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)

This study investigated the effects of insulin therapy, inhibition of advanced glycation end-product formation with aminoguanidine and angiotensin-converting enzyme inhibition with ramipril on diabetes-related increases in protein kinase C (PKC) activity in the streptozotocin-diabetic rat. PKC activity in the glomeruli, retina and mesenteric artery was increased by 1.5-2-fold after induction of diabetes, and this increase was maintained over 24 weeks. Treatment with insulin at 2 units or 6 units per day attenuated glomerular PKC in proportion to the level of glycohaemoglobin after 4 weeks of diabetes (r=0.68, P<0.0001). The higher dose of insulin prevented the diabetes-related increase in glomerular PKC activity, although blood glucose levels were not normalized. After 8 weeks of diabetes, ramipril completely prevented the diabetes-related increases in PKC activity in the glomeruli, retina and mesenteric artery. By contrast, aminoguanidine treatment resulted in no inhibition of glomerular PKC activity, partial inhibition of retinal PKC activity and complete inhibition of mesenteric artery PKC activity. After 24 weeks of diabetes, both aminoguanidine and ramipril prevented the diabetes-related increases in PKC activity in all three tissues, in parallel with suppression of albuminuria by both agents. Aminoguanidine also prevented diabetes-related increases in retinal permeability at 16 weeks. These results suggest that the organ-protective effects of insulin, aminoguanidine and ramipril in diabetes may be mediated, at least in part, through the differential inhibition of PKC activity in various tissues.
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PMID:Aminoguanidine and ramipril prevent diabetes-induced increases in protein kinase C activity in glomeruli, retina and mesenteric artery. 1122 10

This study investigated the role of advanced glycation end products (AGEs) in mediating protein kinase C (PKC) isoform expression in diabetic nephropathy. In vitro, vascular smooth muscle cells incubated in a high-glucose (25-mmol/l) medium demonstrated translocation and increased expression of PKC-alpha as compared with those from a low-glucose (5-mmol/l) environment. Coincubation with the cross-link breaker ALT-711 and, to a lesser extent, with aminoguanidine, an inhibitor of AGE formation, attenuated the increased expression and translocation of PKC-alpha. Streptozotocin-induced diabetic rats were randomized to no treatment, treatment with ALT-711, or treatment with aminoguanidine. Diabetes induced increases in PKC-alpha as well as in the -betaI, -betaII, and -epsilon isoforms. Treatment with ALT-711 and aminoguanidine, which both attenuate renal AGE accumulation, abrogated these increases in PKC expression. However, translocation of phosphorylated PKC-alpha from the cytoplasm to the membrane was reduced only by ALT-711. ALT-711 treatment attenuated expression of vascular endothelial growth factor and the extracellular matrix proteins, fibronectin and laminin, in association with reduced albuminuria. Aminoguanidine had no effect on VEGF expression, although some reduction of fibronectin and laminin was observed. These findings implicate AGEs as important stimuli for the activation of PKC, particularly PKC-alpha, in the diabetic kidney, which can be directly inhibited by ALT-711.
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PMID:Attenuation of extracellular matrix accumulation in diabetic nephropathy by the advanced glycation end product cross-link breaker ALT-711 via a protein kinase C-alpha-dependent pathway. 1550 73

In this paper, we investigate the role of muscarinic acetylcholine receptor (mAChR) activity in the regulation of inducible (i) nitric oxide synthase (iNOS) expression and activity. The signaling pathway involved is also examined. These experiments also provide a link between mAChR activation and the nitric oxide (NO)-dependent regulation of retinal vascular diameter. The diameter of the retinal vessels at a distance of 1 disc diameter from the center of the optic disc was measured in rats using digital retinal photography, and both iNOS-mRNA gene expression and NOS were specifically measured using RT-PCR and [U-(14)C] citrulline assays, respectively. Stimulation of M(1) and M(3) mAChR with carbachol caused an increase in vessel diameter, in iNOS-mRNA levels and in NOS activity in the retina. Aminoguanidine, an inhibitor of iNOS, attenuated all these effects. Inhibitors of phospholipase C (PLC) and protein kinase C (PKC) but not calcium/calmodulin (CaM) prevented the muscarinic-dependent increase in iNOS-mRNA levels. The results obtained suggest that the activation of mAChR increases retinal vessel diameters by increasing the production of nitric oxide (NO) through iNOS activation and iNOS-mRNA gene expression. The mechanism appears to occur secondarily to stimulation of PLC and PKC enzymatic activity.
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PMID:Inducible nitric oxide synthase subserves cholinergic vasodilation in retina. 1607 11

Uropathogenic Escherichia coli is a common cause of urinary tract infection. We determined the effects of intravesical instillation of E. coli lipopolysaccharide (LPS, endotoxin) on muscle contractions, protein kinase C (PKC) translocation, and inducible nitric oxide synthase (iNOS) expression in rat urinary bladder. The contractions of the isolated rat detrusor muscle evoked by electrical field stimulations were measured short-term (1 h) or long-term (24 h) after intravesical instillation of LPS. One hour after LPS intravesical instillation, bladder PKC-alpha translocation from cytosolic fraction to membrane fraction and endothelial (e)NOS protein was elevated, and detrusor muscle contractions were significantly increased. PKC inhibitors chelerythrine and Ro32-0432 inhibited this LPS-enhanced contractile response. Application of PKC activator beta-phorbol-12,13-dibutyrate enhanced the muscle contractions. Three hours after intravesical instillation of LPS, iNOS mRNA was detected in the bladder. Immunoblotting study also demonstrated that the induction of iNOS proteins is detected in bladder in which LPS was instilled. 24 h after intravesical instillation of LPS, PKC-alpha translocation was impaired in the bladder; LPS did not affect PKC-delta translocation. Muscle contractions were also decreased 24 h after LPS intravesical instillation. Aminoguanidine, a selective iNOS inhibitor, blocked the decrease in PKC-alpha translocation and detrusor contractions induced by LPS. These results indicate that there are different mechanisms involved in the alteration of urinary bladder contractions after short-term and long-term treatment of LPS; an iNOS-regulated PKC signaling may participate in causing the inhibition of muscle contractions in urinary bladder induced by long-term LPS treatment.
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PMID:Bladder instillation of Escherichia coli lipopolysaccharide alters the muscle contractions in rat urinary bladder via a protein kinase C-related pathway. 1618 90