Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to determine whether human fibroblasts express CD40, a 50-kDa member of the tumor necrosis factor-alpha-receptor superfamily. CD40 is an important mitogenic receptor on B lymphocytes which regulates B lymphocyte proliferation and differentiation. Interestingly, CD40 mRNA was detected in human lung, gingival, synovial, dermal (foreskin), and spleen fibroblasts using the reverse-transcriptase polymerase chain reaction. Moreover, the CD40 protein was detected on cultured human fibroblasts using anti-CD40 mAbs (G28-5, EA-5) and flow cytometry and on fibroblasts in dermal tissue sections via in situ staining. In contrast to B lymphocytes, where CD40 expression is unregulated both by interleukin-4 and interferon (IFN-gamma), CD40 expression on cultured human fibroblasts could only be upregulated by IFN-gamma. IFN-gamma induced a 10-fold increase in CD40 mRNA and protein levels. Furthermore, via a two-color staining technique for CD40 expression and DNA content, IFN-gamma not only upregulated CD40 expression on cultured human fibroblasts, but also shifted fibroblasts into the G0/G1 phase of the cell cycle. This observation suggested that nonproliferating fibroblasts might display elevated levels of CD40. To test this hypothesis, CD40 expression was analyzed on fibroblasts in log phase growth vs fibroblasts which had reached confluency and were nonproliferating. Interestingly, confluent fibroblasts expressed higher levels of CD40 than fibroblasts in log phase growth. These data suggest that CD40 expression by human fibroblasts is related to cell growth. In summary, this report is the first to demonstrate that human fibroblasts from a variety of tissues display CD40. While the function of CD40 on fibroblasts is not yet known, it may facilitate fibroblast proliferation, an event important for tissue repair, and may facilitate inflammation via interaction with T lymphocytes and mast cells, which display the CD40 ligand.
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PMID:CD40 expression by human fibroblasts. 755 83

In the present study, we have analyzed the pattern of cytokines expressed by two independent dendritic cell (DC) subpopulations generated in vitro from human cord blood CD34+ progenitors cultured with granulocyte-macrophage CSF and TNF-alpha. Molecularly, we confirmed the phenotypic differences discriminating the two subsets: E-cadherin mRNA was only detected in CD1a+-derived DC, whereas CD68 and factor XIIIa mRNAs were observed exclusively in CD14+-derived DC. Semiquantitative reverse-transcriptase PCR analysis revealed that both DC subpopulations spontaneously expressed IL-1alpha, IL-1beta, IL-6, IL-7, IL-12 (p35 and p40), IL-15, IL-18, TNF-alpha, TGF-beta, macrophage CSF, and granulocyte-macrophage CSF, but not IL-2, IL-3, IL-4, IL-5, IL-9, and IFN-gamma transcripts. Both subpopulations were shown to secrete IL-12 after CD40 triggering. Interestingly, only the CD14+-derived DC secreted IL-10 after CD40 activation, strengthening the notion that the two DC subpopulations indeed represent two independent pathways of DC development. Furthermore, both DC subpopulations expressed IL-13 mRNA and protein following activation with PMA-ionomycin, but not with CD40 ligand, in contrast to IL-12 and IL-10, revealing the existence of different pathways for DC activation. Finally, we confirmed the expression of IL-7, IL-10, and IL-13 mRNA by CD4+ CD11c+ CD3- DC isolated ex vivo from tonsillar germinal centers. Thus, CD14+-derived DC expressing IL-10 and factor XIIIa seemed more closely related to germinal center dendritic cellsGCDC than to Langerhans cells.
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PMID:The cytokine profile expressed by human dendritic cells is dependent on cell subtype and mode of activation. 946 23

We describe a long-term, in vitro culture system initiated with CD34(+) or CD34(+)CD38(-) umbilical cord blood hematopoietic progenitors that supports normal human B-lineage development, including the production of mature Ig-secreting B cells. In the first stage (human B-progenitor long-term culture [HB-LTC]), CD34(+) hematopoietic progenitors are cultured on the murine stromal cell line, S17, leading to the sustained production of large numbers of CD10(+), CD19(+) early B progenitors. Reverse transcriptase-polymerase chain reaction (RT-PCR) and three-parameter flow cytometry for VpreB (surrogate light chain), cytoplasmic mu chain, and surface IgM expression were used to characterize the CD19(+) B progenitors present within these cultures. This analysis showed distinct B-lineage subpopulations, including pro-B cells, cycling pre-B cells, and IgM+, IgD-/+ immature B cells. The limited expansion of IgM+ B cells and the immature surface phenotype of this population (IgM+, IgD+, CD10(+), CD38(+)) suggested that HB-LTC conditions were unable to provide appropriate signals for further differentiation. A second culture stage was used to determine if these immature B cells were functionally competent. Purified CD19(+) cells were transferred onto fibroblasts expressing human CD40-ligand in the presence of IL-10 and IL-4. This lead to cell proliferation, modulation of the IgM+ cell surface phenotype to one consistent with an activated mature B cell, secretion of Ig, and isotype switching. Notably, IgM and IgG producing B cells were also generated using two-stage cultures established with highly purified multipotent CD34(+)CD38(-) hematopoietic stem cell progenitors. This culture model should permit detailed in vitro analysis and genetic manipulation of the major transition points in human B ontogeny, beginning with commitment to the B lineage and leading to development and activation of mature B cells.
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PMID:In vitro reconstitution of human B-cell ontogeny: from CD34(+) multipotent progenitors to Ig-secreting cells. 984 15

Livers transplanted across major histocompatibility complex (MHC) barriers in mice are normally accepted without recipient immune suppression, and induce a state of functional tolerance. However, markedly increasing functional dendritic cells (DC) in the 'passenger leucocyte' population by donor pretreatment with the hematopoietic growth factor Flt3-ligand (Flt3L; 10 microg/day for 10 days) results in acute allograft rejection. In this study, molecular, immunohistochemical and flow cytometric analysis of donor cell traffick into recipient lymphoid tissue 24 h after liver transplantation (C57BL/10 [H2b]-->C3H [H2k]) was performed. In addition, the capacity of donor-derived cells in these tissues to stimulate host T cell proliferation was examined. Reverse transcriptase polymerase chain reaction analysis revealed increases in donor genomic DNA in both thymi and spleens of mice given livers from Flt3L-treated donors compared to controls. Donor MHC class II+ (IAb+) cells in spleens were strikingly elevated (10-fold) in the former group. Two-colour flow cytometry revealed a similar increase in donor-derived H-2Kb+/I-Ab+ cells, and in the incidence of donor leucocytes expressing CD40, CD80, and CD86. CD11c+ DC comprised approximately 40% of the I-Ab+ cells in spleens of mice given livers from Flt3L-treated donors. These changes were associated with the presence, in spleens, of potent allostimulatory activity for naive recipient strain T cells, that was not observed in normal liver recipients. Elicitation of allograft rejection, associated with enhanced trafficking of stimulatory donor antigen-presenting cells (APC), in particular DC, suggests that normal liver graft survival and tolerance induction may be linked to failure/counter-regulation of APC-driven stimulation of effective anti-donor T cell responses.
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PMID:Trafficking of APC from liver allografts of Flt3L-treated donors: augmentation of potent allostimulatory cells in recipient lymphoid tissue is associated with a switch from tolerance to rejection. 1037 78

CD40 ligand (CD40L), expressed on activated T cells, binds its receptor, CD40, on dendritic cells, B cells, and monocytes/ macrophages. Human immunodeficiency virus (HIV)-infected individuals exhibit normal B-cell CD40 expression but diminished expression of CD40L on CD4 + T cells. Thus, we studied recombinant human CD40L (huCD40L) in an in vitro rhesus macaque model of acquired immunodeficiency syndrome (AIDS). huCD40L induced peripheral blood mononuclear cell (PBMC) proliferation independent of mitogenic cytokines and led to a 70% reduction in p27 production by simian immunodeficiency virus (SIV) mac239 infected PBMCs (P < 0.05). Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed reduced expression of SIV gag and increased expression of interleukin (IL)-16 mRNA. Supernatants from huCD40L-stimulated PBMC and control cultures contained similar amounts of IL-16, suggesting an intracellular antiviral effect by IL-16. Phytohemagglutinin (PHA)-stimulated PBMCs similarly cultured with huCD40L showed only slight increases in chemokine production (P > 0.05). These results suggest that huCD40L inhibits replication (antigen and mRNA production) of SIVmac239. This response involves huCD40L induction of IL16 mRNA expression and appears to be independent of beta-chemokines.
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PMID:Recombinant human CD40 ligand inhibits simian immunodeficiency virus replication: a role for interleukin- 16. 1059 85

B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type develop against a background of chronic inflammation and have functional autoantigen receptors. Because they respond to environmental factors in vivo, the expression of costimulatory molecules, which play a key role in the differentiation of normal B-lymphocytes and in T-/B-cell interaction, may be critical in early MALT-type lymphoma pathogenesis until further chromosomal aberration leads to progression. We found a high number of tumor-infiltrating T-lymphocytes (TITLs) in all low-grade MALT-type lymphomas. The TITLs in low-grade lymphomas were activated and expressed a memory and immunocompetent phenotype. Reverse transcriptase-polymerase chain reaction analyses and immunohistochemistry confirmed the presence of CD40-ligand and Fas-ligand in 80% of low-grade lymphomas. In contrast to the TITLs, the tumor B cells did not express CD40-ligand or Fas-ligand in vivo or in vitro. Moreover, the cytokine profile in vivo suggested a Th2/Th3-weighted profile (interleukin-10, interleukin-13, transforming growth factor beta(1)) rather than Th1-weighted (interferon-gamma, interleukin-2). By interphase fluorescence in situ hybridization analysis the translocation t(11;18)(q21;q21) was found in four of nine (44%) cases studied. Interestingly, there was a four times higher proliferation and survival rate of purified t(11;18)-positive tumor B cells in vitro, although there were no significant profile differences from the TITLs in vivo. The finding of essential costimulating molecules in low-grade MALT-type lymphomas in vivo indicates a locally directed cognate T-/B-cell interaction. Consequently, a potentially equipped inflammatory background may not only determine the fate of autoreactive B-cells, but is also crucial to lymphoma maintenance and progression.
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PMID:Expression of costimulatory molecules in low-grade mucosa-associated lymphoid tissue-type lymphomas in vivo. 1059 32

Intraoperative lymphatic mapping and sentinel lymphadenectomy (LM/SL) provides a unique opportunity for assessing potential immunologic interactions between the primary tumor and regional lymph node basin. We performed LM/SL in 24 patients with early-stage melanoma and resected an additional nonsentinel node (non-SN) in each case. Sentinel nodes (SNs) and non-SNs were evaluated by routine pathologic analysis, and a portion of each node was processed for expression of three dendritic markers of activation (CD80, CD86, CD40) and their corresponding T-cell receptors (CTLA-4 and CD28). Twenty (83%) patients had matched SNs and non-SNs. A total of 26 nodal pairs were obtained because one patient had three pairs and two other patients each had two pairs. Reverse transcriptase-polymerase chain reaction (RT-PCR) analyses of paired SNs and non-SNs demonstrated a marked reduction in semiquantitative expression of CD80 (77%), CD86 (77%), and CD40 (85%), as well as CTLA-4 (88%) and CD28 (85%) in SNs. The diminished expression appeared to be unrelated to B-cell (CD20) and T-cell (CD2) expression. A quantitative reduction in dendritic cell markers in SNs may be important in the immunologic interaction between the primary site and regional lymph node basin and may also provide useful criteria for identifying SNs.
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PMID:Surgical and molecular approaches to the sentinel lymph nodes. 1159 94

We previously reported elevated levels of serum interleukin-12 (IL-12) in association with increased interferon-gamma (IFN-gamma) levels in patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The interaction between IL-12 and IL-12 receptor (IL-12R) plays an important role in differentiation of the T helper type 1 (Th1) phenotype. In this study, we further examined the IL-12/IL-12R axis by investigating the expression of IL-12R and CD40 ligand (CD40L) in peripheral blood mononuclear cells (PBMC) of 18 HAM/TSP patients, and comparing the levels with those in 25 patients with other neurological disorders, including 4 anti-HTLV-I-seropositive carriers as controls. Two-color analysis by flow cytometry revealed a significantly high percentage of IL-12R beta1+ cells in CD4+ T lymphocytes in HAM/TSP patients compared to the control. Furthermore, IL-12R beta2 mRNA expression in PBMC was detected by reverse-transcriptase polymerase chain reaction in 6 of 18 HAM/TSP patients, but not in any control patients. In contrast, there was no significant difference between the percentage of CD40L+ cells in CD4+ T lymphocytes in HAM/TSP and control patients. Our results suggest Th1 immune activation in patients with HAM/TSP, which leads to chronic inflammation in the spinal cord, mediated by dysregulation of the IL-12/IL-12R axis rather than of the CD40/CD40L interaction.
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PMID:Up-regulation of interleukin-12 receptor expression in peripheral blood mononuclear cells of patients with HTLV-I-associated myelopathy/tropical spastic paraparesis. 1195 51

CD40 is expressed on various immune cells, including macrophages and microglia. Aberrant expression of CD40 is associated with autoimmune inflammatory diseases such as multiple sclerosis and rheumatoid arthritis. Interaction of Toll-like receptor-4 (TLR4) with the Gram-negative bacteria endotoxin lipopolysaccharide (LPS) results in the induction of an array of immune response genes. In this study, we describe that LPS is a strong inducer of CD40 expression in macrophages and microglia, which occurs at the transcriptional level and involves the activation of the transcription factors nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription 1alpha (STAT-1alpha). LPS-induced CD40 expression involves the endogenous production of the cytokine interferon-beta (IFN-beta), which contributes to CD40 expression by the activation of STAT-1alpha. Blocking IFN-beta-induced activation of STAT-1alpha by IFN-beta-neutralizing antibody reduces LPS-induced CD40 gene expression. Furthermore, LPS induces acetylation and phosphorylation of histones H3 and H4 and the recruitment of NF-kappaB, STAT-1alpha, and RNA polymerase II on the CD40 promoter in vivo in a time-dependent manner, all events important for CD40 gene transcription. These results indicate that both LPS-induced NF-kappaB activation and endogenous production of IFN-beta that subsequently induces STAT-1alpha activation play critical roles in the transcriptional activation of the CD40 gene by LPS.
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PMID:LPS induces CD40 gene expression through the activation of NF-kappaB and STAT-1alpha in macrophages and microglia. 1602 May 13

Costimulation between T cells and APCs is required for adaptive immune responses. CD40, an important costimulatory molecule, is expressed on a variety of cell types, including macrophages and microglia. The aberrant expression of CD40 is implicated in diseases including multiple sclerosis, rheumatoid arthritis, and Alzheimer's disease, and inhibition of CD40 signaling has beneficial effects in a number of animal models of autoimmune diseases. In this study, we discovered that IL-10, a cytokine with anti-inflammatory properties, inhibits LPS-induced CD40 gene expression. We previously demonstrated that LPS induction of CD40 in macrophages/microglia involves both NF-kappaB activation and LPS-induced production of IFN-beta, which subsequently activates STAT-1alpha. IL-10 inhibits LPS-induced IFN-beta gene expression and subsequent STAT-1alpha activation, but does not affect NF-kappaB activation. Our results also demonstrate that IL-10 inhibits LPS-induced recruitment of STAT-1alpha, RNA polymerase II, and the coactivators CREB binding protein and p300 to the CD40 promoter, as well as inhibiting permissive histone H3 acetylation (AcH3). IL-10 and LPS synergize to induce suppressor of cytokine signaling (SOCS)-3 gene expression in macrophages and microglia. Ectopic expression of SOCS-3 attenuates LPS-induced STAT activation, and inhibits LPS-induced CD40 gene expression, comparable to that seen by IL-10. These results indicate that SOCS-3 plays an important role in the negative regulation of LPS-induced CD40 gene expression by IL-10.
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PMID:IL-10 inhibits lipopolysaccharide-induced CD40 gene expression through induction of suppressor of cytokine signaling-3. 1711 47


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