Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human peritoneal mesothelial cells (HPMC) respond to tumor necrosis factor alpha (TNF alpha) by releasing various cytokines that may activate the endothelium and induce recruitment of leukocytes during peristonitis. We characterized the receptors for TNF on HPMC to elucidate their functions in peritonitis. Scatchard analysis determined the presence of 70 x 10(3) TNF receptors/cell with a kDa of 0.44 nM. TNF receptor 1 (TNF-R1, p55) and TNF-R2 (p75) mRNA were demonstrated by reverse-transcriptase-PCR (RT-PCR). TNF-R1 protein was solely detected by flow cytometry (FCM). Interleukin-1 alpha (IL-1 alpha) induced down-regulation of TNF-R1. This was concomitant with accumulation of soluble TNF-R1 (sTNF-R1) detected by specific ELISA. LPS had a lower TNF-R1-shedding activity while TNF alpha did not induce shedding. The IL-1-induced-sTNF-R1-shedding was suppressed by the protein-kinase-A (PKA) inhibitor, H-8, or by H-7, the inhibitor of both PKC and PKA, but not by the specific PKC inhibitor GF. These experiments suggest a role for PKA in the IL-1-shedding signal. No change in TNF-R1 mRNA levels was observed after IL-1 alpha or TNF alpha stimulation while TNF-R2 (p75) mRNA basal levels transiently increased three to fivefold, reaching a peak after four hours followed by an accumulation of sTNF-R2 in the supernatant. Our data suggest that the main receptor expressed on HPMC is TNF-R1. Down-regulation and shedding of TNF-R1 induced by IL-1, and the transient expression of TNF-R2 induced by IL-1 and TNF, may regulate the responses to TNF by HPMC. These results may be important in understanding the inflammatory process of peritonitis were TNF plays a major role.
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PMID:TNF-receptors on human peritoneal mesothelial cells: regulation of receptor levels and shedding by IL-1 alpha and TNF alpha. 880 91

1. Endothelial cells can be stimulated by the pro-inflammatory cytokines interleukin (IL)-1 alpha and tumour necrosis factor (TNF) alpha to express the leukocyte adhesion molecules E-selectin, vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1 but the intracellular signalling mechanisms leading to this expression are incompletely understood. We have investigated the role of protein tyrosine kinases (PTK) in adhesion molecule expression by cytokine-activated human umbilical vein endothelial cells (HUVEC) using the PTK inhibitors genistein and herbimycin A, and the protein tyrosine phosphatase (PTP) inhibitor sodium orthovanadate. 2. Maximal E-selectin expression induced by incubation of HUVEC for 4 h with IL-1 alpha (100 u ml-1) and TNF alpha (100 u ml-1) was dose-dependently inhibited by genistein and herbimycin A. Although similar effects were seen on phorbol 12-myristate, 13-acetate (PMA)-induced expression, this was not due to inhibition of protein kinase C (PKC) activity as the selective inhibitors of PKC, bisindolylmaleimide (BIM), Ro31-7549 or Ro31-8220 did not affect IL-1 alpha- or TNF alpha-induced E-selectin expression at concentrations which maximally inhibited PMA-induced expression. 3. Genistein inhibited VCAM-1 expression induced by incubation of HUVEC for 24 h with TNF alpha or IL-1 alpha whereas it did not affect ICAM-1 expression induced by 24 h incubation with either of these cytokines. Herbimycin A inhibited both VCAM-1 and ICAM-1 expression induced by TNF alpha. 4. Basal expression of E-selectin, VCAM-1 and ICAM-1 was dose-dependently enhanced by sodium orthovanadate. In contrast, vanadate differentially affected TNF alpha-induced expression of these molecules with maximal E-selectin and ICAM-1 expression being slightly enhanced and VCAM-1 expression dose-dependently reduced. 5. We also studied the effects of PTK and PTP inhibitors on adhesion of the human pre-myeloid cell line U937 to TNF alpha-stimulated HUVEC. Adhesion of U937 cells to HUVEC pretreated for 4 or 24 h with TNF alpha was dose-dependently inhibited by genistein and herbimycin A but unaffected by daidzein. Adhesion of U937 cells after 4 h was partially inhibited by blocking antibodies against both E-selectin and VCAM-1 but after 24 h was only inhibited by anti-VCAM-1. 6. Sodium orthovanadate had no effect on TNF alpha-induced U937 adhesion but dose-dependently enhanced adhesion to unstimulated HUVEC. Vanadate-induced adhesion was inhibited by an antibody against VCAM-1. 7. These results demonstrate that PTK-mediated phosphorylation events are important for the regulation of adhesion molecule expression by human endothelial cells, and additionally show that PTK inhibitors differentially affect upregulation of different adhesion molecules, implicating divergent regulatory pathways for cytokine-induced adhesion molecule expression.
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PMID:Effects of protein tyrosine kinase inhibitors on cytokine-induced adhesion molecule expression by human umbilical vein endothelial cells. 884 42

1. Rheumatoid arthritis is associated with the accumulation and activation of selected populations of inflammatory cells within the arthritic joint. One putative signal for this process is the production, by resident cells, of a group of inflammatory mediators known as the chemokines. 2. The chemokines interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1) and RANTES (regulated on activation normal T-cell expressed and presumably secreted) are target-cell specific chemoattractants produced by synovial fibroblasts in response to stimulation with interleukin-1 alpha (IL-1 alpha) or tumour necrosis factor alpha (TNF alpha). The signalling pathways involved in their production are not well defined. We therefore used four different protein kinase C inhibitors to investigate the role of this kinase in the regulation of chemokine mRNA and protein expression in human cultured synovial fibroblasts. 3. The non-selective PKC inhibitor, staurosporine (1-300 nM) significantly increased the production of IL-1 alpha-induced IL-8 mRNA and protein. A specific PKC inhibitor, chelerythrine chloride (0.1-3 microM), also caused a small concentration-dependent increase in IL-8 mRNA and protein production. In contrast, 3-[1-[3-(amidinothio)propyl]-3-indoly]-4-(1-methyl-3-indolyl )- 1H-pyrrole-2,5-dione methanesulphonate (Ro 31-8220) and 2[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3- yl)-maleimide (GF 109203X), two selective PKC inhibitors of the substituted bisindolylmaleimide family had a concentration-dependent biphasic effect on IL-1 alpha or TNF alpha-induced chemokine expression. At low concentrations they caused a stimulation in chemokine production, which was especially evident at the mRNA level. At higher concentrations both inhibited IL-1 alpha or TNF alpha-induced chemokine mRNA and protein production. Ro 31-8220 was 10 fold more potent than GF 109203X, with an IC50 of 1.6 +/- 0.08 microM (mean +/- s.e.mean, n = 4) for IL-1 alpha induced IL-8 production. Ro 31-8220 also inhibited the expression of IL-1 alpha or TNF alpha-induced MCP-1 and RANTES mRNA with a similar potency. 4. The stimulatory effect of staurosporine is discussed in relation to the known poor selectivity of this inhibitor for PKC. It is proposed that activation of an isoform of PKC, possibly PKC epsilon or zeta, which is inhibited by higher concentrations of the bisinodolylmaleimides, plays a role in the regulation of chemokine expression induced by IL-1 alpha or TNF alpha in synovial cells. 5. The inhibition of chemokine production by bisindolylmaleimide compounds heralds a novel approach for future anti-inflammatory therapies.
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PMID:Differential effects of protein kinase C inhibitors on chemokine production in human synovial fibroblasts. 888 22

We have previously reported that epidermal growth factor (EGF) augments the translation of pro-matrix metalloproteinase 3 (proMMP-3/prostromelysin 1) and tissue inhibitor of metalloproteinases (TIMP)-1 mRNAs during the first 1-h treatment of human uterine cervical fibroblasts (Hosono, T. et al., FEBS Lett., 381, 115-118, (1996)). In this report, we have investigated the effect of interleukin 1 alpha (IL-1 alpha) and 12-O-tetradecanoylphorbol 13-acetate (TPA), potent stimulators of proMMPs and TIMP-1 production, on the translation of proMMP-3 and TIMP-1 mRNAs. When human uterine cervical fibroblasts were treated with IL-1 alpha or TPA for 2h, their translations were not augmented, whereas the steady-state levels of proMMP-3 and TIMP-1 mRNAs in the cells treated with these stimuli for 24 h were increased 13.3- and 1.3-fold by IL-1 alpha and 52.5- and 5.7-fold by TPA, respectively. By contrast, transforming growth factor alpha(TGF alpha), which also binds to EGF-receptor, enhanced their production as early as 2 h after treatment, indicating that growth factors that bind to EGF-receptor are likely to be involved in the translational enhancement of proMMP-3 and TIMP-1 mRNAs. EGF partially translocated cytoplasmic protein kinase C (PKC) to plasma membrane, but the PKC down-regulation induced by 100nM TPA did not diminish the EGF-mediated translational augmentation of proMMP-3 and TIMP-1 mRNAs. In contrast, the PKC inhibitor of 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7) effectively suppressed the translational regulation of proMMP-3 and TIMP-1 in a dose-dependent manner during the first 2-h treatment with EGF. These results suggest that EGF and TGF alpha, but not IL-1 alpha and TPA, specifically augment the translation of proMMP-3 and TIMP-1 mRNAs and accelerate their accumulation without modifying their transcripts during the first 1-2 h treatment of human uterine cervical fibroblasts. This translational augmentation is suggested to be mediated by a TPA-insensitive atypical PKC subclass in the PKC family.
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PMID:Translational augmentation of pro-matrix metalloproteinase 3 (prostromelysin 1) and a tissue inhibitor of metalloproteinases (TIMP)-1 mRNAs by epidermal growth factor and transforming growth factor alpha, but not by interleukin 1 alpha or 12-O-tetradecanoylphorbol 13-acetate in human uterine cervical fibroblasts: the possible involvement of an atypical protein kinase C. 891 98

Like most cytokines, IL-1 transduces its signals for growth, differentiation and diverse cellular functions after binding to specific receptors on the cell surface. Up to now two IL-1 receptors have been reported, type I which induces signal transduction and type II which binds IL-1 but does not transduce signalling. By using the rat insulinoma RIN-5AH cell line that expresses both types of receptor mRNA, and computer-assisted binding analysis, we show that interleukin-1 beta (IL-1 beta) binds to a single class of high affinity receptors with a Kd of 155 pmol/l. The average number of receptors on adherent cell layer is calculated to be 7300 per cell. 125I-IL-1 beta binding can be competed out by unlabelled IL-1 beta. 125I-IL-1 alpha binding can be also obtained and is subject to competition by cold IL-1 alpha. Its saturation curve, however, varies within experiments due to differential receptor up-regulation. These results have also been confirmed by FACS analysis using specific antibodies to type I and II IL-1 receptors, where type I receptor antibody binds strongly to RIN-5AH cells, and type II receptor antibody shows weak staining, also due to inadequate receptor up-regulation. In order to determine whether functional signal transduction occurs via the receptors detected, it is shown that IL-1 beta is able to induce MHC class II antigen expression on the surface of the RIN cells, whereas IL-1 alpha is unable to do so, indicating different signal reception by the cells. IL-1 beta-induced class II upregulation shows moderate signs of p21ras or/and PKC dependency, whereas IL-1 alpha strongly activates both pathways that probably regulate different functions. Finally, both IL-1 alpha and beta induce nitric oxide (NO) production in a time-dependent fashion which appears to be unrelated to the signals and pathways described, but may be involved in the onset of autoimmune type 1 diabetes.
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PMID:IL-1 beta transduces different signals than IL-1 alpha leading to class II antigen expression on beta-insulinoma RIN-5AH cells through specific receptors. 902 92

The effect of fibronectin (FN) on IL-1 alpha, IL-1 beta, TNF-alpha, and IL-6 production was investigated with cultured monocytes isolated from human peripheral blood. Monokine concentrations were determined by ELISA. FN markedly stimulated the secretion of IL-1 alpha, IL-1 beta, TNF-alpha, and IL-6 from cultured monocytes. Northern blot analysis revealed the up-regulated expression of mRNA specific for each monokine on exposure of monocytes to FN. GM-CSF, IFN-gamma, and LPS synergistically enhanced FN-induced IL-1 alpha production. We further investigated the signal transduction pathways involved in FN-stimulated monokine secretion. FN-stimulated TNF-alpha secretion was markedly inhibited by either herbimycin A or genistein, inhibitors of protein tyrosine kinase (PTK), but was not affected by staurosporin, a inhibitor of protein kinase C (PKC). The results suggest that PTK is required for FN-stimulated TNF-alpha secretion. In contrast, LPS-stimulated TNF-alpha secretion was markedly inhibited by not only herbimycin A or genistein, but also staurosporin. Therefore, both PTK and PKC may be involved in LPS-stimulated TNF-alpha secretion. We also demonstrated that, in monocytes, cytoplasmic proteins of about 70 and 240 kDa were phosphorylated after FN stimulation. Our results indicate that FN may contribute to the inflammatory response of monocyte by inducing monokine production.
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PMID:[Effects of fibronectin on the monokine production by cultured-human monocytes]. 917 68

The paracrine linkage of endothelins (ET) between keratinocytes and melanocytes suggested that ETs are intrinsic mediators for human melanocytes in UVB-induced pigmentation. In this study, the role of ET-1 in the epidermal hyperpigmentation was investigated in vivo and in vitro. The addition of 10 nM ET-1 induced a H-7 (10 microM) suppressible-increase in tyrosinase activity in cultured human melanocytes and was accompanied by elevated levels of tyrosinase and tyrosinase-related protein-1 mRNA expression as shown by Northern blotting. Analysis of signaling mechanisms leading to tyrosinase activation demonstrated the involvements of quick translocation of PKC, the H-7 (10 microM) suppressible-phosphorylation of the threonine residue of several proteins, and highly elevated level of cyclic AMP (4-fold over control). Reverse transcription polymerase chain reaction (RT-PCR) of RNA isolated from the epidermis of human skin exposed to UVB revealed that UVB irradiation with a dose of 2 MED caused a significant increase in the expressions of ET-1, IL-1 alpha, and tyrosinase mRNA signals 5 days after irradiation. The involvement of ET-1 in UVB-pigmentation was also corroborated by the experiments that the extracts of M. Chamomilla, which can act as an antagonist for ET-receptor binding-mediated signaling but has no inhibitory effect on tyrosinase activity in culture, had a significant inhibitory effect on UVB-induced pigmentation in vivo when daily applied immediately after UVB exposure to human skin. These findings suggest that ET-1 is an important mediator in the epidermis for UVB-induced pigmentation in vivo.
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PMID:The role of endothelin-1 in epidermal hyperpigmentation and signaling mechanisms of mitogenesis and melanogenesis. 926 29

Parathyroid hormone (PTH) functions in part by regulating osteoblast cytokine expression. We recently demonstrated that PTH induced a rapid and transient increase in interleukin-6 (IL-6) mRNA expression in rat bones in vivo. To determine the molecular basis of this effect, we analyzed the human IL-6 promoter fused (-1,179 to +9) with the chloramphenicol acetyltransferase (CAT) reporter gene in stable transfections into human osteoblast-like osteosarcoma SaOS-2 cells. We compared the effects of PTH on IL-6 expression with adenylate cyclase activator forskolin, PKC activator phorbol 12-myristate 13-acetate (PMA), calcium ionophore A23187, interleukin-1 alpha (IL-1 alpha), prostaglandin E-2 (PGE-2), RS-66271 (a parathyroid hormone-related peptide analog), and platelet-derived growth factor-BB (PDGF-BB). Analyses of cell clones showed that IL-6 promoter expression was extremely low in the unstimulated state. Exposure to PTH (0.001-100 nM) for 12 h stimulated CAT expression in a dose-dependent manner (200-500% of control). Treatment with IL-1 alpha was more potent than PTH in inducing transcription of the IL-6 promoter (900-1,000%). Activation of the cAMP-PKA pathway by treatment with forskolin induced a comparable level of induction with PTH. Together, the effects of PTH and forskolin were additive. RS-66271, previously shown to have PTH-like effects, induced a comparable level of IL-6 promoter expression. When examined together, PTH+RS-66271 effects were comparable to PTH effects alone. Exposure to PGE-2, PMA, PDGF-BB, or A23187 for 12 h did not significantly alter IL-6 promoter expression. These results demonstrate PTH, forskolin, the PTHrP analog RS-66271, and IL-1 alpha stimulate IL-6 expression by stimulating gene transcription. The response to forskolin suggests that the messenger system mediated by PKA is sufficient to induce IL-6 expression.
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PMID:Parathyroid hormone (1-34)-mediated interleukin-6 induction. 932 32

The enzymes and substrates involved in phosphoinositide signal transduction which have been detected in the nucleus of several cell types have been demonstrated to be responsive to agonists. The complexity of this aspect of inositide function has been previously analyzed in some cell models characterized by a mitogenic or differentiating response to specific factors. An interesting experimental model is represented by human derived osteosarcoma Saos-2 cells, characterized by the expression of high affinity receptors for interleukin 1 alpha (IL-1 alpha), which is one of the most potent stimulators of bone resorption. In particular, we investigated the earliest intracellular events following the binding of IL-1 alpha to its receptor, involving the inositide signal transduction pathway. Saos-2 cells present a partitioning of the phosphoinositidase (PLC) isoforms; in fact, the nucleus contains both PLC beta 1 and gamma 1, while the cytoplasm contains almost exclusively the gamma 1 isoform. IL-1 alpha evokes a rapid and transient increase of the PLC beta 1 activity in the nucleus, which causes the hydrolysis of phosphatidylinositol mono- and bis-phosphate. In response to IL-1 alpha, not only the canonical inositol lipid pathway appears to be involved; also the 3'-phosphorylated lipids generated by phosphatidylinositol 3-kinase (PI 3-K), which may act as second messengers, appear to be affected. In fact, Saos-2 cells present a nuclear PI 3-K activity which can be enhanced by the IL-1 alpha treatment. Among the possible targets of the second messengers released by the nuclear PLC beta 1 activation, we found that some protein kinase C isoforms, namely the epsilon and zeta, which are present within the nucleus, are activated after IL-1 alpha exposure. These activated PKC isoforms, in turn, could modulate the activity of the transcription factor NFkB, which, 5 min after IL-1 alpha treatment, has already translocated to the nucleus and bound to DNA to promote gene activation. The actual role of the inositide pathway in the Saos-2 cell function has also been investigated by utilizing cell clones transfected with the mouse sequence of the PLC beta 1.
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PMID:Nuclear lipid-dependent signal transduction in human osteosarcoma cells. 938 81

By using a specific enzyme-linked immunosorbent assay, the authors demonstrated that human bone marrow stromal cells produce IL-6 and IL-8. Their synthesis is enhanced in a dose-dependent manner after stimulation with lipopolysaccharide (LPS) and phorbol myristate acetate (PMA). Interleukin 6 (IL-6) and IL-8 production in response to PMA were markedly diminished by the PKC inhibitor staurosporine. IL-6 (10 ng/ml) stimulated IL-8 production with 0% and 10% fetal calf serum (FCS) in the culture medium. In similar conditions, IL-8 (10 ng/ml) enhanced IL-6 production. IL-1 alpha, IL-1 beta, and IL-3, tumour necrosis factor alpha (TNF-alpha), Stem cell factor (SCF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (at 10 ng/ml) stimulated IL-6 and IL-8 production in 0% and 10% FCS. G-CSF stimulated and IL-4 inhibited IL-8 production in 10% FCS. IL-2, IL-4 and bFGF stimulated IL-6 production in 0% FCS. These results suggest that bone marrow stromal cells might represent a major source for the cytokine-regulated local production of IL-6 and IL-8 inside human bone marrow.
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PMID:IL-6 and IL-8 production by human bone marrow stromal cells. 951 98


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