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)

Interleukin-1 (IL-1) is the name given to a family of related proteins showing a variety of activities. It was originally shown to be produced by monocytes and macrophages but is now known to be produced by numerous cell types, including synovial cells. From the point of view of arthritis, its most interesting activities are those on connective tissue cells in vitro. These include stimulation of production of prostaglandins, plasminogen activator and metalloproteinases such as collagenase and proteoglycanase. IL-1 is also mitogenic for synoviocytes and bone cells, and can alter rates of production of extracellular matrix constituents. The presence of IL-1 in synovial fluids from rheumatoid and osteoarthritic joints and its actions on connective tissues in vitro suggest that IL-1 may play an important role in the pathogenesis of arthritis. There are several potential cellular sources of IL-1 in the inflamed rheumatoid joint and interactions between these cells, T lymphocytes and plasma cells may continually induce IL-1 so contributing to the chronicity of the disease. The mechanism of action of IL-1 on connective tissue cells is at present uncertain though preliminary studies suggest that IL-1 may induce cellular responses by stimulating phosphoinositide turnover and possibly protein kinase C activity.
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PMID:The effect of interleukin-1 on connective tissue metabolism and its relevance to arthritis. 352 46

TNF stimulated transcription and secretion of the metalloproteinases collagenase and stromelysin in porcine articular chondrocytes. TNF induced metalloproteinase transcription could be inhibited with either protein kinase inhibitors (H7 or staurosporine) or by raising intracellular cAMP levels. HA1004, a protein kinase inhibitor structurally related to H7 but with a higher Ki for protein kinase C had no effect on TNF induced message levels. TNF treatment of chondrocytes did not induce membrane associated PKC or increase intracellular cAMP levels. Our results are consistent with the involvement of a staurosporine and H7 sensitive protein kinase distinct from PKC in TNF signal transduction in chondrocytes.
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PMID:Protein kinase regulation of tumor necrosis factor alpha stimulated collagenase and stromelysin message levels in chondrocytes. 750 65

Basic fibroblast growth factor (bFGF) is a bone cell mitogen that affects osteoblastic function by suppressing type I collagen synthesis. The investigators in this study examined whether bFGF also regulates interstitial collagenase and tissue inhibitors of metalloproteinases (TIMPs) in osteoblast-enriched cells isolated from 22-day fetal rat calvariae. After exposure to 600 pM bFGF, interstitial collagenase messenger RNA (mRNA) levels, as determined by Northern hybridization analysis, increased after 2 h and were maximally stimulated to approximately 13-fold at 6 h. Exposure of osteoblast-enriched cells to 0.06-6 nM bFGF increased collagenase mRNA in a dose-dependent manner, and bFGF also increased immunoreactive collagenase measured in the culture medium by Western blot analysis. The protein synthesis inhibitor cycloheximide, as well as two inhibitors of protein kinase C, staurosporine and sangivamycin, prevented the bFGF induction of collagenase transcripts, whereas indomethacin, an inhibitor of prostaglandin synthesis, decreased the effect of bFGF on collagenase mRNA levels by about 50%. After exposure to 600 pM bFGF, levels of TIMP 1 and TIMP 3 mRNAs were also maximally stimulated to approximately 6-fold at 16 h and 4-fold at 6 h. bFGF did not modify TIMP 2 expression. In conclusion, bFGF may modulate degradation of collagenous bone matrix by inhibiting collagen as well as stimulating collagenase and TIMPs by osteoblasts.
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PMID:Basic fibroblast growth factor stimulates expression of interstitial collagenase and inhibitors of metalloproteinases in rat bone cells. 772 Jun 65

Cirrhotic livers are considered to regenerate less actively than normal livers after hepatic resection. Little is known about the mechanisms responsible for impaired capacity of regeneration in cirrhotic liver. In the present study, we investigated the effect of phorbol ester on hepatocyte proliferation in healthy and cirrhotic hepatocytes, using one of the phorbol esters, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), which has a direct effect on activation of protein kinase C (PKC). Cirrhosis was established by the administration of carbon tetrachloride and phenobarbital to rats. Healthy and cirrhotic hepatocytes were isolated from Wistar male rats by a two-step collagenase perfusion technique. DNA synthesis was estimated by [3H]thymidine incorporation into DNA and by autoradiographic nuclear labeling index. [3H]Thymidine incorporation was measured 24 hr after hepatocytes were stimulated by appropriate reagents. TPA (50 nM) stimulated [3H]thymidine incorporation in healthy hepatocytes (control vs TPA, 991 +/- 247 vs 2569 +/- 766 mean +/- SEM cpm/microgram DNA; P < 0.05), whereas TPA (50 nM) failed to stimulate in cirrhotic hepatocytes (control vs TPA, 1144 +/- 184 vs 1304 +/- 187 cpm/microgram DNA; NS). Staurosporine, a specific PKC inhibitor, suppressed [3H]thymidine incorporation in TPA-stimulated healthy hepatocytes (806 +/- 263 cpm/microgram DNA; P < 0.05); however, it had no effect on cirrhotic hepatocytes (1295 +/- 180 cpm/microgram DNA; NS). An autoradiographic nuclear labeling index exhibited the same results with [3H]thymidine incorporation. We conclude that TPA stimulates hepatocyte proliferation in healthy rat hepatocytes but has no effect on cirrhotic hepatocytes.
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PMID:Impaired phorbol ester-induced hepatocyte proliferation in cirrhosis. 772 25

We examined the common signal transduction mechanisms governing collagenase (MMP-1), stromelysin-1 (MMP-3), and tissue inhibitor of metalloproteases (TIMP-1) gene expression in human synovial fibroblasts for insight into the pathophysiology of arthritis. MMP-1, MMP-3, and TIMP-1 expression and synthesis were induced in cultured human synoviocytes with recombinant human interleukin 1 beta in the absence or presence of either chemical inhibitors of protein kinase A and C (PKA, PKC), or prostaglandin E2, or cyclic AMP (cAMP) mimetics. We used enzyme immunoassays (EIA) to determine MMP-1, MMP-3, and TIMP-1 antigen levels in spent culture medium and Northern hybridization to measure steady state mRNA expression levels. Extracellular signals (e.g., IL-1, phorbol myristic acetate) that result in the activation of cytoplasmic PKC augment in tandem the expression and synthesis of MMP-1, MMP-3, and TIMP-1 in human synovial fibroblasts. In addition, such signals induce nuclear transcription factors (e.g., activator protein 1) that bind to common gene regulatory elements and augment promoter activity of MMP-1, MMP-3, and TIMP-1 gene promoter constructs. In contrast, signals that activate PKA oppose PKC mediated signals, in that the expression of MMP-1, MMP-3, and TIMP-1 are suppressed. Experimental data suggest that the expression of MMP-1, MMP-3, and TIMP-1 are coordinated through a series of common cytoplasmic signal transducing pathways, cis regulatory elements, and nuclear trans acting factors.
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PMID:Coordinate regulation of matrix metalloproteases and tissue inhibitor of metalloproteinase expression in human synovial fibroblasts. 775 15

We have shown previously that phosphatidic acid esterified to polyunsaturated fatty acids is mitogenic for primary cultures of mouse mammary epithelial cells embedded within collagen gels. We hypothesized that this mitogenic competence resulted from the ability of this phospholipid to activate multiple signal transduction pathways in mammary epithelium. A closer examination of this hypothesis was undertaken by examining the effect of exogenous phosphatidic acid on phosphoinositide (PI) hydrolysis and its intracellular metabolism to diglyceride, an activator of protein kinase C. For assays of phosphoinositide-specific phospholipase C activation, mammary epithelial cells from virgin Balb/c mice were isolated by collagenase dissociation of mammary glands and cultured on the surface of Type I collagen-coated culture dishes. Phosphatidic acid (PA) stimulated a sustained increase in inositol phosphates and caused inositol phospholipid depletion when added to cells in which inositol phospholipids were prelabeled with 3H-myoinositol. This effect was specific for PA among phospholipids tested. Neither lineoleic acid, that can be released from PA, nor prostaglandin E2 affected PI hydrolysis. When mammary epithelial cells were cultured inside collagen gels in the presence of exogenous PA or phosphatidylcholine (PC) radiolabeled with 3H-glycerol, PA was found to persist intracellularly and be dephosphorylated to diglyceride (an activator of protein kinase C) to a greater extent than PC, a nonmitogenic phospholipid. In contrast to PA, epidermal growth factor (EGF) only slightly stimulated PI hydrolysis, showing that these two different growth-promoting factors do not actively couple to the same signal transduction pathways in mammary epithelial cells. These results show that PA may activate multiple pathways in mammary epithelial cells either directly or via its metabolism to diglyceride.
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PMID:Multifunctional phosphatidic acid signaling in mammary epithelial cells: stimulation of phosphoinositide hydrolysis and conversion to diglyceride. 777 98

We have previously reported that two closely related protein kinase C (PKC) isoforms, PKC alpha and PKC beta I, had divergent effects on the growth and transformation of the same parental R6 rat embryo fibroblast cell line (Housey, G. M., Johnson, M. D., Hsiao, W.-L. W. O'Brian, C. A., Murphey, J. P., Kirschmeier, P., and Weinstein, I. B. (1988) Cell 52, 343-354; Borner, C., Filipuzzi, I., Weinstein, I. B., and Imber, R. (1991) Nature 353, 78-80). Whereas cells that overexpress PKC beta I lost anchorage dependence, grew to higher saturation densities, and generated small tumors when injected into nude mice, none of these properties were seen with cells that overexpress PKC alpha. In fact, the latter cells grew even slower and to lower saturation densities as compared to control cells. Here we investigate possible molecular mechanisms underlying the reciprocal effects of PKC alpha and PKC beta I. Overexpression of both isoforms enhanced 12-O-tetradecanoyl phorbol-13 acetate-induced expression of the growth regulatory genes c-jun, c-myc, and collagenase and enhanced feedback inhibition of epidermal growth factor receptor binding and cellular levels of diacylglycerol. However, the cells overexpressing PKC beta I differed from those overexpressing PKC alpha by displaying a decreased requirement for growth factors and by the production of a mitogenic factor. Thus, the basis for enhanced growth and transformation of cells overexpressing PKC beta I may be the establishment of an autocrine growth factor loop. These findings may be relevant to the roles of specific isoforms of PKC in carcinogenesis and tumor growth.
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PMID:Two closely related isoforms of protein kinase C produce reciprocal effects on the growth of rat fibroblasts. Possible molecular mechanisms. 781 23

The administration of 150 nM etoposide, an inhibitor of DNA topoisomerase II activity, decreased the proliferation and induced the differentiation of U937 human promonocytic cells, as determined by nitroblue tetrazolium reduction, surface accumulation of CD11b/CD18 and CD11c/CD18 integrins, and c-fms protooncogene expression. The expression of these differentiation markers started to be detected at 24 h of treatment. Etoposide caused little cell damage, as determined by trypan blue exclusion and by apoptotic-like DNA degradation, which was slightly initiated at 48 h. The treatment induced a transient increase in c-fos, c-jun, and jun B mRNA levels, with maximum values at 12 h, a transient increase in collagenase mRNA level, with maximum value at 48 h, and a progressive increase in vimentin and lamin A and C mRNAs. These changes were qualitatively similar to those produced by 12-O-tetradecanoylphorbol-13-acetate. Etoposide also caused a transient increase of total AP-1 binding activity, with maximum value at 12 h of treatment, as determined by gel retardation assays. The drug produced an early transient activation (3-6 h) of membrane-bound protein kinase C, followed by the later activation (48 h) of both the membrane and cytosolic enzyme. The protein kinase C inhibitors, sphinganine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), attenuated the induction of differentiation markers by etoposide. These results suggest that protein kinase C and AP-1-dependent gene expression could be involved in myeloid cell differentiation by DNA topoisomerase II inhibitors.
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PMID:Etoposide-induced differentiation of U937 promonocytic cells: AP-1-dependent gene expression and protein kinase C activation. 781 32

We have previously shown that during wound healing migrating keratinocytes, which are in contact with the dermal matrix, express interstitial collagenase, whereas basal epidermal cells, which reside on an intact basement membrane, do not. Duplicating this in vivo pattern, collagenase production was induced in primary human keratinocytes grown on native type I collagen, but only background levels of enzyme were detected in cells cultured on denatured type I collagen or on Matrigel. Using genistein, herbimycin A, and sodium orthovanadate, we show that tyrosine kinase activity was required for collagen-mediated induction of keratinocyte collagenase. Similarly, collagenase steady-state mRNA levels and the activity of a transfected human collagenase-promoter CAT construct were inhibited by genistein and enhanced by orthovanadate. Staurosporine and H-7 also blocked collagenase production, indicating that protein kinase C activity was also required for collagen-mediated induction of keratinocyte collagenase. All inhibitory effects were dose-dependent, and no compound significantly affected total protein synthesis. Furthermore, both tyrosine kinase and protein kinase C inhibitors blocked phorbol ester-mediated induction of collagenase, but only protein kinase C antagonists abrogated phorbol ester-mediated induction of c-fos mRNA. These data suggest that similar signal transduction pathways are used by various agonists to mediate the stimulation of interstitial collagenase production.
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PMID:Collagen-stimulated induction of keratinocyte collagenase is mediated via tyrosine kinase and protein kinase C activities. 796 3

The indol alkaloid staurosporine is a potent inhibitor of protein kinase C, but has also been shown to have certain effects paradoxically similar to those of protein kinase C-activating phorbol esters. We show here that collagenase mRNA expression is stimulated by 10 nM staurosporine in normal and ras-oncogene-transformed rat fibroblasts. The kinetics of collagenase mRNA induction by staurosporine were slow compared to induction by phorbol ester. Staurosporine induction of the collagenase promoter appeared to be mediated via the TPA response element (TRE). Induction did not involve any increase in jun mRNA expression and did not require expression of c-Jun. Prolonged treatment with phorbol ester to deplete protein kinase C did not inhibit stimulation of the collagenase promoter by staurosporine. Instead, involvement of cAMP-dependent protein kinase (PKA) was indicated by inhibition of staurosporine induction by the PKA inhibitor H-89. In addition, raised levels of cAMP were observed during the first hour of staurosporine treatment. Altogether, our data indicate that staurosporine induces a PKA-dependent pathway leading to c-Jun-independent activation of the collagenase TRE element.
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PMID:Induction of the collagenase phorbol ester response element by staurosporine. 796 79


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