151
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Abstract
Calcium signaling activates the phosphatase calcineurin and induces movement of NFATc proteins into the nucleus, where they cooperate with other proteins to form complexes on DNA. Nuclear import is opposed by kinases such as GSK3, thereby rendering transcription continuously responsive to receptor occupancy. Disruptions of the genes involved in NFAT signaling are implicating this pathway as a regulator of developmental cell-cell interactions.
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Affiliation(s)
- Gerald R Crabtree
- Department of Developmental Biology, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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152
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Natarajan C, Bright JJ. Peroxisome proliferator-activated receptor-gamma agonists inhibit experimental allergic encephalomyelitis by blocking IL-12 production, IL-12 signaling and Th1 differentiation. Genes Immun 2002; 3:59-70. [PMID: 11960303 DOI: 10.1038/sj.gene.6363832] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2001] [Revised: 10/30/2001] [Accepted: 10/30/2001] [Indexed: 12/12/2022]
Abstract
Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a nuclear receptor transcription factor that regulates adipocyte differentiation and glucose homeostasis. PPARgamma agonists are potent therapeutic agents for the treatment of type 2 diabetes and obesity. PPARgamma agonists also prevent inflammation in animal models, suggesting their use for the treatment of human inflammatory diseases. Experimental allergic encephalomyelitis (EAE) is a Th1 cell-mediated inflammatory demyelinating disease model of multiple sclerosis (MS) and IL-12 plays a crucial role in the pathogenesis of EAE and MS. In this study we have examined the effect of PPARgamma agonists on the pathogenesis of EAE. In vivo treatment of SJL/J mice with PPARgamma agonists, 15-deoxydelta(12,14) prostaglandin J2 or Ciglitazone, decreased the duration and clinical severity of active immunization and adoptive transfer models of EAE. PPARgamma agonists inhibited EAE in association with a decrease in IL-12 production and differentiation of neural antigen-specific Th1 cells. In vitro treatment of activated T cells with PPARgamma agonists inhibited IL-12-induced activation of JAK-STAT signaling pathway and Th1 differentiation. These findings highlight the fact that PPARgamma agonists regulate central nervous system inflammation and demyelination by inhibiting IL-12 production, IL-12 signaling and Th1 differentiation in EAE.
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Affiliation(s)
- C Natarajan
- Division of Neuroimmunology, Department of Neurology, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
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153
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Dellis O, Gangloff SC, Paulais M, Tondelier D, Rona JP, Brouillard F, Bouteau F, Guenounou M, Teulon J. Inhibition of the calcium release-activated calcium (CRAC) current in Jurkat T cells by the HIV-1 envelope protein gp160. J Biol Chem 2002; 277:6044-50. [PMID: 11744714 DOI: 10.1074/jbc.m111831200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The HIV-1 envelope glycoprotein gp120/160 has pleiotropic effects on T cell function. We investigated whether Ca(2+) signaling, a crucial step for T cell activation, was altered by prolonged exposure of Jurkat T cells to gp160. Microfluorometric measurements showed that Jurkat cells incubated with gp160 had smaller (approximately 40%) increases in [Ca(2+)](i) in response to phytohemagglutinin and had a reduced Ca(2+) influx (approximately 25%). gp160 had similar effects on Jurkat cells challenged with thapsigargin. We used the patch clamp technique to record the Ca(2+) current, which is responsible for Ca(2+) influx and has properties of the calcium release-activated Ca(2+) current (I(CRAC)). gp160 reduced I(CRAC) by approximately 40%. The inhibitory effects of gp160 were antagonized by staurosporine (0.1 microm), an inhibitor of protein-tyrosine kinases and protein kinase Cs (PKCs), and by Gö 6976 (5 microm), an inhibitor acting especially on PKC alpha and PKC beta I. 12-O-Tetradecanoyl phorbol 13-acetate (16 nm), a PKC activator, reproduced the effects of gp160 in untreated cells. A Western blotting analysis of PKC isoforms alpha, beta I, delta, and zeta showed that only the cellular distribution of PKC alpha and -beta I were significantly modified by gp160. In addition, gp160 was able to modify the subcellular distribution of PKC alpha and PKC beta I caused by phytohemagglutinin. Therefore the reduction in I(CRAC) caused by prolonged incubation with gp160 is probably mediated by PKC alpha or -beta I.
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Affiliation(s)
- Olivier Dellis
- Electrophysiologie des Membranes, Université Denis Diderot (Paris7), 2 place Jussieu, 75251 Paris cedex 05, France.
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154
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Li M, Torres C, Acuña-Castillo C, Walter R, Gardner EM, Murasko DM, Sierra F. Defect in ERK2 and p54(JNK) activation in aging mouse splenocytes. J Gerontol A Biol Sci Med Sci 2002; 57:B41-7. [PMID: 11818422 DOI: 10.1093/gerona/57.2.b41] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have previously reported on a defect in both extracellular signal-regulated protein kinase (ERK) and c-jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) activation in splenocytes obtained from old rats. In order to investigate whether these effects are conserved across species, we have now used mouse splenocytes to measure the effect of aging on the activation of the same two MAPK families: ERK and JNK. Our results demonstrate that, as in rats, both MAPK signal transduction pathways are affected by aging in mice, indicating the existence of a further defect located downstream of the receptor-proximal events. Whereas ERK1 and p46(JNK) activation were not significantly modified, the kinetics of both ERK2 and p54(JNK) activation and inactivation were affected in splenocytes from old animals. Specifically, by analyzing the kinetics of activation and inactivation of these enzymes, we found a nearly 50% decrease in the fold of activation of both ERK2 and p54(JNK). These defects result in an overall diminution of enzyme activities without changes in the steady-state levels of relevant proteins. The impaired activity of these two MAPK pathways is likely to play a role in the reduced expression of interleukin-2 and diminished lymphoproliferation observed in old animals.
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Affiliation(s)
- Min Li
- Center for Gerontological Research, MCP-Hahnemann University, Philadelphia, Pennsylvania, USA
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155
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Gonzalez J, Harris T, Childs G, Prystowsky MB. Rapamycin blocks IL-2-driven T cell cycle progression while preserving T cell survival. Blood Cells Mol Dis 2002; 27:572-85. [PMID: 11355896 DOI: 10.1006/bcmd.2001.0420] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Effective cellular immune responses require increases in antigen-specific T lymphocytes; IL-2 drives antigen-stimulated T cell proliferation and is largely responsible for the increases observed. We used microarrays containing approximately 9000 mouse cDNAs to study IL-2-induced gene expression. IL-2 induces the expression of genes that regulate cell cycle progression, control cell survival, and increase synthetic and metabolic processes during proliferation. IL-2 also suppresses expression of genes that block cell cycle progression and promote cell death. Rapamycin inhibits IL-2-driven proliferation by downregulating the expression of genes required for key processes required for cell cycle progression. Rapamycin also preserves cell survival by keeping intact the IL-2-induced cell survival programs. These complex multifaceted programs of gene expression permit a dynamic regulation of cellular proliferation and cellular survival.
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Affiliation(s)
- J Gonzalez
- Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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156
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Abstract
Transcription factor NF-kappaB is biochemically coupled to the T cell antigen receptor (TCR) and activated transiently during an adaptive immune response. The author's laboratory is investigating the signal-dependent regulation of NF-kappaB, its downstream gene targets, and its function in lymphocyte biology. Our studies have revealed novel enzymatic checkpoints in the NF-kappaB signaling pathway and constitutive repressors of NF-kappaB that might be clinically applicable for therapeutic control of the immune system. We have also found that the Tax transforming protein encoded by human T cell leukemia virus type 1 (HTLV1) binds to and persistently activates an inducible protein kinase in the TCR/NF-kappaB axis. This viral/host interaction appears to trigger the inappropriate expression of NF-kappaB and the development of HTLV1-associated disease.
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Affiliation(s)
- D W Ballard
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-0295, USA.
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157
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Abstract
Transcription factor NF-kappaB is biochemically coupled to the T cell antigen receptor (TCR) and activated transiently during an adaptive immune response. The author's laboratory is investigating the signal-dependent regulation of NF-kappaB, its downstream gene targets, and its function in lymphocyte biology. Our studies have revealed novel enzymatic checkpoints in the NF-kappaB signaling pathway and constitutive repressors of NF-kappaB that might be clinically applicable for therapeutic control of the immune system. We have also found that the Tax transforming protein encoded by human T cell leukemia virus type 1 (HTLV1) binds to and persistently activates an inducible protein kinase in the TCR/NF-kappaB axis. This viral/host interaction appears to trigger the inappropriate expression of NF-kappaB and the development of HTLV1-associated disease.
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Affiliation(s)
- D W Ballard
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-0295, USA.
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158
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Trumpp A, Refaeli Y, Oskarsson T, Gasser S, Murphy M, Martin GR, Bishop JM. c-Myc regulates mammalian body size by controlling cell number but not cell size. Nature 2001; 414:768-73. [PMID: 11742404 DOI: 10.1038/414768a] [Citation(s) in RCA: 357] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Overexpression of the proto-oncogene c-myc has been implicated in the genesis of diverse human tumours. c-Myc seems to regulate diverse biological processes, but its role in tumorigenesis and normal physiology remains enigmatic. Here we report the generation of an allelic series of mice in which c-myc expression is incrementally reduced to zero. Fibroblasts from these mice show reduced proliferation and after complete loss of c-Myc function they exit the cell cycle. We show that Myc activity is not needed for cellular growth but does determine the percentage of activated T cells that re-enter the cell cycle. In vivo, reduction of c-Myc levels results in reduced body mass owing to multiorgan hypoplasia, in contrast to Drosophila c-myc mutants, which are smaller as a result of hypotrophy. We find that c-myc substitutes for c-myc in fibroblasts, indicating they have similar biological activities. This suggests there may be fundamental differences in the mechanisms by which mammals and insects control body size. We propose that in mammals c-Myc controls the decision to divide or not to divide and thereby functions as a crucial mediator of signals that determine organ and body size.
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Affiliation(s)
- A Trumpp
- Swiss Institute for Experimental Cancer Research (ISREC), Ch. des Boveresses 155, CH-1066 Epalinges, Switzerland.
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159
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Du C, Guan Q, Khalil MW, Sriram S. Stimulation of Th2 response by high doses of dehydroepiandrosterone in KLH-primed splenocytes. Exp Biol Med (Maywood) 2001; 226:1051-60. [PMID: 11743142 DOI: 10.1177/153537020122601113] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Although dehydroepiandrosterone (DHEA) has long been considered as a precursor for steroid hormones, it has also been shown to have regulatory effects in immune homeostasis. We have examined the effect of high DHEA doses on T cell proliferation, differentiation, and cytokine secretion patterns following stimulation with mitogens and soluble antigens. DHEA profoundly inhibited T cell receptor-mediated T cell proliferation in the upstream of IL-2R signaling. Addition of DHEA to KLH-primed splenocytes stimulated Th2 response, indicated by an increase of IL-4 or a decrease of IFN-gamma production in the cultures. Further studies showed that DHEA enhanced IL-4, but inhibited IL-12-mediated T cell proliferation and IL-12 production in antigen-presenting cells (APCs). Our data demonstrated that supraphysiologic levels of DHEA favored Th2 immune responses in vitro by inhibition of IL-12 production from APCs and/or stimulation of Th2 proliferation during the interactions of T cells with APCs.
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Affiliation(s)
- C Du
- Department of Neurology, Multiple Sclerosis Research Center, Vanderbilt University Medical Center, Nashville, Tennessee 37212, USA.
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160
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Abstract
The regulation of gene expression by transcription factors is fundamental to the phenotype of all cells. The activated phenotype of cells engaged in inflammatory processes is characterized by induced expression of a diverse set of genes, including cytokines, enzymes and cell adhesion molecules. A relatively small number of inducible transcription factors, particularly NF-kappaB, AP-1, NFATs and STATs, are responsible for the expression of a wide variety of inflammatory phenotypic characteristics and therefore play a central role in the pathogenesis of rheumatic diseases. Each of these transcription factors can be modified by existing anti-rheumatic and anti-inflammatory drugs, although adverse effects and limited efficacy remain problems. The future development of therapeutic agents with specificity for transcription factors, especially NF-kappaB, might lead to safer and more effective treatment.
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Affiliation(s)
- M L Handel
- Garvan Institute of Medical Research & University of New South Wales, 384 Victoria Street, Darlinghurst, NSW, 2010, Australia
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161
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Lyubchenko TA, Wurth GA, Zweifach A. Role of calcium influx in cytotoxic T lymphocyte lytic granule exocytosis during target cell killing. Immunity 2001; 15:847-59. [PMID: 11728345 DOI: 10.1016/s1074-7613(01)00233-3] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One mechanism cytotoxic T lymphocytes use to kill targets is exocytosis of cytotoxic agents from lytic granules, a process that requires Ca(2+) influx. We investigated the role of Ca(2+) influx in granule exocytosis using TALL-104 human leukemic cytotoxic T cells triggered via a bispecific antibody containing an anti-CD3 F(ab') to kill Raji B lymphoma cells. Using a novel fluorescence method, we detected target-directed release of approximately 15% of lytic granules during killing. Consistent with previous work, we observed sustained CTL Ca(2+) gradients during killing, but gradients reflect the behavior of Fura-2 in granules. Rapid imaging experiments suggest that Ca(2+) channels are not polarized during killing, indicating that Ca(2+) influx does not direct granule reorientation. Furthermore, we find that Ca(2+) acts via a high-affinity interaction to promote granule exocytosis.
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Affiliation(s)
- T A Lyubchenko
- Department of Physiology and Biophysics, University of Colorado Health Sciences Center, 4200 East 9th Avenue, Denver, CO 80262, USA
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162
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Heisel O, Keown P. Alterations in transcription factor binding at the IL-2 promoter region in anergized human CD4+ T lymphocytes. Transplantation 2001; 72:1416-22. [PMID: 11685114 DOI: 10.1097/00007890-200110270-00015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The mechanisms responsible for the induction of clonal anergy are not well understood. We have utilized an in vitro model of human T cell anergy to explore the perturbations in cell signaling at the level of interleukin (IL)-2 gene transcription and to define the contribution of other cytokines to this effect. METHODS An in vitro model of clonal anergy was established by using CD4+ T lymphocytes from healthy human donors. Cells were anergized by prestimulation with an anti-CD3 monoclonal antibody (mAb) followed by restimulation 72 hr later with anti-CD3 mAb with or without anti-CD28. RESULTS CD4+ T cells, anergized with anti-CD3 monoclonal antibody (OKT3) prestimulation, displayed a marked reduction in proliferation (P=0.0036) and IL-2 production (P<0.0001). Co-incubation with IL-10 reduced cellular proliferation in OKT3/CD28 pretreated cells by 19% (P=NS) and reduced IL-2 production by 40% (P=0.0024). Anergized T cells demonstrated a reduced binding activity of the AP-1 complex to the IL-2 promoter. Supershift experiments and Western blots confirmed that the binding of c-Fos, JunB, and JunD, but not of FosB, was reduced in anergized cells. At the sis-inducible element (SIE)-binding region of the c-Fos promoter, Stat3 binding was reduced. CONCLUSIONS T cell anergy, induced by prestimulation with OKT3, is characterized by reduced proliferation and a profound decrease in IL-2 production. Anergy can be prevented by co-incubation with anti-CD28 and partially re-established by IL-10. Anergy is accompanied by a reduction in AP-1 binding to the IL-2 promoter, with selective reduction in binding of c-Fos, JunB, and JunD. Defective binding for Stat3 at the c-Fos promoter suggests an involvement of the Jak-Stat pathway.
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Affiliation(s)
- O Heisel
- Department of Medicine, Vancouver General Hospital, 910 West 10th Avenue, Vancouver, B.C., Canada
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163
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Sieg SF, Harding CV, Lederman MM. HIV-1 infection impairs cell cycle progression of CD4(+) T cells without affecting early activation responses. J Clin Invest 2001; 108:757-64. [PMID: 11544282 PMCID: PMC209381 DOI: 10.1172/jci12685] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Failure of CD4(+) T cells to proliferate in response to antigenic stimulation is a characteristic of HIV infection. Analysis of the proliferation defect has been hampered by an inability to identify CD4(+) cells with T cell receptor specificity for antigen. To focus only on cells that had been stimulated through the T cell receptor, CD4(+) T cells were stimulated with an anti-Vbeta3 Ab that activates approximately 3-5% of peripheral blood T cells. This approach revealed proliferation defects in cells from HIV-infected patients that were not appreciated using anti-CD3 Ab stimulation and provided the capacity to examine responses on a single cell basis. After anti-Vbeta3 Ab stimulation, CD4(+)Vbeta3(+) cells from HIV-infected patients demonstrated defects in expression of cell cycle-associated proteins, D-type cyclins, and cyclin A. However, the expression of early activation markers, CD69 and CD25, was not significantly impaired in cells from most patients. Thus, CD4(+) T cell proliferation failure in HIV disease is characterized by dysregulated activation that precludes cell cycle progression. This proliferation defect was most apparent in patients with diminished CD4(+) T cell numbers and higher plasma HIV RNA levels. CD4(+) T cell proliferation failure may be a key determinant of immune impairment in HIV disease.
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Affiliation(s)
- S F Sieg
- Department of Medicine, Division of Infectious Diseases, Center for AIDS Research, Case Western Reserve University, Cleveland, Ohio, USA
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164
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Sieg SF, Harding CV, Lederman MM. HIV-1 infection impairs cell cycle progression of CD4+ T cells without affecting early activation responses. J Clin Invest 2001. [DOI: 10.1172/jci200112685] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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165
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Vogel KW, Briesewitz R, Wandless TJ, Crabtree GR. Calcineurin inhibitors and the generalization of the presenting protein strategy. ADVANCES IN PROTEIN CHEMISTRY 2001; 56:253-91. [PMID: 11329856 DOI: 10.1016/s0065-3233(01)56008-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- K W Vogel
- Department of Pathology, Stanford University Medical School, USA
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166
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Abstract
Elevation of intracellular free Ca(2+) is one of the key triggering signals for T-cell activation by antigen. A remarkable variety of Ca(2+) signals in T cells, ranging from infrequent spikes to sustained oscillations and plateaus, derives from the interactions of multiple Ca(2+) sources and sinks in the cell. Following engagement of the T cell receptor, intracellular channels (IP3 and ryanodine receptors) release Ca(2+) from intracellular stores, and by depleting the stores trigger prolonged Ca(2+) influx through store-operated Ca(2+) (CRAC) channels in the plasma membrane. The amplitude and dynamics of the Ca(2+) signal are shaped by several mechanisms, including K(+) channels and membrane potential, slow modulation of the plasma membrane Ca(2+)-ATPase, and mitochondria that buffer Ca(2+) and prevent the inactivation of CRAC channels. Ca(2+) signals have a number of downstream targets occurring on multiple time scales. At short times, Ca(2+) signals help to stabilize contacts between T cells and antigen-presenting cells through changes in motility and cytoskeletal reorganization. Over periods of minutes to hours, the amplitude, duration, and kinetic signature of Ca(2+) signals increase the efficiency and specificity of gene activation events. The complexity of Ca(2+) signals contains a wealth of information that may help to instruct lymphocytes to choose between alternate fates in response to antigenic stimulation.
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Affiliation(s)
- R S Lewis
- Department of Molecular and Cellular Physiology and Program in Immunology, Stanford University School of Medicine, Stanford, California 94305, USA.
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167
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Ayroldi E, Migliorati G, Bruscoli S, Marchetti C, Zollo O, Cannarile L, D'Adamio F, Riccardi C. Modulation of T-cell activation by the glucocorticoid-induced leucine zipper factor via inhibition of nuclear factor kappaB. Blood 2001; 98:743-53. [PMID: 11468175 DOI: 10.1182/blood.v98.3.743] [Citation(s) in RCA: 245] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Previously a novel gene was identified that encodes a glucocorticoid-induced leucine zipper (GILZ) whose expression is up-regulated by dexamethasone. This study analyzed the role of GILZ in the control of T-cell activation and its possible interaction with nuclear factor kappaB (NF-kappaB). Results indicate that GILZ inhibits both T-cell receptor (TCR)-induced interleukin-2/interleukin-2 receptor expression and NF-kappaB activity. In particular, GILZ inhibits NF-kappaB nuclear translocation and DNA binding due to a direct protein-to-protein interaction of GILZ with the NF-kappaB subunits. Moreover, GILZ-mediated modulation of TCR-induced responses is part of a circuit because TCR triggering down-regulates GILZ expression. These results identify a new molecular mechanism involved in the dexamethasone-induced regulation of NF-kappaB activity and T-cell activation. (Blood. 2001;98:743-753)
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Affiliation(s)
- E Ayroldi
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Perugia, Via del Giochetto, 06100 Perugia, Italy
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168
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Lombardi G, Dianzani C, Miglio G, Canonico PL, Fantozzi R. Characterization of ionotropic glutamate receptors in human lymphocytes. Br J Pharmacol 2001; 133:936-44. [PMID: 11454668 PMCID: PMC1572842 DOI: 10.1038/sj.bjp.0704134] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The effect of L-glutamate (Glu) on human lymphocyte function was studied by measuring anti-CD(3) monoclonal antibody (mAb) or phytohaemagglutinin (PHA)-induced intracellular Ca(2+) ([Ca(2+)](i)) rise (Fura-2 method), and cell proliferation (MTT assay). Glu (0.001 - 100 microM) did not modify basal lymphocyte [Ca(2+)](i), but significantly potentiated the effects of anti-CD(3) mAb or PHA. Maximal [Ca(2+)](i) rises over resting cells were: 165+/-8 and 247+/-10 nM at 3.0x10(-2) mg ml(-1) anti-CD(3) mAb; 201+/-4 and 266+/-9 nM at 5.0x10(-2) mg ml(-1) PHA, in the absence or presence of 1 microM Glu, respectively. The Glu effect showed a bell-shape concentration-dependent relationship, with a maximum (+90+/-3% for anti-CD(3) mAb and +57+/-2% for PHA over Glu-untreated cells) at 1 microM. Non-NMDA receptor agonists (1 microM) showed a greater efficacy (+76+/-2% for (S)-AMPA; +78+/-4% for KA), if compared to NMDA (+46+/-2%), or Glu itself. Ionotropic Glu receptor antagonists completely inhibited the effects of the corresponding specific receptor agonists (1 microM). The IC(50) values calculated were: 0.9 microM for D-AP5; 0.6 microM for (+)-MK801; 0.3 microM for NBQX. Both NBQX and KYNA were able to abolish Glu effect. The IC(50s) calculated were: 3.4 microM for NBQX; 0.4 microM for KYNA. Glu (0.1 - 1 mM) did not change the resting cell proliferation, whereas Glu (1 mM) significant inhibited (-27+/-4%) PHA (1.0x10(-2) mg ml(-1))-induced lymphocyte proliferation at 72 h. In conclusion, human lymphocytes express ionotropic Glu receptors functionally operating as modulators of cell activation.
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Affiliation(s)
- G Lombardi
- DISCAFF Department, University of Piemonte Orientale, 28100 Novara, Italy.
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169
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Lanzavecchia A, Sallusto F. Antigen decoding by T lymphocytes: from synapses to fate determination. Nat Immunol 2001; 2:487-92. [PMID: 11376334 DOI: 10.1038/88678] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Naïve T lymphocytes sense foreign antigens by establishing contacts with dendritic cells (DCs). At the immunological synapse between the T cell and a DC, T cell receptors (TCRs) are serially engaged and triggered by specific ligands. The amount and duration of TCR triggering and the efficiency of signal amplification determine T cell commitment to proliferation and differentiation. The nature and availability of DCs bearing antigen and costimulatory molecules shape the T cell response, giving rise to distinct functional outputs such as effector and memory T cell generation or T cell tolerance.
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Affiliation(s)
- A Lanzavecchia
- Institute for Research in Biomedicine, Via Vincenzo Vela 6, CH-6500 Bellinzona, Switzerland.
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170
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Abstract
T cells are essential to initiation, amplification, and regulation of an immune response. This response is terminated when T cells undergo apoptosis, a physiological process of cell death triggered by various mechanisms and regulated by signaling pathways leading to enzymatic degradation of chromatin. An effective immune response depends on the proper balance between proliferation and death of activated T cells. This is particularly important in the intestine, where mucosal T cells are subjected to the high antigenic pressure of lumenal antigens and apoptosis is required to induce tolerance and maintain a state of 'physiological' inflammation. Insufficient apoptosis may result in excessive T cell retention and chronic intestinal inflammation, as seen in conditions associated with defective apoptosis of lamina propria T cells.
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Affiliation(s)
- A D Levine
- Division of Gastroenterology, University Hospitals of Cleveland, OH 44106-4952, USA
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171
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Graef IA, Gastier JM, Francke U, Crabtree GR. Evolutionary relationships among Rel domains indicate functional diversification by recombination. Proc Natl Acad Sci U S A 2001; 98:5740-5. [PMID: 11344309 PMCID: PMC33283 DOI: 10.1073/pnas.101602398] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2000] [Indexed: 02/07/2023] Open
Abstract
The recent sequencing of several complete genomes has made it possible to track the evolution of large gene families by their genomic structure. Following the large-scale association of exons encoding domains with well defined functions in invertebrates could be useful in predicting the function of complex multidomain proteins in mammals produced by accretion of domains. With this objective, we have determined the genomic structure of the 14 genes in invertebrates and vertebrates that contain rel domains. The sequence encoding the rel domain is defined by intronic boundaries and has been recombined with at least three structurally and functionally distinct genomic sequences to generate coding sequences for: (i) the rel/Dorsal/NFkappaB proteins that are retained in the cytoplasm by IkB-like proteins; (ii) the NFATc proteins that sense calcium signals and undergo cytoplasmic-to-nuclear translocation in response to dephosphorylation by calcineurin; and (iii) the TonEBP tonicity-responsive proteins. Remarkably, a single exon in each NFATc family member encodes the entire Ca(2+)/calcineurin sensing region, including nuclear import/export, calcineurin-binding, and substrate regions. The Rel/Dorsal proteins and the TonEBP proteins are present in Drosophila but not Caenorhabditis elegans. On the other hand, the calcium-responsive NFATc proteins are present only in vertebrates, suggesting that the NFATc family is dedicated to functions specific to vertebrates such as a recombinational immune response, cardiovascular development, and vertebrate-specific aspects of the development and function of the nervous system.
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Affiliation(s)
- I A Graef
- Department of Genetics, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305-5323, USA
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172
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Ellisen LW, Palmer RE, Maki RG, Truong VB, Tamayo P, Oliner JD, Haber DA. Cascades of transcriptional induction during human lymphocyte activation. Eur J Cell Biol 2001; 80:321-8. [PMID: 11432721 DOI: 10.1078/0171-9335-00162] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lymphocyte activation is known to be associated with the induction of genes implicated in cytokine signaling and cellular proliferation. High-density microarrays offer the means to monitor global cellular expression profiles, temporal relationships between classes of transcripts, and alterations associated with human disease or immunosuppression. We sought to determine whether microarray analysis would accurately reflect the normal pattern of gene expression following human T cell activation, and whether the complex expression patterns identified could be analyzed to produce a functional profile of lymphocyte activation. We examined a time course of sequential expression profiles for 6,800 cellular transcripts in human lymphocytes activated with concanavalin A. Expression patterns were grouped using clustering analysis and validated using Northern blotting. Genes known to be induced following T cell activation were accurately identified, and the qualitative patterns of gene expression were well correlated between Northern and microarray analyses. Quantitative differences in gene expression levels were less well correlated between these two techniques. Expression profile analysis revealed the sequential induction of groups of functionally similar genes, whose temporal coregulation underscores known cellular events during T cell activation. This functional "fingerprint" of lymphocyte activation may prove useful for comparisons of lymphocyte responses under experimental conditions and in disease states.
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Affiliation(s)
- L W Ellisen
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown 02129, USA
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173
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Maccioni M, Riera CM, Rivero VE. Identification of rat prostatic steroid binding protein (PSBP) as an immunosuppressive factor. J Reprod Immunol 2001; 50:133-49. [PMID: 11334995 DOI: 10.1016/s0165-0378(01)00060-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Prostatic steroid binding protein (PSBP) is the major protein produced ( approximately 20% of the total cytosolic protein) and secreted into the seminal fluid by the rat ventral prostate but its physiological function has not been elucidated yet. Since PSBP is secreted into the seminal fluid (which is itself a potent immunosuppressor) and has strong homology with uteroglobin (which possess an important anti-inflammatory function) our aim was to determine what effect, if any, PSBP would have on the immune system. With that purpose in mind we performed mononuclear cell cultures in the presence or absence of purified PSBP and analysed the effect of this protein on different functional parameters. PSBP inhibits the mitogen-induced proliferation of normal rat spleen mononuclear cells (MNC) specifically and in a dose-dependent manner. It reduces the production of IL-2 and the expression of its receptor (analysed by flow cytometry) which are important events for lymphocyte proliferation. Also, PSBP was able to inhibit OVA-specific proliferation of lymph node cells from previously primed animals. The immunosuppressive effect of PSBP is not due to an inherent toxic effect to the cells, since the cell viability was kept intact at the different times of culture studied. We also analysed the effect of rat PSBP on mitogen-induced proliferation of mouse spleen and human blood MNC. The proliferation was strongly abolished in a dose-dependent and non-species specific fashion. Moreover, PSBP strongly inhibits the human mixed lymphocyte reaction. Taken together, the present data support evidence for a new type of function for PSBP. We report that PSBP is a potent immunosuppressor factor and we describe its effect on the immune function in vitro. Here, we discuss the possible implications of these findings in the protection of sperm from immunologic damage in the feminine reproductive tract.
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Affiliation(s)
- M Maccioni
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas. Universidad Nacional de Córdoba, 5000, Cordoba, Argentina
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174
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Min B, Legge KL, Bell JJ, Gregg RK, Li L, Caprio JC, Zaghouani H. Neonatal exposure to antigen induces a defective CD40 ligand expression that undermines both IL-12 production by APC and IL-2 receptor up-regulation on splenic T cells and perpetuates IFN-gamma-dependent T cell anergy. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:5594-603. [PMID: 11313399 DOI: 10.4049/jimmunol.166.9.5594] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cell deletion and/or inactivation were considered the leading mechanisms for neonatal tolerance. However, recent investigations have indicated that immunity develops at the neonatal stage but evolves to guide later T cell responses to display defective and/or biased effector functions. Although neonatal-induced T cell modulation provides a useful approach to suppress autoimmunity, the mechanism underlying the biased function of the T cells remains unclear. In prior studies, we found that exposure of newborn mice to Ig-PLP1, a chimera expressing the encephalitogenic proteolipid protein (PLP) sequence 139-151, induced deviated Th2 lymph node cells producing IL-4 instead of IL-2 and anergic splenic T cells that failed to proliferate or produce IFN-gamma yet secreted significant amounts of IL-2. However, if assisted with IFN-gamma or IL-12, these anergic splenic T cells regained full responsiveness. The consequence of such biased/defective T cells responses was protection of the mice against experimental allergic encephalomyelitis. In this study, investigations were performed to delineate the mechanism underlying the novel form of IFN-gamma-dependent splenic anergy. Our findings indicate that CD40 ligand expression on these splenic T cells is defective, leading to noneffective cooperation between T lymphocytes and APCs and a lack of IL-12 production. More striking, this cellular system revealed a requirement for IL-2R expression for CD40 ligand-initiated, IL-12-driven progression of T cells into IFN-gamma production.
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Affiliation(s)
- B Min
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
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175
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Stankunas K, Graef IA, Neilson JR, Park SH, Crabtree GR. Signaling through calcium, calcineurin, and NF-AT in lymphocyte activation and development. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2001; 64:505-16. [PMID: 11232327 DOI: 10.1101/sqb.1999.64.505] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- K Stankunas
- Department of Developmental Biology and Department of Pathology, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, California 94305, USA
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176
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Mariotti R, Tongiorgi E, Bressan C, Armellin M, Kristensson K, Bentivoglio M. Retrograde response of the rat facial motor nucleus to muscle inflammation elicited by phytohaemagglutinin. Eur J Neurosci 2001; 13:1329-38. [PMID: 11298793 DOI: 10.1046/j.0953-816x.2001.01507.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To investigate whether motoneurons react to signals deriving from target inflammation, we studied the facial motor nucleus after injections of phytohaemagglutinin in the snout of adult rats. This plant lectin is a tool widely used to induce proliferation and activation of T lymphocytes, and we observed marked lymphocyte infiltration in the injected facial muscles. Retrograde labelling of motoneurons was not detected after peripheral injections of fluorochrome-conjugated phytohaemagglutinin. Nitric oxide synthase, revealed by NADPH-diaphorase histochemistry, OX-42-immunoreactive microglia, and expression of the cell death repressor gene bcl-2, investigated with nonradioactive in situ hybridization and immunohistochemistry, were evaluated in the facial nucleus. Daily phytohaemagglutinin injections for 4 days, mimicking repeated muscle exposure to inflammatory stimuli, resulted after 2-day survival in NADPH-diaphorase induction in motoneurons and marked activation of the surrounding microglia. Quantitative image analysis of NADPH-diaphorase staining, and OX-42 immunoreactivity and microglial cell counts indicated highly significant increases with respect to saline-injected control cases. The occurrence of a neuroprotective retrograde response was evaluated monitoring bcl-2 expression. Following single phytohaemagglutinin administration, bcl-2 mRNA was significantly upregulated at 6 h in facial motoneurons and returned to basal levels at 24 h. Bcl-2 immunoreactivity was markedly upregulated at 24 h and was still significantly higher than in controls at 7 days, when concomitant NADPH-diaphorase induction in motoneurons and microglia activation was also observed. No degenerative features were observed in motoneurons after phytohaemagglutinin injections at the examined time-points. The data point out that local muscle inflammation retrogradely elicits gene activation in motoneurons and their microenvironment.
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Affiliation(s)
- R Mariotti
- Department of Morphological and Biomedical Sciences, Section of Anatomy and Histology, Medical Faculty, Strada Le Grazie 8, 37134 Verona, Italy
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177
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Abstract
In this chapter we have described a powerful technology that has allowed the functional dissection of individual subunits from oligomeric receptors. We have focused primarily on chimeras derived from antigen receptors or their downstream signaling components to illustrate the wide utility of the approach; however, the technology has been applied to numerous multimeric receptors of the immune system including cytokine receptors, Fc receptors, and natural killer (NK) cell inhibitory receptors. Although the significance of the structural complexity of oligomeric receptors is by no means understood, it is certain that valuable benefits must be derived from the integrated function of their subunits. In the case of antigen receptors, the multiplicity of ITAMs likely allows the cell to distinguish subtle variations in ligand affinities with exquisite sensitivity. Clearly, an isolated subunit that is ligated with antibodies cannot confer such complex function. For instance, it cannot reveal the subtle changes in signal transduction that likely occur on stimulation with altered antigenic peptide ligands or during a complex cell-cell interaction. However, before the intricacies of integrated receptor function can be appreciated, the potential or unique functional properties contributed by each individual receptor component must first be understood. Providing a tool to acquire this kind of understanding has been the greatest asset of this technology. Acknowledging its limitations, the use of surface chimeric receptors remains an invaluable approach toward our understanding the complex function of oligomeric receptors.
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Affiliation(s)
- B A Irving
- Department of Microbiology and Immunology, University of California, San Francisco 94143-0414, USA
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178
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Bounou S, Dumais N, Tremblay MJ. Attachment of human immunodeficiency virus-1 (HIV-1) particles bearing host-encoded B7-2 proteins leads to nuclear factor-kappa B- and nuclear factor of activated T cells-dependent activation of HIV-1 long terminal repeat transcription. J Biol Chem 2001; 276:6359-69. [PMID: 11096063 DOI: 10.1074/jbc.m002198200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous studies have shown that human immunodeficiency virus type-1 (HIV-1) can incorporate several surface proteins of host origin. Recent findings indicate that host-encoded cell surface constituents retain their functionality when found embedded into the viral envelope. The primary objective of the current study was to define whether interaction between some specific virion-bound host proteins with their natural cognate ligands present on target cells could mediate intracellular signaling cascade(s). For this purpose, we have generated a whole series of isogenic virus stocks (NL4-3 backbone) bearing or not bearing on their surface foreign CD28, CD54 (ICAM-1), CD80 (B7-1) or CD86 (B7-2) proteins. Our results indicate that incubation of human T lymphoid cells with virions bearing host-derived B7-2 proteins and anti-CD3 antibody can potently activate HIV-1 long terminal repeat-driven gene expression. This up-regulating effect necessitates the involvement of nuclear factor-kappa B (NF-kappa B) and nuclear factor of activated T cells (NFAT) as revealed by the use of vectors coding for dominant negative versions of both transcription factors (i.e. I kappa B alpha S32A/36A and dnNFAT) and band shift assays. The increase of NF-kappa B activity was abolished when infection with B7-2-bearing HIV-1 particles was performed in the presence of the fusion protein CTLA-4 Ig suggesting that the interaction between virally embedded B7-2 and CD28 on the target cell is responsible for the observed NF-kappa B induction. The findings presented here provide the first demonstration that host-encoded proteins acquired by HIV-1 can mediate signal transduction events.
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Affiliation(s)
- S Bounou
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec, Pavillon CHUL, Ste-Foy, Québec G1V 4G2, Canada
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179
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Azenabor AA, Hoffman-Goetz L. 17 beta-estradiol increases Ca(2+) influx and down regulates interleukin-2 receptor in mouse thymocytes. Biochem Biophys Res Commun 2001; 281:277-81. [PMID: 11181041 DOI: 10.1006/bbrc.2001.4341] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The influx of Ca(2+) across the T lymphocyte membrane is an essential triggering signal for activation and proliferation by an antigen. The aim of this study was to determine if Ca(2+) influx through estradiol receptor (ER) operated channels of Ca(2+) entry induced activation of lymphoid cells. Mouse thymocytes were incubated with 17 beta-estradiol (E) and in the presence or absence of the mitogen, phytohemagglutinin (PHA). Despite evidence of an enhanced binding of E to ER on thymocyte membranes, and an E dose-related influx of Ca(2+), there was a consistent down regulation of IL-2 receptor expression (P < 0.001). Incubation of thymocytes with PHA enhanced IL-2 receptor expression although the down regulatory effect of E was still evident. The results suggest that the Ca(2+) channel activated by E may have a down regulatory effect on the IL-2 receptor in thymus cells leading to the dampening of cell activation process.
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Affiliation(s)
- A A Azenabor
- Department of Health Studies and Gerontology, University of Waterloo, Waterloo, Ontario, Canada
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180
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Behrens A, Sabapathy K, Graef I, Cleary M, Crabtree GR, Wagner EF. Jun N-terminal kinase 2 modulates thymocyte apoptosis and T cell activation through c-Jun and nuclear factor of activated T cell (NF-AT). Proc Natl Acad Sci U S A 2001; 98:1769-74. [PMID: 11172026 PMCID: PMC29332 DOI: 10.1073/pnas.98.4.1769] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2000] [Indexed: 12/22/2022] Open
Abstract
The Jun N-terminal kinases (JNKs) recently have been shown to be required for thymocyte apoptosis and T cell differentiation and/or proliferation. To investigate the molecular targets of JNK signaling in lymphoid cells, we used mice in which the serines phosphorylated by JNK in c-Jun were replaced by homologous recombination with alanines (junAA mice). Lymphocytes from these mice showed no phosphorylation of c-Jun in response to activation stimuli, whereas c-Jun was rapidly phosphorylated in wild-type cells. Despite the fact that c-jun is essential for early development, junAA mice develop normally; however, c-Jun N-terminal phosphorylation was required for efficient T cell receptor-induced and tumor necrosis factor-alpha-induced thymocyte apoptosis. In contrast, c-Jun phosphorylation by JNK is not required for T cell proliferation or differentiation. Because jnk2-/- T cells display a proliferation defect, we concluded that JNK2 must have other substrates required for lymphocyte function. Surprisingly, jnk2-/- T cells showed reduced NF-AT DNA-binding activity after activation. Furthermore, overexpression of JNK2 in Jurkat T cells strongly enhanced NF-AT-dependent transcription. These results demonstrate that JNK signaling differentially uses c-Jun and NF-AT as molecular effectors during thymocyte apoptosis and T cell proliferation.
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Affiliation(s)
- A Behrens
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
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181
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Sabapathy K, Kallunki T, David JP, Graef I, Karin M, Wagner EF. c-Jun NH2-terminal kinase (JNK)1 and JNK2 have similar and stage-dependent roles in regulating T cell apoptosis and proliferation. J Exp Med 2001; 193:317-28. [PMID: 11157052 PMCID: PMC2195924 DOI: 10.1084/jem.193.3.317] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Apoptotic and mitogenic stimuli activate c-Jun NH2-terminal kinases (JNKs) in T cells. Although T cells express both JNK1 and JNK2 isozymes, the absence of JNK2 alone can result in resistance to anti-CD3-induced thymocyte apoptosis and defective mature T cell proliferation. Similar defects in thymocyte apoptosis and mature T cell proliferation, the latter due to reduced interleukin 2 production, are also caused by JNK1 deficiency. Importantly, T cell function was compromised in Jnk1(+/-)Jnk2(+/-) double heterozygous mice, indicating that JNK1 and JNK2 play similar roles in regulating T cell function. The reduced JNK dose results in defective c-Jun NH2-terminal phosphorylation in thymocytes but not in peripheral T cells, in which nuclear factors of activated T cells (NK-ATs)-DNA binding activity is affected. Thus, JNK1 and JNK2 control similar functions during T cell maturation through differential targeting of distinct substrates.
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Affiliation(s)
- Kanaga Sabapathy
- Research Institute of Molecular Pathology, Vienna A 1030, Austria
| | - Tuula Kallunki
- Department of Pharmacology, School of Medicine, Cancer Center, University of California at San Diego, La Jolla, California 92093
| | | | - Isabella Graef
- Department of Pathology, Stanford Medical School, Stanford, California 94305
| | - Michael Karin
- Department of Pharmacology, School of Medicine, Cancer Center, University of California at San Diego, La Jolla, California 92093
| | - Erwin F. Wagner
- Research Institute of Molecular Pathology, Vienna A 1030, Austria
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182
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Neal JW, Clipstone NA. Glycogen synthase kinase-3 inhibits the DNA binding activity of NFATc. J Biol Chem 2001; 276:3666-73. [PMID: 11063740 DOI: 10.1074/jbc.m004888200] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The NFAT family of transcription factors is required for the expression of numerous immunologically important genes and plays a pivotal role in both the initiation and coordination of the immune response. NFAT family members appear to be regulated primarily at the level of their subcellular localization. Here we show that NFATc is additionally regulated at the level of its DNA binding activity. Using gel mobility shift assays, we demonstrate that the intrinsic DNA binding activity of NFATc is negatively regulated by phosphorylation. We found that activation of calcineurin activity in cells and dephosphorylation of NFATc in vitro enhanced NFATc DNA binding activity, whereas phosphorylation of NFATc in vitro inhibited its ability to bind DNA. Through the analysis of NFATc mutants, we identified the conserved Ser-Pro repeat motifs as critical quantitative determinants of NFATc DNA binding activity. In addition, we provide several lines of evidence to suggest that the phosphorylation of the Ser-Pro repeats by glycogen synthase kinase-3 inhibits the ability of NFATc to bind DNA. Taken together, these studies afford new insights into the regulation of NFATc and underscore the potential role of glycogen synthase kinase-3 in the regulation of NFAT-dependent gene expression.
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Affiliation(s)
- J W Neal
- Department of Microbiology-Immunology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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183
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Yu S, Medling B, Yagita H, Braley-Mullen H. Characteristics of inflammatory cells in spontaneous autoimmune thyroiditis of NOD.H-2h4 mice. J Autoimmun 2001; 16:37-46. [PMID: 11221995 DOI: 10.1006/jaut.2000.0458] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thyroid lesions develop in most NOD.H-2h4 mice 6 weeks after they are given 0.05% NaI in drinking water. B cells are required for spontaneous autoimmune thyroiditis (SAT) development, and anti-thyroglobulin autoantibody levels correlate with SAT severity. Immunohistochemical staining of thyroids obtained 2-10 weeks after administration of NaI water suggested that CD4+ T cells initially infiltrated the thryoid, followed by CD8+ T cells and B cells. Intrathyroidal CD4+ T cells are more numerous than CD8+ T cells. CD4+ T cells and B cells form aggregates in the thyroid, while CD8+ T cells are scattered throughout the thyroid. Intrathyroidal germinal centre-like structures could be observed in thyroid lesions with 2-3+ SAT and intrathyroidal B cells co-expressed OX40L. By RT-PCR, intrathyroidal expression of OX40L, OX40, CD40L, IL-2R, CTLA-4 and Igbeta mRNA correlated closely with the SAT severity score. These molecules were not expressed in normal thyroids. In the spleen, OX40L-positive cells were detected at 2 weeks and increased 4-6 weeks after NaI water. OX40, OX40L, CD40L, IL-2R and B7-1 as well as IFN-gamma and IL-4 mRNA were minimally expressed in normal spleens, usually began to be expressed at 2 weeks and increased to maximal level 4-8 weeks after NaI water. These results suggest that in NOD.H-2h4 mice, the OX40L, OX40, CD40L and B7 molecules, which increase in the spleen and thyroid of these mice after receiving NaI water, may play a role in SAT development, implying that one or more of these molecules might be good targets for the prevention or treatment of SAT.
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MESH Headings
- Abatacept
- Animals
- Antigens, CD
- Antigens, Differentiation/genetics
- CD40 Ligand/genetics
- CTLA-4 Antigen
- Gene Expression
- Immunoconjugates
- Interleukin-2/genetics
- Kinetics
- Lymphocyte Activation
- Lymphocytes/immunology
- Membrane Glycoproteins
- Mice
- Mice, Inbred NOD
- OX40 Ligand
- RNA, Messenger
- Receptors, OX40
- Receptors, Tumor Necrosis Factor/genetics
- Sodium Iodide/administration & dosage
- Spleen/cytology
- Thyroid Gland/cytology
- Thyroid Gland/immunology
- Thyroiditis, Autoimmune/immunology
- Thyroiditis, Autoimmune/pathology
- Thyroiditis, Autoimmune/physiopathology
- Tumor Necrosis Factor Receptor Superfamily, Member 7/genetics
- Tumor Necrosis Factors
- Water
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Affiliation(s)
- S Yu
- Department of Internal Medicine, University of Missouri-Columbia, Columbia, MO 65212, USA
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184
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Affiliation(s)
- G R Crabtree
- Department of Developmental Biology and Department of Pathology, Stanford University Medical School, California 94305, USA.
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185
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Kirk AD. Immunology of Transplantation. Surgery 2001. [DOI: 10.1007/978-3-642-57282-1_62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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186
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Metzler DE, Metzler CM, Sauke DJ. Biochemical Defense Mechanisms. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50034-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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187
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Miyamoto S, Kimball SR, Safer B. Signal transduction pathways that contribute to increased protein synthesis during T-cell activation. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1494:28-42. [PMID: 11072066 DOI: 10.1016/s0167-4781(00)00208-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Protein synthesis rates were maximally stimulated in human lymphocytes by ionomycin and the phorbol ester PMA (I+P), which promotes proliferation, whereas PMA alone, which does not promote proliferation, stimulated protein synthesis to a lesser degree. Three translation-associated activities, eIF4E phosphorylation, eIF2B activity and 4E-BP1 phosphorylation also increased with stimulation by I+P and PMA, but only 4E-BP1 phosphorylation was differentially stimulated by these conditions. Correspondingly, signaling pathways activated in T cells were probed for their connection to these activities. Immunosuppressants FK506 and rapamycin partially blocked the protein synthesis rate increases by I+P stimulation. FK506 had less of an inhibitory effect with PMA stimulation suggesting that its mechanism mostly affected ionomycin-activated signals. I+P and PMA equally stimulated phosphorylation of ERK1/2, but I+P more strongly stimulated Akt, and p70(S6K) phosphorylation. An inhibitor that blocks ERK1/2 phosphorylation only slightly reduced protein synthesis rates stimulated by I+P or PMA, but greatly reduced eIF4E phosphorylation and eIF2B activity. In contrast, inhibitors of the PI-3 kinase and mTOR pathways strongly blocked early protein synthesis rate stimulated by I+P and PMA and also blocked 4E-BP1 phosphorylation and release of eIF4E suggesting that these pathways regulate protein synthesis activities, which are important for proliferation in T cells.
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Affiliation(s)
- S Miyamoto
- Molecular Hematology Branch, NHLBI, Bethesda, MD 20892-1654, USA.
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188
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Bikah G, Pogue-Caley RR, McHeyzer-Williams LJ, McHeyzer-Williams MG. Regulating T helper cell immunity through antigen responsiveness and calcium entry. Nat Immunol 2000; 1:402-12. [PMID: 11062500 DOI: 10.1038/80841] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We evaluated changes in the signaling potentials and proliferative capacity of single antigen-specific T helper (TH) cells during a primary immune response to a protein antigen. At the peak of cellular expansion in vivo all antigen-specific TH cells exhibited a profound block in CD3- and CD4-mediated mobilization of intracellular calcium together with a more global block in T cell receptor-independent capacitative calcium entry (CCE). The proliferative response of these antigen-specific TH cells to anti-CD3, anti-CD28 and IL-2 was also severely blunted. Cross-linking CD69 on a substantial fraction of CD69+ antigen-specific TH cells relieved this block in CCE and restored proliferative capacity in vitro. The CCE rescue operated through a CD69-coupled G protein and required calcium-bound calmodulin and calcineurin. These data reveal critical changes in the responsiveness of antigen-specific TH cells and provide evidence of new mechanisms for the regulation of antigen-specific TH cell development in vivo.
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Affiliation(s)
- G Bikah
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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189
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Zhou PJ, Tang XD, Wang XH, Xu D. Immune activation gene expression in CD28 costimulated lymphocytes and its application as a diagnostic tool in kidney transplantation. Transplant Proc 2000; 32:1774-6. [PMID: 11119929 DOI: 10.1016/s0041-1345(00)01381-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- P J Zhou
- Center of Renal Transplantation, Shanghai First People's Hospital, Shanghai, People's Republic of China
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190
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Sun SC, Harhaj EW, Xiao G, Good L. Activation of I-kappaB kinase by the HTLV type 1 Tax protein: mechanistic insights into the adaptor function of IKKgamma. AIDS Res Hum Retroviruses 2000; 16:1591-6. [PMID: 11080796 DOI: 10.1089/08892220050193001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Tax protein encoded by human T cell leukemia virus type 1 (HTLV-1) induces constitutive nuclear expression of the transcription factor NF-kappaB, causing aberrant expression of a large array of cellular genes. Tax activates NF-kappaB by stimulating the activity of the I-kappaB kinase (IKK), which in turn leads to phosphorylation and degradation of the NF-kappaB inhibitor I-kappaBalpha. In normal T cells, IKK activation occurs transiently on cellular stimulation through the T cell receptor (TCR) and the CD28 costimulatory molecule. However, this inducible kinase is constitutively activated in Tax-expressing and HTLV-1-infected T cells, which contributes to the deregulated nuclear expression of NF-kappaB. As a genetic approach to dissect the pathways mediating IKK activation by Tax and T cell activation signals, somatic cell mutagenesis was performed to isolate signaling-defective mutant Jurkat T cell lines. One of the mutant cell lines was shown to have a defect in NF-kappaB activation by both T cell mitogens and Tax. Interestingly, this mutant cell line lacks expression of the IKK regulatory protein, IKKgamma. Expression of exogenous IKKgamma in the mutant cells restored NF-kappaB activation, thus confirming the essential role of this regulatory factor in IKK activation by the cellular and viral stimuli. Mechanistic studies have shown that Tax physically interacts with IKKgamma via specific domains, including two homologous leucine zipper motifs present in IKKgamma. The Tax/IKKgamma interaction serves to recruit Tax to the IKK catalytic subunits, IKKalpha and IKKbeta, and this recruitment appears to be an essential mechanism by which Tax stimulates the activity of IKK.
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Affiliation(s)
- S C Sun
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
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191
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Trama J, Lu Q, Hawley RG, Ho SN. The NFAT-related protein NFATL1 (TonEBP/NFAT5) is induced upon T cell activation in a calcineurin-dependent manner. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:4884-94. [PMID: 11046013 DOI: 10.4049/jimmunol.165.9.4884] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
NFAT DNA binding complexes regulate programs of cellular activation and differentiation by translating receptor-dependent signaling events into specific transcriptional responses. NFAT proteins, originally defined as calcium/calcineurin-dependent regulators of cytokine gene transcription in T lymphocytes, are expressed in many different cell types and represent critical signaling intermediates that mediate an increasingly wide spectrum of biologic responses. Recent studies have identified a novel protein containing a region of similarity to the NFAT DNA binding domain. Here we demonstrate that this protein, designated NFATL1 (also known as tonicity enhancer binding protein and NFAT5) is expressed at high levels in the thymus but is undetectable in mature lymphocytes. However, NFATL1 can be induced in both primary quiescent T lymphocytes and differentiated Th1 and Th2 cell populations upon mitogen- or Ag receptor-dependent activation. The induction of NFATL1 protein, as well as NFATL1-dependent transcription, is inhibited by cyclosporin A and FK506, and expression of constitutively active calcineurin induces NFATL1-dependent transcription. Overexpression of NFATc1 and inhibition of NFATc activity through the use of a dominant negative NFATc1 protein have no affect on NFATL1-dependent transcription, indicating that NFATc proteins do not play a role in the calcineurin-dependent induction of NFATL1. Interestingly, induction of NFATL1 by a hyperosmotic stimulus is not blocked by the inhibition of calcineurin. Moreover, osmotic stress response genes such as aldose reductase are not induced upon T cell activation. Thus inducible expression of NFATL1 represents a mechanism by which receptor-dependent signals as well as osmotic stress signals are translated into transcriptional responses that regulate cell function.
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Affiliation(s)
- J Trama
- Department of Pathology, University of California at San Diego, La Jolla, CA 92093, USA
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192
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Li X, Multon MC, Henin Y, Schweighoffer F, Venot C, Josef J, Zhou C, LaVecchio J, Stuckert P, Raab M, Mhashilkar A, Tocque B, Marasco WA. Grb3-3 is up-regulated in HIV-1-infected T-cells and can potentiate cell activation through NFATc. J Biol Chem 2000; 275:30925-33. [PMID: 10906142 DOI: 10.1074/jbc.m005535200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The MAPK pathway is required for T-cell activation; however, its role in modulating T-cell function following human immunodeficiency virus type 1 (HIV-1) infection is poorly understood. In this report, we investigated whether Grb3-3, an isoform of the Grb2 (growth factor receptor-bound protein-2) adaptor molecule that is associated with the MAPK pathway, could be involved. We found that Grb3-3, but not its isoform Grb2, is markedly up-regulated in CD4(+) peripheral blood mononuclear cells derived from either in vitro HIV-1-infected cultures or HIV-1-infected human subjects. Analysis of HIV-1 gene products indicated that Tat and Nef, both of which have been implicated in modulating T-cell function, can independently induce expression of Grb3-3. By using NFAT/AP-1, AP-1, or NFAT reporter assays, we found that Grb3-3 can potentiate NFAT (but not AP-1) promoter activity in Jurkat T-cells upon engagement of the T-cell receptor and CD28 co-receptor. In addition, potentiation of NFAT by Grb3-3 is substantially suppressed by MEKK1, a kinase that may play an important role in retaining NFAT in the cytoplasm, and by cyclosporin A. Finally, we also found that Grb3-3 potentiates HIV-1 long terminal (LTR) repeat promoter activity following T-cell receptor stimulation, an effect that can be largely suppressed by cyclosporin A. Taken together, this study indicates that Grb3-3 is a cellular factor that can be up-regulated by HIV-1. In addition, Grb3-3 can also function as a positive factor for T-cell activation and, in doing so, may aid in establishing an intracellular environment that can optimally support HIV-1 replication.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adult
- Antibodies, Monoclonal/metabolism
- Blotting, Western
- CD28 Antigens/metabolism
- CD4-Positive T-Lymphocytes/metabolism
- CD4-Positive T-Lymphocytes/virology
- Cell Nucleus/metabolism
- Cyclosporine/pharmacology
- Cytoplasm/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Female
- GRB2 Adaptor Protein
- Gene Products, nef/metabolism
- Gene Products, tat/metabolism
- HIV Infections/metabolism
- HIV-1/metabolism
- Humans
- Immunosuppressive Agents/pharmacology
- Jurkat Cells
- Leukocytes, Mononuclear/virology
- Luciferases/metabolism
- MAP Kinase Kinase Kinase 1
- MAP Kinase Signaling System
- Male
- Middle Aged
- NFATC Transcription Factors
- Nuclear Proteins
- Plasmids/metabolism
- Promoter Regions, Genetic
- Protein Isoforms
- Protein Serine-Threonine Kinases/metabolism
- Proteins/chemistry
- Proteins/genetics
- Proteins/metabolism
- RNA, Messenger/metabolism
- Receptors, Antigen, T-Cell/metabolism
- Signal Transduction
- Terminal Repeat Sequences
- Time Factors
- Transcription Factor AP-1/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transfection
- Up-Regulation
- nef Gene Products, Human Immunodeficiency Virus
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- X Li
- Departments of Cancer Immunology and AIDS and Medicine, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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193
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Dower NA, Stang SL, Bottorff DA, Ebinu JO, Dickie P, Ostergaard HL, Stone JC. RasGRP is essential for mouse thymocyte differentiation and TCR signaling. Nat Immunol 2000; 1:317-21. [PMID: 11017103 DOI: 10.1038/79766] [Citation(s) in RCA: 298] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Ras signaling pathway plays a critical role in thymopoiesis and T cell activation, but the mechanism of Ras regulation is controversial. At least one mode of Ras regulation in T cells involves the messenger diacylglycerol (DAG). RasGRP, a Ras activator with a DAG-binding C1 domain, is expressed in T cells and thymocytes. Here we show that thymi of RasGRP-null mutant mice have approximately normal numbers of immature thymocytes but a marked deficiency of mature, single-positive (CD4+CD8- and CD4-CD8+) thymocytes. In Ras signaling and proliferation assays, mutant thymocytes showed a complete lack of response to DAG analogs or T cell receptor (TCR) stimulation by antibodies. Thus, TCR and DAG are linked through RasGRP to Ras signaling.
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Affiliation(s)
- N A Dower
- Department of Pediatrics, University of Alberta, Edmonton Alberta, Canada, T6G 2H7
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194
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Abstract
T cell activation is supposed to require two signals via the TCR and a co-stimulatory molecule. However, the signaling cascade of co-stimulatory molecules has remained elusive. Here we provide evidence that CD44, which is constitutively associated with Ick and fyn, supports proliferation as well as apoptosis mainly, if not exclusively, by enhancing signal transduction via the TCR/CD3 complex. Antigenic stimulation of a T helper line in the presence of a CD44 receptor globulin was accompanied by a significant decrease in IL-2 production. To evaluate the underlying mechanism, CD44 was cross-linked via an immobilized antibody (IM-7). Cross-linking of CD44 induces proliferation of peripheral T cells and apoptosis of thymocytes and a T helper line in the presence of subthreshold levels of anti-CD3. Several proteins are rapidly tyrosine phosphorylated; erk and c-jun are strongly activated; expression of CD69 and CD25 is up-regulated on mature T cells; and expression of CD95 and CD95L is up-regulated on the T helper line. All these phenomena become less dependent of CD44 in the presence of high amounts of anti-CD3. Furthermore, cross-linking of CD44 is only effective when supporting co-localization of CD44 with the TCR/CD3 complex, since mixtures of beads coated with either anti-CD3 (low dose) or anti-CD44 do not induce T cell activation. These findings imply the rearrangement of adhesion molecules with apposition of protein kinases as a critical event for the initiation of signaling via the TCR/CD3 complex.
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MESH Headings
- Animals
- Antigens, CD/biosynthesis
- Antigens, CD/genetics
- Antigens, Differentiation, T-Lymphocyte/biosynthesis
- Antigens, Differentiation, T-Lymphocyte/genetics
- Apoptosis
- Cell Adhesion Molecules/physiology
- Cells, Cultured
- Gene Expression Regulation
- Humans
- Hyaluronan Receptors/immunology
- Immunologic Capping/physiology
- Interleukin-2/metabolism
- Lectins, C-Type
- Lymphocyte Activation
- MAP Kinase Signaling System
- Mice
- Mice, Inbred BALB C
- Models, Immunological
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, T-Cell/immunology
- Signal Transduction
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- N Föger
- Department of Tumor Progression and Immune Defense, German Cancer Research Center, Heidelberg, Germany
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195
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Fomina AF, Fanger CM, Kozak JA, Cahalan MD. Single channel properties and regulated expression of Ca(2+) release-activated Ca(2+) (CRAC) channels in human T cells. J Cell Biol 2000; 150:1435-44. [PMID: 10995447 PMCID: PMC2150694 DOI: 10.1083/jcb.150.6.1435] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2000] [Accepted: 07/25/2000] [Indexed: 11/22/2022] Open
Abstract
Although the crucial role of Ca(2+) influx in lymphocyte activation has been well documented, little is known about the properties or expression levels of Ca(2+) channels in normal human T lymphocytes. The use of Na(+) as the permeant ion in divalent-free solution permitted Ca(2+) release-activated Ca(2+) (CRAC) channel activation, kinetic properties, and functional expression levels to be investigated with single channel resolution in resting and phytohemagglutinin (PHA)-activated human T cells. Passive Ca(2+) store depletion resulted in the opening of 41-pS CRAC channels characterized by high open probabilities, voltage-dependent block by extracellular Ca(2+) in the micromolar range, selective Ca(2+) permeation in the millimolar range, and inactivation that depended upon intracellular Mg(2+) ions. The number of CRAC channels per cell increased greatly from approximately 15 in resting T cells to approximately 140 in activated T cells. Treatment with the phorbol ester PMA also increased CRAC channel expression to approximately 60 channels per cell, whereas the immunosuppressive drug cyclosporin A (1 microM) suppressed the PHA-induced increase in functional channel expression. Capacitative Ca(2+) influx induced by thapsigargin was also significantly enhanced in activated T cells. We conclude that a surprisingly low number of CRAC channels are sufficient to mediate Ca(2+) influx in human resting T cells, and that the expression of CRAC channels increases approximately 10-fold during activation, resulting in enhanced Ca(2+) signaling.
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Affiliation(s)
- A F Fomina
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California 92697-4561, USA
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196
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Pierson T, Hoffman TL, Blankson J, Finzi D, Chadwick K, Margolick JB, Buck C, Siliciano JD, Doms RW, Siliciano RF. Characterization of chemokine receptor utilization of viruses in the latent reservoir for human immunodeficiency virus type 1. J Virol 2000; 74:7824-33. [PMID: 10933689 PMCID: PMC112312 DOI: 10.1128/jvi.74.17.7824-7833.2000] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Latently infected resting CD4(+) T cells provide a long-term reservoir for human immunodeficiency virus type 1 (HIV-1) and are likely to represent the major barrier to virus eradication in patients on combination antiretroviral therapy. The mechanisms by which viruses enter the latent reservoir and the nature of the chemokine receptors involved have not been determined. To evaluate the phenotype of the virus in this compartment with respect to chemokine receptor utilization, full-length HIV-1 env genes were cloned from latently infected cells and assayed functionally. We demonstrate that the majority of the viruses in the latent reservoir utilize CCR5 during entry, although utilization of several other receptors, including CXCR4, was observed. No alternative coreceptors were shown to be involved in a systematic fashion. Although R5 viruses are present in the latent reservoir, CCR5 was not expressed at high levels on resting CD4(+) T cells. To understand the mechanism by which R5 viruses enter latent reservoir, the ability of an R5 virus, HIV-1 Ba-L, to infect highly purified resting CD4(+) T lymphocytes from uninfected donors was evaluated. Entry of Ba-L could be observed when virus was applied at a multiplicity approaching 1. However, infection was limited to a subset of cells expressing low levels of CCR5 and markers of immunologic memory. Naive cells could not be infected by an R5 virus even when challenged with a large inoculum. Direct cell fractionation studies showed that latent virus is present predominantly in resting memory cells but also at lower levels in resting naive cells. Taken together, these findings provide support for the hypothesis that the direct infection of naive T cells is not the major mechanism by which the latent infection of resting T cells is established.
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Affiliation(s)
- T Pierson
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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197
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Yun CO, Nolan KF, Beecham EJ, Reisfeld RA, Junghans RP. Targeting of T lymphocytes to melanoma cells through chimeric anti-GD3 immunoglobulin T-cell receptors. Neoplasia 2000; 2:449-59. [PMID: 11191112 PMCID: PMC1507984 DOI: 10.1038/sj.neo.7900108] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Immunoglobulin T-cell receptors (IgTCRs) combine the specificity of antibodies with the potency of cellular killing by grafting antibody recognition domains onto TCR signaling chains. IgTCR-modified T cells are thus redirected to kill tumor cells based on their expression of intact antigen on cell surfaces, bypassing the normal mechanism of activation through TCR-peptide-major histocompatibility complex (MHC) recognition. Melanoma is one of the most immunoresponsive of human cancers and has served as a prototype for the development of a number of immunotherapies. The target antigen for this study is the ganglioside GD3, which is highly expressed on metastatic melanoma with only minor immunologic cross-reaction with normal tissues. To determine an optimal configuration for therapy, four combinations of IgTCRs were prepared and studied: sFv-epsilon, sFv-zeta, Fab-epsilon, Fab-zeta. These were expressed on the surface of human T cells by retroviral transduction. IgTCR successfully redirected T-cell effectors in an MHC-unrestricted manner, in this case against a non-T-dependent antigen, with specific binding, activation, and cytotoxicity against GD3+ melanoma cells. Soluble GD3 in concentrations up to 100 microg/ml did not interfere with recognition and binding of membrane-bound antigen. Based on the outcomes of these structural and functional tests, the sFv-zeta construct was selected for clinical development. These results demonstrate key features that emphasize the potential of anti-GD3 IgTCR-modified autologous T cells for melanoma therapies.
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MESH Headings
- Animals
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/immunology
- Antigens, Neoplasm/immunology
- Binding Sites
- Cell Line
- Chemotaxis, Leukocyte/physiology
- Cytotoxicity, Immunologic
- Gangliosides/immunology
- Genes, Immunoglobulin
- Humans
- Immunoglobulin Fab Fragments/genetics
- Immunoglobulin Fab Fragments/immunology
- Immunoglobulin Fragments/genetics
- Immunoglobulin Fragments/immunology
- Immunoglobulin Variable Region/genetics
- Immunoglobulin Variable Region/immunology
- Immunotherapy, Adoptive
- Interleukin-2/biosynthesis
- Jurkat Cells
- Kidney
- Melanoma/immunology
- Membrane Proteins/genetics
- Mice
- Rats
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- T-Lymphocytes, Cytotoxic/cytology
- T-Lymphocytes, Cytotoxic/immunology
- Transfection
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Affiliation(s)
- C O Yun
- Biotherapeutics Development Lab, Harvard Institute of Human Genetics, Harvard Medical School, Boston, MA 02215, USA
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198
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Martin AG, Fresno M. Tumor necrosis factor-alpha activation of NF-kappa B requires the phosphorylation of Ser-471 in the transactivation domain of c-Rel. J Biol Chem 2000; 275:24383-91. [PMID: 10823840 DOI: 10.1074/jbc.m909396199] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of the transcription factor NF-kappaB is controlled at two levels in resting T cells: an initial activation induced by the triggering of the TcR.CD3 complex and a second phase controlled by paracrine- or autocrine-secreted TNFalpha. The initial phase is regulated by p65 (RelA), whereas the second one is mainly dependent on c-Rel. We describe here a mutant clone, D6, derived from the parental T lymphoblastic line Jurkat that fails to activate NF-kappaB upon TNFalpha stimulation. This clone had no alteration in tumor necrosis factor-alpha (TNFalpha) signaling pathways nor in IkappaBalpha, -beta, or -epsilon expression and degradation. However, TNFalpha induced an exacerbated apoptotic response in this clone compared with Jurkat cells. This mutant clone showed a defect in the intermediate-late translocation of c-Rel to the nucleus promoted by TNFalpha stimulation, whereas early translocation is not affected. Activation or translocation of p65-containing complexes was not altered in this mutant clone. Sequencing of the c-Rel gene from this clone revealed a mutation of Ser-471 to Asn in the transactivation domain. The mutant S471N transactivation domain fused to the Gal4 DNA binding domain could not be activated by TNFalpha, unlike the wild type. Moreover, the overexpression of the mutant protein c-Rel S471N into Jurkat cells abolished TNFalpha-induced NF-kappaB activity, thus demonstrating that this mutation is responsible for the failure of TNFalpha stimulation of NF-kappaB. Moreover, extracts from TNFalpha-stimulated Jurkat cells phosphorylated in vitro recombinant wild type GST-c-Rel 464-481 but not the GST-c-Rel mutant. Thus, TNFalpha-induced phosphorylation of Ser-471 seems to be absolutely necessary for TNFalpha activation of c-Rel.
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Affiliation(s)
- A G Martin
- Centro de Biologia Molecular Severo Ochoa, Cantoblanco, Madrid 28049, Spain
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199
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Maraldi NM, Zini N, Santi S, Riccio M, Falconi M, Capitani S, Manzoli FA. Nuclear domains involved in inositol lipid signal transductionmaltese cross. ADVANCES IN ENZYME REGULATION 2000; 40:219-53. [PMID: 10828353 DOI: 10.1016/s0065-2571(99)00032-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- N M Maraldi
- Institute of Cytomorphology, CNR Chieti and Bologna, c/o IOR, Bologna, Italy
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200
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Mao T, Van De Water J, Keen CL, Schmitz HH, Gershwin ME. Cocoa procyanidins and human cytokine transcription and secretion. J Nutr 2000; 130:2093S-9S. [PMID: 10917928 DOI: 10.1093/jn/130.8.2093s] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We examined whether cocoa, in its isolated procyanidin fractions (monomer through decamer), would modulate cytokine production at the levels of transcription and protein secretion in both resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC). In resting cells, interleukin (IL)-1beta and IL-4 gene expression from cocoa-treated cells varied markedly among the subjects tested. However, at the protein level, the larger fractions (pentamer through decamer) stimulated a dramatic increase in IL-1beta concentration (up to ninefold) with increasing degree of polymerization. Similarly, these larger fractions augmented IL-4 concentration by as much as 2 pg/ml, whereas the control displayed levels nearly undetectable. In the presence of PHA, gene expression also seemed to be most affected by the larger procyanidin fractions. The pentameric through decameric fractions increased IL-1 beta expression by 7-19% compared with PHA control, whereas the hexameric through decameric fractions significantly inhibited PHA-induced IL-4 transcription in the range of 71-86%. This observation at the transcription level for IL-1 beta was reflected at the protein level in PHA-stimulated PBMC. Significant reductions in mitogen-induced IL-4 production were also seen at the protein level with the hexamer, heptamer and octamer. Individual oligomeric cocoa fractions were unstimulatory for IL-2 in resting PBMC. However, when induced with PHA, the pentamer, hexamer and heptamer fractions caused a 61-73% inhibition in IL-2 gene expression. This study offers additional data for the consideration of the health benefits of dietary polyphenols from a wide variety of foods, including those benefits associated specifically with cocoa and chocolate consumption.
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Affiliation(s)
- T Mao
- Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis, Davis, California 95616, USA
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