by fluorescent optical projection tomography and segmented into individual elements provide a resource for understanding the 3D structure of the zebrafish craniofacial skeleton. These data provide the user an anatomical entry point to confocal images of Alizarin red-stained zebrafish with transgenically-labelled pharyngeal arch ectomesenchyme, chondrocytes, and osteoblasts, which illustrate the appearance, morphogenesis, and growth of the mandibular and hyoid cartilages and bones, as viewed in live, anesthetized zebrafish during embryonic and larval development. Confocal image stacks at high magnification during the same stages provide cellular detail and suggest developmental and evolutionary hypotheses. Conclusion The FishFace Atlas is a novel learning tool for understanding craniofacial skeletal development, and can serve as a reference for a variety of studies, including comparative and mutational analyses. PMID:23714426

Mequindox induced cellular DNA damage via generation of reactive oxygen species.

PubMed

Liu, Jing; Ouyang, Man; Jiang, Jun; Mu, Peiqiang; Wu, Jun; Yang, Qi; Zhang, Caihui; Xu, Weiying; Wang, Lijuan; Huen, Michael S Y; Deng, Yiqun

2012-01-24

Mequindox, a quinoxaline-N-dioxide derivative that possesses antibacterial properties, has been widely used as a feed additive in the stockbreeding industry in China. While recent pharmacological studies have uncovered potential hazardous effects of mequindox, exactly how mequindox induces pathological changes and the cellular responses associated with its consumption remain largely unexplored. In this study, we investigated the cellular responses associated with mequindox treatment. We report here that mequindox inhibits cell proliferation by arresting cells at the G2/M phase of the cell cycle. Interestingly, this mequindox-associated deleterious effect on cell proliferation was observed in human, pig as well as chicken cells, suggesting that mequindox acts on evolutionarily conserved target(s). To further understand the mequindox-host interaction and the mechanism underlying mequindox-induced cell cycle arrest, we measured the cellular content of DNA damage, which is known to perturb cell proliferation and compromise cell survival. Accordingly, using γ-H2AX as a surrogate marker for DNA damage, we found that mequindox treatment induced cellular DNA damage, which paralleled the chemical-induced elevation of reactive oxygen species (ROS) levels. Importantly, expression of the antioxidant enzyme catalase partially alleviated these mequindox-associated effects. Taken together, our results suggest that mequindox cytotoxicity is attributable, in part, to its role as a potent inducer of DNA damage via ROS. © 2011 Elsevier B.V. All rights reserved.

Mechanisms of cellular invasion by intracellular parasites.

PubMed

Walker, Dawn M; Oghumu, Steve; Gupta, Gaurav; McGwire, Bradford S; Drew, Mark E; Satoskar, Abhay R

2014-04-01

Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.

47 CFR 22.923 - Cellular system configuration.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 2 2013-10-01 2013-10-01 false Cellular system configuration. 22.923 Section 22.923 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.923 Cellular system configuration. Mobile stations...

47 CFR 22.923 - Cellular system configuration.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 2 2014-10-01 2014-10-01 false Cellular system configuration. 22.923 Section 22.923 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.923 Cellular system configuration. Mobile stations...

Oscillatory cellular patterns in three-dimensional directional solidification

DOE PAGES

Tourret, D.; Debierre, J. -M.; Song, Y.; ...

2015-09-11

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in micro-gravity. Directional solidification experiments conducted onboard the International Space Station have allowed for the first time to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 minutes. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelatedmore » at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (\\ie low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exist, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global

Oscillatory cellular patterns in three-dimensional directional solidification

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

Tourret, D.; Debierre, J. -M.; Song, Y.

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in micro-gravity. Directional solidification experiments conducted onboard the International Space Station have allowed for the first time to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 minutes. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelatedmore » at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (\\ie low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exist, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global

Pneumolysin induces cellular senescence by increasing ROS production and activation of MAPK/NF-κB signal pathway in glial cells.

PubMed

Kwon, Ii-Seul; Kim, Jinwook; Rhee, Dong-Kwon; Kim, Byung-Oh; Pyo, Suhkneung

2017-04-01

Senescence is an irreversible proliferation arrest that is induced by various stress stimuli including genotoxin. Pneumolysin (PLY) is a pathogenicity factor unique to Streptococcus pneumoniae that is important in pneumococcal-induced diseases such as otitis media, meningitis and pneumonia. However, the cell fate response to the toxin is mechanistically unclear. We investigated the effect of PLY on cellular senescence in BV-2 microglial cells. Exposure to PLY resulted in changes in the expression of phospho-p53, p21, p16, pRb and CDK2 and increased the number of senescence associated β-gal positive cells. PLY-treatment also increased PAI-1 expression and cell proliferation arrest in concentration- and time-dependent manners. PLY induced NF-κB activation and phosphorylation of SIRT-1, ERK1/2, JNK, and p38 MAPK. In addition, PLY increased the production of reactive oxygen species. Overall, the results suggest that PLY regulates microglial cellular senescence by enhancing production of reactive oxygen species, activation of MAPK and NF-κB, and phosphorylation of SIRT-1. Copyright © 2017 Elsevier Ltd. All rights reserved.

Translational Cellular Research on the International Space Station

NASA Technical Reports Server (NTRS)

Love, John; Cooley, Vic

2016-01-01

The emerging field of Translational Research aims to coalesce interdisciplinary findings from basic science for biomedical applications. To complement spaceflight research using human subjects, translational studies can be designed to address aspects of space-related human health risks and help develop countermeasures to prevent or mitigate them, with therapeutical benefits for analogous conditions experienced on Earth. Translational research with cells and model organisms is being conducted onboard the International Space Station (ISS) in connection with various human systems impacted by spaceflight, such as the cardiovascular, musculoskeletal, and immune systems. Examples of recent cell-based translational investigations on the ISS include the following. The JAXA investigation Cell Mechanosensing seeks to identify gravity sensors in skeletal muscle cells to develop muscle atrophy countermeasures by analyzing tension fluctuations in the plasma membrane, which changes the expression of key proteins and genes. Earth applications of this study include therapeutic approaches for some forms of muscular dystrophy, which appear to parallel aspects of muscle wasting in space. Spheroids is an ESA investigation examining the system of endothelial cells lining the inner surface of all blood vessels in terms of vessel formation, cellular proliferation, and programmed cell death, because injury to the endothelium has been implicated as underpinning various cardiovascular and musculoskeletal problems arising during spaceflight. Since endothelial cells are involved in the functional integrity of the vascular wall, this research has applications to Earth diseases such as atherosclerosis, diabetes, and hypertension. The goal of the T-Cell Activation in Aging NASA investigation is to understand human immune system depression in microgravity by identifying gene expression patterns of candidate molecular regulators, which will provide further insight into factors that may play a

A synthetic ion transporter that disrupts autophagy and induces apoptosis by perturbing cellular chloride concentrations

NASA Astrophysics Data System (ADS)

Busschaert, Nathalie; Park, Seong-Hyun; Baek, Kyung-Hwa; Choi, Yoon Pyo; Park, Jinhong; Howe, Ethan N. W.; Hiscock, Jennifer R.; Karagiannidis, Louise E.; Marques, Igor; Félix, Vítor; Namkung, Wan; Sessler, Jonathan L.; Gale, Philip A.; Shin, Injae

2017-07-01

Perturbations in cellular chloride concentrations can affect cellular pH and autophagy and lead to the onset of apoptosis. With this in mind, synthetic ion transporters have been used to disturb cellular ion homeostasis and thereby induce cell death; however, it is not clear whether synthetic ion transporters can also be used to disrupt autophagy. Here, we show that squaramide-based ion transporters enhance the transport of chloride anions in liposomal models and promote sodium chloride influx into the cytosol. Liposomal and cellular transport activity of the squaramides is shown to correlate with cell death activity, which is attributed to caspase-dependent apoptosis. One ion transporter was also shown to cause additional changes in lysosomal pH, which leads to impairment of lysosomal enzyme activity and disruption of autophagic processes. This disruption is independent of the initiation of apoptosis by the ion transporter. This study provides the first experimental evidence that synthetic ion transporters can disrupt both autophagy and induce apoptosis.

Bovine Foamy Virus Transactivator BTas Interacts with Cellular RelB To Enhance Viral Transcription▿

PubMed Central

Wang, Jian; Tan, Juan; Guo, Hongyan; Zhang, Qicheng; Jia, Rui; Xu, Xuan; Geng, Yunqi; Qiao, Wentao

2010-01-01

Viruses are obligate intracellular parasites that depend on cellular machinery for their efficient transcription and replication. In a previous study we reported that bovine foamy virus (BFV) is able to activate the nuclear factor κB (NF-κB) pathway through the action of its transactivator BTas to enhance viral transcription. However, the mechanism used by NF-κB to enhance BFV transcription remains elusive. To address this question, we employed a yeast two-hybrid assay to screen for BTas-interacting proteins. We found that RelB, a member of NF-κB protein family, interacts with BTas. We confirmed the putative RelB-BTas interaction in vitro and in vivo and identified the protein regions responsible for the RelB-BTas interaction. Using a luciferase reporter assay, we next showed that RelB enhances BFV transcription (BTas-induced long terminal repeat [LTR] transactivation) and that this process requires both the localization of the RelB-BTas interaction in the nucleus and the Rel homology domain of RelB. The knockdown of the cellular endogenous RelB protein using small interfering RNA (siRNA) significantly attenuated BTas-induced LTR transcription. The results of chromatin immunoprecipitation (ChIP) analysis showed that endogenous RelB binds to the viral LTR in BFV-infected cells. Together, these results suggest that BFV engages the RelB protein as a cotransactivator of BTas to enhance viral transcription. In addition, our findings indicate that BFV infection upregulates cellular RelB expression through BTas-induced NF-κB activation. Thus, this study demonstrates the existence of a positive-feedback circuit in which BFV utilizes the host's NF-κB pathway through the RelB protein for efficient viral transcription. PMID:20844054

Bovine foamy virus transactivator BTas interacts with cellular RelB to enhance viral transcription.

PubMed

Wang, Jian; Tan, Juan; Guo, Hongyan; Zhang, Qicheng; Jia, Rui; Xu, Xuan; Geng, Yunqi; Qiao, Wentao

2010-11-01

Viruses are obligate intracellular parasites that depend on cellular machinery for their efficient transcription and replication. In a previous study we reported that bovine foamy virus (BFV) is able to activate the nuclear factor κB (NF-κB) pathway through the action of its transactivator BTas to enhance viral transcription. However, the mechanism used by NF-κB to enhance BFV transcription remains elusive. To address this question, we employed a yeast two-hybrid assay to screen for BTas-interacting proteins. We found that RelB, a member of NF-κB protein family, interacts with BTas. We confirmed the putative RelB-BTas interaction in vitro and in vivo and identified the protein regions responsible for the RelB-BTas interaction. Using a luciferase reporter assay, we next showed that RelB enhances BFV transcription (BTas-induced long terminal repeat [LTR] transactivation) and that this process requires both the localization of the RelB-BTas interaction in the nucleus and the Rel homology domain of RelB. The knockdown of the cellular endogenous RelB protein using small interfering RNA (siRNA) significantly attenuated BTas-induced LTR transcription. The results of chromatin immunoprecipitation (ChIP) analysis showed that endogenous RelB binds to the viral LTR in BFV-infected cells. Together, these results suggest that BFV engages the RelB protein as a cotransactivator of BTas to enhance viral transcription. In addition, our findings indicate that BFV infection upregulates cellular RelB expression through BTas-induced NF-κB activation. Thus, this study demonstrates the existence of a positive-feedback circuit in which BFV utilizes the host's NF-κB pathway through the RelB protein for efficient viral transcription.

Probabilistic Cellular Automata

PubMed Central

Agapie, Alexandru; Giuclea, Marius

2014-01-01

Abstract Cellular automata are binary lattices used for modeling complex dynamical systems. The automaton evolves iteratively from one configuration to another, using some local transition rule based on the number of ones in the neighborhood of each cell. With respect to the number of cells allowed to change per iteration, we speak of either synchronous or asynchronous automata. If randomness is involved to some degree in the transition rule, we speak of probabilistic automata, otherwise they are called deterministic. With either type of cellular automaton we are dealing with, the main theoretical challenge stays the same: starting from an arbitrary initial configuration, predict (with highest accuracy) the end configuration. If the automaton is deterministic, the outcome simplifies to one of two configurations, all zeros or all ones. If the automaton is probabilistic, the whole process is modeled by a finite homogeneous Markov chain, and the outcome is the corresponding stationary distribution. Based on our previous results for the asynchronous case—connecting the probability of a configuration in the stationary distribution to its number of zero-one borders—the article offers both numerical and theoretical insight into the long-term behavior of synchronous cellular automata. PMID:24999557

Probabilistic cellular automata.

PubMed

Agapie, Alexandru; Andreica, Anca; Giuclea, Marius

2014-09-01

Cellular automata are binary lattices used for modeling complex dynamical systems. The automaton evolves iteratively from one configuration to another, using some local transition rule based on the number of ones in the neighborhood of each cell. With respect to the number of cells allowed to change per iteration, we speak of either synchronous or asynchronous automata. If randomness is involved to some degree in the transition rule, we speak of probabilistic automata, otherwise they are called deterministic. With either type of cellular automaton we are dealing with, the main theoretical challenge stays the same: starting from an arbitrary initial configuration, predict (with highest accuracy) the end configuration. If the automaton is deterministic, the outcome simplifies to one of two configurations, all zeros or all ones. If the automaton is probabilistic, the whole process is modeled by a finite homogeneous Markov chain, and the outcome is the corresponding stationary distribution. Based on our previous results for the asynchronous case-connecting the probability of a configuration in the stationary distribution to its number of zero-one borders-the article offers both numerical and theoretical insight into the long-term behavior of synchronous cellular automata.

Identification of cellular and viral factors related to anti-hepatitis C virus activity of cyclophilin inhibitor.

PubMed

Goto, Kaku; Watashi, Koichi; Inoue, Daisuke; Hijikata, Makoto; Shimotohno, Kunitada

2009-10-01

We have so far reported that an immunosuppressant cyclosporin A (CsA), a well-known cyclophilin (CyP) inhibitor (CPI), strongly suppressed hepatitis C virus (HCV) replication in cell culture, and that CyPB was a cellular cofactor for viral replication. To further investigate antiviral mechanisms of CPI, we here developed cells carrying CsA-resistant HCV replicons, by culturing the HCV subgenomic replicon cells for 4 weeks in the presence of CsA with G418. Transfection of total RNA from the isolated CsA-resistant cells to naïve Huh7 cells conferred CsA resistance, suggesting that the replicon RNA itself was responsible for the resistant phenotype. Of the identified amino acid mutations, D320E in NS5A conferred the CsA resistance. The replicon carrying the D320E mutation was sensitive to interferon-alpha, but was resistant to CsA and other CPIs including NIM811 and sanglifehrin A. Knockdown of individual CyP subtypes revealed CyP40, in addition to CyPA and CyPB, contributed to viral replication, and CsA-resistant replicons acquired independence from CyPA for efficient replication. These data provide important evidence on the mechanisms underlying the regulation of HCV replication by CyP and for designing novel and specific anti-HCV strategies with CPIs.

CELLULAR BIOAVAILABILITY OF NATURAL HORMONES AND ENVIRONMENTAL CONTAMINANTS AS A FUNCTION OF SERUM AND CYTOSOLIC BINDING FACTORS

EPA Science Inventory

Environmental contaminants have been reported to function as hormone mimics in various wildlife species. To investigate a potential mechanism for the interaction of contaminants with the endocrine system, we evaluated the cellular bioavailability of numerous chemicals. Hormone bi...

Snail regulates cell survival and inhibits cellular senescence in human metastatic prostate cancer cell lines.

PubMed

Emadi Baygi, Modjtaba; Soheili, Zahra Soheila; Schmitz, Ingo; Sameie, Shahram; Schulz, Wolfgang A

2010-12-01

The epithelial-mesenchymal transition (EMT) is regarded as an important step in cancer metastasis. Snail, a master regulator of EMT, has been recently proposed to act additionally as a cell survival factor and inducer of motility. We have investigated the function of Snail (SNAI1) in prostate cancer cells by downregulating its expression via short (21-mer) interfering RNA (siRNA) and measuring the consequences on EMT markers, cell viability, death, cell cycle, senescence, attachment, and invasivity. Of eight carcinoma cell lines, the prostate carcinoma cell lines LNCaP and PC-3 showed the highest and moderate expression of SNAI1 mRNA, respectively, as measured by quantitative RT-PCR. Long-term knockdown of Snail induced a severe decline in cell numbers in LNCaP and PC-3 and caspase activity was accordingly enhanced in both cell lines. In addition, suppression of Snail expression induced senescence in LNCaP cells. SNAI1-siRNA-treated cells did not tolerate detachment from the extracellular matrix, probably due to downregulation of integrin α6. Expression of E-cadherin, vimentin, and fibronectin was also affected. Invasiveness of PC-3 cells was not significantly diminished by Snail knockdown. Our data suggest that Snail acts primarily as a survival factor and inhibitor of cellular senescence in prostate cancer cell lines. We therefore propose that Snail can act as early driver of prostate cancer progression.

The Presence of ADP-Ribosylated Fe Protein of Nitrogenase in Rhodobacter capsulatus Is Correlated with Cellular Nitrogen Status

PubMed Central

Yakunin, Alexander F.; Laurinavichene, Tatyana V.; Tsygankov, Anatoly A.; Hallenbeck, Patrick C.

1999-01-01

The photosynthetic bacterium Rhodobacter capsulatus has been shown to regulate its nitrogenase by covalent modification via the reversible ADP-ribosylation of Fe protein in response to darkness or the addition of external NH4+. Here we demonstrate the presence of ADP-ribosylated Fe protein under a variety of steady-state growth conditions. We examined the modification of Fe protein and nitrogenase activity under three different growth conditions that establish different levels of cellular nitrogen: batch growth with limiting NH4+, where the nitrogen status is externally controlled; batch growth on relatively poor nitrogen sources, where the nitrogen status is internally controlled by assimilatory processes; and continuous culture. When cultures were grown to stationary phase with different limiting concentrations of NH4+, the ADP-ribosylation state of Fe protein was found to correlate with cellular nitrogen status. Additionally, actively growing cultures (grown with N2 or glutamate), which had an intermediate cellular nitrogen status, contained a portion of their Fe protein in the modified state. The correlation between cellular nitrogen status and ADP-ribosylation state was corroborated with continuous cultures grown under various degrees of nitrogen limitation. These results show that in R. capsulatus the modification system that ADP-ribosylates nitrogenase in the short term in response to abrupt changes in the environment is also capable of modifying nitrogenase in accordance with long-term cellular conditions. PMID:10094674

Functional characterization of novel genotypes and cellular oxidative stress studies in propionic acidemia.

PubMed

Gallego-Villar, Lorena; Pérez-Cerdá, Celia; Pérez, Belén; Abia, David; Ugarte, Magdalena; Richard, Eva; Desviat, Lourdes R

2013-09-01

Propionic acidemia (PA), caused by a deficiency of the mitochondrial biotin dependent enzyme propionyl-CoA carboxylase (PCC) is one of the most frequent organic acidurias in humans. PA is caused by mutations in either the PCCA or PCCB genes encoding the α- and β-subunits of the PCC enzyme which are assembled as an α6β6 dodecamer. In this study we have investigated the molecular basis of the defect in ten fibroblast samples from PA patients. Using homology modeling with the recently solved crystal structure of the PCC holoenzyme and a eukaryotic expression system we have analyzed the structural and functional effect of novel point mutations, also revealing a novel splice defect by minigene analysis. In addition, we have investigated the contribution of oxidative stress to cellular damage measuring reactive oxygen species (ROS) levels and apoptosis parameters in patient fibroblasts, as recent studies point to a secondary mitochondrial dysfunction as pathophysiological mechanism in this disorder. The results show an increase in intracellular ROS content compared to controls, correlating with the activation of the JNK and p38 signaling pathways. Highest ROS levels were present in cells harboring functionally null mutations, including one severe missense mutation. This work provides molecular insight into the pathogenicity of PA variants and indicates that oxidative stress may be a major contributing factor to the cellular damage, supporting the proposal of antioxidant strategies as novel supplementary therapy in this rare disease.

Altered cellular magnesium responsiveness to hyperglycemia in hypertensive subjects.

PubMed

Barbagallo, M; Dominguez, L J; Bardicef, O; Resnick, L M

2001-09-01

Previous studies by our group have identified ionic aspects of insulin resistance in hypertension, in which cellular responses to insulin were influenced by the basal intracellular ionic environment-the lower the cytosolic free magnesium (Mg(i)), the less Mg(i) increased following insulin stimulation. To investigate whether this ionic insulin resistance represents a more general abnormality of cellular responsiveness in hypertension, we studied Mg(i) responses to nonhormonal signals such as hyperglycemia (15 mmol/L) and used (31)P-nuclear magnetic resonance (NMR) spectroscopy to measure Mg(i) in erythrocytes from normal (NL, n=14) and hypertensive (HTN, n=12) subjects before and 30, 60, 120, and 180 minutes after in vitro glucose incubations. Basal Mg(i) levels were significantly lower in HTN subjects than in NL subjects (169+/-10 versus 205+/-8 micromol.L(-1), P<0.01). In NL cells, hyperglycemia significantly lowered Mg(i), from 205+/-8 micromol.L(-1) (basal, T=0) to 181+/-8, 162+/-6, 152+/-7, and 175+/-9 micromol.L(-1) (T=30, 60, 120, and 180, respectively; P<0.005 versus T=0 at all times). In HTN cells, maximal Mg(i) responses to hyperglycemia were blunted, from 169+/-10 micromol.L(-1) (basal, T=0) to 170+/-11, 179+/-12, 181+/-14, and 173+/-15 micromol.L(-1) (T=30, 60, 120, and 180, respectively; P=NS versus T=0 at all times). For all subjects, Mg(i) responses to hyperglycemia were closely related to basal Mg(i) levels: the higher the Mg(i), the greater the response (n=26, r=0.620, P<0.001). Thus, (1) erythrocytes from hypertensive vis-à-vis normotensive subjects are resistant to the ionic effects of extracellular hyperglycemia on Mg(i) levels, and (2) cellular ionic responses to glucose depend on the basal Mg(i) environment. Altogether, these data support a role for altered extracellular glucose levels in regulating cellular magnesium metabolism and also suggest the importance of ionic factors in determining cellular responsiveness to nonhormonal as well as

The emergence of extracellular matrix mechanics and cell traction forces as important regulators of cellular self-organization.

PubMed

Checa, Sara; Rausch, Manuel K; Petersen, Ansgar; Kuhl, Ellen; Duda, Georg N

2015-01-01

Physical cues play a fundamental role in a wide range of biological processes, such as embryogenesis, wound healing, tumour invasion and connective tissue morphogenesis. Although it is well known that during these processes, cells continuously interact with the local extracellular matrix (ECM) through cell traction forces, the role of these mechanical interactions on large scale cellular and matrix organization remains largely unknown. In this study, we use a simple theoretical model to investigate cellular and matrix organization as a result of mechanical feedback signals between cells and the surrounding ECM. The model includes bi-directional coupling through cellular traction forces to deform the ECM and through matrix deformation to trigger cellular migration. In addition, we incorporate the mechanical contribution of matrix fibres and their reorganization by the cells. We show that a group of contractile cells will self-polarize at a large scale, even in homogeneous environments. In addition, our simulations mimic the experimentally observed alignment of cells in the direction of maximum stiffness and the building up of tension as a consequence of cell and fibre reorganization. Moreover, we demonstrate that cellular organization is tightly linked to the mechanical feedback loop between cells and matrix. Cells with a preference for stiff environments have a tendency to form chains, while cells with a tendency for soft environments tend to form clusters. The model presented here illustrates the potential of simple physical cues and their impact on cellular self-organization. It can be used in applications where cell-matrix interactions play a key role, such as in the design of tissue engineering scaffolds and to gain a basic understanding of pattern formation in organogenesis or tissue regeneration.

Correlation of transforming growth factor-β messenger RNA (TGF-β mRNA) expression with cellular immunoassays in Triamcinolone-treated captive hybrid striped bass

USGS Publications Warehouse

Harms, Craig A.; Ottinger, Christopher A.; Kennedy-Stoskopf, S.

2000-01-01

Assessing fish immune status with molecular markers has been hampered by a lack of specific reagents. A quantitative polymerase chain reaction (PCR) method (reverse transcription quantitative–competitive PCR, RT-qcPCR) for measuring transforming growth factor-β (TGF-β) transcription from a broad range of teleost fish has recently been developed. The quantitative PCR now permits monitoring production of this important immunosuppressive cytokine in response to immunomodulating agents and conditions. We examined anterior kidney and spleen mononuclear cells from hybrid striped bass (female striped bass Morone saxatilis× male white bass M. chrysops) for production of TGF-β messenger RNA (mRNA) in response to administration of the synthetic glucocorticoid triamcinolone. We also compared TGF-β transcription with anterior kidney macrophage bactericidal activity and splenic lymphocyte blastogenesis. Anterior kidney mononuclear cell TGF-β mRNA levels decreased, whereas bactericidal activity increased. Spleen TGF-β mRNA levels did not change significantly, and splenic lymphocyte pokeweed mitogen stimulation index increased in triamcinolone-treated fish. Since triamcinolone is used therapeutically as a suppressive immunomodulator, the enhanced immune functions indicated by the cellular immunoassays were unexpected; however, the inverse response of TGF-β production and macrophage bactericidal activity was consistent with the known relationship between TGF-β and macrophage activation in mammals. Induced immunomodulation in hybrid striped bass was detectable by both traditional cellular immunoassays and the new RT-qcPCR for TGF-β.

Role of c-Src in cellular events associated with colony-stimulating factor-1-induced spreading in osteoclasts.

PubMed

Insogna, K; Tanaka, S; Neff, L; Horne, W; Levy, J; Baron, R

1997-01-01

We and others have observed that in response to treatment with Colony Stimulating Factor-1 (CSF-1) neonatal rat osteoclasts demonstrate rapid cytoplasmic spreading. The receptor for CSF-1, c-Fms, is expressed in osteoclasts, possesses intrinsic tyrosine-kinase activity, and signals via rapid phosphorylation of selected proteins. It has been reported previously that c-Src becomes tyrosine phosphorylated following CSF-1 treatment of fibroblasts overexpressing c-Fms. We therefore examined the cellular events associated with CSF-1-induced spreading in osteoclasts and what role, if any, c-Src played in these processes. Confocal microscopic studies using phosphotyrosine (P-tyr) monoclonal antibodies demonstrated that CSF-1 induced a significant dose- and time-dependent increase in P-tyr labeling of neonatal rat osteoclasts. Phalloidin staining was consistent with partial to complete disassembly of the actin attachment ring with redistribution of actin to the spreading cytoplasmic edge of the cell. Quantitation of cellular F-actin using NBD-phallicidin confirmed a decrease in polymerized actin following exposure to CSF-1. In contrast, CSF-1 failed to induce any cytoplasmic spreading in osteoclasts isolated from mice with targeted disruption of the src gene. Further, in src- osteoclasts no well defined attachment ring could be identified. To investigate cell-signaling events associated with osteoclast spreading, detergent lysates were made from purified multinucleated osteoclast-like cells (OCLs) obtained by coculturing murine bone marrow and osteoblasts with calcitriol. Western blot analyses of lysates from control and CSF-1-treated normal cells indicated that several proteins were specifically phosphorylated in response to CSF-1, most notably proteins of 165, 60, and 85-90 kDa. Immunoprecipitation studies revealed that the 165 and 60 kDa proteins were, respectively, c-Fms and c-Src. The c-Src kinase activity was increased 2.9-fold following CSF-1 treatment. The 85-90 k

Fabrication of cellular materials

NASA Astrophysics Data System (ADS)

Prud'homme, Robert K.; Aksay, Ilhan A.; Garg, Rajeev

1996-02-01

Nature uses cellular materials in applications requiring strength while, simultaneously, minimizing raw materials requirements. Minimizing raw materials is efficient both in terms of the energy expended by the organism to synthesize the structure and in terms of the strength- to-weight ratio of the structure. Wood is the most obvious example of cellular bio-materials, and it is the focus of other presentations in this symposium. The lightweight bone structure of birds is another excellent example where weight is a key criterion. The anchoring foot of the common muscle [Mytilus edulis] whereby it attaches itself to objects is a further example of a biological system that uses a foam to fill space and yet conserve on raw materials. In the case of the muscle the foam is water filled and the foot structure distributes stress over a larger area so that the strength of the byssal thread from which it is suspended is matched to the strength of interfacial attachment of the foot to a substrate. In these examples the synthesis and fabrication of the cellular material is directed by intercellular, genetically coded, biochemical reactions. The resulting cell sizes are microns in scale. Cellular materials at the next larger scale are created by organisms at the next higher level of integration. For example an African tree frog lays her eggs in a gas/fluid foam sack she builds on a branch overhanging a pond. The outside of the foam sack hardens in the sun and prevents water evaporation. The foam structure minimizes the amount of fluid that needs to be incorporated into the sack and minimizes its weight. However, as far as the developing eggs are concerned, they are in an aqueous medium, i.e. the continuous fluid phase of the foam. After precisely six days the eggs hatch, and the solidified outer wall re-liquefies and dumps the emerging tadpoles into the pond below. The bee honeycomb is an example of a cellular material with exquisite periodicity at millimeter length scales. The

Effects of reactive oxygen species on cellular wall disassembly of banana fruit during ripening.

PubMed

Cheng, Guiping; Duan, Xuewu; Shi, John; Lu, Wangjin; Luo, Yunbo; Jiang, Weibo; Jiang, Yueming

2008-07-15

Fruit softening is generally attributed to cell wall disassembly. Experiments were conducted to investigate effects of various reactive oxygen species (ROS) on in vitro cellular wall disassembly of harvested banana fruit. The alcohol-extracted insoluble residue (AEIR) was obtained from the pulp tissues of banana fruit at various ripening stages and then used to examine the disassembly of cellular wall polysaccharides in the presence of superoxide anion (O2(-)), hydrogen peroxide (H2O2) or hydroxyl radical (OH) and their scavengers. The presence of OH accelerated significantly disassembly of cellular wall polysaccharides in terms of the increase in contents of total sugars released and uronic acid, and the decrease in molecular mass of soluble polysaccharides, using gel permeation chromatography. However, the treatment with H2O2 or O2(-) showed no significant effect on the disassembly of cellular wall polysaccharides. Furthermore, the degradation of the de-esterified AEIR was more susceptible to OH attack than the esterified AEIR. In addition, the effect of OH could be inhibited in the presence of OH scavenger. This study suggests that disassembly of cellular wall polysaccharides could be initiated by OH as the solublisation of the polysaccharides increased, which, in turn, accelerated fruit softening. Copyright © 2008 Elsevier Ltd. All rights reserved.

A dynamic cellular vertex model of growing epithelial tissues

NASA Astrophysics Data System (ADS)

Lin, Shao-Zhen; Li, Bo; Feng, Xi-Qiao

2017-04-01

Intercellular interactions play a significant role in a wide range of biological functions and processes at both the cellular and tissue scales, for example, embryogenesis, organogenesis, and cancer invasion. In this paper, a dynamic cellular vertex model is presented to study the morphomechanics of a growing epithelial monolayer. The regulating role of stresses in soft tissue growth is revealed. It is found that the cells originating from the same parent cell in the monolayer can orchestrate into clustering patterns as the tissue grows. Collective cell migration exhibits a feature of spatial correlation across multiple cells. Dynamic intercellular interactions can engender a variety of distinct tissue behaviors in a social context. Uniform cell proliferation may render high and heterogeneous residual compressive stresses, while stress-regulated proliferation can effectively release the stresses, reducing the stress heterogeneity in the tissue. The results highlight the critical role of mechanical factors in the growth and morphogenesis of epithelial tissues and help understand the development and invasion of epithelial tumors.

Complement-Mediated Regulation of Metabolism and Basic Cellular Processes.

PubMed

Hess, Christoph; Kemper, Claudia

2016-08-16

Complement is well appreciated as a critical arm of innate immunity. It is required for the removal of invading pathogens and works by directly destroying them through the activation of innate and adaptive immune cells. However, complement activation and function is not confined to the extracellular space but also occurs within cells. Recent work indicates that complement activation regulates key metabolic pathways and thus can impact fundamental cellular processes, such as survival, proliferation, and autophagy. Newly identified functions of complement include a key role in shaping metabolic reprogramming, which underlies T cell effector differentiation, and a role as a nexus for interactions with other effector systems, in particular the inflammasome and Notch transcription-factor networks. This review focuses on the contributions of complement to basic processes of the cell, in particular the integration of complement with cellular metabolism and the potential implications in infection and other disease settings. Copyright © 2016 Elsevier Inc. All rights reserved.

Removal of cellular debris formed in the Disse space in patients with cholestasis.

PubMed

Dubuisson, L; Bioulac-Sage, P; Boussarie, L; Quinton, A; Saric, J; de Mascarel, A; Balabaud, C

1987-01-01

Using electron microscopy, we investigated how cellular debris, formed in the Disse space during cholestasis, was cleared. Ten patients with cholestasis of varied origin and severity were studied and compared with 10 controls without liver disease. In cholestatic patients, sinusoidal cells contained variable amounts of amylase PAS-positive material. In clean perfusion-fixed sinusoids the endothelial cells often appeared swollen and active, with few fenestrations. Hepatocyte blebs and cellular debris were sometimes seen in the Disse space. Two mechanisms were apparently involved in the clearing process: phagocytosis by macrophages either infiltrated into the Disse space, or forming the barrier; and the passage of debris from the Disse space into the sinusoidal lumen through the endothelial wall. Debris was either forced through enlarged pores or through the wall, with a progressive invagination followed by an outpouching in the lumen. The force, possibly provided by endothelial massage, may not be sufficient to push out cellular debris from the Disse space; morphological data seemed to indicate that endothelial damage may be a necessary factor. Debris present in the lumen was phagocytized by numerous active macrophages. Cellular debris was not observed in the Disse space of control patients.

Cellular solitary fibrous tumor (hemangiopericytoma) with anaplasia at cerebellopontine angle--a case report.

PubMed

Zeng, Jianying; Ogera, Patricia; Benardete, Ethan A; Nicastri, Anthony D; Rao, Chandrakant

2012-08-15

Cellular solitary fibrous tumor is currently considered a synonym for hemangiopericytoma, as it became increasingly clear that the morphological and immunohistochemical features that separate these two entities have become tenuous, and evidence for a unifying concept has emerged. Furthermore, as no evidence of pericytic differentiation is given in most cases of hemangiopericytoma, this diagnostic term is waning in popularity. We present here a case of cellular solitary fibrous tumor in a 22-year-old man. Neuroimaging revealed a right cerebellopontine angle tumor. Most of the tumor was cellular although some less cellular areas were seen. Sinusoidally dilated large vessels, including staghorn type, were seen. Nuclear pleomorphism and increased mitotic activity (5 mitosis/10 high power field) were regarded as evidence of anaplasia. Diffuse CD34 immunoreactivity and focal positivity for Factor XIIIa were seen in the tumor, which was negative for EMA and S100. The tumor also displayed rich reticulin network. Solitary fibrous tumor at cerebellopontine angle is rare, and 20 such cases (five reported as hemangiopericytoma) have been reported in the English literature. Copyright © 2012 Elsevier GmbH. All rights reserved.

Identification of novel host factors via conserved domain search: Cns1 cochaperone is a novel restriction factor of tombusvirus replication in yeast.

PubMed

Lin, Jing-Yi; Nagy, Peter D

2013-12-01

A large number of host-encoded proteins affect the replication of plus-stranded RNA viruses by acting as susceptibility factors. Many other cellular proteins are known to function as restriction factors of viral infections. Previous studies with tomato bushy stunt tombusvirus (TBSV) in a yeast model host have revealed the inhibitory function of TPR (tetratricopeptide repeat) domain-containing cyclophilins, which are members of the large family of host prolyl isomerases, in TBSV replication. In this paper, we tested additional TPR-containing yeast proteins in a cell-free TBSV replication assay and identified the Cns1p cochaperone for heat shock protein 70 (Hsp70) and Hsp90 chaperones as a strong inhibitor of TBSV replication. Cns1p interacted with the viral replication proteins and inhibited the assembly of the viral replicase complex and viral RNA synthesis in vitro. Overexpression of Cns1p inhibited TBSV replication in yeast. The use of a temperature-sensitive (TS) mutant of Cns1p in yeast revealed that at a semipermissive temperature, TS Cns1p could not inhibit TBSV replication. Interestingly, Cns1p and the TPR-containing Cpr7p cyclophilin have similar inhibitory functions during TBSV replication, although some of the details of their viral restriction mechanisms are different. Our observations indicate that TPR-containing cellular proteins could act as virus restriction factors.

Two distinct cellular proteins interact with the EIa-responsive element of an adenovirus early promoter.

PubMed Central

Jansen-Durr, P; Wintzerith, M; Reimund, B; Hauss, C; Kédinger, C

1990-01-01

EIa-dependent transactivation of the adenovirus EIIa early (EIIaE) promoter is correlated with the activation of the cellular transcription factor E2F. In this study we identified a cellular protein, C alpha, that is distinct from E2F and that binds two sites in the EIIaE promoter, one of which overlaps with the proximal E2F binding site of the EIIaE promoter. The possible involvement of C alpha in the EIa responsiveness of this promoter is discussed. Images PMID:2139142

Piezoelectricity and ferroelectricity of cellular polypropylene electrets films characterized by piezoresponse force microscopy

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

Miao, Hongchen; Sun, Yao; Zhou, Xilong

Cellular electrets polymer is a new ferroelectret material exhibiting large piezoelectricity and has attracted considerable attentions in researches and industries. Property characterization is very important for this material and current investigations are mostly on macroscopic properties. In this work, we conduct nanoscale piezoelectric and ferroelectric characterizations of cellular polypropylene (PP) films using piezoresponse force microscopy (PFM). First, both the single-frequency PFM and dual-frequency resonance-tracking PFM testings were conducted on the cellular PP film. The localized piezoelectric constant d{sub 33} is estimated to be 7–11pC/N by correcting the resonance magnification with quality factor and it is about one order lower thanmore » the macroscopic value. Next, using the switching spectroscopy PFM (SS-PFM), we studied polarization switching behavior of the cellular PP films. Results show that it exhibits the typical ferroelectric-like phase hysteresis loops and butterfly-shaped amplitude loops, which is similar to that of a poly(vinylidene fluoride) (PVDF) ferroelectric polymer film. However, both the phase and amplitude loops of the PP film are intensively asymmetric, which is thought to be caused by the nonzero remnant polarization after poling. Then, the D-E hysteresis loops of both the cellular PP film and PVDF film were measured by using the same wave form as that used in the SS-PFM, and the results show significant differences. Finally, we suggest that the ferroelectric-like behavior of cellular electrets films should be distinguished from that of typical ferroelectrics, both macroscopically and microscopically.« less

Coarse-grained Brownian ratchet model of membrane protrusion on cellular scale.

PubMed

Inoue, Yasuhiro; Adachi, Taiji

2011-07-01

Membrane protrusion is a mechanochemical process of active membrane deformation driven by actin polymerization. Previously, Brownian ratchet (BR) was modeled on the basis of the underlying molecular mechanism. However, because the BR requires a priori load that cannot be determined without information of the cell shape, it cannot be effective in studies in which resultant shapes are to be solved. Other cellular-scale models describing the protrusion have also been suggested for modeling a whole cell; however, these models were not developed on the basis of coarse-grained physics representing the underlying molecular mechanism. Therefore, to express the membrane protrusion on the cellular scale, we propose a novel mathematical model, the coarse-grained BR (CBR), which is derived on the basis of nonequilibrium thermodynamics theory. The CBR can reproduce the BR within the limit of the quasistatic process of membrane protrusion and can estimate the protrusion velocity consistently with an effective elastic constant that represents the state of the energy of the membrane. Finally, to demonstrate the applicability of the CBR, we attempt to perform a cellular-scale simulation of migrating keratocyte in which the proposed CBR is used for the membrane protrusion model on the cellular scale. The results show that the experimentally observed shapes of the leading edge are well reproduced by the simulation. In addition, The trend of dependences of the protrusion velocity on the curvature of the leading edge, the temperature, and the substrate stiffness also agreed with the other experimental results. Thus, the CBR can be considered an appropriate cellular-scale model to express the membrane protrusion on the basis of its underlying molecular mechanism.

CREG1 enhances p16INK4a-induced cellular senescence

PubMed Central

Moolmuang, Benchamart

2011-01-01

Cellular senescence is an irreversible growth arrest that is activated in normal cells upon shortening of telomere and other cellular stresses. Bypassing cellular senescence is a necessary step for cells to become immortal during oncogenic transformation. During the spontaneous immortalization of Li-Fraumeni Syndrome (LFS) fibroblasts, we found that CREG1 (Cellular Repressor of E1A-stimulated Genes 1) expression was decreased during immortalization and increased in senescence. Moreover, we found that repression of CREG1 expression occurs via an epigenetic mechanism, promoter DNA methylation. Ectopic expression of CREG1 in the immortal LFS cell lines decreases cell proliferation but does not directly induce senescence. We confirmed this in osteosarcoma and fibrosarcoma cancer cell lines, cancers commonly seen in Li-Fraumeni Syndrome. In addition, we found that p16INK4a is also downregulated in immortal cells and that coexpression of CREG1 and p16INK4a, an inhibitor of CDK4/6 and Rb phosphorylation, has a greater effect than either CREG1 and p16INK4a alone to reduce cell growth, induce cell cycle arrest and cellular senescence in immortal LFS fibroblasts, osteosarcoma and fibrosarcoma cell lines. Moreover, cooperation of CREG1 and p16INK4a inhibits the expression of cyclin A and cyclin B by inhibiting promoter activity, thereby decreasing mRNA and protein levels; these proteins are required for S-phase entry and G2/M transition. In conclusion, this is the first evidence to demonstrate that CREG1 enhances p16INK4a-induced senescence by transcriptional repression of cell cycle-regulated genes. PMID:21263217

47 CFR 22.901 - Cellular service requirements and limitations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.901 Cellular service requirements and limitations. The licensee of each cellular system is responsible for ensuring that its cellular system operates in compliance with this section. (a) Each cellular system must provide either mobile service...

Pericentrin in cellular function and disease

PubMed Central

Delaval, Benedicte

2010-01-01

Pericentrin is an integral component of the centrosome that serves as a multifunctional scaffold for anchoring numerous proteins and protein complexes. Through these interactions, pericentrin contributes to a diversity of fundamental cellular processes. Recent studies link pericentrin to a growing list of human disorders. Studies on pericentrin at the cellular, molecular, and, more recently, organismal level, provide a platform for generating models to elucidate the etiology of these disorders. Although the complexity of phenotypes associated with pericentrin-mediated disorders is somewhat daunting, insights into the cellular basis of disease are beginning to come into focus. In this review, we focus on human conditions associated with loss or elevation of pericentrin and propose cellular and molecular models that might explain them. PMID:19951897

The effects of scaffold architecture and fibrin gel addition on tendon cell phenotype.

PubMed

Pawelec, K M; Wardale, R J; Best, S M; Cameron, R E

2015-01-01

Development of tissue engineering scaffolds relies on careful selection of pore architecture and chemistry of the cellular environment. Repair of skeletal soft tissue, such as tendon, is particularly challenging, since these tissues have a relatively poor healing response. When removed from their native environment, tendon cells (tenocytes) lose their characteristic morphology and the expression of phenotypic markers. To stimulate tendon cells to recreate a healthy extracellular matrix, both architectural cues and fibrin gels have been used in the past, however, their relative effects have not been studied systematically. Within this study, a combination of collagen scaffold architecture, axial and isotropic, and fibrin gel addition was assessed, using ovine tendon-derived cells to determine the optimal strategy for controlling the proliferation and protein expression. Scaffold architecture and fibrin gel addition influenced tendon cell behavior independently in vitro. Addition of fibrin gel within a scaffold doubled cell number and increased matrix production for all architectures studied. However, scaffold architecture dictated the type of matrix produced by cells, regardless of fibrin addition. Axial scaffolds, mimicking native tendon, promoted a mature matrix, with increased tenomodulin, a marker for mature tendon cells, and decreased scleraxis, an early transcription factor for connective tissue. This study demonstrated that both architectural cues and fibrin gel addition alter cell behavior and that the combination of these signals could improve clinical performance of current tissue engineering constructs.

Advances in the cellular and molecular biology of angiogenesis.

PubMed

Egginton, Stuart; Bicknell, Roy

2011-12-01

Capillaries have been recognized for over a century as one of the most important components in regulating tissue oxygen transport, and their formation or angiogenesis a pivotal element of tissue remodelling during development and adaptation. Clinical interest stems from observations that both excessive and inadequate vascular growth plays a major role in human diseases, and novel developments in treatments for cancer and eye disease increasingly rely on anti-angiogenic therapies. Although the discovery of VEGF (vascular endothelial growth factor) provided the first clue for specificity of signalling in endothelial cell activation, understanding the integrative response that drives angiogenesis requires a much broader perspective. The Advances in the Cellular and Molecular Biology of Angiogenesis meeting brought together researchers at the forefront of this rapidly moving field to provide an update on current understanding, and the most recent insights into molecular and cellular mechanisms of vascular growth. The plenary lecture highlighted the integrative nature of the angiogenic process, whereas invited contributions from basic and clinician scientists described fundamental mechanisms and disease-associated issues of blood vessel formation, grouped under a number of themes to aid discussion. These articles will appeal to academic, clinical and pharmaceutical scientists interested in the molecular and cellular basis of angiogenesis, their modulation or dysfunction in human diseases, and application of these findings towards translational medicine.

Human leukocyte antigens and cellular immune responses to anthrax vaccine adsorbed.

PubMed

Ovsyannikova, Inna G; Pankratz, V Shane; Vierkant, Robert A; Pajewski, Nicholas M; Quinn, Conrad P; Kaslow, Richard A; Jacobson, Robert M; Poland, Gregory A

2013-07-01

Interindividual variations in vaccine-induced immune responses are in part due to host genetic polymorphisms in the human leukocyte antigen (HLA) and other gene families. This study examined associations between HLA genotypes, haplotypes, and homozygosity and protective antigen (PA)-specific cellular immune responses in healthy subjects following immunization with Anthrax Vaccine Adsorbed (AVA). While limited associations were observed between individual HLA alleles or haplotypes and variable lymphocyte proliferative (LP) responses to AVA, analyses of homozygosity supported the hypothesis of a "heterozygote advantage." Individuals who were homozygous for any HLA locus demonstrated significantly lower PA-specific LP than subjects who were heterozygous at all eight loci (median stimulation indices [SI], 1.84 versus 2.95, P = 0.009). Similarly, we found that class I (HLA-A) and class II (HLA-DQA1 and HLA-DQB1) homozygosity was significantly associated with an overall decrease in LP compared with heterozygosity at those three loci. Specifically, individuals who were homozygous at these loci had significantly lower PA-specific LP than subjects heterozygous for HLA-A (median SI, 1.48 versus 2.13, P = 0.005), HLA-DQA1 (median SI, 1.75 versus 2.11, P = 0.007), and HLA-DQB1 (median SI, 1.48 versus 2.13, P = 0.002) loci, respectively. Finally, homozygosity at an increasing number (≥ 4) of HLA loci was significantly correlated with a reduction in LP response (P < 0.001) in a dose-dependent manner. Additional studies are needed to reproduce these findings and determine whether HLA-heterozygous individuals generate stronger cellular immune response to other virulence factors (Bacillus anthracis LF and EF) than HLA-homozygous subjects.

A "distorted-BODIPY"-based fluorescent probe for imaging of cellular viscosity in live cells.

PubMed

Zhu, Hao; Fan, Jiangli; Li, Miao; Cao, Jianfang; Wang, Jingyun; Peng, Xiaojun

2014-04-14

Cellular viscosity is a critical factor in governing diffusion-mediated cellular processes and is linked to a number of diseases and pathologies. Fluorescent molecular rotors (FMRs) have recently been developed to determine viscosity in solutions or biological fluid. Herein, we report a "distorted-BODIPY"-based probe BV-1 for cellular viscosity, which is different from the conventional "pure rotors". In BV-1, the internal steric hindrance between the meso-CHO group and the 1,7-dimethyl group forced the boron-dipyrrin framework to be distorted, which mainly caused nonradiative deactivation in low-viscosity environment. BV-1 gave high sensitivity (x=0.62) together with stringent selectivity to viscosity, thus enabling viscosity mapping in live cells. Significantly, the increase of cytoplasmic viscosity during apoptosis was observed by BV-1 in real time. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Driving mechanisms of passive and active transport across cellular membranes as the mechanisms of cell metabolism and development as well as the mechanisms of cellular distance reactions on hormonal expression and the immune response.

PubMed

Ponisovskiy, M R

2011-01-01

The article presents mechanisms of cell metabolism, cell development, cell activity, and maintenance of cellular stability. The literature is reviewed from the point of view of these concepts. The balance between anabolic and catabolic processes induces chemical potentials in the extracellular and intracellular media. The chemical potentials of these media are defined as the driving forces of both passive and active transport of substances across cellular membranes. The driving forces of substance transport across cellular membranes as in cellular metabolism and in immune responses and hormonal expressions are considered in the biochemical and biophysical models, reflecting the mechanisms for maintenance of stability of the internal medium and internal energy of an organism. The interactions of passive transport and active transport of substances across cellular walls promote cell proliferation, as well as the mechanism of cellular capacitors, promoting remote reactions across distance for hormonal expression and immune responses. The offered concept of cellular capacitors has given the possibility to explain the mechanism of remote responses of cells to new situations, resulting in the appearance of additional agents. The biophysical model develops an explanation of some cellular functions: cellular membrane action have been identified with capacitor action, based on the similarity of the structures and as well as on similarity of biophysical properties of electric data that confirm the action of the compound-specific interactions of cells within an organism, promoting hormonal expressions and immune responses to stabilize the thermodynamic system of an organism. Comparison of a cellular membrane action to a capacitor has given the possibility for the explanations of exocytosis and endocytosis mechanisms, internalization of the receptor-ligand complex, selection as a receptor reaction to a ligand by immune responses or hormonal effects, reflecting cellular

Integrated Circuit-Based Biofabrication with Common Biomaterials for Probing Cellular Biomechanics.

PubMed

Sung, Chun-Yen; Yang, Chung-Yao; Yeh, J Andrew; Cheng, Chao-Min

2016-02-01

Recent advances in bioengineering have enabled the development of biomedical tools with modifiable surface features (small-scale architecture) to mimic extracellular matrices and aid in the development of well-controlled platforms that allow for the application of mechanical stimulation for studying cellular biomechanics. An overview of recent developments in common biomaterials that can be manufactured using integrated circuit-based biofabrication is presented. Integrated circuit-based biofabrication possesses advantages including mass and diverse production capacities for fabricating in vitro biomedical devices. This review highlights the use of common biomaterials that have been most frequently used to study cellular biomechanics. In addition, the influence of various small-scale characteristics on common biomaterial surfaces for a range of different cell types is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cellular, ultrastructural and molecular analyses of epidermal cell development in the planarian Schmidtea mediterranea.

PubMed

Cheng, Li-Chun; Tu, Kimberly C; Seidel, Chris W; Robb, Sofia M C; Guo, Fengli; Sánchez Alvarado, Alejandro

2018-01-15

The epidermis is essential for animal survival, providing both a protective barrier and cellular sensor to external environments. The generally conserved embryonic origin of the epidermis, but the broad morphological and functional diversity of this organ across animals is puzzling. We define the transcriptional regulators underlying epidermal lineage differentiation in the planarian Schmidtea mediterranea, an invertebrate organism that, unlike fruitflies and nematodes, continuously replaces its epidermal cells. We find that Smed-p53, Sox and Pax transcription factors are essential regulators of epidermal homeostasis, and act cooperatively to regulate genes associated with early epidermal precursor cell differentiation, including a tandemly arrayed novel gene family (prog) of secreted proteins. Additionally, we report on the discovery of distinct and previously undescribed secreted organelles whose production is dependent on the transcriptional activity of soxP-3, and which we term Hyman vesicles. Copyright © 2017 Elsevier Inc. All rights reserved.

Studies of elongation factor Tu in Streptococcus faecium (ATCC 9790)

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

Bourbeau, P.P.

1986-01-01

It has been known for over twenty years that elongation factor Tu (Ef-Tu) is one of the proteins involved in protein synthesis in bacteria. Several years ago, it was proposed that Ef-Tu may, in addition, have other structural functions in bacterial. The author's research has examined the function of Ef-Tu in Streptococcus faecium. Using an antibiotic kirromycin, which specifically inhibits Ef-Tu function, the effects upon a number of cellular parameters were determined. Inhibition of both protein and RNA synthesis was found to be similar to the effect of chloramphenicol. Using the residual division technique for the determination of cell cyclemore » events with both heterogeneous and sucrose gradient fractionated cell populations, a kirromycin sensitive event was detected between 8 min. (Td = 30 min.) and 19 min. (Td = 175 min.) later in the cell cycle than the chloramphenical sensitive event. This suggests that kirromycin is inhibiting a terminal cell cycle event which is in addition to the inhibition of protein synthesis. Purification of Ef-Tu was performed using two different methods: ion exchange and molecular exclusion chromatography; and GDP affinity chromatography. Various schemes were employed to try and obtain optimum cellular fractionation, allowing for both proper separation of ribosomes from the other cellular fractions and retention of enzymatic activity by Ef-Tu as determined by a /sup 3/H-GDP binding assay. Analysis of the cell cycle of S. faecium using the residual division technique was also performed. In addition, certain cell wall antibiotics were used to determine if other cell cycle events could be determined using the residual division technique.« less

The impact of cellular senescence in skin ageing: A notion of mosaic and therapeutic strategies.

PubMed

Toutfaire, Marie; Bauwens, Emilie; Debacq-Chainiaux, Florence

2017-10-15

Cellular senescence is now recognized as one of the nine hallmarks of ageing. Recent data show the involvement of senescent cells in tissue ageing and some age-related diseases. Skin represents an ideal model for the study of ageing. Indeed, skin ageing varies between individuals depending on their chronological age but also on their exposure to various exogenous factors (mainly ultraviolet rays). If senescence traits can be detected with ageing in the skin, the senescent phenotype varies among the various skin cell types. Moreover, the origin of cellular senescence in the skin is still unknown, and multiple origins are possible. This reflects the mosaic of skin ageing. Senescent cells can interfere with their microenvironment, either via the direct secretion of factors (the senescence-associated secretory phenotype) or via other methods of communication, such as extracellular vesicles. Knowledge regarding the impact of cellular senescence on skin ageing could be integrated into dermatology research, especially to limit the appearance of senescent cells after photo(chemo)therapy or in age-related skin diseases. Therapeutic approaches include the clearance of senescent cells via the use of senolytics or via the cooperation with the immune system. Copyright © 2017 Elsevier Inc. All rights reserved.

Cellular phone use while driving at night.

PubMed

Vivoda, Jonathon M; Eby, David W; St Louis, Renée M; Kostyniuk, Lidia P

2008-03-01

Use of a cellular phone has been shown to negatively affect one's attention to the driving task, leading to an increase in crash risk. At any given daylight hour, about 6% of US drivers are actively talking on a hand-held cell phone. However, previous surveys have focused only on cell phone use during the day. Driving at night has been shown to be a riskier activity than driving during the day. The purpose of the current study was to assess the rate of hand-held cellular phone use while driving at night, using specialized night vision equipment. In 2006, two statewide direct observation survey waves of nighttime cellular phone use were conducted in Indiana utilizing specialized night vision equipment. Combined results of driver hand-held cellular phone use from both waves are presented in this manuscript. The rates of nighttime cell phone use were similar to results found in previous daytime studies. The overall rate of nighttime hand-held cellular phone use was 5.8 +/- 0.6%. Cellular phone use was highest for females and for younger drivers. In fact, the highest rate observed during the study (of 11.9%) was for 16-to 29-year-old females. The high level of cellular phone use found within the young age group, coupled with the increased crash risk associated with cellular phone use, nighttime driving, and for young drivers in general, suggests that this issue may become an important transportation-related concern.

Additional Value of Diffusion-Weighted Imaging to Evaluate Prognostic Factors of Breast Cancer: Correlation with the Apparent Diffusion Coefficient.

PubMed

Park, Eun Kyung; Cho, Kyu Ran; Seo, Bo Kyoung; Woo, Ok Hee; Cho, Sung Bum; Bae, Jeoung Won

2016-01-01

Breast cancer is a heterogeneous disease with diverse prognoses. The main prognostic determinants are lymph node status, tumor size, histological grade, and biological factors, such as hormone receptors, human epidermal growth factor receptor 2 (HER2), Ki-67 protein levels, and p53 expression. Diffusion-weighted imaging (DWI) can be used to measure the apparent diffusion coefficient (ADC) that provides information related to tumor cellularity and the integrity of the cell membranes. The goal of this study was to evaluate whether ADC measurements could provide information on the prognostic factors of breast cancer. A total of 71 women with invasive breast cancer, treated consecutively, who underwent preoperative breast MRIs with DWI at 3.0 Tesla and subsequent surgery, were prospectively included in this study. Each DWI was acquired with b values of 0 and 1000 s/mm(2). The mean ADC values of the lesions were measured, including the entire lesion on the three largest sections. We performed histopathological analyses for the tumor size, lymph node status, histological grade, hormone receptors, human epidermal growth factor receptor 2 (HER2), Ki-67, p53, and molecular subtypes. The associations with the ADC values and prognostic factors of breast cancer were evaluated using the independent-samples t test and the one-way analysis of variance (ANOVA). A low ADC value was associated with lymph node metastasis (P < 0.01) and with high Ki-67 protein levels (P = 0.03). There were no significant differences in the ADC values among the histological grade (P = 0.48), molecular subtype (P = 0.51), tumor size (P = 0.46), and p53 protein level (P = 0.62). The pre-operative use of the 3.0 Tesla DWI could provide information about the lymph node status and tumor proliferation for breast cancer patients, and could help determine the optimal treatment plan.

Cellular telephone as reservoir of bacterial contamination: myth or fact.

PubMed

Walia, Satinder S; Manchanda, Adesh; Narang, Ramandeep S; N, Anup; Singh, Balwinder; Kahlon, Sukhdeep S

2014-01-01

To assess bacterial contamination of cellular telephone of dental care personnel, and to determine factors contributing to their contamination. A descriptive, cross-sectional study was conducted, which included 300 people using a cellular telephone The study group (hundred in each group) comprised of Dental Health Care Personnel (DHCP), In-Hospital Personnel (IHP) and Out-Hospital Personnel (OHP) of a dental college cum hospital. Swab was wiped along the front and all sides of cellular handset and it was incubated in glucose broth. The swab was subplated onto growth media plates made with half Mac Conkey's agar and half blood agar and allowed to incubate for 48 hours at 37(o)C. Isolates were tested for antimicrobial susceptibility. The analysis of presence or absence of microorganisms in the DHCP, IHP and OHP group showed no pyogenic growth in 28%, 31% and 41% cases respectively, the distribution of which was not significant (p>.05). Among non potential pathogens, spore bearing gram positive bacilli were seen in 20 cases of DHCP group, 16 cases of IHP group and 17 cases of OHP group; the distribution of which was not significant (p>.05) Among potential pathogens, significant differences were observed in the distribution of growth of Enterobacter (p<.001), Pseudomonas species (p<.05), Acinetobacter bacteria (p<.05) and Methicillin-resistant Staphylococcus aureus (MRSA) bacteria (p<.001) between the participants of different groups. RESULTs of this study showed that fomites such as cellular telephones can potentially act as "Trojan horses", thus causing Hospital-Acquired Infections (HAIs) in the dental setting.

Inter-Cellular Exchange of Cellular Components via VE-Cadherin-Dependent Trans-Endocytosis

PubMed Central

Sakurai, Takashi; Woolls, Melissa J.; Jin, Suk-Won

2014-01-01

Cell-cell communications typically involve receptor-mediated signaling initiated by soluble or cell-bound ligands. Here, we report a unique mode of endocytosis: proteins originating from cell-cell junctions and cytosolic cellular components from the neighboring cell are internalized, leading to direct exchange of cellular components between two adjacent endothelial cells. VE-cadherins form transcellular bridges between two endothelial cells that are the basis of adherence junctions. At such adherens junction sites, we observed the movement of the entire VE-cadherin molecule from one endothelial cell into the other with junctional and cytoplasmic components. This phenomenon, here termed trans-endocytosis, requires the establishment of a VE-cadherin homodimer in trans with internalization proceeding in a Rac1-, and actomyosin-dependent manner. Importantly, the trans-endocytosis is not dependent on any known endocytic pathway including clathrin-dependent endocytosis, macropinocytosis or phagocytosis. This novel form of cell-cell communications, leading to a direct exchange of cellular components, was observed in 2D and 3D-cultured endothelial cells as well as in the developing zebrafish vasculature. PMID:24603875

Cellular IRES-mediated translation: the war of ITAFs in pathophysiological states.

PubMed

Komar, Anton A; Hatzoglou, Maria

2011-01-15

Translation of cellular mRNAs via initiation at Internal Ribosome Entry Sites (IRESs) has received increased attention during recent years due to its emerging significance for many physiological and pathological stress conditions in eukaryotic cells. Expression of genes bearing IRES elements in their mRNAs is controlled by multiple molecular mechanisms, with IRES-mediated translation favored under conditions when cap-dependent translation is compromised. In this review, we discuss recent advances in the field and future directions that may bring us closer to understanding the complex mechanisms that guide cellular IRES-mediated expression. We present examples in which the competitive action of IRES-transacting factors (ITAFs) plays a pivotal role in IRES-mediated translation and thereby controls cell-fate decisions leading to either pro-survival stress adaptation or cell death.

Mechanical properties of porous and cellular materials

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

Sieradzki, K.; Green, D.J.; Gibson, L.J.

1991-01-01

This symposium successfully brought scientists together from a wide variety of disciplines to focus on the mechanical behavior of porous and cellular solids composed of metals, ceramics, polymers, or biological materials. For cellular materials, papers ranged from processing techniques through microstructure-mechanical property relationships to design. In an overview talk, Mike Ashby (Cambridge Univ.) showed how porous cellular materials can be more efficient than dense materials in designs that require minimum weight. He indicated that many biological materials have been able to accomplish such efficiency but there exists an opportunity to design even more efficient, manmade materials controlling microstructures at differentmore » scale levels. In the area of processing, James Aubert (Sandia National Laboratories) discussed techiques for manipulating polymersolvent phase equilibria to control the microstructure of microcellular foams. Other papers on processing discussed the production of cellular ceramics by CVD, HIPing and sol- gel techniques. Papers on the mechanical behavior of cellular materials considered various ceramics microcellular polymers, conventional polymer foams and apples. There were also contributions that considered optimum design procedures for cellular materials. Steven Cowin (City Univ. of New York) discussed procedures to match the discrete microstructural aspects of cellular materials with the continuum mechanics approach to their elastic behavior.« less

Plate-impact loading of cellular structures formed by selective laser melting

NASA Astrophysics Data System (ADS)

Winter, R. E.; Cotton, M.; Harris, E. J.; Maw, J. R.; Chapman, D. J.; Eakins, D. E.; McShane, G.

2014-03-01

Porous materials are of great interest because of improved energy absorption over their solid counterparts. Their properties, however, have been difficult to optimize. Additive manufacturing has emerged as a potential technique to closely define the structure and properties of porous components, i.e. density, strut width and pore size; however, the behaviour of these materials at very high impact energies remains largely unexplored. We describe an initial study of the dynamic compression response of lattice materials fabricated through additive manufacturing. Lattices consisting of an array of intersecting stainless steel rods were fabricated into discs using selective laser melting. The resulting discs were impacted against solid stainless steel targets at velocities ranging from 300 to 700 m s-1 using a gas gun. Continuum CTH simulations were performed to identify key features in the measured wave profiles, while 3D simulations, in which the individual cells were modelled, revealed details of microscale deformation during collapse of the lattice structure. The validated computer models have been used to provide an understanding of the deformation processes in the cellular samples. The study supports the optimization of cellular structures for application as energy absorbers.

Predictability in Cellular Automata

PubMed Central

Agapie, Alexandru; Andreica, Anca; Chira, Camelia; Giuclea, Marius

2014-01-01

Modelled as finite homogeneous Markov chains, probabilistic cellular automata with local transition probabilities in (0, 1) always posses a stationary distribution. This result alone is not very helpful when it comes to predicting the final configuration; one needs also a formula connecting the probabilities in the stationary distribution to some intrinsic feature of the lattice configuration. Previous results on the asynchronous cellular automata have showed that such feature really exists. It is the number of zero-one borders within the automaton's binary configuration. An exponential formula in the number of zero-one borders has been proved for the 1-D, 2-D and 3-D asynchronous automata with neighborhood three, five and seven, respectively. We perform computer experiments on a synchronous cellular automaton to check whether the empirical distribution obeys also that theoretical formula. The numerical results indicate a perfect fit for neighbourhood three and five, which opens the way for a rigorous proof of the formula in this new, synchronous case. PMID:25271778

Predictability in cellular automata.

PubMed

Agapie, Alexandru; Andreica, Anca; Chira, Camelia; Giuclea, Marius

2014-01-01

Modelled as finite homogeneous Markov chains, probabilistic cellular automata with local transition probabilities in (0, 1) always posses a stationary distribution. This result alone is not very helpful when it comes to predicting the final configuration; one needs also a formula connecting the probabilities in the stationary distribution to some intrinsic feature of the lattice configuration. Previous results on the asynchronous cellular automata have showed that such feature really exists. It is the number of zero-one borders within the automaton's binary configuration. An exponential formula in the number of zero-one borders has been proved for the 1-D, 2-D and 3-D asynchronous automata with neighborhood three, five and seven, respectively. We perform computer experiments on a synchronous cellular automaton to check whether the empirical distribution obeys also that theoretical formula. The numerical results indicate a perfect fit for neighbourhood three and five, which opens the way for a rigorous proof of the formula in this new, synchronous case.

Development of a Sox2 reporter system modeling cellular heterogeneity in glioma.

PubMed

Stoltz, Kevin; Sinyuk, Maksim; Hale, James S; Wu, Qiulian; Otvos, Balint; Walker, Kiera; Vasanji, Amit; Rich, Jeremy N; Hjelmeland, Anita B; Lathia, Justin D

2015-03-01

Malignant gliomas are complex systems containing a number of factors that drive tumor initiation and progression, including genetic aberrations that lead to extensive cellular heterogeneity within the neoplastic compartment. Mouse models recapitulate these genetic aberrations, but readily observable heterogeneity remains challenging. To interrogate cellular heterogeneity in mouse glioma models, we utilized a replication-competent avian sarcoma-leukosis virus long terminal repeat with splice acceptor/tumor virus A (RCAS-tva) system to generate spontaneous mouse gliomas that contained a Sox2-enhanced green fluorescent protein (EGFP) reporter. Glial fibrillary acidic protein-tva mice were crossed with Sox2-EGFP mice, and tumors were initiated that contained a subpopulation of Sox2-EGFP-high cells enriched for tumor-initiating cell properties such as self-renewal, multilineage differentiation potential, and perivascular localization. Following implantation into recipient mice, Sox2-EGFP-high cells generated tumors containing Sox2-EGFP-high and Sox2-EGFP-low cells. Kinomic analysis of Sox2-EGFP-high cells revealed activation of known glioma signaling pathways that are strongly correlated with patient survival including platelet-derived growth factor receptor beta, phosphoinositide-3 kinase, and vascular endothelial growth factor. Our functional analysis identified active feline sarcoma (Fes) signaling in Sox2-EGFP-high cells. Fes negatively correlated with glioma patient survival and was coexpressed with Sox2-positive cells in glioma xenografts and primary patient-derived tissue. Our RCAS-tva/Sox2-EGFP model will empower closer examination of cellular heterogeneity and will be useful for identifying novel glioma pathways as well as testing preclinical treatment efficacy. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Nuclear protein accumulation in cellular senescence and organismal aging revealed with a novel single-cell resolution fluorescence microscopy assay.

PubMed

De Cecco, Marco; Jeyapalan, Jessie; Zhao, Xiaoai; Tamamori-Adachi, Mimi; Sedivy, John M

2011-10-01

Replicative cellular senescence was discovered some 50 years ago. The phenotypes of senescent cells have been investigated extensively in cell culture, and found to affect essentially all aspects of cellular physiology. The relevance of cellular senescence in the context of age-associated pathologies as well as normal aging is a topic of active and ongoing interest. Considerable effort has been devoted to biomarker discovery to enable the microscopic detection of single senescent cells in tissues. One characteristic of senescent cells documented very early in cell culture studies was an increase in cell size and total protein content, but whether this occurs in vivo is not known. A limiting factor for studies of protein content and localization has been the lack of suitable fluorescence microscopy tools. We have developed an easy and flexible method, based on the merocyanine dye known as NanoOrange, to visualize and quantitatively measure total protein levels by high resolution fluorescence microscopy. NanoOrange staining can be combined with antibody-based immunofluorescence, thus providing both specific target and total protein information in the same specimen. These methods are optimally combined with automated image analysis platforms for high throughput analysis. We document here increasing protein content and density in nuclei of senescent human and mouse fibroblasts in vitro, and in liver nuclei of aged mice in vivo. Additionally, in aged liver nuclei NanoOrange revealed protein-dense foci that colocalize with centromeric heterochromatin.

Nuclear protein accumulation in cellular senescence and organismal aging revealed with a novel single-cell resolution fluorescence microscopy assay

PubMed Central

De Cecco, Marco; Jeyapalan, Jessie; Zhao, Xiaoai; Tamamori-Adachi, Mimi; Sedivy, John M.

2011-01-01

Replicative cellular senescence was discovered some 50 years ago. The phenotypes of senescent cells have been investigated extensively in cell culture, and found to affect essentially all aspects of cellular physiology. The relevance of cellular senescence in the context of age-associated pathologies as well as normal aging is a topic of active and ongoing interest. Considerable effort has been devoted to biomarker discovery to enable the microscopic detection of single senescent cells in tissues. One characteristic of senescent cells documented very early in cell culture studies was an increase in cell size and total protein content, but whether this occurs in vivo is not known. A limiting factor for studies of protein content and localization has been the lack of suitable fluorescence microscopy tools. We have developed an easy and flexible method, based on the merocyanine dye known as NanoOrange, to visualize and quantitatively measure total protein levels by high resolution fluorescence microscopy. NanoOrange staining can be combined with antibody-based immunofluorescence, thus providing both specific target and total protein information in the same specimen. These methods are optimally combined with automated image analysis platforms for high throughput analysis. We document here increasing protein content and density in nuclei of senescent human and mouse fibroblasts in vitro, and in liver nuclei of aged mice in vivo. Additionally, in aged liver nuclei NanoOrange revealed protein-dense foci that colocalize with centromeric heterochromatin. PMID:22006542

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: frequency, time course and risk factors.

PubMed

Nys, Monique; Venneman, Ingrid; Deby-Dupont, Ginette; Preiser, Jean-Charles; Vanbelle, Sophie; Albert, Adelin; Camus, Gérard; Damas, Pierre; Larbuisson, Robert; Lamy, Maurice

2007-05-01

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively.

The mammary cellular hierarchy and breast cancer.

PubMed

Oakes, Samantha R; Gallego-Ortega, David; Ormandy, Christopher J

2014-11-01

Advances in the study of hematopoietic cell maturation have paved the way to a deeper understanding the stem and progenitor cellular hierarchy in the mammary gland. The mammary epithelium, unlike the hematopoietic cellular hierarchy, sits in a complex niche where communication between epithelial cells and signals from the systemic hormonal milieu, as well as from extra-cellular matrix, influence cell fate decisions and contribute to tissue homeostasis. We review the discovery, definition and regulation of the mammary cellular hierarchy and we describe the development of the concepts that have guided our investigations. We outline recent advances in in vivo lineage tracing that is now challenging many of our assumptions regarding the behavior of mammary stem cells, and we show how understanding these cellular lineages has altered our view of breast cancer.

47 CFR 90.672 - Unacceptable interference to non-cellular 800 MHz licensees from 800 MHz cellular systems or part...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Unacceptable interference to non-cellular 800 MHz licensees from 800 MHz cellular systems or part 22 Cellular Radiotelephone systems, and within the 900 MHz Business/Industrial Land Transportation Pool. 90.672 Section 90.672 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY...

DNA Polymerase κ Is a Key Cellular Factor for the Formation of Covalently Closed Circular DNA of Hepatitis B Virus

PubMed Central

Qi, Yonghe; Gao, Zhenchao; Peng, Bo; Yan, Huan; Tang, Dingbin; Song, Zilin; He, Wenhui; Sun, Yinyan; Guo, Ju-Tao; Li, Wenhui

2016-01-01

Hepatitis B virus (HBV) infection of hepatocytes begins by binding to its cellular receptor sodium taurocholate cotransporting polypeptide (NTCP), followed by the internalization of viral nucleocapsid into the cytoplasm. The viral relaxed circular (rc) DNA genome in nucleocapsid is transported into the nucleus and converted into covalently closed circular (ccc) DNA to serve as a viral persistence reservoir that is refractory to current antiviral therapies. Host DNA repair enzymes have been speculated to catalyze the conversion of rcDNA to cccDNA, however, the DNA polymerase(s) that fills the gap in the plus strand of rcDNA remains to be determined. Here we conducted targeted genetic screening in combination with chemical inhibition to identify the cellular DNA polymerase(s) responsible for cccDNA formation, and exploited recombinant HBV with capsid coding deficiency which infects HepG2-NTCP cells with similar efficiency of wild-type HBV to assure cccDNA synthesis is exclusively from de novo HBV infection. We found that DNA polymerase κ (POLK), a Y-family DNA polymerase with maximum activity in non-dividing cells, substantially contributes to cccDNA formation during de novo HBV infection. Depleting gene expression of POLK in HepG2-NTCP cells by either siRNA knockdown or CRISPR/Cas9 knockout inhibited the conversion of rcDNA into cccDNA, while the diminished cccDNA formation in, and hence the viral infection of, the knockout cells could be effectively rescued by ectopic expression of POLK. These studies revealed that POLK is a crucial host factor required for cccDNA formation during a de novo HBV infection and suggest that POLK may be a potential target for developing antivirals against HBV. PMID:27783675

In Vivo Cardiac Cellular Reprogramming Efficacy Is Enhanced by Angiogenic Preconditioning of the Infarcted Myocardium With Vascular Endothelial Growth Factor

PubMed Central

Mathison, Megumi; P. Gersch, Robert; Nasser, Ahmed; Lilo, Sarit; Korman, Mallory; Fourman, Mitchell; Hackett, Neil; Shroyer, Kenneth; Yang, Jianchang; Ma, Yupo; Crystal, Ronald G.; Rosengart, Todd K.

2012-01-01

Background In situ cellular reprogramming offers the possibility of regenerating functional cardiomyocytes directly from scar fibroblasts, obviating the challenges of cell implantation. We hypothesized that pretreating scar with gene transfer of the angiogenic vascular endothelial growth factor (VEGF) would enhance the efficacy of this strategy. Methods and Results Gata4, Mef2c, and Tbx5 (GMT) administration via lentiviral transduction was demonstrated to transdifferentiate rat fibroblasts into (induced) cardiomyocytes in vitro by cardiomyocyte marker studies. Fisher 344 rats underwent coronary ligation and intramyocardial administration of an adenovirus encoding all 3 major isoforms of VEGF (AdVEGF‐All6A+) or an AdNull control vector (n=12/group). Lentivirus encoding GMT or a GFP control was administered to each animal 3 weeks later, followed by histologic and echocardiographic analyses. GMT administration reduced the extent of fibrosis by half compared with GFP controls (12±2% vs 24±3%, P<0.01) and reduced the number of myofibroblasts detected in the infarct zone by 4‐fold. GMT‐treated animals also demonstrated greater density of cardiomyocyte‐specific marker beta myosin heavy chain 7+ cells compared with animals receiving GFP with or without VEGF (P<0.01). Ejection fraction was significantly improved after GMT vs GFP administration (12±3% vs −7±3%, P<0.01). Eight (73%) GFP animals but no GMT animals demonstrated decreased ejection fraction during this interval (P<0.01). Also, improvement in ejection fraction was 4‐fold greater in GMT/VEGF vs GMT/null animals (17±2% vs 4±1%, P<0.05). Conclusions VEGF administration to infarcted myocardium enhances the efficacy of GMT‐mediated cellular reprogramming in improving myocardial function and reducing the extent of myocardial fibrosis compared with the use of GMT or VEGF alone. PMID:23316332

In vivo cardiac cellular reprogramming efficacy is enhanced by angiogenic preconditioning of the infarcted myocardium with vascular endothelial growth factor.

PubMed

Mathison, Megumi; Gersch, Robert P; Nasser, Ahmed; Lilo, Sarit; Korman, Mallory; Fourman, Mitchell; Hackett, Neil; Shroyer, Kenneth; Yang, Jianchang; Ma, Yupo; Crystal, Ronald G; Rosengart, Todd K

2012-12-01

In situ cellular reprogramming offers the possibility of regenerating functional cardiomyocytes directly from scar fibroblasts, obviating the challenges of cell implantation. We hypothesized that pretreating scar with gene transfer of the angiogenic vascular endothelial growth factor (VEGF) would enhance the efficacy of this strategy. Gata4, Mef2c, and Tbx5 (GMT) administration via lentiviral transduction was demonstrated to transdifferentiate rat fibroblasts into (induced) cardiomyocytes in vitro by cardiomyocyte marker studies. Fisher 344 rats underwent coronary ligation and intramyocardial administration of an adenovirus encoding all 3 major isoforms of VEGF (AdVEGF-All6A(+)) or an AdNull control vector (n=12/group). Lentivirus encoding GMT or a GFP control was administered to each animal 3 weeks later, followed by histologic and echocardiographic analyses. GMT administration reduced the extent of fibrosis by half compared with GFP controls (12 ± 2% vs 24 ± 3%, P<0.01) and reduced the number of myofibroblasts detected in the infarct zone by 4-fold. GMT-treated animals also demonstrated greater density of cardiomyocyte-specific marker beta myosin heavy chain 7(+) cells compared with animals receiving GFP with or without VEGF (P<0.01). Ejection fraction was significantly improved after GMT vs GFP administration (12 ± 3% vs -7 ± 3%, P<0.01). Eight (73%) GFP animals but no GMT animals demonstrated decreased ejection fraction during this interval (P<0.01). Also, improvement in ejection fraction was 4-fold greater in GMT/VEGF vs GMT/null animals (17 ± 2% vs 4 ± 1%, P<0.05). VEGF administration to infarcted myocardium enhances the efficacy of GMT-mediated cellular reprogramming in improving myocardial function and reducing the extent of myocardial fibrosis compared with the use of GMT or VEGF alone.

High-Risk Human Papillomaviral Oncogenes E6 and E7 Target Key Cellular Pathways to Achieve Oncogenesis.

PubMed

Yeo-Teh, Nicole S L; Ito, Yoshiaki; Jha, Sudhakar

2018-06-08

Infection with high-risk human papillomavirus (HPV) has been linked to several human cancers, the most prominent of which is cervical cancer. The integration of the viral genome into the host genome is one of the manners in which the viral oncogenes E6 and E7 achieve persistent expression. The most well-studied cellular targets of the viral oncogenes E6 and E7 are p53 and pRb, respectively. However, recent research has demonstrated the ability of these two viral factors to target many more cellular factors, including proteins which regulate epigenetic marks and splicing changes in the cell. These have the ability to exert a global change, which eventually culminates to uncontrolled proliferation and carcinogenesis.

Mitochondrial oxidative stress caused by Sod2 deficiency promotes cellular senescence and aging phenotypes in the skin

PubMed Central

Velarde, Michael C.; Flynn, James M.; Day, Nicholas U.; Melov, Simon; Campisi, Judith

2012-01-01

Cellular senescence arrests the proliferation of mammalian cells at risk for neoplastic transformation, and is also associated with aging. However, the factors that cause cellular senescence during aging are unclear. Excessive reactive oxygen species (ROS) have been shown to cause cellular senescence in culture, and accumulated molecular damage due to mitochondrial ROS has long been thought to drive aging phenotypes in vivo. Here, we test the hypothesis that mitochondrial oxidative stress can promote cellular senescence in vivo and contribute to aging phenotypes in vivo, specifically in the skin. We show that the number of senescent cells, as well as impaired mitochondrial (complex II) activity increase in naturally aged mouse skin. Using a mouse model of genetic Sod2 deficiency, we show that failure to express this important mitochondrial anti-oxidant enzyme also impairs mitochondrial complex II activity, causes nuclear DNA damage, and induces cellular senescence but not apoptosis in the epidermis. Sod2 deficiency also reduced the number of cells and thickness of the epidermis, while increasing terminal differentiation. Our results support the idea that mitochondrial oxidative stress and cellular senescence contribute to aging skin phenotypes in vivo. PMID:22278880

Fibroblast growth factor (FGF) signaling in development and skeletal diseases.

PubMed

Teven, Chad M; Farina, Evan M; Rivas, Jane; Reid, Russell R

2014-12-01

Fibroblast growth factors (FGF) and their receptors serve many functions in both the developing and adult organism. Humans contain 18 FGF ligands and four FGF receptors (FGFR). FGF ligands are polypeptide growth factors that regulate several developmental processes including cellular proliferation, differentiation, and migration, morphogenesis, and patterning. FGF-FGFR signaling is also critical to the developing axial and craniofacial skeleton. In particular, the signaling cascade has been implicated in intramembranous ossification of cranial bones as well as cranial suture homeostasis. In the adult, FGFs and FGFRs are crucial for tissue repair. FGF signaling generally follows one of three transduction pathways: RAS/MAP kinase, PI3/AKT, or PLCγ. Each pathway likely regulates specific cellular behaviors. Inappropriate expression of FGF and improper activation of FGFRs are associated with various pathologic conditions, unregulated cell growth, and tumorigenesis. Additionally, aberrant signaling has been implicated in many skeletal abnormalities including achondroplasia and craniosynostosis. The biology and mechanisms of the FGF family have been the subject of significant research over the past 30 years. Recently, work has focused on the therapeutic targeting and potential of FGF ligands and their associated receptors. The majority of FGF-related therapy is aimed at age-related disorders. Increased understanding of FGF signaling and biology may reveal additional therapeutic roles, both in utero and postnatally. This review discusses the role of FGF signaling in general physiologic and pathologic embryogenesis and further explores it within the context of skeletal development.

Fibroblast growth factor (FGF) signaling in development and skeletal diseases

PubMed Central

Teven, Chad M.; Farina, Evan M.; Rivas, Jane; Reid, Russell R.

2014-01-01

Fibroblast growth factors (FGF) and their receptors serve many functions in both the developing and adult organism. Humans contain 18 FGF ligands and four FGF receptors (FGFR). FGF ligands are polypeptide growth factors that regulate several developmental processes including cellular proliferation, differentiation, and migration, morphogenesis, and patterning. FGF-FGFR signaling is also critical to the developing axial and craniofacial skeleton. In particular, the signaling cascade has been implicated in intramembranous ossification of cranial bones as well as cranial suture homeostasis. In the adult, FGFs and FGFRs are crucial for tissue repair. FGF signaling generally follows one of three transduction pathways: RAS/MAP kinase, PI3/AKT, or PLCγ. Each pathway likely regulates specific cellular behaviors. Inappropriate expression of FGF and improper activation of FGFRs are associated with various pathologic conditions, unregulated cell growth, and tumorigenesis. Additionally, aberrant signaling has been implicated in many skeletal abnormalities including achondroplasia and craniosynostosis. The biology and mechanisms of the FGF family have been the subject of significant research over the past 30 years. Recently, work has focused on the therapeutic targeting and potential of FGF ligands and their associated receptors. The majority of FGF-related therapy is aimed at age-related disorders. Increased understanding of FGF signaling and biology may reveal additional therapeutic roles, both in utero and postnatally. This review discusses the role of FGF signaling in general physiologic and pathologic embryogenesis and further explores it within the context of skeletal development. PMID:25679016

Role of Mitochondrial Ca2+ in the Regulation of Cellular Energetics

PubMed Central

Glancy, Brian; Balaban, Robert S.

2012-01-01

Calcium is an important signaling molecule involved in the regulation of many cellular functions. The large free energy in the Ca2+ ion membrane gradients make Ca2+ signaling inherently sensitive to the available cellular free energy, primarily in the form of ATP. In addition, Ca2+ regulates many cellular ATP consuming reactions such as muscle contraction, exocytosis, biosynthesis and neuronal signaling. Thus, Ca2+ becomes a logical candidate as a signaling molecule to modulate ATP hydrolysis and synthesis during changes in numerous forms of cellular work. Mitochondria are the primary source of aerobic energy production in mammalian cells and also maintain a large Ca2+ gradient across their inner membrane providing a signaling potential for this molecule. The demonstrated link between cytosolic and mitochondrial [Ca2+], identification of transport mechanisms as well as proximity of mitochondria to Ca2+ release sites further supports the notion that Ca2+ can be an important signaling molecule in the energy metabolism interplay of the cytosol with the mitochondria. Here we review sites within the mitochondria where Ca2+ plays a role in the regulation of ATP generation and potentially contributes to the orchestration of the cellular metabolic homeostasis. Early work on isolated enzymes pointed to several matrix dehydrogenases that are stimulated by Ca2+, which were confirmed in the intact mitochondrion as well as cellular and in vivo systems. However, studies in these intact systems suggested a more expansive influence of Ca2+ on mitochondrial energy conversion. Numerous non-invasive approaches monitoring NADH, mitochondrial membrane potential, oxygen consumption and workloads suggest significant Ca2+ effects on other elements of NADH generation as well as downstream elements of oxidative phosphorylation including the F1FO-ATPase and the cytochrome chain. These other potential elements of Ca2+ modification of mitochondrial energy conversion will be the focus of this

Approaches to utilize mesenchymal progenitor cells as cellular vehicles.

PubMed

Pereboeva, L; Komarova, S; Mikheeva, G; Krasnykh, V; Curiel, D T

2003-01-01

Mammalian cells represent a novel vector approach for gene delivery that overcomes major drawbacks of viral and nonviral vectors and couples cell therapy with gene delivery. A variety of cell types have been tested in this regard, confirming that the ideal cellular vector system for ex vivo gene therapy has to comply with stringent criteria and is yet to be found. Several properties of mesenchymal progenitor cells (MPCs), such as easy access and simple isolation and propagation procedures, make these cells attractive candidates as cellular vehicles. In the current work, we evaluated the potential utility of MPCs as cellular vectors with the intent to use them in the cancer therapy context. When conventional adenoviral (Ad) vectors were used for MPC transduction, the highest transduction efficiency of MPCs was 40%. We demonstrated that Ad primary-binding receptors were poorly expressed on MPCs, while the secondary Ad receptors and integrins presented in sufficient amounts. By employing Ad vectors with incorporated integrin-binding motifs (Ad5lucRGD), MPC transduction was augmented tenfold, achieving efficient genetic loading of MPCs with reporter and anticancer genes. MPCs expressing thymidine kinase were able to exert a bystander killing effect on the cancer cell line SKOV3ip1 in vitro. In addition, we found that MPCs were able to support Ad replication, and thus can be used as cell vectors to deliver oncolytic viruses. Our results show that MPCs can foster expression of suicide genes or support replication of adenoviruses as potential anticancer therapeutic payloads. These findings are consistent with the concept that MPCs possess key properties that ensure their employment as cellular vehicles and can be used to deliver either therapeutic genes or viruses to tumor sites.

Plasma and cellular fibronectin: distinct and independent functions during tissue repair

PubMed Central

2011-01-01

Fibronectin (FN) is a ubiquitous extracellular matrix (ECM) glycoprotein that plays vital roles during tissue repair. The plasma form of FN circulates in the blood, and upon tissue injury, is incorporated into fibrin clots to exert effects on platelet function and to mediate hemostasis. Cellular FN is then synthesized and assembled by cells as they migrate into the clot to reconstitute damaged tissue. The assembly of FN into a complex three-dimensional matrix during physiological repair plays a key role not only as a structural scaffold, but also as a regulator of cell function during this stage of tissue repair. FN fibrillogenesis is a complex, stepwise process that is strictly regulated by a multitude of factors. During fibrosis, there is excessive deposition of ECM, of which FN is one of the major components. Aberrant FN-matrix assembly is a major contributing factor to the switch from normal tissue repair to misregulated fibrosis. Understanding the mechanisms involved in FN assembly and how these interplay with cellular, fibrotic and immune responses may reveal targets for the future development of therapies to regulate aberrant tissue-repair processes. PMID:21923916

Space experiment "Cellular Responses to Radiation in Space (CELLRAD)": Hardware and biological system tests

NASA Astrophysics Data System (ADS)

Hellweg, Christine E.; Dilruba, Shahana; Adrian, Astrid; Feles, Sebastian; Schmitz, Claudia; Berger, Thomas; Przybyla, Bartos; Briganti, Luca; Franz, Markus; Segerer, Jürgen; Spitta, Luis F.; Henschenmacher, Bernd; Konda, Bikash; Diegeler, Sebastian; Baumstark-Khan, Christa; Panitz, Corinna; Reitz, Günther

2015-11-01

One factor contributing to the high uncertainty in radiation risk assessment for long-term space missions is the insufficient knowledge about possible interactions of radiation with other spaceflight environmental factors. Such factors, e.g. microgravity, have to be considered as possibly additive or even synergistic factors in cancerogenesis. Regarding the effects of microgravity on signal transduction, it cannot be excluded that microgravity alters the cellular response to cosmic radiation, which comprises a complex network of signaling pathways. The purpose of the experiment ;Cellular Responses to Radiation in Space; (CELLRAD, formerly CERASP) is to study the effects of combined exposure to microgravity, radiation and general space flight conditions on mammalian cells, in particular Human Embryonic Kidney (HEK) cells that are stably transfected with different plasmids allowing monitoring of proliferation and the Nuclear Factor κB (NF-κB) pathway by means of fluorescent proteins. The cells will be seeded on ground in multiwell plate units (MPUs), transported to the ISS, and irradiated by an artificial radiation source after an adaptation period at 0 × g and 1 × g. After different incubation periods, the cells will be fixed by pumping a formaldehyde solution into the MPUs. Ground control samples will be treated in the same way. For implementation of CELLRAD in the Biolab on the International Space Station (ISS), tests of the hardware and the biological systems were performed. The sequence of different steps in MPU fabrication (cutting, drilling, cleaning, growth surface coating, and sterilization) was optimized in order to reach full biocompatibility. Different coatings of the foil used as growth surface revealed that coating with 0.1 mg/ml poly-D-lysine supports cell attachment better than collagen type I. The tests of prototype hardware (Science Model) proved its full functionality for automated medium change, irradiation and fixation of cells. Exposure of

Mangiferin inhibits tumor necrosis factor-α-induced matrix metalloproteinase-9 expression and cellular invasion by suppressing nuclear factor-κB activity.

PubMed

Dilshara, Matharage Gayani; Kang, Chang-Hee; Choi, Yung Hyun; Kim, Gi-Young

2015-10-01

We investigated the effects of mangiferin on the expression and activity of metalloproteinase (MMP)-9 and the invasion of tumor necrosis factor (TNF)-α-stimulated human LNCaP prostate carcinoma cells. Reverse-transcription polymerase chain reaction (RT-PCR) and western blot analysis showed that mangiferin significantly reversed TNF-α-induced mRNA and protein expression of MMP-9 expression. Zymography data confirmed that stimulation of cells with TNF-α significantly increased MMP-9 activity. However, mangiferin substantially reduced the TNF-α-induced activity of MMP-9. Additionally, a matrigel invasion assay showed that mangiferin significantly reduced TNF-α-induced invasion of LNCaP cells. Compared to untreated controls, TNF-α-stimulated LNCaP cells showed a significant increase in nuclear factor-κB (NF-κB) luciferase activity. However, mangiferin treatment markedly decreased TNF-α-induced NF-κB luciferase activity. Furthermore, mangiferin suppressed nuclear translocation of the NF-κB subunits p65 and p50. Collectively, our results indicate that mangiferin is a potential anti-invasive agent that acts by suppressing NF-κB-mediated MMP-9 expression.

Analysis of cellular and extracellular DNA in fingerprints

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

Button, Julie M.

It has been previously shown that DNA can be recovered from latent fingerprints left on various surfaces [R. A. H. van Oorschot and M. K. Jones, Nature 387, 767 (1997)]. However, the source of the DNA, extracellular versus cellular origin, is difficult to determine. If the DNA is cellular, it is believed to belong to skin cells while extracellular DNA is believed to originate from body fluids such as sweat [D. J. Daly et. al, Forensic Sci. Int. Genet. 6, 41-46 (2012); V. V. Vlassov et. al, BioEssays 29, 654-667 (2007)]. The origin of the DNA in fingerprints has implicationsmore » for processing and interpretation of forensic evidence. The determination of the origin of DNA in fingerprints is further complicated by the fact that the DNA in fingerprints tends to be at a very low quantity [R. A. H. van Oorschot and M. K. Jones, Nature 387, 767 (1997)]. This study examined fingerprints from five volunteers left on sterilized glass slides and plastic pens. Three fingerprints were left on each glass slide (thumb, index, and middle fingers) while the pens were held as if one was writing with them. The DNA was collected from the objects using the wet swabbing technique (TE buffer). Following collection, the cellular and extracellular components of each sample were separated using centrifugation and an acoustofluidics system. Centrifugation is still the primary separation technique utilized in forensics laboratories, while acoustic focusing uses sound waves to focus large particles (cells) into low pressure nodes, separating them from the rest of the sample matrix. After separation, all samples were quantified using real-time quantitative PCR (qPCR). The overall trend is that there is more DNA in the extracellular fractions than cellular fractions for both centrifugation and acoustofluidic processing. Additionally, more DNA was generally collected from the pen samples than the samples left on glass slides.« less

A Programmable Cellular-Automata Polarized Dirac Vacuum

NASA Astrophysics Data System (ADS)

Osoroma, Drahcir S.

2013-09-01

We explore properties of a `Least Cosmological Unit' (LCU) as an inherent spacetime raster tiling or tessellating the unique backcloth of Holographic Anthropic Multiverse (HAM) cosmology as an array of programmable cellular automata. The HAM vacuum is a scale-invariant HD extension of a covariant polarized Dirac vacuum with `bumps' and `holes' typically described by extended electromagnetic theory corresponding to an Einstein energy-dependent spacetime metric admitting a periodic photon mass. The new cosmology incorporates a unique form of M-Theoretic Calabi-Yau-Poincaré Dodecadedral-AdS5-DS5space (PDS) with mirror symmetry best described by an HD extension of Cramer's Transactional Interpretation when integrated also with an HD extension of the de Broglie-Bohm-Vigier causal interpretation of quantum theory. We incorporate a unique form of large-scale additional dimensionality (LSXD) bearing some similarity to that conceived by Randall and Sundrum; and extend the fundamental basis of our model to the Unified Field, UF. A Sagnac Effect rf-pulsed incursive resonance hierarchy is utilized to manipulate and ballistically program the geometric-topological properties of this putative LSXD space-spacetime network. The model is empirically testable; and it is proposed that a variety of new technologies will arise from ballistic programming of tessellated LCU vacuum cellular automata.

Unstable vicinal crystal growth from cellular automata

NASA Astrophysics Data System (ADS)

Krasteva, A.; Popova, H.; KrzyŻewski, F.; Załuska-Kotur, M.; Tonchev, V.

2016-03-01

In order to study the unstable step motion on vicinal crystal surfaces we devise vicinal Cellular Automata. Each cell from the colony has value equal to its height in the vicinal, initially the steps are regularly distributed. Another array keeps the adatoms, initially distributed randomly over the surface. The growth rule defines that each adatom at right nearest neighbor position to a (multi-) step attaches to it. The update of whole colony is performed at once and then time increases. This execution of the growth rule is followed by compensation of the consumed particles and by diffusional update(s) of the adatom population. Two principal sources of instability are employed - biased diffusion and infinite inverse Ehrlich-Schwoebel barrier (iiSE). Since these factors are not opposed by step-step repulsion the formation of multi-steps is observed but in general the step bunches preserve a finite width. We monitor the developing surface patterns and quantify the observations by scaling laws with focus on the eventual transition from diffusion-limited to kinetics-limited phenomenon. The time-scaling exponent of the bunch size N is 1/2 for the case of biased diffusion and 1/3 for the case of iiSE. Additional distinction is possible based on the time-scaling exponents of the sizes of multi-step Nmulti, these are 0.36÷0.4 (for biased diffusion) and 1/4 (iiSE).

Characterizing heterogeneous cellular responses to perturbations.

PubMed

Slack, Michael D; Martinez, Elisabeth D; Wu, Lani F; Altschuler, Steven J

2008-12-09

Cellular populations have been widely observed to respond heterogeneously to perturbation. However, interpreting the observed heterogeneity is an extremely challenging problem because of the complexity of possible cellular phenotypes, the large dimension of potential perturbations, and the lack of methods for separating meaningful biological information from noise. Here, we develop an image-based approach to characterize cellular phenotypes based on patterns of signaling marker colocalization. Heterogeneous cellular populations are characterized as mixtures of phenotypically distinct subpopulations, and responses to perturbations are summarized succinctly as probabilistic redistributions of these mixtures. We apply our method to characterize the heterogeneous responses of cancer cells to a panel of drugs. We find that cells treated with drugs of (dis-)similar mechanism exhibit (dis-)similar patterns of heterogeneity. Despite the observed phenotypic diversity of cells observed within our data, low-complexity models of heterogeneity were sufficient to distinguish most classes of drug mechanism. Our approach offers a computational framework for assessing the complexity of cellular heterogeneity, investigating the degree to which perturbations induce redistributions of a limited, but nontrivial, repertoire of underlying states and revealing functional significance contained within distinct patterns of heterogeneous responses.

Movies of cellular and sub-cellular motion by digital holographic microscopy.

PubMed

Mann, Christopher J; Yu, Lingfeng; Kim, Myung K

2006-03-23

Many biological specimens, such as living cells and their intracellular components, often exhibit very little amplitude contrast, making it difficult for conventional bright field microscopes to distinguish them from their surroundings. To overcome this problem phase contrast techniques such as Zernike, Normarsky and dark-field microscopies have been developed to improve specimen visibility without chemically or physically altering them by the process of staining. These techniques have proven to be invaluable tools for studying living cells and furthering scientific understanding of fundamental cellular processes such as mitosis. However a drawback of these techniques is that direct quantitative phase imaging is not possible. Quantitative phase imaging is important because it enables determination of either the refractive index or optical thickness variations from the measured optical path length with sub-wavelength accuracy. Digital holography is an emergent phase contrast technique that offers an excellent approach in obtaining both qualitative and quantitative phase information from the hologram. A CCD camera is used to record a hologram onto a computer and numerical methods are subsequently applied to reconstruct the hologram to enable direct access to both phase and amplitude information. Another attractive feature of digital holography is the ability to focus on multiple focal planes from a single hologram, emulating the focusing control of a conventional microscope. A modified Mach-Zender off-axis setup in transmission is used to record and reconstruct a number of holographic amplitude and phase images of cellular and sub-cellular features. Both cellular and sub-cellular features are imaged with sub-micron, diffraction-limited resolution. Movies of holographic amplitude and phase images of living microbes and cells are created from a series of holograms and reconstructed with numerically adjustable focus, so that the moving object can be accurately tracked

Alginate-Iron Speciation and Its Effect on In Vitro Cellular Iron Metabolism

PubMed Central

Horniblow, Richard D.; Dowle, Miriam; Iqbal, Tariq H.; Latunde-Dada, Gladys O.; Palmer, Richard E.

2015-01-01

Alginates are a class of biopolymers with known iron binding properties which are routinely used in the fabrication of iron-oxide nanoparticles. In addition, alginates have been implicated in influencing human iron absorption. However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear. Thus the aims of this study were to determine how alginate and iron interact at gastric-comparable pH conditions and how this influences iron metabolism. Employing a range of spectroscopic techniques under physiological conditions alginate-iron complexation was confirmed and, in conjunction with aberration corrected scanning transmission electron microscopy, nanoparticles were observed. The results infer a nucleation-type model of iron binding whereby alginate is templating the condensation of iron-hydroxide complexes to form iron oxide centred nanoparticles. The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised. These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease. PMID:26378798

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

PubMed

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

2015-07-01

Members of the WRKY transcription factor superfamily are essential for the regulation of many plant pathways. Functional redundancy due to duplications of WRKY transcription factors, however, complicates genetic analysis by allowing single-mutant plants to maintain wild-type phenotypes. Our analyses indicate that three group I WRKY genes, OsWRKY24, -53, and -70, act in a partially redundant manner. All three showed characteristics of typical WRKY transcription factors: each localized to nuclei and yeast one-hybrid assays indicated that they all bind to W-boxes, including those present in their own promoters. Quantitative real time-PCR (qRT-PCR) analyses indicated that the expression levels of the three WRKY genes varied in the different tissues tested. Particle bombardment-mediated transient expression analyses indicated that all three genes repress the GA and ABA signaling in a dosage-dependent manner. Combination of all three WRKY genes showed additive antagonism of ABA and GA signaling. These results suggest that these WRKY proteins function as negative transcriptional regulators of GA and ABA signaling. However, different combinations of these WRKY genes can lead to varied strengths in suppression of their targets. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Cellular solidification in a monotectic system

NASA Technical Reports Server (NTRS)

Kaukler, W. F.; Curreri, P. A.

1987-01-01

Succinonitrile-glycerol, SN-G, transparent organic monotectic alloy is studied with particular attention to cellular growth. The phase diagram is determined, near the monotectic composition, with greater accuracy than previous studies. A solidification interface stability diagram is determined for planar growth. The planar-to-cellular transition is compared to predictions from the Burton, Primm, Schlichter theory. A new technique to determine the solute segregation by Fourier transform infrared spectroscopy is developed. Proposed models that involve the cellular interface for alignment of monotectic second-phase spheres or rods are compared with observations.

Intracellular delivery of nanomaterials for sub-cellular imaging and tracking of biomolecules

NASA Astrophysics Data System (ADS)

Medepalli, Krishna Kiran

. Confocal microscopy and flow cytometric studies are performed to characterize the interactions. Results from this acute immune response study demonstrate the biocompatibility of SWCNTs in whole blood and also confirm the cellular delivery of single stranded DNA. The second part of the research is on colloidal quantum dots (QDs): nanometer sized semiconductor crystals typically between 1 nm to 20 nm in diameter. In addition to being size comparable with many biological systems, and having large surface area for multiple biomolecules attachment, they possess high resistance to chemical and photo degradation, tunable emission based on size and composition which makes them excellent candidates for cellular delivery and imaging. The main objectives of this research was to demonstrate the use of QDs for cellular imaging as well as targeted biomolecule delivery by conjugating the QDs with an antibody to a functional protein and delivery into live cells. Conventional techniques deliver QDs as aggregates, however, a major challenge in the use of QDs for cellular imaging and biomolecule delivery is achieving freely dispersed QDs inside the cells. In this research, a new technique to deliver monodispersed QDs inside live cells was developed. The approach combines osmosis driven fluid transport into cells achieved by creating hypotonic environment and reversible permeabilization using low concentrations of cell permeabilization agents like Saponin. The results confirm that highly efficient endocytosis-free intracellular delivery of QDs can be accomplished using this method. Confocal microscopy is used to image the QDs inside the cells and flow cytometry is used for quantifying the fluorescence. To demonstrate targeted delivery, QDs are conjugated to the antibody of a protein: the nuclear transcriptional factor, NFkB (Nuclear Factor kappa-light chain-enhancer of activated B cells) using EDC/sulfo NHS chemistry methods. NFkB is a family of proteins with 5 different subunits and is

A new concept for medical imaging centered on cellular phone technology.

PubMed

Granot, Yair; Ivorra, Antoni; Rubinsky, Boris

2008-04-30

According to World Health Organization reports, some three quarters of the world population does not have access to medical imaging. In addition, in developing countries over 50% of medical equipment that is available is not being used because it is too sophisticated or in disrepair or because the health personnel are not trained to use it. The goal of this study is to introduce and demonstrate the feasibility of a new concept in medical imaging that is centered on cellular phone technology and which may provide a solution to medical imaging in underserved areas. The new system replaces the conventional stand-alone medical imaging device with a new medical imaging system made of two independent components connected through cellular phone technology. The independent units are: a) a data acquisition device (DAD) at a remote patient site that is simple, with limited controls and no image display capability and b) an advanced image reconstruction and hardware control multiserver unit at a central site. The cellular phone technology transmits unprocessed raw data from the patient site DAD and receives and displays the processed image from the central site. (This is different from conventional telemedicine where the image reconstruction and control is at the patient site and telecommunication is used to transmit processed images from the patient site). The primary goal of this study is to demonstrate that the cellular phone technology can function in the proposed mode. The feasibility of the concept is demonstrated using a new frequency division multiplexing electrical impedance tomography system, which we have developed for dynamic medical imaging, as the medical imaging modality. The system is used to image through a cellular phone a simulation of breast cancer tumors in a medical imaging diagnostic mode and to image minimally invasive tissue ablation with irreversible electroporation in a medical imaging interventional mode.

25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 1 2011-04-01 2011-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR EDUCATION THE INDIAN SCHOOL EQUALIZATION PROGRAM Pre-kindergarten Programs § 39.1101 Addition of...

25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR EDUCATION THE INDIAN SCHOOL EQUALIZATION PROGRAM Pre-kindergarten Programs § 39.1101 Addition of...

25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR EDUCATION THE INDIAN SCHOOL EQUALIZATION PROGRAM Pre-kindergarten Programs § 39.1101 Addition of...

25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR EDUCATION THE INDIAN SCHOOL EQUALIZATION PROGRAM Pre-kindergarten Programs § 39.1101 Addition of...

25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 1 2012-04-01 2011-04-01 true Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR EDUCATION THE INDIAN SCHOOL EQUALIZATION PROGRAM Pre-kindergarten Programs § 39.1101 Addition of...

Cellular immunotherapy for malignant gliomas.

PubMed

Lin, Yi; Okada, Hideho

2016-10-01

Cancer immunotherapy has made much progress in recent years. Clinical trials evaluating a variety of immunotherapeutic approaches are underway in patients with malignant gliomas. Thanks to recent advancements in cell engineering technologies, infusion of ex vivo prepared immune cells have emerged as promising strategies of cancer immunotherapy. Herein, the authors review recent and current studies using cellular immunotherapies for malignant gliomas. Specifically, they cover the following areas: a) cellular vaccine approaches using tumor cell-based or dendritic cell (DC)-based vaccines, and b) adoptive cell transfer (ACT) approaches, including lymphokine-activated killer (LAK) cells, γδ T cells, tumor-infiltrating lymphocytes (TIL), chimeric antigen receptor (CAR)-T cells and T-cell receptor (TCR) transduced T cells. While some of the recent studies have shown promising results, the ultimate success of cellular immunotherapy in brain tumor patients would require improvements in the following areas: 1) feasibility in producing cellular therapeutics; 2) identification and characterization of targetable antigens given the paucity and heterogeneity of tumor specific antigens; 3) the development of strategies to promote effector T-cell trafficking; 4) overcoming local and systemic immune suppression, and 5) proper interpretation of imaging data for brain tumor patients receiving immunotherapy.

Radiation-Induced Loss of Salivary Gland Function Is Driven by Cellular Senescence and Prevented by IL6 Modulation.

PubMed

Marmary, Yitzhak; Adar, Revital; Gaska, Svetlana; Wygoda, Annette; Maly, Alexander; Cohen, Jonathan; Eliashar, Ron; Mizrachi, Lina; Orfaig-Geva, Carmit; Baum, Bruce J; Rose-John, Stefan; Galun, Eithan; Axelrod, Jonathan H

2016-03-01

Head and neck cancer patients treated by radiation commonly suffer from a devastating side effect known as dry-mouth syndrome, which results from the irreversible loss of salivary gland function via mechanisms that are not completely understood. In this study, we used a mouse model of radiation-induced salivary hypofunction to investigate the outcomes of DNA damage in the head and neck region. We demonstrate that the loss of salivary function was closely accompanied by cellular senescence, as evidenced by a persistent DNA damage response (γH2AX and 53BP1) and the expression of senescence-associated markers (SA-βgal, p19ARF, and DcR2) and secretory phenotype (SASP) factors (PAI-1 and IL6). Notably, profound apoptosis or necrosis was not observed in irradiated regions. Signs of cellular senescence were also apparent in irradiated salivary glands surgically resected from human patients who underwent radiotherapy. Importantly, using IL6 knockout mice, we found that sustained expression of IL6 in the salivary gland long after initiation of radiation-induced DNA damage was required for both senescence and hypofunction. Additionally, we demonstrate that IL6 pretreatment prevented both senescence and salivary gland hypofunction via a mechanism involving enhanced DNA damage repair. Collectively, these results indicate that cellular senescence is a fundamental mechanism driving radiation-induced damage in the salivary gland and suggest that IL6 pretreatment may represent a promising therapeutic strategy to preserve salivary gland function in head and neck cancer patients undergoing radiotherapy. ©2016 American Association for Cancer Research.

The Safety Dance: Biophysics of Membrane Protein Folding and Misfolding in a Cellular Context

PubMed Central

Schlebach, Jonathan P.; Sanders, Charles R.

2015-01-01

Most biological processes require the production and degradation of proteins, a task that weighs heavily on the cell. Mutations that compromise the conformational stability of proteins place both specific and general burdens on cellular protein homeostasis (proteostasis) in ways that contribute to numerous diseases. Efforts to elucidate the chain of molecular events responsible for diseases of protein folding address one of the foremost challenges in biomedical science. However, relatively little is known about the processes by which mutations prompt the misfolding of α-helical membrane proteins, which rely on an intricate network of cellular machinery to acquire and maintain their functional structures within cellular membranes. In this review, we summarize the current understanding of the physical principles that guide membrane protein biogenesis and folding in the context of mammalian cells. Additionally, we explore how pathogenic mutations that influence biogenesis may differ from those that disrupt folding and assembly, as well as how this may relate to disease mechanisms and therapeutic intervention. These perspectives indicate an imperative for the use of information from structural, cellular, and biochemical studies of membrane proteins in the design of novel therapeutics and in personalized medicine. PMID:25420508

Attenuation of the suppressive activity of cellular splicing factor SRSF3 by Kaposi sarcoma–associated herpesvirus ORF57 protein is required for RNA splicing

PubMed Central

Majerciak, Vladimir; Lu, Mathew; Li, Xiaofan

2014-01-01

Kaposi sarcoma–associated herpesvirus (KSHV) ORF57 is a multifunctional post-transcriptional regulator essential for viral gene expression during KSHV lytic infection. ORF57 requires interactions with various cellular proteins for its function. Here, we identified serine/arginine-rich splicing factor 3 (SRSF3, formerly known as SRp20) as a cellular cofactor involved in ORF57-mediated splicing of KSHV K8β RNA. In the absence of ORF57, SRSF3 binds to a suboptimal K8β intron and inhibits K8β splicing. Knockdown of SRSF3 promotes K8β splicing, mimicking the effect of ORF57. The N-terminal half of ORF57 binds to the RNA recognition motif of SRSF3, which prevents SRSF3 from associating with the K8β intron RNA and therefore attenuates the suppressive effect of SRSF3 on K8β splicing. ORF57 also promotes splicing of heterologous non-KSHV transcripts that are negatively regulated by SRSF3, indicating that the effect of ORF57 on SRSF3 activity is independent of RNA target. SPEN proteins, previously identified as ORF57-interacting partners, suppress ORF57 splicing activity by displacing ORF57 from SRSF3–RNA complexes. In summary, we have identified modulation of SRSF3 activity as the molecular mechanism by which ORF57 promotes RNA splicing. PMID:25234929

Nitric oxide and S-nitrosoglutathione function additively during plant immunity.

PubMed

Yun, Byung-Wook; Skelly, Michael J; Yin, Minghui; Yu, Manda; Mun, Bong-Gyu; Lee, Sang-Uk; Hussain, Adil; Spoel, Steven H; Loake, Gary J

2016-07-01

Nitric oxide (NO) is emerging as a key regulator of diverse plant cellular processes. A major route for the transfer of NO bioactivity is S-nitrosylation, the addition of an NO moiety to a protein cysteine thiol forming an S-nitrosothiol (SNO). Total cellular levels of protein S-nitrosylation are controlled predominantly by S-nitrosoglutathione reductase 1 (GSNOR1) which turns over the natural NO donor, S-nitrosoglutathione (GSNO). In the absence of GSNOR1 function, GSNO accumulates, leading to dysregulation of total cellular S-nitrosylation. Here we show that endogenous NO accumulation in Arabidopsis, resulting from loss-of-function mutations in NO Overexpression 1 (NOX1), led to disabled Resistance (R) gene-mediated protection, basal resistance and defence against nonadapted pathogens. In nox1 plants both salicylic acid (SA) synthesis and signalling were suppressed, reducing SA-dependent defence gene expression. Significantly, expression of a GSNOR1 transgene complemented the SNO-dependent phenotypes of paraquat resistant 2-1 (par2-1) plants but not the NO-related characters of the nox1-1 line. Furthermore, atgsnor1-3 nox1-1 double mutants supported greater bacterial titres than either of the corresponding single mutants. Our findings imply that GSNO and NO, two pivotal redox signalling molecules, exhibit additive functions and, by extension, may have distinct or overlapping molecular targets during both immunity and development. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

77 FR 15665 - Cellular Service, Including Changes in Licensing of Unserved Area; Interim Restrictions and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-16

... SUPPLEMENTARY INFORMATION section of this document. FOR FURTHER INFORMATION CONTACT: Nina Shafran, Wireless... produced. In addition, the Cellular Service stands apart from virtually all other commercial wireless... flexibly licensed commercial wireless services, the Commission proposes to establish a signal field...

Simulation of root forms using cellular automata model

NASA Astrophysics Data System (ADS)

Winarno, Nanang; Prima, Eka Cahya; Afifah, Ratih Mega Ayu

2016-02-01

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled "A New Kind of Science" discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram's investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.

Simulation of root forms using cellular automata model

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

Winarno, Nanang, E-mail: nanang-winarno@upi.edu; Prima, Eka Cahya; Afifah, Ratih Mega Ayu

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation usedmore » four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.« less

Association between Breast Cancer Recurrence and Cellular Dissociation Assessed Using Fine-Needle Aspiration.

PubMed

Koike, Etsuko; Iwaya, Keiichi; Watanabe, Akinori; Miyake, Shinji; Sato, Eiichi; Ishikawa, Takashi

2016-01-01

To determine the associations between breast cancer recurrence and cytological findings of fine-needle aspiration cytology (FNAC). The study included 117 women who had undergone a modified radical mastectomy for invasive ductal carcinoma of the breast. FNAC samples of these patients were reexamined, and cytological findings, such as cellular dissociation, nuclear pleomorphism, nuclear atypia, chromatin pattern, and nuclear size, were scored. Uni- and multivariate analyses were performed to determine the prognostic significance of the cytological findings. Corresponding cancer tissues were immunostained for estrogen receptor, progesterone receptor, human epidermal growth factor 2 (HER2), p53, and E-cadherin to determine their associations with cytological findings. Coexpression of Arp2 and WAVE2 was also examined immunohistochemically as a cell locomotion signal. Cellular dissociation (p = 0.0259) and nuclear size (p = 0.0417) were significantly associated with cancer recurrence. Multivariate analysis showed that cellular dissociation and histological grade were significant independent predictors of cancer recurrence. Cellular dissociation was found to be associated with coexpression of Arp2 and WAVE2 (p = 0.0356) and HER2 (p = 0.0469). The cytological finding of cell dissociation was associated with the activation of Arp2 and WAVE2 signals and was an independent predictor of recurrence. © 2016 S. Karger AG, Basel.

Integration of mobile satellite and cellular systems

NASA Technical Reports Server (NTRS)

Drucker, Elliott H.; Estabrook, Polly; Pinck, Deborah; Ekroot, Laura

1993-01-01

By integrating the ground based infrastructure component of a mobile satellite system with the infrastructure systems of terrestrial 800 MHz cellular service providers, a seamless network of universal coverage can be established. Users equipped for both cellular and satellite service can take advantage of a number of features made possible by such integration, including seamless handoff and universal roaming. To provide maximum benefit at lowest posible cost, the means by which these systems are integrated must be carefully considered. Mobile satellite hub stations must be configured to efficiently interface with cellular Mobile Telephone Switching Offices (MTSO's), and cost effective mobile units that provide both cellular and satellite capability must be developed.

Integration of mobile satellite and cellular systems

NASA Astrophysics Data System (ADS)

Drucker, Elliott H.; Estabrook, Polly; Pinck, Deborah; Ekroot, Laura

By integrating the ground based infrastructure component of a mobile satellite system with the infrastructure systems of terrestrial 800 MHz cellular service providers, a seamless network of universal coverage can be established. Users equipped for both cellular and satellite service can take advantage of a number of features made possible by such integration, including seamless handoff and universal roaming. To provide maximum benefit at lowest posible cost, the means by which these systems are integrated must be carefully considered. Mobile satellite hub stations must be configured to efficiently interface with cellular Mobile Telephone Switching Offices (MTSO's), and cost effective mobile units that provide both cellular and satellite capability must be developed.

Cellular membrane collapse by atmospheric-pressure plasma jet

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

Kim, Kangil; Sik Yang, Sang, E-mail: jsjlee@ajou.ac.kr, E-mail: ssyang@ajou.ac.kr; Jun Ahn, Hak

2014-01-06

Cellular membrane dysfunction caused by air plasma in cancer cells has been studied to exploit atmospheric-pressure plasma jets for cancer therapy. Here, we report that plasma jet treatment of cervical cancer HeLa cells increased electrical conductivity across the cellular lipid membrane and caused simultaneous lipid oxidation and cellular membrane collapse. We made this finding by employing a self-manufactured microelectrode chip. Furthermore, increased roughness of the cellular lipid membrane and sequential collapse of the membrane were observed by atomic force microscopy following plasma jet treatment. These results suggest that the cellular membrane catastrophe occurs via coincident altered electrical conductivity, lipid oxidation,more » and membrane roughening caused by an atmospheric-pressure plasma jet, possibly resulting in cellular vulnerability to reactive species generated from the plasma as well as cytotoxicity to cancer cells.« less

Toxicity of pyrolysis gases from some cellular polymers

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Machado, A. M.

1978-01-01

Various samples of cellular polymers were evaluated for toxicity of pyrolysis gases, using the screening test method developed at the University of San Francisco. The cellular polymer samples included polyimide, polymethacrylimide, polybismaleimide, polyurethane, polyisocyanurate, polyethylene, polychloroprene, polyvinyl chloride, polystyrene, polysiloxane, and polyphosphazene. The cellular polymers exhibited varying levels of toxicity under these test conditions. Among the rigid cellular polymers, times to death were shortest with the imide type foams and longest with polyvinyl chloride and polystyrene. Among the flexible cellular polymers, times to death were shortest with polyimide and polyester, and longest with polychloroprene and polysiloxane. Increased char yield was not necessarily associated with reduced toxicity.

The E-domain region of mechano-growth factor inhibits cellular apoptosis and preserves cardiac function during myocardial infarction.

PubMed

Mavrommatis, Evangelos; Shioura, Krystyna M; Los, Tamara; Goldspink, Paul H

2013-09-01

Insulin-like growth factor-1 (IGF-1) isoforms are expressed via alternative splicing. Expression of the minor isoform IGF-1Eb [also known as mechano-growth factor (MGF)] is responsive to cell stress. Since IGF-1 isoforms differ in their E-domain regions, we are interested in determining the biological function of the MGF E-domain. To do so, a synthetic peptide analog was used to gain mechanistic insight into the actions of the E-domain. Treatment of H9c2 cells indicated a rapid cellular uptake mechanism that did not involve IGF-1 receptor activation but resulted in a nuclear localization. Peptide treatment inhibited the intrinsic apoptotic pathway in H9c2 cells subjected to cell stress with sorbitol by preventing the collapse of the mitochondrial membrane potential and inhibition of caspase-3 activation. Therefore, we administered the peptide at the time of myocardial infarction (MI) in mice. At 2 weeks post-MI cardiac function, gene expression and cell death were assayed. A significant decline in both systolic and diastolic function was evident in untreated mice based on PV loop analysis. Delivery of the E-peptide ameliorated the decline in function and resulted in significant preservation of cardiac contractility. Associated with these changes were an inhibition of pathologic hypertrophy and significantly fewer apoptotic nuclei in the viable myocardium of E-peptide-treated mice post-MI. We conclude that administration of the MGF E-domain peptide may provide a means of modulating local tissue IGF-1 autocrine/paracrine actions to preserve cardiac function, prevent cell death, and pathologic remodeling in the heart.

Wavefront cellular learning automata.

PubMed

Moradabadi, Behnaz; Meybodi, Mohammad Reza

2018-02-01

This paper proposes a new cellular learning automaton, called a wavefront cellular learning automaton (WCLA). The proposed WCLA has a set of learning automata mapped to a connected structure and uses this structure to propagate the state changes of the learning automata over the structure using waves. In the WCLA, after one learning automaton chooses its action, if this chosen action is different from the previous action, it can send a wave to its neighbors and activate them. Each neighbor receiving the wave is activated and must choose a new action. This structure for the WCLA is necessary in many dynamic areas such as social networks, computer networks, grid computing, and web mining. In this paper, we introduce the WCLA framework as an optimization tool with diffusion capability, study its behavior over time using ordinary differential equation solutions, and present its accuracy using expediency analysis. To show the superiority of the proposed WCLA, we compare the proposed method with some other types of cellular learning automata using two benchmark problems.

Wavefront cellular learning automata

NASA Astrophysics Data System (ADS)

Moradabadi, Behnaz; Meybodi, Mohammad Reza

2018-02-01

This paper proposes a new cellular learning automaton, called a wavefront cellular learning automaton (WCLA). The proposed WCLA has a set of learning automata mapped to a connected structure and uses this structure to propagate the state changes of the learning automata over the structure using waves. In the WCLA, after one learning automaton chooses its action, if this chosen action is different from the previous action, it can send a wave to its neighbors and activate them. Each neighbor receiving the wave is activated and must choose a new action. This structure for the WCLA is necessary in many dynamic areas such as social networks, computer networks, grid computing, and web mining. In this paper, we introduce the WCLA framework as an optimization tool with diffusion capability, study its behavior over time using ordinary differential equation solutions, and present its accuracy using expediency analysis. To show the superiority of the proposed WCLA, we compare the proposed method with some other types of cellular learning automata using two benchmark problems.

Fracture mechanics of cellular glass

NASA Technical Reports Server (NTRS)

Zwissler, J. G.; Adams, M. A.

1981-01-01

The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solr concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses.

Norovirus P particle efficiently elicits innate, humoral and cellular immunity.

PubMed

Fang, Hao; Tan, Ming; Xia, Ming; Wang, Leyi; Jiang, Xi

2013-01-01

Norovirus (NoV) P domain complexes, the 24 mer P particles and the P dimers, induced effective humoral immunity, but their role in the cellular immune responses remained unclear. We reported here a study on cellular immune responses of the two P domain complexes in comparison with the virus-like particle (VLP) of a GII.4 NoV (VA387) in mice. The P domain complexes induced significant central memory CD4(+) T cell phenotypes (CD4(+) CD44(+) CD62L(+) CCR7(+)) and activated polyclonal CD4(+) T cells as shown by production of Interleukin (IL)-2, Interferon (IFN)-γ, and Tumor Necrosis Factor (TNF)-α. Most importantly, VA387-specific CD4(+) T cell epitope induced a production of IFN-γ, indicating an antigen-specific CD4(+) T cell response in P domain complex-immunized mice. Furthermore, P domain complexes efficiently induced bone marrow-derived dendritic cell (BMDC) maturation, evidenced by up-regulation of co-stimulatory and MHC class II molecules, as well as production of IL-12 and IL-1β. Finally, P domain complex-induced mature dendritic cells (DCs) elicited proliferation of specific CD4(+) T cells targeting VA387 P domain. Overall, we conclude that the NoV P domain complexes are efficiently presented by DCs to elicit not only humoral but also cellular immune responses against NoVs. Since the P particle is highly effective for both humoral and cellular immune responses and easily produced in Escherichia coli (E. coli), it is a good choice of vaccine against NoVs and a vaccine platform against other diseases.

Cellular Telephone as Reservoir of Bacterial Contamination: Myth or Fact

PubMed Central

Walia, Satinder S.; Manchanda, Adesh; Narang, Ramandeep S.; N., Anup; Singh, Balwinder; Kahlon, Sukhdeep S.

2014-01-01

Objective: To assess bacterial contamination of cellular telephone of dental care personnel, and to determine factors contributing to their contamination. Materials and Methods: A descriptive, cross-sectional study was conducted, which included 300 people using a cellular telephone The study group (hundred in each group) comprised of Dental Health Care Personnel (DHCP), In-Hospital Personnel (IHP) and Out-Hospital Personnel (OHP) of a dental college cum hospital. Swab was wiped along the front and all sides of cellular handset and it was incubated in glucose broth. The swab was subplated onto growth media plates made with half Mac Conkey’s agar and half blood agar and allowed to incubate for 48 hours at 37oC. Isolates were tested for antimicrobial susceptibility. Result: The analysis of presence or absence of microorganisms in the DHCP, IHP and OHP group showed no pyogenic growth in 28%, 31% and 41% cases respectively, the distribution of which was not significant (p>.05). Among non potential pathogens, spore bearing gram positive bacilli were seen in 20 cases of DHCP group, 16 cases of IHP group and 17 cases of OHP group; the distribution of which was not significant (p>.05) Among potential pathogens, significant differences were observed in the distribution of growth of Enterobacter (p<.001), Pseudomonas species (p<.05), Acinetobacter bacteria (p<.05) and Methicillin-resistant Staphylococcus aureus (MRSA) bacteria (p<.001) between the participants of different groups. Conclusion: Results of this study showed that fomites such as cellular telephones can potentially act as “Trojan horses”, thus causing Hospital-Acquired Infections (HAIs) in the dental setting. PMID:24596722

Cell-to-cell communication and cellular environment alter the somatostatin status of delta cells

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

Kelly, Catriona, E-mail: catriona.kelly@qub.ac.uk; Flatt, Peter R.; McClenaghan, Neville H.

2010-08-20

Research highlights: {yields} TGP52 cells display enhanced functionality in pseudoislet form. {yields} Somatostatin content was reduced, but secretion increased in high glucose conditions. {yields} Cellular interactions and environment alter the somatostatin status of TGP52 cells. -- Abstract: Introduction: Somatostatin, released from pancreatic delta cells, is a potent paracrine inhibitor of insulin and glucagon secretion. Islet cellular interactions and glucose homeostasis are essential to maintain normal patterns of insulin secretion. However, the importance of cell-to-cell communication and cellular environment in the regulation of somatostatin release remains unclear. Methods: This study employed the somatostatin-secreting TGP52 cell line maintained in DMEM:F12 (17.5 mMmore » glucose) or DMEM (25 mM glucose) culture media. The effect of pseudoislet formation and culture medium on somatostatin content and release in response to a variety of stimuli was measured by somatostatin EIA. In addition, the effect of pseudoislet formation on cellular viability (MTT and LDH assays) and proliferation (BrdU ELISA) was determined. Results: TGP52 cells readily formed pseudoislets and showed enhanced functionality in three-dimensional form with increased E-cadherin expression irrespective of the culture environment used. However, culture in DMEM decreased cellular somatostatin content (P < 0.01) and increased somatostatin secretion in response to a variety of stimuli including arginine, calcium and PMA (P < 0.001) when compared with cells grown in DMEM:F12. Configuration of TGP52 cells as pseudoislets reduced the proliferative rate and increased cellular cytotoxicity irrespective of culture medium used. Conclusions: Somatostatin secretion is greatly facilitated by cell-to-cell interactions and E-cadherin expression. Cellular environment and extracellular glucose also significantly influence the function of delta cells.« less

47 CFR 22.911 - Cellular geographic service area.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 2 2012-10-01 2012-10-01 false Cellular geographic service area. 22.911 Section 22.911 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.911 Cellular geographic service area. The...

Dependence of Impedance of Embedded Single Cells on Cellular Behaviour.

PubMed

Cho, Sungbo; Castellarnau, Marc; Samitier, Josep; Thielecke, Hagen

2008-02-21

Non-invasive single cell analyses are increasingly required for the medicaldiagnostics of test substances or the development of drugs and therapies on the single celllevel. For the non-invasive characterisation of cells, impedance spectroscopy whichprovides the frequency dependent electrical properties has been used. Recently,microfludic systems have been investigated to manipulate the single cells and tocharacterise the electrical properties of embedded cells. In this article, the impedance ofpartially embedded single cells dependent on the cellular behaviour was investigated byusing the microcapillary. An analytical equation was derived to relate the impedance ofembedded cells with respect to the morphological and physiological change ofextracellular interface. The capillary system with impedance measurement showed afeasibility to monitor the impedance change of embedded single cells caused bymorphological and physiological change of cell during the addition of DMSO. By fittingthe derived equation to the measured impedance of cell embedded at different negativepressure levels, it was able to extrapolate the equivalent gap and gap conductivity betweenthe cell and capillary wall representing the cellular behaviour.

Elevated hypothalamic TCPTP in obesity contributes to cellular leptin resistance

PubMed Central

Loh, Kim; Fukushima, Atsushi; Zhang, Xinmei; Galic, Sandra; Briggs, Dana; Enriori, Pablo J.; Simonds, Stephanie; Wiede, Florian; Reichenbach, Alexander; Hauser, Christine; Sims, Natalie A.; Bence, Kendra K.; Zhang, Sheng; Zhang, Zhong-Yin; Kahn, Barbara B.; Neel, Benjamin G.; Andrews, Zane B.; Cowley, Michael A.; Tiganis, Tony

2011-01-01

SUMMARY In obesity, anorectic responses to leptin are diminished, giving rise to the concept of ‘leptin resistance’. Increased expression of protein tyrosine phosphatase 1B (PTP1B) has been associated with the attenuation of leptin signaling and development of cellular leptin resistance. Here we report that hypothalamic levels of the tyrosine phosphatase TCPTP are also elevated in obesity to attenuate the leptin response. We show that mice that lack TCPTP in neuronal cells have enhanced leptin sensitivity and are resistant to high fat diet-induced weight gain and the development of leptin resistance. Also, intracerebroventricular administration of a TCPTP inhibitor enhances leptin signaling and responses in mice. Moreover, the combined deletion of TCPTP and PTP1B in neuronal cells has additive effects in the prevention of diet-induced obesity. Our results identify TCPTP as a critical negative regulator of hypothalamic leptin signaling and causally link elevated TCPTP to the development of cellular leptin resistance in obesity. PMID:22000926

Static allometry of unicellular green algae: scaling of cellular surface area and volume in the genus Micrasterias (Desmidiales).

PubMed

Neustupa, J

2016-02-01

The surface area-to-volume ratio of cells is one of the key factors affecting fundamental biological processes and, thus, fitness of unicellular organisms. One of the general models for allometric increase in surface-to-volume scaling involves fractal-like elaboration of cellular surfaces. However, specific data illustrating this pattern in natural populations of the unicellular organisms have not previously been available. This study shows that unicellular green algae of the genus Micrasterias (Desmidiales) have positive allometric surface-to-volume scaling caused by changes in morphology of individual species, especially in the degree of cell lobulation. This allometric pattern was also detected within most of the cultured and natural populations analysed. Values of the allometric S:V scaling within individual populations were closely correlated to the phylogenetic structure of the clade. In addition, they were related to species-specific cellular morphology. Individual populations differed in their allometric patterns, and their position in the allometric space was strongly correlated with the degree of allometric S:V scaling. This result illustrates that allometric shape patterns are an important correlate of the capacity of individual populations to compensate for increases in their cell volumes by increasing the surface area. However, variation in allometric patterns was not associated with phylogenetic structure. This indicates that the position of the populations in the allometric space was not evolutionarily conserved and might be influenced by environmental factors. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Imaging analysis of nuclear antiviral factors through direct detection of incoming adenovirus genome complexes.

PubMed

Komatsu, Tetsuro; Will, Hans; Nagata, Kyosuke; Wodrich, Harald

2016-04-22

Recent studies involving several viral systems have highlighted the importance of cellular intrinsic defense mechanisms through nuclear antiviral proteins that restrict viral propagation. These factors include among others components of PML nuclear bodies, the nuclear DNA sensor IFI16, and a potential restriction factor PHF13/SPOC1. For several nuclear replicating DNA viruses, it was shown that these factors sense and target viral genomes immediately upon nuclear import. In contrast to the anticipated view, we recently found that incoming adenoviral genomes are not targeted by PML nuclear bodies. Here we further explored cellular responses against adenoviral infection by focusing on specific conditions as well as additional nuclear antiviral factors. In line with our previous findings, we show that neither interferon treatment nor the use of specific isoforms of PML nuclear body components results in co-localization between incoming adenoviral genomes and the subnuclear domains. Furthermore, our imaging analyses indicated that neither IFI16 nor PHF13/SPOC1 are likely to target incoming adenoviral genomes. Thus our findings suggest that incoming adenoviral genomes may be able to escape from a large repertoire of nuclear antiviral mechanisms, providing a rationale for the efficient initiation of lytic replication cycle. Copyright © 2016 Elsevier Inc. All rights reserved.

The role of focal adhesion kinase in the regulation of cellular mechanical properties

NASA Astrophysics Data System (ADS)

Mierke, Claudia Tanja

2013-12-01

The regulation of mechanical properties is necessary for cell invasion into connective tissue or intra- and extravasation through the endothelium of blood or lymph vessels. Cell invasion is important for the regulation of many healthy processes such as immune response reactions and wound healing. In addition, cell invasion plays a role in disease-related processes such as tumor metastasis and autoimmune responses. Until now the role of focal adhesion kinase (FAK) in regulating mechanical properties of cells and its impact on cell invasion efficiency is still not well known. Thus, this review focuses on mechanical properties regulated by FAK in comparison to the mechano-regulating protein vinculin. Moreover, it points out the connection between cancer cell invasion and metastasis and FAK by showing that FAK regulates cellular mechanical properties required for cellular motility. Furthermore, it sheds light on the indirect interaction of FAK with vinculin by binding to paxillin, which then impairs the binding of paxillin to vinculin. In addition, this review emphasizes whether FAK fulfills regulatory functions similar to vinculin. In particular, it discusses the differences and the similarities between FAK and vinculin in regulating the biomechanical properties of cells. Finally, this paper highlights that both focal adhesion proteins, vinculin and FAK, synergize their functions to regulate the mechanical properties of cells such as stiffness and contractile forces. Subsequently, these mechanical properties determine cellular invasiveness into tissues and provide a source sink for future drug developments to inhibit excessive cell invasion and hence, metastases formation.

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Billings, Marcus D.

2001-01-01

The nonlinear finite element program MSC.Dytran was used to predict the impact pulse for (he drop test of an energy absorbing cellular structure. This pre-test simulation was performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. In addition, a goal of the simulation was to bound the acceleration pulse produced and delivered to the simulated space cargo container. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the enter of the EEV's cellular structure. The material models and failure criteria were varied to determine their effect on the resulting acceleration pulse. Pre-test analytical predictions using MSC.Dytran were compared with the test results obtained from impact test #4 using bungee accelerator located at the NASA Langley Research Center Impact Dynamics Research Facility. The material model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAMI model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for drop test #4.

Cellular v-ATPase is required for virion assembly compartment formation in human cytomegalovirus infection

PubMed Central

Pavelin, Jonathan; McCormick, Dominique; Chiweshe, Stephen; Ramachandran, Saranya; Lin, Yao-Tang

2017-01-01

Successful generation of virions from infected cells is a complex process requiring orchestrated regulation of host and viral genes. Cells infected with human cytomegalovirus (HCMV) undergo a dramatic reorganization of membrane organelles resulting in the formation of the virion assembly compartment, a process that is not fully understood. Here we show that acidification of vacuoles by the cellular v-ATPase is a crucial step in the formation of the virion assembly compartment and disruption of acidification results in mis-localization of virion components and a profound reduction in infectious virus levels. In addition, knockdown of ATP6V0C blocks the increase in nuclear size, normally associated with HCMV infection. Inhibition of the v-ATPase does not affect intracellular levels of viral DNA synthesis or gene expression, consistent with a defect in assembly and egress. These studies identify a novel host factor involved in virion production and a potential target for antiviral therapy. PMID:29093211

Agent-Based Modeling of Mitochondria Links Sub-Cellular Dynamics to Cellular Homeostasis and Heterogeneity.

PubMed

Dalmasso, Giovanni; Marin Zapata, Paula Andrea; Brady, Nathan Ryan; Hamacher-Brady, Anne

2017-01-01

Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis) and the removal of damaged mitochondria by selective autophagy (mitophagy). While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM) to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1) mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2) restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3) maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4) our model suggests sources of, and stress conditions amplifying

Agent-Based Modeling of Mitochondria Links Sub-Cellular Dynamics to Cellular Homeostasis and Heterogeneity

PubMed Central

Dalmasso, Giovanni; Marin Zapata, Paula Andrea; Brady, Nathan Ryan; Hamacher-Brady, Anne

2017-01-01

Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis) and the removal of damaged mitochondria by selective autophagy (mitophagy). While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM) to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1) mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2) restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3) maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4) our model suggests sources of, and stress conditions amplifying