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Symptom
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Pivot Concepts:
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Target Concepts:
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Query: EC:2.7.11.1 (
protein kinase
)
81,284
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The immunological consequences of apoptosis have been hotly debated. Apoptosis was originally described as a set of cellular morphological changes that occur in the absence of inflammation but the term has been redefined on the basis of a set of conserved molecular events that include the activation of caspases. Though the apoptosis occurring during normal development is immunologically bland or even tolerizing, the apoptotic death after viral infection or after the ligation of Fas can trigger powerful innate and adaptive immune responses. The molecular machinery at the nexus of apoptosis and inflammation includes caspase-1 --an activator of IL-1beta and
IL-18
- as well as the double-stranded-RNA-dependent
protein kinase
pathway and RNaseL pathway, which are key effectors of antiviral immunity. New proapoptotic vaccines induce immune responses that may be able to prevent or treat infectious disease and cancer.
...
PMID:Building better vaccines: how apoptotic cell death can induce inflammation and activate innate and adaptive immunity. 1100 65
Vascular cell adhesion molecule (VCAM)-1 has been implicated in interactions between leukocytes and connective tissue, including rheumatoid arthritis (RA) synovial tissue fibroblasts. Such interactions within the synovium contribute to RA inflammation. Using phosphoinositide 3-kinase (PI3-kinase) inhibitor LY294002 and Src inhibitor PP2, we show that interleukin (IL)-18-induced ERK1/2 activation is Src kinase-dependent. Antisense (AS) c-Src oligonucleotide (ODN) treatment reduced
IL-18
-induced ERK1/2 expression by 32% compared with control, suggesting an upstream role of Src in ERK1/2 activation. AS c-Src ODN treatment also inhibited Akt expression by 74% compared with sense control. PI3-kinase inhibitor LY294002 or AS PI3-kinase ODN inhibited Akt expression. AS c-Src ODN inhibited Akt phosphorylation, confirming Src is upstream of PI3-kinase in
IL-18
-induced RA synovial fibroblast signaling.
IL-18
induced a time-dependent activation of c-Src, Ras, and
Raf-1
, suggesting this signaling cascade plays a role in ERK activation.
IL-18
directly activated Src kinase by more than 4-fold over basal levels by enzymatic assay. Electrophoretic mobility shift assay showed that activator protein-1 (AP-1) is activated by
IL-18
through ERK and Src but not through PI3-kinase. In an alternate pathway, inhibition of IL-1 receptor-associated kinase-1 (IRAK) with AS ODN to IRAK reduced
IL-18
-induced expression of nuclear factor kappaB (NFkappaB). Finally,
IL-18
-induced cell surface VCAM-1 expression was inhibited by treatment with AS ODNs to c-Src, IRAK, PI3-kinase, and ERK1/2 by 57, 43, 41, and 32% compared with control sense ODN treatment, respectively. These data support a role for
IL-18
activation of three distinct pathways during RA synovial fibroblast stimulation: two Src-dependent pathways and the IRAK/NFkappaB pathway. Targeting VCAM-1 signaling mechanisms may represent therapeutic approaches to inflammatory and angiogenic diseases characterized by adhesion molecule up-regulation.
...
PMID:Signal transduction pathways involved in rheumatoid arthritis synovial fibroblast interleukin-18-induced vascular cell adhesion molecule-1 expression. 1210 9
Interleukin (IL)-18 is a cloned cytokine that was identified originally as a factor having potent interferon (IFN)-gamma-inducing activity on Kupffer cells. First, we analyzed
IL-18
gene expression by reverse transcription-polymerase chain reaction (RT-PCR) in rat thyroid FRTL-5 cells and human thyroid tissue samples. The expression of
IL-18
mRNA in FRTL-5 cells was enhanced by thryoid-stimulating hormone (TSH) in a dose-dependent manner. 8-Bromo-cyclic adenosine monophosphate (cAMP) also increased in
IL-18
mRNA levels. Furthermore, TGCT clones that exhibited an increase in intracellular cAMP accumulation showed an increased
IL-18
mRNA signal when compared to controls. Taken together, these data suggested that the effect of TSH on
IL-18
gene expression was mediated by activating
protein kinase A
. Treatment of FRTL-5 cells with the antithyroid drug, methimazole (MMI), suppressed this stimulatory action of TSH on
IL-18
gene expression. Next, we examined
IL-18
expression in human thyroid tissue derived from patients with autoimmune thyroid diseases (ATD). RT-PCR and immunohistology demonstrated that human thyroid follicular cells expressed
IL-18
. Especially in thyroid tissue from a patient with Hashimoto's thyroiditis, expression was more diffuse and extensive, generally observed in close relation to a lymphocytic infiltrate. Also,
IL-18
protein was distributed in the same follicles that express Fas-L and HLA-DR. This study is the first to demonstrate the detection of
IL-18
in the thyroid gland. The frequent expression of
IL-18
in thyrocytes suggests that
IL-18
itself might be a secreted immunomodulator in ATD.
...
PMID:Thyroid-stimulating hormone induces interleukin-18 gene expression in FRTL-5 cells: immunohistochemical detection of interleukin-18 in autoimmune thyroid disease. 1249 70
IL-1 and
IL-18
are members of the IL-1 family of ligands, and their receptors are members of the IL-1 receptor family. Although several biological properties overlap for these cytokines, differences exist.
IL-18
uniquely induces IFN-gamma from T lymphocytes and natural killer cells but does not cause fever, whereas fever is a prominent characteristic of IL-1 in humans and animals. In the present study, human epithelial cells were stably transfected with the IL-18 receptor beta chain and responded to
IL-18
with increased production of IL-1alpha, IL-6, and IL-8. Five minutes after exposure to either cytokine, phosphorylation of mitogen activated
protein kinase
(MAPK) p38 was present; specific inhibition of p38 MAPK reduced
IL-18
activity to background levels. Whereas IL-1beta induced the expression of the NF-kappaB-reporter gene and was suppressed by competitive inhibition of NF-kappaB binding,
IL-18
responses were weak or absent. In contrast to IL-1beta,
IL-18
also did not activate degradation of the NF-kappaB inhibitor. After 4 h, both cytokines induced comparable levels of mRNA for the chemokine IL-8 but, in the same cells, steady-state levels of cyclooxygenase (COX)-2 mRNA were high after IL-1beta but low or absent after
IL-18
. After 30 h,
IL-18
-induced COX-2 appeared in part to be IL-1 dependent. Similarly, low levels of prostaglandin E2 were measured in
IL-18
-stimulated A549 cells and freshly obtained primary human monocytes and mouse macrophages. We conclude that in epithelial cells,
IL-18
signal transduction is primarily via the MAPK p38 pathway rather than NF-kappaB, which may explain the absence of COX-2 and the failure of
IL-18
to cause fever.
...
PMID:Differences in signaling pathways by IL-1beta and IL-18. 1516 79
Interferons (IFN)s are involved in numerous immune interactions during viral infections and contribute to both induction and regulation of innate and adaptive antiviral mechanisms. IFNs play a pivotal rule in the outcome of a viral infection, as demonstrated by the impaired resistance against different viruses in mice deficient for the receptors IFNAR-2 and IFNGR. During viral infections, IFNs are involved in numerous immune interactions as inducers, regulators, and effectors of both innate and adaptive antiviral mechanisms. IFN-alpha/beta is produced rapidly when viral factors, such as envelope glycoproteins, CpG DNA, or dsRNA, interact with cellular pattern-recognition receptors (PRRs), such as mannose receptors, toll-like receptors (TLRs), and cytosolic receptors. These host-virus interactions signal downstream to activate transcription factors needed to achieve expression from IFN-alpha/beta genes. These include IFN regulatory factor-3 (IRF-3), IRF-5, IRF-7, c-Jun/ATF-2, and NF-kappaB. In contrast, IFN-gamma is induced by receptor-mediated stimulation or in response to early produced cytokines, including interleukin-2 (IL-12),
IL-18
, and IFN-alpha/beta, or by stimulation through T cell receptors (TCRs) or natural killer (NK) cell receptors. IFNs signal through transmembrane receptors, activating mainly Jak-Stat pathways but also other signal transduction pathways. Cytokine and TCR-induced IFN-gamma expression uses distinct signal transduction pathways involving such transcription factors as NFAT, Stats and NF-kappaB. This results in induction and activation of numerous intrinsic antiviral factors, such as RNA-activated
protein kinase
(PKR), the 2-5A system, Mx proteins, and several apoptotic pathways. In addition, IFNs modulate distinct aspects of both innate and adaptive immunity. Thus, IFN-alpha/beta and IFN-gamma affect activities of macrophages, NK cells, dendritic cells (DC), and T cells by enhancing antigen presentation, cell trafficking, and cell differentiation and expression profiles, ultimately resulting in enhanced antiviral effector functions. This review focuses on the latest findings regarding induction and regulation of IFNs, primarily during the early phase of an antiviral immune response. Both cellular and molecular aspects are discussed from the perspective of host-virus interactions.
...
PMID:Induction and regulation of IFNs during viral infections. 1532 Sep 58
Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, is known to induce the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40 and CD40 ligand (CD40L) on monocytes, the production of interferon (IFN)-gamma and IL-12 and the proliferation of lymphocytes during the human mixed lymphocyte reaction (MLR). Ciprofloxacin (CIP), which is useful for the clinical treatment of infections due to its antibacterial properties after transplantation, was shown to suppress the IFN-gamma and IL-12 production, the lymphocyte proliferation and the ICAM-1, B7.1, B7.2 and CD40 expression on monocytes during MLR in the presence of
IL-18
. CIP also induced the production of prostaglandin (PG) E2. In order to determine whether the effects of CIP on the expression of the activation markers were due to CIP-dependent production of PGE2, we examined the effect of cyclooxygenase (COX)-2 and
protein kinase A
(
PKA
) inhibitors on the actions of CIP. Thereby, the inhibitors were found to abolish the actions of CIP. These results therefore suggest that CIP might exert its immune modulatory effects via the production of PGE2.
...
PMID:The immunosuppressive effects of ciprofloxacin during human mixed lymphocyte reaction. 1645 73
The present study demonstrates a possible mechanism for the improvement of gastrointestinal cancer patients' prognosis by the histamine receptor type 2 (H2R) antagonist cimetidine. This agent, but not the H2R antagonists ranitidine and famotidine, induced the production of an antitumor cytokine, interleukin (IL)-18, by human monocytes and dendritic cells (DC). In fact, ranitidine and famotidine antagonized cimetidine-induced
IL-18
production. Cimetidine induced the activation of caspase-1, which is reported to modify immature
IL-18
to mature/active
IL-18
, and the elevation of intracellular cAMP, leading to the activation of
protein kinase A
(
PKA
). The
PKA
inhibitor H89 abolished the
IL-18
production induced by cimetidine. Moreover, the effects of cimetidine on
IL-18
production were reproduced in peripheral blood mononuclear cells from wild-type mice, but not in those from H2R knockout mice. In conclusion, cimetidine, a partial agonist for H2R, has a pharmacological profile different from ranitidine and famotidine, possibly contributing to its antitumor activity on gastrointestinal cancers.
...
PMID:Cimetidine induces interleukin-18 production through H2-agonist activity in monocytes. 1672 95
Nicotine is thought to inhibit the production of proinflammatory cytokines from macrophages through an anti-inflammatory pathway that is dependent on nicotinic acetylcholine receptor alpha7 subunit (alpha7-nAChR).
IL-18
, an important proinflammatory cytokine, is reported to induce the expression of adhesion molecules on monocytes, thus enhancing cell-to-cell interactions with T-cells and contributing to
IL-18
-initiated cytokine production. Accordingly, inhibition of
IL-18
suppresses systemic inflammatory responses. In the present study, we found that nicotine inhibited the
IL-18
-enhanced expression of ICAM-1, B7.2, and CD40 on monocytes, and the production of IL-12, IFN-gamma, and TNF-alpha by PBMC. A nonselective and a selective alpha7-nAChR antagonist, mecamylamine, and alpha-bungarotoxin abolished the effects of nicotine, suggesting that this depends on alpha7-nAChR stimulation. It is reported that nicotine induces prostaglandinE2 (PGE(2)) production in PBMC through the up-regulation of cyclooxygenase (COX)-2 expression. PGE(2) is known to activate the EP2/EP4-receptor, leading to an increase in cyclic adenosine monophosphate (cAMP) levels and
protein kinase A
(
PKA
) activity. Consistent with this, we found that COX-2 and
PKA
inhibitors prevented the effects of nicotine on adhesion molecule expression and cytokine production, indicating that the mechanism of action of nicotine may be via endogenous PGE(2) production.
...
PMID:Effect of nicotine on IL-18-initiated immune response in human monocytes. 1696 84
Cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1, B7.1, B7.2 and CD40 on monocytes and their ligands on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1, B7.1, B7.2 and CD40, production of interferon (IFN)-gamma and IL-12 and proliferation of lymphocytes during human mixed lymphocyte reaction. Nicotine is known to inhibit the production of pro-inflammatory cytokines from macrophages through the stimulation of nicotinic acetylcholine receptor alpha7 subunit. In the present study, we examined the effect of increasing concentrations ranging from 0.1 to 100 microM of nicotine on the expression of ICAM-1, B7.1, B7.2 and CD40, production of IFN-gamma and IL-12 and proliferation of lymphocytes during mixed lymphocyte reaction treated with
IL-18
at 100 ng/ml for 48 h. Nicotine inhibited the expression of adhesion molecules, cytokine production and lymphocyte proliferation. The IC50 values of nicotine for inhibition of the
IL-18
-enhanced ICAM-1 expression, IFN-gamma production and proliferation were 1, 1 and 2 microM, respectively. A non-selective and a selective antagonist for nicotinic acetylcholine receptor alpha7 subunit, mecamylamine and alpha-bungarotoxin abolished the effects of nicotine. The actions of nicotine might depend on stimulation of nicotinic acetylcholine receptor alpha7 subunit. Nicotine induced prostaglandin E(2) production during mixed lymphocyte reaction. The inhibitors of cyclooxygenase (COX)-2 and
protein kinase A
(
PKA
) at 100 microM inhibited the actions of nicotine, suggesting that the endogenous prostaglandin E(2) might be, at least, partially involved the actions of nicotine.
...
PMID:The immunosuppressive effects of nicotine during human mixed lymphocyte reaction. 1725 63
The cell-to-cell interaction through binding of intercellular adhesion molecule (ICAM)-1 on monocytes to their ligands lymphocyte function-associated antigen (LFA)-1 on T-cells plays important roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which plasma levels are elevated in patients during acute rejection following organ transplantation, induces the expression of ICAM-1 on monocytes, production of interferon (IFN)-gamma and IL-12 and lymphocyte proliferation during human mixed lymphocyte reaction. Activation of the adenosine A(2A) receptor on during reperfusion of various tissues has been found to markedly reduce ischemia-reperfusion injury. In the present study, we examined the effect of adenosine at increasing concentrations ranging from 0.1 to 100 microM on the
IL-18
-enhanced expression of ICAM-1, production of IFN-gamma and IL-12 and lymphocyte proliferation during human mixed lymphocyte reaction. Adenosine inhibited the
IL-18
-initiated immune responses. The IC(50) values of adenosine for inhibition of the
IL-18
-enhanced ICAM-1 expression, IFN-gamma production and lymphocyte proliferation were 20 microM, respectively. The actions of adenosine depended on the stimulation of adenosine A(2A) receptor. An inhibitor of
protein kinase A
(
PKA
) at 100 microM inhibited the actions of adenosine, suggesting that
PKA
might be involved in the actions of adenosine. On the other hand, the stimulation of adenosine A(1) and A(3) receptor blocked the actions of adenosine A(2A) receptor stimulation. These results suggest that adenosine inhibits the immune responses during mixed lymphocyte reaction via adenosine A(2A) receptor.
...
PMID:Effect of adenosine receptor subtypes stimulation on mixed lymphocyte reaction. 1737 32
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