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Enzyme
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Query: EC:3.4.22.36 (
caspase-1
)
6,285
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The interleukin-1beta (IL-1beta) converting enzyme (
ICE
) processes the inactive IL-1beta precursor to the proinflammatory cytokine.
ICE
was also shown to cleave the precursor of
interferon-gamma
inducing factor (IGIF) at the authentic processing site with high efficiency, thereby activating IGIF and facilitating its export. Lipopolysaccharide-activated
ICE
-deficient (
ICE
-/-) Kupffer cells synthesized the IGIF precursor but failed to process it into the active form. Interferon-gamma and IGIF were diminished in the sera of
ICE
-/- mice exposed to Propionibacterium acnes and lipopolysaccharide. The lack of multiple proinflammatory cytokines in
ICE
-/- mice may account for their protection from septic shock.
...
PMID:Activation of interferon-gamma inducing factor mediated by interleukin-1beta converting enzyme. 899 48
Recently, human interleukin 18 (hIL-18) cDNA was cloned, and the recombinant protein with a tentatively assigned NH2-terminal amino acid sequence was generated. However, natural hIL-18 has not yet been isolated, and its cellular processing is therefore still unclear. To clarify this, we purified natural hIL-18 from the cytosolic extract of monocytic THP.1 cells. Natural hIL-18 exhibited a molecular mass of 18.2 kDa, and the NH2-terminal amino acid was Tyr37. Biological activities of the purified protein were identical to those of recombinant hIL-18 with respect to the enhancement of natural killer cell cytotoxicity and
interferon-gamma
production by human peripheral blood mononuclear cells. We also found two precursor hIL-18 (prohIL-18)-processing activities in the cytosol of THP.1 cells. These activities were blocked separately by the caspase inhibitors Ac-YVAD-CHO and Ac-DEVD-CHO. Further analyses of the partially purified enzymes revealed that one is
caspase-1
, which cleaves prohIL-18 at the Asp36-Tyr37 site to generate the mature hIL-18, and the other is caspase-3, which cleaves both precursor and mature hIL-18 at Asp71-Ser72 and Asp76-Asn77 to generate biologically inactive products. These results suggest that the production and processing of natural hIL-18 are regulated by two processing enzymes,
caspase-1
and caspase-3, in THP.1 cells.
...
PMID:Involvement of caspase-1 and caspase-3 in the production and processing of mature human interleukin 18 in monocytic THP.1 cells. 933 40
When injected intravenously into humans and animals, interleukin-1 beta (IL-1 beta) is perhaps the most potent of the endogenous pyrogens. However, IL-1 beta is initially synthesized as a relatively inactive precursor molecule (proIL-1 beta) which lacks a signal peptide and hence remains inside the cell. To be active as a fever-producing molecule, proIL-1 beta must first be processed to an active mature molecule and secreted. Although several enzymes associated with inflammatory tissues are capable of processing proIL-1 beta into an active molecule in the extracellular compartment, the IL-1 beta converting enzyme (
ICE
, also called
caspase-1
) cuts intracellular proIL-1 beta after the aspartic acid residue in position 116, resulting in a highly active mature IL-1 beta that is secreted into the extracellular space. IL-18 is also initially synthesized as an inactive precursor molecule (proIL-18) lacking a signal peptide. IL-18 is a member of the IL-1 family, and like IL-1 beta, proIL-18 is cleaved by
ICE
to yield an active molecule. However, unlike IL-1 beta, IL-18 is not an endogenous pyrogen following intraperitoneal injection into mice. Nevertheless, IL-18 may contribute to inflammation and fever because IL-18 is a potent inducer of tumor necrosis factor, chemokines, and
interferon-gamma
production.
...
PMID:Interleukin-1 beta, interleukin-18, and the interleukin-1 beta converting enzyme. 991 59
We investigated the expression of Fas antigen (CD95) in the pure erythroid cell line AS-E2 in the presence and absence of
interferon-gamma
(
IFN-gamma
) and tumor necrosis factor-alpha (TNF-alpha). TNF-alpha induced apoptosis in AS-E2 cells, whereas
IFN-gamma
did not. In culture containing no
IFN-gamma
or TNF-alpha, AS-E2 cells expressed little Fas antigen. However,
IFN-gamma
and
IFN-gamma
and TNF-alpha both induced expression of Fas antigen and its mRNA within 24 hours after the stimulation. When anti-Fas monoclonal antibody (IgM) was added to AS-E2 cells after the induction of Fas expression, AS-E2 cells underwent apoptosis as shown by the induction of DNA fragmentation. This apoptotic change was inhibited by an inhibitor of caspase-3-like proteases (Ac-DEVD-CHO) and an inhibitor of CED-3/
ICE
family proteases (Z-Asp-CH2-DCB) but not by an inhibitor of
caspase-1
-like proteases (Ac-YVAD-CHO), suggesting a role for caspase-3-like proteases in Fas-receptor signaling. Although AS-E2 cells expressed Fas ligand mRNA, treatment with ZB4, an antibody that inhibits Fas-mediated cell death, failed to suppress
IFN-gamma
- or TNF-alpha-mediated cytotoxicity. These findings suggest that the late erythroid progenitor cells are negatively regulated by
IFN-gamma
and TNF-alpha, both of which are capable of inducing functional Fas expression.
...
PMID:Fas antigen (CD95) in pure erythroid cell line AS-E2 is induced by interferon-gamma and tumor necrosis factor-alpha and potentiates apoptotic death. 1008 5
Interleukin 18 (IL-18 or
interferon-gamma
inducing factor) is a recently discovered pro-inflammatory cytokine and powerful stimulator of the cell-mediated immune response. IL-18 is produced by several sources including monocytes/macrophages, keratinocytes and the zona reticularis and zona fasciculata of the adrenal cortex. IL-18 occurs in brain but its cellular source in the CNS has never been investigated. The presence of IL-18 and its response to stimulation in the brain was tested with primary cultures of microglia, astrocytes and hippocampal neurons. IL-18 mRNA was present in astrocytes and microglia, but not in neurons. The endotoxin lipopolysaccharide (LPS) did not affect IL-18 in astrocytes, but LPS robustly increased IL-18 mRNA in microglia. IL-18 protein was constitutively expressed in astrocytes and induced in microglia by LPS. The levels of
interleukin-1beta converting enzyme
(
ICE
), an activating enzyme, and caspase 3 (CPP32), an inactivating enzyme, were assessed to investigate the presence of the appropriate processing enzymes in the cultured cells.
ICE
was present at constitutive levels in microglia and astrocytes suggesting that these cell types may produce and secrete matured IL-18. Active forms of CPP32 were not detectable in either cell type indicating the absence of a degradative pathway of IL-18. The present results demonstrate that microglia and astrocytes are sources of brain IL-18 and add a new member to the family of cytokines produced in the brain.
...
PMID:Cultures of astrocytes and microglia express interleukin 18. 1010 Dec 31
1. Activation of macrophages with lipopolysaccharide (LPS) and low doses of
interferon-gamma
(
IFN-gamma
) induced apoptotic death through a nitric oxide-dependent pathway. 2. Treatment of cells with the immunosuppressors cyclosporin A (CsA) or FK506 inhibited the activation-dependent apoptosis. 3. These drugs decreased the up-regulation of p53 and Bax characteristic of activated macrophages. Moreover, incubation of activated macrophages with CsA and FK506 contributed to maintain higher levels of Bcl-2 than in LPS/
IFN-gamma
treated cells. 4. The inhibition of apoptosis exerted by CsA and FK506 in macrophages was also observed when cell death was induced by treatment with chemical nitric oxide donors. 5. Incubation of macrophages with LPS/
IFN-gamma
barely affected
caspase-1
but promoted an important activation of caspase-3. Both CsA and FK506 inhibited pathways leading to caspase-3 activation. Moreover, the cleavage of poly(ADP-ribose) polymerase, a well established caspase substrate, was reduced by these immunosuppressive drugs. 6. CsA and FK506 reduced the release of cytochrome c to the cytosol and the activation of caspase-3 in cells treated with nitric oxide donors. 7. These results indicate that CsA and FK506 protect macrophages from nitric oxide-dependent apoptosis and suggest a contribution of the macrophage to innate immunity under conditions of immunosuppression of the host.
...
PMID:Protective effect of cyclosporin A and FK506 from nitric oxide-dependent apoptosis in activated macrophages. 1020 1
The production in colon cancer of
interferon-gamma
(
IFN-gamma
), a type-1 T-helper (TH1) cytokine, is considered as a marker of good prognosis. We asked whether interleukin-18 (IL-18), which strongly induces
IFN-gamma
and regulates Fas ligand (Fas-L)-dependent cytotoxicity, may play a role in colon homeostasis, and if its expression was modulated in colon adenocarcinomas. We analyzed 14 specimens of colon adenocarcinomas, 6 of normal colon mucosa of the series, and 6 colon-tumor cell lines. The expression of IL-18, of
ICE
protease, involved in the processing of this cytokine, and of the downstream effectors of IL-18,
IFN-gamma
and Fas-L was analyzed by RT-PCR. We further performed IL-18 immunostaining of normal and tumor specimens. The results were correlated with tumor dissemination and clinical outcome. We report the synthesis of IL-18 in human normal colon, mainly by epithelial cells of the mucosa. Out of the 6 tumor cell lines, 4 expressed IL-18 transcripts, but neither
ICE
mRNA nor secreted forms of IL-18 were detected. We observed decreased or abolished synthesis of IL-18 in colon adenocarcinomas, as compared with normal mucosa. Thus, half of the colon-cancer tissues (7/14 cases) expressed neither
IFN-gamma
nor Fas-L. This feature was correlated with the existence of distant metastases (Fischer's exact test, p = 0.02) and an unfavorable outcome. These findings suggest that production of IL-18 in human colon may play a role in homeostasis and in tumor immune surveillance, by enhancing
IFN-gamma
production and Fas-L-dependent cytotoxicity of immune cells.
...
PMID:Modulation of interleukin-18 expression in human colon carcinoma: consequences for tumor immune surveillance. 1037 55
Overproduction of proinflammatory cytokines in the brains of transgenic animals causes brain pathology. To investigate the relationship between brain cytokines and pathology in the brains of animals with adult-onset, pathophysiologically induced brain cytokine expression, we studied rats infected with the parasite Trypanosoma brucei. Several weeks after infection, in situ hybridization histochemistry showed a pattern of chronic overexpression of the mRNAs for proinflammatory cytokines interleukin-1beta and tumor necrosis factor-alpha in the brains of the animals. Similar spatiotemporal inductions of mRNAs for inhibitory factor kappaBalpha and
interleukin-1beta converting enzyme
were found and quantified. The mRNAs for inducible nitric oxide synthase and interleukin-1 receptor antagonist were highly localized to the choroid plexus, which showed evidence of structural abnormalities associated with the parasites' presence there. The mRNAs for interleukin-6,
interferon-gamma
, and inducible cyclooxygenase showed restricted induction patterns. Another set of animals was processed for degeneration-induced silver staining, TdT-mediated dUTP-digoxigenin nick end-labeling (TUNEL) staining, glial fibrillary acidic protein (GFAP) immunohistochemistry, and several other histological markers. Apoptosis of scattered small cells and degeneration of certain nerve fibers was found in patterns spatially related to the cytokine mRNA patterns and to cerebrospinal fluid diffusion pathways. Furthermore, striking cytoarchitectonically defined clusters of degenerating non-neuronal cells, probably astrocytes, were found. The results reveal chronic overexpression of potentially cytotoxic cytokines in the brain and selective histopathology patterns in this natural disease model. J. Comp. Neurol. 414:114-130, 1999. Published 1999 Wiley-Liss, Inc.
...
PMID:Chronic overexpression of proinflammatory cytokines and histopathology in the brains of rats infected with Trypanosoma brucei. 1049 82
We have reported previously that axonal degeneration in specific brain regions occurs in rats infected with the parasite Trypanosoma brucei. These degenerative changes occur in spatiotemporal association with over-expression of pro-inflammatory cytokine messenger RNAs in the brain. To test how aspirin-like anti-inflammatory drugs might alter the disease process, we fed trypanosome-infected rats with 200mg/kg of sodium salicylate (the first metabolite of aspirin) daily in their drinking water. Sodium salicylate treatment in uninfected rats did not cause any neural damage. However, sodium salicylate treatment greatly exacerbated neurodegeneration in trypanosome-infected rats, resulting in extensive terminal and neuronal cell body degeneration in the cortex, hippocampus, striatum, thalamus, and anterior olfactory nucleus. The exaggerated neurodegeneration, which occurred in late stages of infection, was temporally and somewhat spatially associated with a late-appearing enhancement of messenger RNA expression of interleukin-1beta,
interleukin-1beta converting enzyme
, tumor necrosis factor-alpha, and inhibitory factor kappaBalpha in the brain parenchyma. Restricted areas showed elevations in messenger RNA expression of interleukin-1 receptor antagonist, interleukin-6, inducible nitric oxide synthase,
interferon-gamma
, and inducible cyclooxygenase. The association suggests that increased production of pro-inflammatory cytokines in the brain may be an underlying mechanism for neural damage induced by the chronic sodium salicylate treatment. Furthermore, the results reveal a serious complication in using aspirin-like drugs for the treatment of trypanosome infection.
...
PMID:Chronic sodium salicylate treatment exacerbates brain neurodegeneration in rats infected with Trypanosoma brucei. 1068 22
We show here that exposure of cardiac cells to simulated ischemia results in apoptosis and is accompanied by phosphorylation and increased expression and transcriptional activity of STAT-1. Similarly,
interferon-gamma
, which is known to induce STAT-1 activation, also induced apoptosis in cardiac cells. STAT-1-transfected cells were more susceptible to ischemia-induced cell death than cells transfected with a control plasmid lacking the STAT-1 coding sequence. Furthermore, an antisense STAT-1 vector reduced both ischemia- and overexpressed STAT-1-induced cell death in cardiac cells. Both STAT-1 overexpression and
interferon-gamma
treatment or exposure to ischemia activated the promoter of the pro-apoptotic
caspase-1
gene in cardiomyocytes. Finally, ischemia/reperfusion also induced STAT-1 activation and
caspase-1
processing in ventricular myocytes in the intact heart ex vivo. Immunofluorescent staining demonstrated an increase in STAT-1-positive staining in cardiomyocytes in response to ischemia/reperfusion that co-localized with terminal deoxynucleotidyl transferase dVTP nick end-labeling-positive apoptotic cells. These results suggest that STAT-1 plays a critical role in the regulation of ischemia/reperfusion-induced apoptosis in cardiac cells, acting at least in part via a
caspase-1
activation-dependent pathway.
...
PMID:Ischemia-induced STAT-1 expression and activation play a critical role in cardiomyocyte apoptosis. 1074 76
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