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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)
Fractalkine (FKN) has been implicated in modulation of angiogenesis and vascular inflammation, but the underlying mechanism has not been elucidated. We have investigated the molecular mechanism by which FKN regulates angiogenesis. We found that recombinant FKN increases in vitro proliferation, migration, and tube formation of human umbilical vein endothelial cells and stimulates in vivo angiogenesis. FKN-induced angiogenesis was accompanied by phosphorylation of ERK, Akt, and endothelial nitric oxide (NO) synthase (
eNOS
), as well as an increase in NO production. These biochemical events and angiogenesis were completely inhibited by the G protein-coupled receptor inhibitor pertussis toxin. Inhibitors of
Raf-1
, MEK, phosphatidylinositol 3-kinase (PI3K), and
eNOS
or transfection with dominant-negative forms of ERK and Akt significantly suppressed the angiogenic activity of FKN. However, inhibitors of
Raf-1
and MEK or a dominant-negative ERK mutant blocked FKN-induced ERK, but not Akt and
eNOS
, phosphorylation. The PI3K inhibitor and a dominant-negative mutant of Akt suppressed Akt and
eNOS
phosphorylation and NO production. Our results demonstrated that FKN stimulated angiogenesis by activating the
Raf-1
/MEK/ERK and PI3K/Akt/
eNOS
/NO signal pathways via the G protein-coupled receptor CX3CR1, indicating that two pathways are required for full angiogenic activity of FKN. This study suggests that FKN may play an important role in the pathophysiological process of inflammatory angiogenesis.
...
PMID:Fractalkine stimulates angiogenesis by activating the Raf-1/MEK/ERK- and PI3K/Akt/eNOS-dependent signal pathways. 1687 65
Nitric oxide (NO) has both prooxidant and antioxidant activities in the endothelium; however, the molecular mechanisms involved are still a matter of controversy. PGC-1alpha [peroxisome proliferators-activated receptor (PPAR) gamma coactivator 1-alpha] induces the expression of several members of the mitochondrial reactive oxygen species (ROS) detoxification system. Here, we show that NO regulates this system through the modulation of PGC-1alpha expression. Short-term (<12 h) treatment of endothelial cells with NO donors down-regulates PGC-1alpha expression, whereas long-term (>24 h) treatment up-regulates it. Treatment with the NOS inhibitor l-NAME has the opposite effect. Down-regulation of PGC-1alpha by NO is mediated by
protein kinase
G (PKG). It is blocked by the soluble guanylate cyclase (sGC) inhibitor ODQ and the PKG inhibitor KT5823, and mimicked by the cGMP analog 8-Br-cGMP. Changes in PGC-1alpha expression are in all cases paralleled by corresponding variations in the mitochondrial ROS detoxification system. Cells that transiently overexpress PGC-1alpha from the cytomeglovirus (CMV) promoter respond poorly to NO donors. Analysis of tissues from
eNOS
(-/-) mice showed reduced levels of PGC-1alpha and the mitochondrial ROS detoxification system. These data suggest that NO can regulate the mitochondrial ROS detoxification system both positively and negatively through PGC-1alpha.
...
PMID:Nitric oxide regulates mitochondrial oxidative stress protection via the transcriptional coactivator PGC-1alpha. 1689 21
Interleukin 6 (IL-6) is an independent predictor of type 2 diabetes and cardiovascular disease and is correlated with insulin resistance. Insulin stimulates nitric oxide (NO) production through the IRS-1/PI3-kinase/Akt/
eNOS
pathway (where IRS-1 is insulin receptor substrate 1, PI3-kinase is phosphatidylinositol 3-kinase, and
eNOS
is endothelial NO synthase). We asked if IL-6 affects insulin vasodilator action both in human umbilical vein endothelial cells (HUVEC) and in the aortas of C57BL/6J mice and whether this inhibitory effect was caused by increased Ser phosphorylation of IRS-1. We observed that IL-6 increased IRS-1 phosphorylation at Ser(312) and Ser(616); these effects were paralleled by increased Jun N-terminal
protein kinase
(JNK) and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and reversed by JNK and ERK1/2 inhibition. In addition, IL-6 treatment resulted in impaired IRS-1 phosphorylation at Tyr(612), a site essential for engaging PI3-kinase. Furthermore, IL-6 treatment reduced insulin-stimulated phosphorylation of
eNOS
at the stimulatory Ser(1177) site and impaired insulin-stimulated
eNOS
dephosphorylation at the inhibitory Thr(495) site. Insulin-stimulated
eNOS
activation and NO production were also inhibited by IL-6; these effects were reversed by inhibition of JNK and ERK1/2. Treatment of C57BL/6J mice with IL-6 resulted in impaired insulin-dependent activation of the Akt/
eNOS
pathway in the aorta as a result of JNK and ERK1/2 activation. Our data suggest that IL-6 impairs the vasodilator effects of insulin that are mediated by the IRS-1/PI3-kinase/Akt/
eNOS
pathway through activation of JNK and ERK1/2.
...
PMID:Interleukin-6 impairs the insulin signaling pathway, promoting production of nitric oxide in human umbilical vein endothelial cells. 1724 12
In Alzheimer disease (AD), increased
nitric oxide synthase 3
(
NOS3
) expression correlates with apoptosis in cortical neurons and colocalizes with amyloid precursor protein (APP)-amyloid beta (Abeta) deposits in the brain. In the present study we examined the potential role of
NOS3
in relation to AD-type neurodegeneration using an in vivo model of gene delivery. Long Evans rat pups were given a single intracerebral injection of recombinant plasmid DNA containing the human
NOS3
cDNA (p-hNOS3) or the luciferase (p-Luc) gene as a negative control, and complexed with polyamine reagent. Overexpression of
NOS3
in the brain increased the levels of APP, APP-Abeta, p53, Tau, glial fibrillary acidic protein, and peroxisome proliferator activated receptors (PPAR) delta and gamma and decreased the levels of Hu (neuronal marker) mRNA, phosphorylated
glycogen synthase kinase
3beta, ATP synthase, and choline acetyltransferase expression as demonstrated by real-time quantitative reverse-transcribed polymerase chain reaction, Western blot analysis, or immunohistochemical staining. These effects of
NOS3
overexpression were accompanied by increased single-stranded DNA immunoreactivity, reflecting DNA damage. The results suggest that increased cerebral expression of
NOS3
causes several molecular abnormalities related to AD-type neurodegeneration, including oxidative stress, mitochondrial dysfunction, and impaired acetylcholine homeostasis. The coexisting increases in PPAR-delta and -gamma expression suggest that the adverse effects of
NOS3
overexpression may be abated by PPAR agonist treatment.
...
PMID:Nitric oxide synthase 3-mediated neurodegeneration after intracerebral gene delivery. 1741 18
Vasodilatation is a vital mechanism of systemic blood flow regulation that occurs during periods of increased energy demand. The AMP-dependent
protein kinase
(AMPK) is a serine/threonine kinase that is activated by conditions that increase the AMP-to-ATP ratio, such as exercise and metabolic stress. We hypothesized that AMPK could trigger vasodilatation and participate in blood flow regulation. Rings of thoracic aorta were isolated from C57Bl6 mice and mice deficient in the AMPK catalytic alpha1 (AMPKalpha1-/-) or alpha2 (AMPKalpha2-/-) subunit and their littermate controls, and mounted in an organ bath. Aortas were preconstricted with phenylephrine (1 microM) and activation of AMPK was induced by addition of increasing concentrations of 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR). AICAR (0.1-3 mM) dose-dependently induced relaxation of precontracted C57BL6, AMPKalpha1+/+ and alpha2+/+ aorta (P<0.001, n=5-7 per group). This AICAR induced vasorelaxation was not inhibited by the addition of adenosine receptor antagonists. Moreover, when aortic rings were freed of endothelium by gentle rubbing, AICAR still induced aortic ring relaxation, suggesting a direct effect of AICAR on smooth muscle cells. When aortic rings were pretreated with L-NMMA (30 microM) to inhibit nitric oxide synthase activity, AICAR still induced relaxation. Western blot analysis of C57Bl6 mice denuded aorta showed that AMPK was phosphorylated after incubation with AICAR and that AMPKalpha1 was the main catalytic subunit expressed. Finally, AICAR-induced relaxation of aortic rings was completely abolished in AMPKalpha1-/- but not AMPKalpha2-/- mice. Taken together, the results show that activation of AMPKalpha1 but not AMPKalpha2 is able to induce aortic relaxation in mice, in an endothelium- and
eNOS
-independent manner.
...
PMID:Activation of AMP kinase alpha1 subunit induces aortic vasorelaxation in mice. 1744 19
Thromboxane (TX) A(2) plays a central role in hemostasis, regulating platelet activation status and vascular tone. We have recently established that the TP beta isoform of the human TXA(2) receptor (TP) undergoes rapid, agonist-induced homologous desensitization of signalling largely through a G protein-coupled receptor kinase (GRK) 2/3-dependent mechanism with a lesser role for
protein kinase
(PK) C. Herein, we investigated the mechanism of desensitization of signalling by the TP alpha isoform. TP alpha undergoes profound agonist-induced desensitization of signalling (intracellular calcium mobilization and inositol 1,4,5 trisphosphate generation) in response to the TXA(2) mimetic U46619 but, unlike that of TP beta, this is independent of GRKs. Similar to TP beta, TP alpha undergoes partial agonist-induced desensitization that occurs through a GF 109203X-sensitive, PKC mechanism where Ser(145) within intracellular domain (IC)(2) represents the key phospho-target. TP alpha also undergoes more profound sustained PKC- and PKG-dependent desensitization where Thr(337) and Ser(331), respectively, within its unique C-tail domain were identified as the phospho-targets. Desensitization was impaired by the nitric oxide synthase (NOS), soluble guanylyl cyclase (sGC) and PKG inhibitors L-NAME, LY 83583 and KT5823, respectively, indicating that homologous desensitization of TP alpha involves nitric oxide generation and signalling. Consistent with this, U46619 led to rapid phosphorylation/activation of endogenous
eNOS
. Collectively, data herein suggest a mechanism whereby agonist-induced PKC phosphorylation of Ser(145) partially and transiently impairs TP alpha signalling while PKG- and PKC-phosphorylation at both Ser(331) and Thr(337), respectively, within its C-tail domain profoundly desensitizes TP alpha, effectively terminating its signalling. Hence, in addition to the agonist-mediated PKC feedback mechanism, U46619-activation of the NOS/sGC/PKG pathway plays a significant role in inducing homologous desensitization of TP alpha.
...
PMID:Homologous desensitization of signalling by the alpha (alpha) isoform of the human thromboxane A2 receptor: a specific role for nitric oxide signalling. 1746 90
To estimate the state of different parts of intracellular signaling system associated with NO production after a2-adrenoreceptors stimulation under endothelial dysfunction in 22 patients with diabetic foot, the inhibitory analysis of clophelin-induced platelets aggregation modulation by administration of
eNOS
stimulator (L-arginin) and inhibitor (L-NAME), modulator of Ca-calmoduline (triphtazine), guanilate cyclase stimulator (sodium nitroprusside), inhibitors of phosphodiesterases (theophillinum) and
protein kinase A
(butamide). It was shown that endothelial dysfunction in patients with diabetic foot is associated with alteration of adrenoreactivity and inhibition of
eNOS
, guanilate cyclase,
protein kinase A
and stimulation of phosphodiesterases activity.
...
PMID:[State of intracellular signaling systems in endothelial dysfunction]. 1830 34
Nitric Oxide (NO) can be cytotoxic or cytoprotective depending on amount and location of its generation.
eNOS
is important in modulating blood flow and is allosterically regulated. Inducible NOS (iNOS) tends to produce large quantities of NO leading to cell injury. We studied the role and regulation of NOS in carbon tetrachloride (CCl(4))-induced hepatotoxicity in newborn rats.
eNOS
was expressed before birth, significantly increased on day of life (DOL) 2 reaching a maximum at DOL-20. iNOS was absent at all ages. CCl(4) treatment resulted in hepatic injury in newborn rats and damage was intensified by co-administration of a general NOS inhibitor. CCl(4) treatment increased
eNOS
activity without change in mRNA or protein levels. Administration of CCl(4) resulted in an increase in phosphorylation of threonine
protein kinase
(Akt) and
eNOS
, associated with an increase in
eNOS
activity. Administration of wortmannin (phosphatidylinositol 3-kinase, PI3 K, inhibitor) attenuated the phosphorylation of Akt and
eNOS
and reduced
eNOS
activity. Co-administration of CCl(4) and wortmannin potentiated the degree of hepatic injury. iNOS was not detectable in CCl(4)-treated rats. This data indicates a protective role for
eNOS
in CCl(4)-induced hepatotoxicity in newborn rats with protection accomplished by activation of
eNOS
via posttranslational modification of the PI3 K/Akt signaling pathway.
...
PMID:Posttranslational activation of endothelial nitric oxide synthase attenuates carbon tetrachloride-induced hepatotoxicity in newborn rats. 1831
The purpose of this study was to examine the modulating effects of
protein kinase A
(
PKA
) on the performance of signal systems triggered while activating alpha2-adrenoceptors and
eNOS
in the course of a wound process in patients with type 2 diabetes mellitus. Patients with the diabetic foot were shown to have impaired adrenergic responsiveness, accompanied by reduced
eNOS
activity and
PKA
inhibition. The positive therapeutic effect was noted with the increased stimulating effect of the
PKA
system on PKG on days 3 to 5 and on
eNOS
on days 10-14 of therapy. The preserving
eNOS
activity deficit was compensated for by the
PKA
-induced increase in PKG stimulation. The modulating effects of
PKA
are a compensatory intracellular mechanism of adaptation when NO production is decreased, which may be used to develop new therapeutic corrections of the dysregeneratory syndrome.
...
PMID:[Modulating effects of protein kinase A on intracellular signal systems in the course of skin wound healing in patients with diabetes mellitus]. 1845 57
To date, there is an increasing interest in the nitric oxide (NO) pathway as a potential pharmacological target to treat male lower urinary tract symptomatology (LUTS). In the transition zone of the human prostate, a dense nitrinergic innervation has been shown of the fibromuscular stroma, glandular epithelium and blood vessels. The expression of key proteins of the NO pathway, such as the endothelial and neuronal nitric oxide synthase (
eNOS
, nNOS), cGMP-degrading phosphodiesterase type 5 (PDE5) and cGMP-binding
protein kinase
(cGK), has also been demonstrated. The hypothesis that an impaired NO/cGMP-signaling may contribute to the pathophysiology of benign prostatic hyperplasia (BPH) is supported by the results from randomized, placebo-controlled clinical studies, indicating that NO donor drugs and PDE5-inhibitors sildenafil, tadalafil and vardenafil may be useful to treat storage and voiding dysfunctions resulting from LUTS in men. Thus, given a potential role of the NO-pathway in the prostate and/or in other parts of lower urinary tract (e.g. bladder), the enhancement of the NO signaling by NO donor drugs, PDE5 inhibitors or activators of the soluble guanylyl cyclase (sGC) may represent a new therapeutic strategy for the treatment of LUTS. This review serves to focus on the role of NO and the NO-dependent signaling in the control of smooth muscle function in the human prostate. Results from clinical trials in men with LUTS/BPH are also discussed.
...
PMID:The nitric oxide pathway in the human prostate: clinical implications in men with lower urinary tract symptoms. 1860 96
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