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Query: EC:2.7.11.13 (
protein kinase C
)
49,245
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Nitric oxide (NO) generated by either endothelial nitric oxide synthase (eNOS) or
inducible nitric oxide synthase
(
iNOS
) may be involved in prostate tumorigenesis through the inhibition of reactive oxygen species (ROS)-induced apoptosis. Multicellular DU-145 prostate tumor spheroids endogenously generated NO that paralleled the production of ROS. With increasing spheroid size, eNOS expression was downregulated, whereas an upregulation of
iNOS
expression was observed. In parallel, NO generation declined, as evaluated by the NO indicator diaminofluorescein-2 diacetate (DAF-2DA), suggesting that NO generation in DU-145 tumor spheroids is mainly mediated by eNOS. Elevation of ROS by treatment of tumor spheroids with either buthionine sulfoximine (BSO) or hydrogen peroxide resulted in upregulation of eNOS, whereas
iNOS
was downregulated. Furthermore, eNOS expression was increased by epidermal growth factor (EGF) in a redox-sensitive manner. Upregulation of eNOS after treatment with hydrogen peroxide was apparently transduced through receptor tyrosine kinase signaling pathways since it was abolished by the
protein kinase C
(
PKC
) inhibitor bisindolylmaleimide-1 (BIM-1), the p21(ras) inhibitor S-trans-trans-farnesylthiosalicylic acid (FTS), the c-Raf inhibitor ZM 336372 and PD98059, which inhibits ERK1/2 activation. Endogenous NO may serve to escape from oxidative stress-induced apoptosis since treatment of tumor spheroids with the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl imidazoline-1-oxyl 3-oxide (carboxy-PTIO) as well as the NO synthase inhibitor N-omega-amino-L-arginine (L-NAA) increased cleaved caspase-3. Consequently, lowering intracellular NO levels with either L-NAA or PTIO significantly raised ROS levels, indicating that endogenously generated NO may play a role as a ROS scavenger, thereby protecting exponentially growing tumor spheroids from ROS-induced apoptosis.
...
PMID:Reactive oxygen species-mediated regulation of eNOS and iNOS expression in multicellular prostate tumor spheroids. 1256 50
This study examined the hypothesis that the activation of A1 adenosine receptor (A1AR) induces delayed cellular protection (DCP) in porcine coronary smooth muscle cells (PCSMC). The following groups of cultured PCSMC, subjected to simulated ischemia (SI) at 20 h were studied: (a) SI: with ischemia alone; (b) A1AR agonist chloro-N6-cyclopentyl adenosine (CCPA: CCPA (1 microM) alone; (c) CCPA +
PKC
inhibitor chelerythrine chloride (CCL): CCPA and 1 microM CCL; (d) CCPA +
iNOS
inhibitor S-methylthiourea (SMT): CCPA and 100 nM SMT; (e) CCPA + KATP channel blocker Glibenclamide (Glb): CCPA and 50 microM Glb; (f) CCPA + mitochondrial KATP channel blocker 5-hydroxydecanoate (5-HD): CCPA and 100 microM of 5-HD; (g) CCPA + A1AR antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX): CCPA and 1 microM DPCPX. The release of LDH into the medium as well as the amount of LDH remaining in the cells was used as a marker of cellular injury and cell viability. Up-regulation of A1AR, epsilon-
PKC
,
iNOS
and HSP 72i was detected through Westem blot analysis. The cellular resistance (%LDH remaining in the cells) acquired by PCSMC due to CCPA (59.42 +/- 1.57) was significantly blocked by CCL: 39.30 +/- 2.03; SMT: 41.37 +/- 1.98; Glb: 47.24 +/- 1.31; 5-HD: 47.69 +/- 1.40 and DPCPX: 42.92 +/- 0.79. CCPA increased the expression of A1AR (1.30 fold), epsilon-
PKC
(1.20 fold),
iNOS
(1.50 fold), and HSP 72i (1.70 fold) compared to the controls. CCPA-induced up-regulation of A1AR, epsilon-
PKC
,
iNOS
, HSP 72i, and the opening of both mitochondrial and sarcolemmal KATP channels may possibly participate in signaling cascade. Our study suggests that A1AR activation up-regulates
iNOS
, HSP 72i via epsilon-
PKC
signaling pathway to activate both mitochondrial and sarcolemmal KATP channels for cellular protection against SI in the cultured PCSMC.
...
PMID:Mechanisms of delayed preconditioning with A1 adenosine receptor activation in porcine coronary smooth muscle cells. 1259 31
This study investigates the signaling pathway involved in
inducible nitric oxide synthase
(
iNOS
) expression and nitric oxide (NO) release caused by Staphylococcus aureus lipoteichoic acid (LTA) in RAW 264.7 macrophages. A phosphatidylcholine-phospholipase C (PC-PLC) inhibitor (D-609) and a phosphatidylinositol-phospholipase C (PI-PLC) inhibitor (U-73122) attenuated LTA-induced
iNOS
expression and NO release. Two
PKC
inhibitors (Go 6976 and Ro 31-8220), an NF-kappaB inhibitor (pyrrolidine dithiocarbamate; PDTC), and long-term (24 h) 12-phorbol-13-myristate acetate (PMA) treatment each also inhibited LTA-induced
iNOS
expression and NO release. Treatment of cells with LTA caused an increase in
PKC
activity; this stimulatory effect was inhibited by D-609, U-73122, or Ro 31-8220. Stimulation of cells with LTA caused IkappaB-alpha phosphorylation and IkappaB-alpha degradation in the cytosol, and translocation of p65 and p50 NF-kappaB from the cytosol to the nucleus. Treatment of cells with LTA caused NF-kappaB activation by detecting the formation of NF-kappaB-specific DNA-protein complexes in the nucleus; this effect was inhibited by Go 6976, Ro 31-8220, long-term PMA treatment, PDTC, L-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK), and calpain inhibitor I. These results suggest that LTA might activate PC-PLC and PI-PLC to induce
PKC
activation, which in turn initiates NF-kappaB activation, and finally induces
iNOS
expression and NO release in RAW 264.7 macrophages.
...
PMID:Induction of nitric oxide synthase in RAW 264.7 macrophages by lipoteichoic acid from Staphylococcus aureus: involvement of protein kinase C- and nuclear factor-kB-dependent mechanisms. 1260 34
The purpose of this study was to elucidate the signalling pathways involved in the cytokine-activated
inducible nitric oxide synthase
(
iNOS
) response in a human kidney epithelial cell line, A498. Unstimulated cells did not express
iNOS
. Exposure of A498 cells to a cytokine mixture consisting of interferon gamma, interleukin-1 beta and tumor necrosis factor-alpha (TNF-alpha) increased nitrite production,
iNOS
mRNA and protein expression. Pharmacological inhibition of tyrosine kinases, including janus kinase (JAK2), and
protein kinase C
(
PKC
) inhibited cytokine-mediated nitrite production and
iNOS
protein expression. The involvement of mitogen-activated protein kinases (MAPKs) was investigated. Inhibition of p38 MAPK, but not of an upstream activator of extracellular signal-regulated kinase (ERK), caused a decrease in
iNOS
expression and nitrite production in response to cytokines. Electrophoretic mobility shift assay of nuclear extract from cytokine-stimulated cells demonstrated a pronounced binding to a nuclear factor kappa B (NF-kappa B) sequence present in the human
iNOS
promoter. Furthermore, the NF-kappa B inhibitor pyrrolidinedithiocarbamate (PDTC) decreased cytokine-activated
iNOS
protein expression and nitrite production. The present study has demonstrated that cytokine-stimulated
iNOS
expression in human kidney epithelial cells involves activation of tyrosine kinases, including JAK2,
PKC
, p38 MAPK and NF-kappa B.
...
PMID:Signalling pathways regulating inducible nitric oxide synthase expression in human kidney epithelial cells. 1278 81
In the present study, the roles of
protein kinase C
(
PKC
) in BSA-derived advanced glycosylation end products (BSA-AGEs)-induced nitric oxide (NO) production and
inducible nitric oxide synthase
(
iNOS
) expression were investigated. Treatment of RAW 264.7 cells with BSA-AGEs caused dose- and time-dependent increases in NO release and
iNOS
expression in RAW 264.7 cells, whereas BSA alone had no effect on
iNOS
induction. The tyrosine kinase inhibitor (genistein), the phosphatidylinositol-specific phospholipase C inhibitor (U-73122), the phosphatidylcholine-specific phospholipase C inhibitor (D-609), and the
PKC
inhibitors (staurosporine, Ro 31-8220, and Go 6976) all inhibited BSA-AGE-induced NO release and
iNOS
expression in RAW 264.7 cells. Stimulation of RAW 264.7 cells with BSA-AGEs resulted in the formation of inositol monophosphate; the response was attenuated by U-73122 and genistein. BSA-AGEs stimulated PKC-alpha, -betaI, -delta, and -eta but not -zeta translocation from the cytosol to the membrane. However, incubation of RAW 264.7 cells with BSA-AGEs increased phosphorylation of
PKC
-zeta at threonine-410, which reflects activation of
PKC
-zeta, indicating the possible involvement of these
PKC
isoforms in AGE-mediated effects. Pretreatment of RAW 264.7 cells with U-73122, D-609, and genistein reduced the AGE-stimulated translocation of PKC-alpha, -betaI, -delta, and -eta and activation of
PKC
-zeta. Taken together, these data suggest that BSA-AGEs might activate
PKC
and subsequently induce
iNOS
expression and NO release.
...
PMID:Role of protein kinase C in BSA-AGE-mediated inducible nitric oxide synthase expression in RAW 264.7 macrophages. 1282 63
1. Endothelin-1 (ET-1) and tumor necrosis factor alpha (TNFalpha) by their action on adipocytes have been independently linked to the pathogenesis of insulino-resistance. In isolated adipocytes, TNFalpha induces the expression of the
inducible nitric oxide synthase
(
iNOS
). The purpose of the present work was, in the 3T3-F442A adipocyte cell line, to characterise TNFalpha-induced
iNOS
expression and to determine whether or not ET-1 could influence TNFalpha-induced
iNOS
expression and NO production. 2. In differentiated 3T3-F442A, treatment with TNFalpha (20 ng ml(-1)) induced the expression of a functional
iNOS
as demonstrated by nitrite assay, Western blot, reverse transcription-polymerase chain reaction and Northern blot analysis. TNFalpha-induced
iNOS
expression requires nuclear factor kappaB activation, but does not necessitate the activation of the PI-3 kinase/Akt and P38-MAP kinase pathways. 3. ET-1, but not ET-3, inhibited the TNFalpha-induced expression of
iNOS
protein and mRNA as well as nitrite production. The effects of ET-1 were blocked by a specific ETA (BQ123, pA(2) 7.4) but not by a specific ETB receptor antagonist (BQ788). 3T3-F442A adipocytes express the mRNAs for prepro-ET-1 and the ET-A receptor subtype, but not for the ET-B subtype. 4. The inhibitory effect of ET-1 was not affected by bisindolylmaleimide, SB 203580 or indomethacin, inhibitors of
protein kinase C
, p38-MAP kinase and cyclooxygenase, respectively, and was not associated with cAMP production. However, the effect of ET-1 was partially reversed by wortmannin, suggesting the involvement of PI3 kinase in the transduction signal of ET-1. 5. Differentiated 3T3-F442A adipocytes did not release ET-1 with or without exposure to TNFalpha, although the mRNA for preproET-1 was detected in both pre- and differentiated adipocytes. 6. Thus, these results confirm that adipocytes are a target for circulating ET-1 and demonstrate that the activation of the ETA receptor subtype can prevent TNFalpha-induced
iNOS
expression.
...
PMID:Endothelin-1 inhibits TNF alpha-induced iNOS expression in 3T3-F442A adipocytes. 1283 67
In this paper we have determined the different signaling pathways involved in M(1) muscarinic acetylcholine receptor (mAChR)-dependent stimulation of m1 mAChRs, neural and inducible isoforms of nitric oxide synthase (nNOS and
iNOS
)-mRNA gene expression of rat frontal cortex. Carbachol-stimulation of M(1) mAChRs exerts an increase in m1 mAChR-mRNA, activation of phosphoinositide (PI) turnover, translocation of
protein kinase C
(
PKC
) and stimulation of NOS activity. Inhibitors of phospholipase C (PLC), calcium/calmodulin and NOS, but not guanylate cyclase, prevent the carbachol-dependent increase of m1 mAChR-mRNA levels. These inhibitors also attenuate the muscarinic receptor-dependent increase in nNOS and
iNOS
mRNA levels. These results suggest that carbachol-activation of M(1) mAChRs increases m1 mAChR, nNOS and
iNOS
mRNA levels associated with increased production of nitric oxide (NO). The mechanism appears to occur secondarily to stimulation of PI turnover via PLC activation. This in turn, triggers a cascade reaction involving calcium/calmodulin and
PKC
, leading to activation of NOS. On the basis of our results, the activation of M(1) mAChRs appears to induce nNOS and
iNOS
expression and, reciprocally, the activator of NOS up-regulates m1 mAChR gene expression. These results may contribute to a better understanding of the effects and side effects of cholinomimetic treatment in patients with neurodegenerative diseases.
...
PMID:Novel insight into the mechanisms involved in the regulation of the m1 muscarinic receptor, iNOS and nNOS mRNA levels. 1284 32
Microglial activation by amyloid beta-protein in senile plaques contributes to neurodegeneration in Alzheimer disease. In BV-2 microglial cells, amyloid beta-protein 1-40 (Abeta 1-40) elicited a dose-dependent increase (3-4 fold) of Myristoylated alanine-rich C kinase substrate (MARCKS) and MARCKS-related protein (MRP), two
protein kinase C
substrates implicated in membrane-cytoskeletal alterations underlying microglial adhesion, migration, secretion, and phagocytosis. Neither MARCKS nor MRP was induced by the amyloid fragment Abeta 25-35, although both Abeta 1-40 and Abeta 25-35 caused extensive aggregation of BV-2 cells. Interferon-gamma synergistically enhanced the induction by Abeta 1-40 of
inducible nitric oxide synthase
, but not MARCKS or MRP. Our results suggest that MARCKS and MRP may play important roles in microglia activated by amyloid peptides.
...
PMID:Induction of protein kinase C substrates, Myristoylated alanine-rich C kinase substrate (MARCKS) and MARCKS-related protein (MRP), by amyloid beta-protein in mouse BV-2 microglial cells. 1286 29
There is increasing evidence that cyclooxygenase (COX)-2 possess both angiogenic and cardioprotective properties. We examined the effects of hypoxic cardiac myocytes (H9c2 cells) on COX-2 expression in human umbilical vein endothelial cells (HUVECs) to determine the pathway involved in COX-2 regulation. The medium from hypoxic (<1% O2) cardiac myocytes (HMCM) or normoxic cardiac myocytes (21% O2) was added to HUVEC cultures. HMCM induced a transient increase of COX-2 mRNA expression at 1 and 3 h without affecting the COX-1 mRNA level. A similar effect also observed in HMCM from cultured primary cardiac myocytes (rat neonatal cardiac myocytes). The increased COX-2 mRNA was associated with a time-dependent increase in COX-2 protein expression. COX-2 was significantly induced by VEGF (4.86 +/- 1.03-fold) and IL-1beta (3.93 +/- 0.89-fold) and slightly increased by TNF-alpha but not by FGF2, IGF-1, or PDGFs. Analysis of proteins secreted in HMCM showed increased levels of VEGF but not IL-1 beta or TNF-alpha. The HMCM-induced COX-2 expression was inhibited by the addition of an anti-VEGF neutralizing antibody. VEGF induced endothelial cell COX-2 expression by both increasing COX-2 transcription and prolonging the COX-2 mRNA half-life. Furthermore, staurosporine, a nonselective
PKC
inhibitor, prevented the induction of VEGF by hypoxia. Both a selective PKC-alpha and -beta inhibitor and an
inducible nitric oxide synthase
(NOS) inhibitor decreased the induction of COX-2 by HMCM and VEGF. Finally, HMCM-induced upregulation of COX-2 was accompanied by upregulation of PGI2 and PGE2. These results suggest that VEGF is one of the principal factors produced by hypoxic myocytes that is responsible for the induction of endothelial cell COX-2 expression. This process likely involves both
PKC
and NOS pathways. Our findings have important implications regarding the cardiac protection of COX-2 in ischemic heart disease.
...
PMID:Hypoxia induces myocyte-dependent COX-2 regulation in endothelial cells: role of VEGF. 1288 Dec 20
Ginsenoside Rg3 (Rg3) isolated from Panax ginseng relaxes vessels and exerts a cytoprotective effect. In view of the fact that nitric oxide (NO) is involved in vascular hyporeactivity and immunostimulation, the effects of total ginsenosides (GS) and Rg3 on the vascular responses and the expression of
inducible nitric oxide synthase
(
iNOS
) were investigated. Vasocontraction of endothelium-denuded aortic ring was induced by phenylephrine with or without GS or Rg3. The expression of
iNOS
was assessed by Western blot and RT-PCR analyses. NF-kappaB activation was monitored by gel shift, immunoblot and immunocytochemical analyses. Incubation of the endothelium-denuded aortic ring with GS or Rg3 inhibited phenylephrine-induced vasocontraction, which was abrogated by NOS inhibition. GS or Rg3 increased NO production in aortic rings, but Rb1, Rc, Re and Rg1 had no effect. Aortic rings obtained from rats treated with GS or Rg3 responded to phenylnephrine to a lesser extent, while producing NO to a larger extent, than those from control animals. GS or Rg3 induced
iNOS
in vascular smooth muscle. Rg3 induced
iNOS
with increase in NO production in Raw264.7 cells. Rg3 increased NF-kappaB DNA binding, whose band was supershifted with anti-p65 and anti-p50 antibodies, and elicited p65 nuclear translocation, which was accompanied by phosphorylation and degradation of I-kappaBalpha.
PKC
regulated
iNOS
induction by Rg3. In conclusion, Rg3 relaxes vessels as a consequence of NO production, to which
iNOS
induction contributes, and
iNOS
induction by Rg3 accompanied NF-kappaB activation, which involves phosphorylation and degradation of I-kappaBalpha and nuclear translocation of p65.
...
PMID:Ginsenoside Rg3 inhibits phenylephrine-induced vascular contraction through induction of nitric oxide synthase. 1453 50
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