EPILEPSIA, Issue 3 2003
Daniël M. Jonker
Summary: ,Purpose: The objective of this study was to characterize quantitatively the pharmacodynamic interaction between midazolam (MDL), an allosteric modulator of the ,-aminobutyric acid subtype A (GABAA) receptor, and tiagabine (TGB), an inhibitor of synaptic GABA uptake. Methods: The in vivo concentration,response relation of TGB was determined through pharmacokinetic/pharmacodynamic (PK/PD) modeling. Rats received a single intravenous dose of 10 mg/kg TGB in the absence and the presence of a steady-state plasma concentration of MDL. The EEG response in the 11.5- to 30-Hz frequency band was used as the pharmacodynamic end point. Results: Infusion of MDL resulted in a mean steady-state plasma concentration of 66 ± 3 ng/ml. A significant pharmacokinetic interaction with TGB was observed. MDL inhibited TGB clearance by 20 ± 7 ml/min/kg from the original value of 89 ± 6 ml/min/kg. However, no changes in plasma protein binding of both drugs were observed. The concentration,EEG relation of TGB was described by the sigmoid- Emax model. The pharmacodynamic parameter estimates of TGB were: Emax = 327 ± 10 ,V, EC50 = 392 ± 20 ng/ml, and nH = 3.1 ± 0.3. These values were not significantly different in the presence of MDL. Factors that may explain the lack of synergism were identified by a mechanism-based interaction model that separates the receptor activation from the signal-transduction process. High efficiency of signal transduction and the presence of a baseline response were shown to diminish the degree of synergism. Conclusions: We conclude that the in vivo pharmacodynamic interaction between MDL and TGB is additive rather than synergistic. This strongly suggests that allosteric modulation of the antiseizure activity of a GAT-1 inhibitor by a benzodiazepine does not offer a therapeutic advantage. [source]

Human natural Treg microRNA signature: Role of microRNA-31 and microRNA-21 in FOXP3 expression

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2009
Redouane Rouas
Abstract Treg are the main mediators of dominant tolerance. Their mechanisms of action and applications are subjects of considerable debate currently. However, a human microRNA (miR) Treg signature has not been described yet. We investigated human natural Treg and identified a signature composed of five miR (21, 31, 125a, 181c and 374). Among those, two were considerably under-expressed (miR-31 and miR-125a). We identified a functional target sequence for miR-31 in the 3, untranslated region (3, UTR) of FOXP3 mRNA. Using lentiviral transduction of fresh cord blood T cells, we demonstrated that miR-31 and miR-21 had an effect on FOXP3 expression levels. We showed that miR-31 negatively regulates FOXP3 expression by binding directly to its potential target site in the 3, UTR of FOXP3 mRNA. We next demonstrated that miR-21 acted as a positive, though indirect, regulator of FOXP3 expression. Transduction of the remaining three miR had no direct effect on FOXP3 expression or on the phenotype and will remain the subject of future investigations. In conclusion, not only have we identified and validated a miR signature for human natural Treg, but also unveiled some of the mechanisms by which this signature was related to the control of FOXP3 expression in these cells. [source]

Genetic transduction in freshwater ecosystems

FRESHWATER BIOLOGY, Issue 6 2008
OLADELE A. OGUNSEITAN
Summary 1. Lateral genetic exchange is a profound consequence of the co-existence of viruses (bacteriophages) and bacteria in freshwater ecosystems. Transduction is distinct from other mechanisms of genetic exchange because it is driven by potentially lethal agents external to the donor and recipient cells. Therefore, transduction is reputed to be a major driving force behind the diversity in natural populations and communities of bacteria. 2. Both generalized transduction (where every segment of the donor's genome has equal chance of being transferred to a recipient cell) and specialized transduction (where certain donor gene sequences are transferred at higher frequencies than others based on their proximity to the integration site of the transducing bacteriophage genome) have been demonstrated for various freshwater bacteria. However, these genetic exchange events occur at frequencies that vary widely, from 10,2 to 10,10 transductants per recipient, depending on the influence of various physical, chemical and biotic environmental factors on the outcome of phage,host encounters. Methodological constraints limit the interpretation of results from early studies of transduction in freshwaters because those studies introduced exogenous organisms in microcosms and excluded, to different extents, naturally occurring environmental conditions and their variability. 3. To assist the design and extrapolation of empirical observations, mathematical models including application of Group Theory are useful to estimate boundaries of the impact of transduction in generating and maintaining microbial diversity in freshwater. These theoretical excursions generate hypotheses and questions that can only be answered through refinement of current empirical estimates of transduction frequency, polarity of gene mobilization, bacteriophage host ranges, and the influence of gradients in environmental parameters that characterize freshwater ecosystems. [source]

Engineered measles virus as a novel oncolytic viral therapy system for hepatocellular carcinoma,

HEPATOLOGY, Issue 6 2006
Boris Blechacz
The oncolytic measles virus Edmonston strain (MV-Edm), a nonpathogenic virus targeting cells expressing abundant CD46, selectively destroys neoplastic tissue. Clinical development of MV-Edm would benefit from noninvasive monitoring strategies to determine the speed and extent of the spread of the virus in treated patients and the location of virus-infected cells. We evaluated recombinant MV-Edm expressing carcinoembryonic antigen (CEA) or the human sodium iodide symporter (hNIS) for oncolytic potential in hepatocellular carcinoma (HCC) and efficiency in tracking viruses in vivo by noninvasive monitoring. CD46 expression in human HCC and primary hepatocytes was assessed by flow cytometry and immunohistochemistry. Infectivity, syncytium formation, and cytotoxicity of recombinant MV-Edm in HCC cell lines were evaluated by fluorescence microscopy, crystal violet staining, and the MTS assay. Transgene expression in HCC cell lines after infection with recombinant MV-Edm in vitro and in vivo was assessed by CEA concentration, 125I-uptake, and 123I-imaging studies. Toxicology studies were performed in IfnarKO×CD46 transgenic mice. The CD46 receptor was highly expressed in HCC compared to nonmalignant hepatic tissue. Recombinant MV-Edm efficiently infected HCC cell lines, resulting in extensive syncytium formation followed by cell death. Transduction of HCC cell lines and subcutaneous HCC xenografts with recombinant MV-Edm resulted in high-level expression of transgenes in vitro and in vivo. MV-Edm was nontoxic in susceptible mice. Intratumoral and intravenous therapy with recombinant MV-Edm resulted in inhibition of tumor growth and prolongation of survival with complete tumor regression in up to one third of animals. In conclusion, engineered MV-Edm may be a potent and novel cancer gene therapy system for HCC. MV-Edm expressing CEA or hNIS elicited oncolytic effects in human HCC cell lines in vitro and in vivo, enabling the spread of the virus to be monitored in a noninvasive manner. (HEPATOLOGY 2006;44:1465,1477.) [source]

Synthetic pH-Responsive Polymers for Protein Transduction

ADVANCED MATERIALS, Issue 38-39 2009
William B. Liechty
A pH-responsive, endosomal membrane disruptive, metabolite-derived polyamide PP-75 is developed to deliver the MBP-Apoptin fusion protein, which induces tumor-specific apoptosis into human osteogenic sarcoma Saos-2 cells. The intracellular distribution and colocalization of MBP-Apoptin-AF647 (MA-AF649) and PP-75-FITC provide strong evidence that PP-75 both enhances uptake and facilitates cytoplasmic release of MBP-Apoptin. [source]

CELLULAR LOCALIZATION AND EXPRESSION OF pygo DURING DROSOPHILA DEVELOPMENT

INSECT SCIENCE, Issue 2 2003
LIN Xin-da
Abstract Wg/Wnt signaling is a key signaling pathway in Drosophila. Many genes involved in Wingless(wg) signal transduction pathway downstream of Wg, or it s vertebrate Wg homologue Wnt, have been identified. Transduction of the Wg signal downstream of Wg is mediated by nuclear TCF/LEF-1, through association with Armadillo (Arm),-catenin. Pygopus (pygo) is a new identified component in this pathway. Cellular localization experiment showed that pygo was expressed specifically in the nucleus. The expression profile of pygo in embryos was examined using in situ hybridization. Although pygo expressed ubiquitously in the embryos, it expressed at relatively high level in pre-blastoderm embryos which indicate a high degree of maternally provided message, followed by a low level of ubiquitous zygotic expression. This continues into larval tissues (including wing disc, eye disc and leg disc), where pygo appears to be expressed at low level. Comparison of pygo expression levels, in the wing disc, eye disc and leg disc, showed pygo expression level in the wing disc pouch and leg disc were relative higher. [source]

Loss of RAB25 expression in breast cancer

INTERNATIONAL JOURNAL OF CANCER, Issue 12 2006
Ji-Ming Cheng
Abstract A novel breast cancer cell line (RAO-3) was established by transduction of the Q61L mutant RAS into human mammary epithelial cells that were immortalized with catalytic subunit of telomerase (hTERT). The cells displayed anchorage-independent growth and proliferation, and formed human mammary spindle cell carcinoma when injected into nude mice. Chromosome locus 1q22-23 was partially duplicated and inverted on one of the 3 chromosomes present in the cell line. We report here that mutations of chromosome 1q22-23 locus have resulted in the loss of RAB25 expression in the breast cancer cell line. Transduction of RAB25 into the breast cancer cell line arrests anchorage-independent growth. We have also demonstrated loss of RAB25 in human breast tumor tissue. These data suggest that loss of RAB25 might contribute to tumorigenesis of breast cancer, and RAB25 is likely to be an important factor in the development of breast cancer. RAB25 could be used as biological marker of breast cancer and provides a target for gene replacement therapy. © 2006 Wiley-Liss, Inc. [source]

Reactive Oxygen Species and Signal Transduction

IUBMB LIFE, Issue 1 2001
Toren Finkel
Abstract Increasing evidence suggests a role for intracellular reactive oxygen species (ROS) as mediators of normal and pathological signal transduction pathways. In particular, a growing list of recent reports have demonstrated a rapid and significant increases in intracellular ROS following growth factor or cytokine stimulation. These ROS appear essential for a host of downstream signaling events. Biochemical characterization of this ligand-activated ROS production has revealed important information regarding the molecular composition of the cellular oxidases and the regulation of their activity by small GTPases. Work is proceeding on identifying strategies to identify how ROS might specifically regulate signaling pathways by altering the activity of direct target molecules. This review will focus on the progress in the rapid emerging area of oxidant or redox-dependent signal transduction and speculate how these insights might alter our view and treatment of diseases thought to be caused by oxidative stress. [source]

Poster Sessions CP08: Signal Transduction

JOURNAL OF NEUROCHEMISTRY, Issue 2002
G. Taglialatela
Inducible nitric oxide synthase (iNOS) and high levels of nitric oxide (NO) are present in the CNS of patients with Alzheimer's disease (AD), resulting in both DNA and protein oxidative damage. While iNOS can result in damaging levels of NO, the neuronal constitutive form of NOS (nNOS) has a role in cell signalling and can prevent neuronal apoptosis. iNOS can be induced by inflammatory cytokines such as tumor necrosis alpha (TNF,). TNF, is found in the CNS of AD, where neurons dependent on neurotrophins such as nerve growth factor (NGF) are particularly affected. Here we determined the effect of TNF, on the three NOS isoforms (endothelial, neuronal and inducible) in NGF-responsive PC12 cells. We found that while TNF, and NGF alone were uneffective, their simultaneous addition resulted in iNOS induction and the release of NO. In addition TNF, and NGF synergistically reduced nNOS, independently of the presence of high NO levels promoted by iNOS, while no effect was observed on eNOS. A similar pattern was observed in the brain of aged human subjects as compared to young individuals. Our results suggest that synergistic iNOS induction by TNF, and NGF may occur in selective populations of NGF-responsive neurons. Oxidative damage in such neurons could then occur in the presence of elevated levels of TNF,, that potentially occur in the brain of AD patients. This damaging scenario may further be aggravated by a concomitant reduction of nNOS, brought about by similar synergistic effects between TNF, and NGF. Acknowledgements:, Supported by NIA (AG13945) and Sealy Res. Dev. grants to GT. [source]

14-3-3 Proteins in Pineal Photoneuroendocrine Transduction: How Many Roles?

JOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2003
D. C. Klein
Abstract Recent studies suggest that a common theme links the diverse elements of pineal photoneuroendocrine transduction ,regulation via binding to 14-3-3 proteins. The elements include photoreception, neurotransmission, signal transduction and the synthesis of melatonin from tryptophan. We review general aspects of 14-3-3 proteins and their biological function as binding partners, and also focus on their roles in pineal photoneuroendocrine transduction. [source]

Efficient gene transfer in mouse neural precursors with a bicistronic retroviral vector

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 3 2001
Isabelle A. Franceschini
Abstract Gene transfer into neural precursors is a powerful approach to study the function of specific gene products during nervous system development. Here we describe a retrovirus-based methodology to transduce foreign genes into mouse neural precursors. We used a high-titer bicistronic retroviral vector that encodes a marker gene, placental alkaline phosphatase (plap), and a selection gene, neomycin phosphotransferase II (neoR), under the translational control of two retroviral internal ribosome entry segments. Transduction efficiency even without selection was up to 95% for multipotential neurospheres derived from embryonic striata and grown with basic fibroblast growth factor 2. Expression of plap and neoR was sustained with time in culture and upon differentiation into neurons, astrocytes, and oligodendrocytes, as shown by double immunofluorescence labeling with cell type-specific markers, Western blotting, and neomycin resistance. However, levels of plap were decreased in differentiated oligodendrocytes. Transduction with the same vector of neonatal oligodendrocyte precursors grown in oligospheres consistently resulted in a lower proportion of plap-immunoreactive cells and enhanced cell death in the absence of neomycin. However, plap expression was maintained in some differentiated oligodendrocytes expressing galactocerebroside or myelin basic protein. In that neurospheres can be easily expanded in vitro and factors enabling their differentiation into the three main central nervous system cell types are being elucidated, this methodology could be used in the future to produce large number of transduced, differentiated neural cells. J. Neurosci. Res. 65:208,219, 2001. © 2001 Wiley-Liss, Inc. [source]

Signal Transduction in Alcohol-Related Diseases

ALCOHOLISM, Issue 7 2005
Minoti V. Apte
This article summarizes the proceedings of a symposium presented at the 12th World Congress on Biomedical Alcohol Research, organized by the International Society for Biomedical Research on Alcoholism, held at the University of Heidelberg in Mannheim, Germany, in September and October 2004. The organizers and chairpersons were Manfred V. Singer and Stephen J. Pandol. The presentations were (1) Ethanol-induced acinar cell injury, by Minoti V. Apte; (2) Oxidants and antioxidants: signal transduction and alcohol, by Thomá Zima; (3) Anti,TGF-, strategies for the treatment of chronic liver disease, by Steven Dooley; (4) Immune mechanisms in alcohol-induced liver disease, by Sören V. Siegmund; and (5) Alcoholic pancreatitis: insights from animal models, by Steven J. Pandol. [source]

Differential Effects of Ethanol on Signal Transduction

ALCOHOLISM, Issue 1 2000
Gail H. Levine
Background: PC12 pheochromocytoma cells were used as a model to study the effect of long-term ethanol exposure on signal transduction systems. In PC12 cells, the agonist bradykinin stimulates a phospholipase C specific for inositol-containing phospholipids and a phospholipase D specific for phosphatidylcholine. Methods: PC12 cells were grown in monolayer and cultured in the presence and absence of 1% ethanol for 5 days. After this period, bradykinin-stimulated phospholipase C and D were measured. The effect of long-term ethanol on the bradykinin-mediated activation of mitogen-activated protein (MAP) kinase was also measured. Results: In cells exposed to 1% ethanol for 5 days, bradykinin-stimulated phospholipase D was greatly attenuated, whereas bradykinin-stimulated phospholipase C was not altered. The tyrosine kinase inhibitor, genistein, blocked the bradykinin-mediated activation of phospholipase D but did not affect the stimulation of phospholipase C. However, long-term ethanol treatment did not attenuate the ability of bradykinin to activate MAP kinase, which suggests that ethanol did not have a general effect on all tyrosine kinase pathways. Conclusions: Ethanol has a differential effect on signal transduction in PC12 cells. Activation of phospholipase D may be mediated by a kinase, whereas the activation of phospholipase C is probably mediated by the guanine nucleotide binding protein, Gq. Because of these differences in activation mechanism, the pathways may adapt differently to long-term exposure to ethanol. [source]

Study of the effects of interferon a on several human hepatoma cell lines: analysis of the signalling pathway of the cytokine and of its effects on apoptosis and cell proliferation

LIVER INTERNATIONAL, Issue 2 2004
A. Legrand
Background: Interferon , (IFN,), currently used for the treatment of chronic viral hepatitis, is also known to prevent the development of hepatocellular carcinoma (HCC), the mechanism of this action being still debatable. Aims: To study thoroughly in human hepatoma cell lines (HHL) , Hep3B, HepG2, HuH7, SKHep1, and Chang-Liver , submitted to rhIFN,, the signalling pathway of IFN,, the binding activity of the cytokine on specific gamma-activated sequence (GAS) and interferon-stimulated regulatory element (ISRE) nuclear sequences, and its effects on apoptosis and cell proliferation. Methods: The behaviour of signal transducer and activator of transcription (STAT)1, STAT2, p48IRF9 and the binding of nuclear proteins were investigated by immunoblot and electro-mobility shift assay. Expression of some IFN,-dependent proteins , p21/WAF1, inducible nitric oxide synthase, IRF1 and 2 , were studied by immunoblot. Apoptosis and the cell cycle were studied by morphological and biochemical methods. Results: Transduction of INF, was unaltered, although there were some variations in the different HHL. Nuclear protein binding to GAS or ISRE showed that ISRE was mainly involved. Apoptosis did not occur. The cell cycle was slightly modified in HuH7. Three GAS- and/or ISRE-dependent proteins increased, suggesting that IFN, may have some biological effects on HHL. Conclusions: The IFN, signalling pathway is functional in several HHL, but the cytokine has no apoptotic effect and a moderate anti-proliferative effect. This suggests that the preventive role of IFN, on HCC cannot be explained by an apoptotic and/or an anti-proliferative effect, but possibly by its action on several specific nuclear sequences that protect liver cells from transformation. [source]

Sensor Mechanism and Afferent Signal Transduction of the Urinary Bladder: Special Focus on transient receptor potential Ion Channels

LUTS, Issue 2 2010
Masayuki TAKEDA
In the urine storage phase, mechanical stretch stimulates bladder afferents. These urinary bladder afferent sensory nerves consist of small diameter A, - and C-fibers running in the hypogastic and pelvic nerves. Neuroanatomical studies have revealed a complex neuronal network within the bladder wall. The exact mechanisms that underline mechano-sensory transduction in bladder afferent terminals remain ambiguous; however, a wide range of ion channels (e.g. TTX-resistant Na+ channels, Kv channels and hyperpolarization-activated cyclic nucleotidegated cation channels, degenerin/epithelial Na+ channel), and receptors (e.g. TRPV1, TRPM8, TRPA1, P2X2/3, etc.) have been identified at bladder afferent terminals and have implicated in the generation and modulation of afferent signals, which are elcited by a wide range of bladder stimulations including physiological bladder filling, noxious distension, cold, chemical irritation and inflammation. The mammalian transient receptor potential (TRP) family consists of 28 channels that can be subdivided into six different classes: TRPV (Vanilloid), TRPC (Canonical), TRPM (Melastatin), TRPP (Polycystin), TRPML (Mucolipin), and TRPA (Ankyrin). TRP channels are activated by a diversity of physical (voltage, heat, cold, mechanical stress) or chemical (pH, osmolality) stimuli and by binding of specific ligands, enabling them to act as multifunctional sensors at the cellular level. TRPV1, TRPV2, TRPV4, TRPM8, and TRPA1 have been described in different parts of the urogenital tract. Although only TRPV1 among TRPs has been extensively studied so far, more evidence is slowly accumulating about the role of other TRP channels, ion channels, and receptors in the pathophysiology of the urogenital tract, and may provide a new strategy for the treatment of bladder dysfunction. [source]

The Physiology of Endothelial Xanthine Oxidase: From Urate Catabolism to Reperfusion Injury to Inflammatory Signal Transduction

MICROCIRCULATION, Issue 3 2002
AVEDIS MENESHIAN
ABSTRACT Xanthine oxidoreductase (XOR) is a ubiquitous metalloflavoprotein that appears in two interconvertible yet functionally distinct forms: xanthine dehydrogenase (XD), which is constitutively expressed in vivo; and xanthine oxidase (XO), which is generated by the posttranslational modification of XD, either through the reversible, incremental thiol oxidation of sulfhydryl residues on XD or the irreversible proteolytic cleavage of a segment of XD, which occurs at low oxygen tension and in the presence of several proinflammatory mediators. Functionally, both XD and XO catalyze the oxidation of purines to urate. However, whereas XD requires NAD+ as an electron acceptor for these redox reactions, thereby generating the stable product NADH, XO is unable to use NAD+ as an electron acceptor, requiring instead the reduction of molecular oxygen for this purine oxidation and generating the highly reactive superoxide free radical. Nearly 100 years of study has documented the physiologic role of XD in urate catabolism. However, the rapid, posttranslational conversion of XD to the oxidantgenerating form XO provides a possible physiologic mechanism for rapid, posttranslational, oxidant-mediated signaling. XO-generated reactive oxygen species (ROS) have been implicated in various clinicopathologic entities, including ischemia/reperfusion injury and multisystem organ failure. More recently, the concept of physiologic signal transduction mediated by ROS has been proposed, and the possibility of XD to XO conversion, with subsequent ROS generation, serving as the trigger of the microvascular inflammatory response in vivo has been hypothesized. This review presents the evidence and basis for this hypothesis. [source]

Proceedings,targeting carcinogenesis: Transduction, transcription, translation,

MOLECULAR CARCINOGENESIS, Issue 6 2006
Zigang Dong Guest Editor
[source]

Upward mobility and alternative lifestyles: a report from the 10th biennial meeting on Bacterial Locomotion and Signal Transduction

MOLECULAR MICROBIOLOGY, Issue 1 2009
Birgit E. Scharf
Summary This past January, in Cuernavaca Mexico, a conglomerate of scientists met to discuss the contemporary view of Bacterial Locomotion and Signal Transduction (BLAST). The BLAST meetings represent a field that has its roots in chemotaxis and the flagellum-based motility but now encompass all types of cellular movement and signalling. The topics varied from the interactions between molecules to the interactions between species. We heard about 3D reconstructions of transmembrane chemoreceptors within cells, new biophysical methods for understanding cellular engines, intricate phosphorelays, elaborate gene networks, new messenger molecules and emerging behaviours within complex populations of cells. At BLAST X we gained an appreciation for the lifestyle choices bacteria make, how they get to where they are going and the molecular mechanisms that underlie their decisions. Herein we review the highlights of the meeting. [source]

Phosphate availability regulates biosynthesis of two antibiotics, prodigiosin and carbapenem, in Serratia via both quorum-sensing-dependent and -independent pathways

MOLECULAR MICROBIOLOGY, Issue 2 2003
Holly Slater
Summary Serratia sp. ATCC 39006 produces two secondary metabolite antibiotics, 1-carbapen-2-em-3-carboxylic acid (Car) and the red pigment, prodigiosin (Pig). We have previously reported that production of Pig and Car is controlled by N -acyl homoserine lactone (N -AHL) quorum sensing, with synthesis of N -AHLs directed by the LuxI homologue SmaI, and is also regulated by Rap, a member of the SlyA family. We now describe further characterization of the SmaI quorum-sensing system and its connection with other regulatory mechanisms. We show that the genes responsible for biosynthesis of Pig, pigA,O, are transcribed as a single polycistronic message in an N -AHL-dependent manner. The smaR gene, transcribed convergently with smaI and predicted to encode the LuxR homologue partner of SmaI, was shown to possess a negative regulatory function, which is uncommon among the LuxR-type transcriptional regulators. SmaR represses transcription of both the pig and car gene clusters in the absence of N -AHLs. Specifically, we show that SmaIR exerts its effect on car gene expression via transcriptional control of carR, encoding a pheromone-independent LuxR homologue. Transcriptional activation of the pig and car gene clusters also requires a functional Rap protein, but Rap dependency can be bypassed by secondary mutations. Transduction of these suppressor mutations into wild-type backgrounds confers a hyper-Pig phenotype. Multiple mutations cluster in a region upstream of the pigA gene, suggesting this region may represent a repressor target site. Two mutations mapped to genes encoding pstS and pstA homologues, which are parts of a high-affinity phosphate transport system (Pst) in Escherichia coli. Disruption of pstS mimicked phosphate limitation and caused concomitant hyper-production of Pig and Car, which was mediated, in part, through increased transcription of the smaI gene. The Pst and SmaIR systems define distinct, yet overlapping, regulatory circuits which form part of a complex regulatory network controlling the production of secondary metabolites in Serratia ATCC 39006. [source]

FAK silencing inhibits leukemogenesis in BCR/ABL-transformed hematopoietic cells,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 5 2009
Yi Le
Focal adhesion kinase (FAK) is constitutively activated and tyrosine phosphorylated in BCR/ABL-transformed hematopoietic cells, but the role it plays during leukemogenesis remains unclear. Here, we examined the effects of RNA interference-mediated FAK silencing on leukemogenesis induced by a BCR/ABL-transformed cell line. Transduction of BCR/ABL-BaF3 cells with FAK shRNA inhibited FAK expression and reduced STAT5 phosphorylation, but induced caspase-3 activation. In vitro studies showed that treatment with FAK shRNA resulted in impaired cell proliferation and colony formation, while increasing cell apoptosis. Mice that received transplants of BCR/ABL-BaF3 cells with FAK shRNA displayed significantly prolonged survival time and diminished leukemia progression. In addition, FAK silencing enhanced in vitro and in vivo efficacy of ABL tyrosine kinase inhibitor imatinib in BCR/ABL-BaF3 cells. Our results suggest that FAK is critical for leukemogenesis and might be a potential target for leukemia therapy. Am. J. Hematol. 2009. © 2009 Wiley-Liss, Inc. [source]

Introduction to the Symposium-in-Print on Photoreceptors and Signal Transduction in Honor of Professor Fumio Tokunaga

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2008
Osamu Hisatomi
No abstract is available for this article. [source]

Survival Pathway Signal Transduction is Reduced in Alveolar Macrophages during Pneumocystis Pneumonia

THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2006
MARK E. LASBURY
[source]

Feline immunodeficiency virus vectors.

THE JOURNAL OF GENE MEDICINE, Issue 5 2002
Gene transfer to mouse retina following intravitreal injection
Abstract Background Transduction of the murine retinal pigmented epithelium (RPE) with adenovirus vectors requires technically difficult and invasive subretinal injections. This study tested the hypothesis that recombinant vectors based on feline immunodeficiency virus (FIV) could access the retina following intravitreal injection. Methods FIV vectors expressing E. coli ,-galactosidase (FIV,gal) were injected alone, or in combination with adenovirus vectors expressing eGFP, into the vitreous of normal mice and eyes evaluated for transgene expression. In further studies, the utility of FIV-mediated gene transfer to correct lysosomal storage defects in the anterior and posterior chambers of eyes was tested using recombinant FIV vectors expressing ,-glucuronidase. FIV,gluc vectors were injected into ,-glucuronidase-deficient mice, an animal model of mucopolysacharridoses type VII. Results The results of this study show that similar to adenovirus, both corneal endothelium and cells of the iris could be transduced following intravitreal injection of FIV,gal. However, in contrast to adenovirus, intravitreal injection of FIV,gal also resulted in transduction of the RPE. Immunohistochemistry following an intravitreal injection of an AdeGFP (adenovirus expressing green fluorescent protein) and FIV,gal mixture confirmed that both viruses mediated transduction of corneal endothelium and cells of the iris, while only FIV,gal transduced cells in the retina. Using the ,-glucuronidase-deficient mouse, the therapeutic efficacy of intravitreal injection of FIV,gluc (FIV expressing ,-glucuronidase) was tested. Intravitreal injection of FIV,gluc to the eyes of ,-glucuronidase-deficient mice resulted in rapid reduction (within 2,weeks) of the lysosomal storage defect within the RPE, corneal endothelium, and the non-pigmented epithelium of the ciliary process. Transgene expression and correction of the lysosomal storage defect remained for at least 12,weeks, the latest time point tested. Conclusion These studies demonstrate that intravitreal injection of FIV-based vectors can mediate efficient and lasting transduction of cells in the cornea, iris, and retina. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Connecting the Dots for Mechanochemical Transduction in Muscle

THE JOURNAL OF PHYSIOLOGY, Issue 1 2003
Michael J. Rennie
No abstract is available for this article. [source]

ORIGINAL ARTICLE: Genistein Reverses Diminished T-Cell Signal Transduction, Induced by Post-Menopausal Estrogen Levels

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2009
J. Preston Parry
Problem, This study addressed the ability of genistein to reverse the loss of T-cell signaling components, induced by estrogen deficiency associated with aging. Method of study, Using Jurkat 6.1 T cells, genistein regulation of CD3,, JAK3, and NF,B was analysed by Western immunoblotting at 4 or 40 pg/mL (post- and pre-menopausal levels, respectively) estradiol (E2). Corresponding gene expressions were quantified by real-time polymerase chain reaction (RT-PCR). For functionality, levels of IL-2 were correlated with its transcription by RT-PCR. Results, At 4 pg/mL E2, signaling proteins were decreased compared with 40 pg/mL: CD3,, 1.58-fold; JAK3, 1.75-fold; and NF,B, 1.73-fold (P < 0.001). Genistein, at 0.5 and 5.0 ,m, added to 4 pg/mL E2 induced their expression to 40 pg/mL levels. While significantly diminished IL-2 mRNA levels were observed at 4 pg/mL E2, genistein induced IL-2 mRNA to 40 pg/mL levels. Conclusion, Genistein restores CD3,, NF,B and JAK3 proteins and mRNAs at post-meonopausal estrogen levels, in vitro, with no significant effect at pre-menopausal estrogen levels. [source]

Connective Tissue Growth Factor Promotes Fibrosis Downstream of TGF, and IL-6 in Chronic Cardiac Allograft Rejection

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2010
A. J. Booth
Cardiac transplantation is an effective treatment for multiple types of heart failure refractive to therapy. Although immunosuppressive therapeutics have increased survival rates within the first year posttransplant, chronic rejection (CR) remains a significant barrier to long-term graft survival. Indicators of CR include patchy interstitial fibrosis, vascular occlusion and progressive loss of graft function. Multiple factors have been implicated in the onset and progression of CR, including TGF,, IL-6 and connective tissue growth factor (CTGF). While associated with CR, the role of CTGF in CR and the factors necessary for CTGF induction in vivo are not understood. To this end, we utilized forced expression and neutralizing antibody approaches. Transduction of allografts with CTGF significantly increased fibrotic tissue development, though not to levels observed with TGF, transduction. Further, intragraft CTGF expression was inhibited by IL-6 neutralization whereas TGF, expression remained unchanged, indicating that IL-6 effects may potentiate TGF,-mediated induction of CTGF. Finally, neutralizing CTGF significantly reduced graft fibrosis without reducing TGF, and IL-6 expression levels. These findings indicate that CTGF functions as a downstream mediator of fibrosis in CR, and that CTGF neutralization may ameliorate fibrosis and hypertrophy associated with CR. [source]

Gene Transduction of an Active Mutant of Akt Exerts Cytoprotection and Reduces Graft Injury After Liver Transplantation

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2007
M. Morales-Ruiz
Akt is expected to be an effective target for the treatment of ischemia-reperfusion injury (I/R) due to its anti-apoptotic properties and its ability to activate the endothelial nitric oxide synthase (eNOS) enzyme. Therefore, this study was aimed to determine the efficacy of an active mutant of Akt (myr-Akt) to decrease I/R injury in a model of orthotopic liver transplantation in pigs. In addition, we analyzed the contribution of nitric oxide in the Akt-mediated effects by using an eNOS mutant (S1179DeNOS) that mimics the phosphorylation promoted by Akt in the eNOS sequence. Donors were treated with adenoviruses codifying for myr-Akt, S1179DeNOS or ,-galactosidase 24 h before liver harvesting. Then, liver grafts were orthotopically transplanted into their corresponding recipients. Levels of transaminases and lactate dehydrogenase (LDH) increased in all recipients after 24 h of transplant. However, transaminases and LDH levels were significantly lower in the myr-Akt group compared with vehicle. The percentage of apoptotic cells and the amount of activated-caspase 3 protein were also markedly reduced in myr-Akt-treated grafts after 4 days of liver transplant compared with vehicle and S1179DeNOS groups. In conclusion, myr-Akt gene therapy effectively exerts cytoprotection against hepatic I/R injury regardless of the Akt-dependent eNOS activation. [source]

Phospholipid-Coated Carbon Nanotubes as Sensitive Electrochemical Labels with Controlled-Assembly-Mediated Signal Transduction for Magnetic Separation Immunoassay,

ANGEWANDTE CHEMIE, Issue 52 2009
Huagui Nie Dr.
Ein elektrochemisches Immunassay nutzt mehrwandige Kohlenstoffnanoröhren (MWNTs) mit Phospholipidüberzug als elektrochemische Markierungen (siehe Schema; PSA=Antigenprotein; MB=magnetisches Kügelchen). Die Signalübertragung bei dieser Strategie ist hoch empfindlich und spezifisch. [source]

Entirely Artificial Signal Transduction with a Primary Messenger,

ANGEWANDTE CHEMIE, Issue 43 2009
Kai Bernitzki
In einem künstlichen System gelingt die Botenstoff-induzierte Signalleitung über eine Membran. Die Zugabe des primären Botenstoffs (DET; siehe Bild) führt zur Bildung eines heterodimeren Komplexes aus Transmembran-Einheiten mit Tryptophan-Donor (Trp) und Dansyl-Akzeptor (Dan), der wiederum einen starken FRET-Effekt auf der Innenseite der Membran induziert (FRET: resonanter Fluoreszenzenergietransfer). [source]

Retrovirus-Polymer Complexes: Study of the Factors Affecting the Dose Response of Transduction

BIOTECHNOLOGY PROGRESS, Issue 2 2007
Natalia Landázuri
We have previously shown that complexes of Polybrene (PB), chondroitin sulfate C (CSC), and retrovirus transduce cells more efficiently than uncomplexed virus because the complexes are large and sediment, reaching the cells more rapidly than by diffusion. Transduction reaches a peak at equal weight concentrations of CSC and PB and declines when the dose of PB is higher or lower than CSC. We hypothesized that the nonlinear dose response of transduction was a complex function of the molecular characteristics of the polymers, cell viability, and the number of viruses incorporated into the complexes. To test this hypothesis, we formed complexes using an amphotropic retrovirus and several pairs of oppositely charged polymers and used them to transduce murine fibroblasts. We examined the effect of the type and concentration of polymers used on cell viability, the size and charge of the complexes, the number of viruses incorporated into the complexes, and virus binding and transduction. Transduction was enhanced (2.5- to 5.5-fold) regardless of which polymers were used and was maximized when the number of positive charge groups was in slight excess (15,28%) of the number of negative charge groups. Higher doses of cationic polymer were cytotoxic, whereas complexes formed with lower doses were smaller, contained fewer viruses, and sedimented more slowly. These results show that the dose response of transduction by virus-polymer complexes is nonlinear because excess cationic polymer is cytotoxic, whereas excess anionic polymer reduces the number of active viruses that are delivered to the cells. [source]