curcumin and chelerythrine

Curcumin is an active principle contained in rhizome of Curcuma longa, and it has been recently mentioned to show affinity to muscarinic M-1 cholinoceptors (M(1)-mAChR). In the present study, we found that curcumin caused a concentration-dependent increase of muscle tone in urinary bladder isolated from Wistar rats. This action was inhibited by pirenzepine at concentration enough to block M(1)-mAChR. In radioligand-binding assay, specific binding of [(3)H]-oxotremorine (OXO-M) in the rat bladder homogenates was also displaced by curcumin in a concentration-dependent manner. In the presence of inhibitors for PLC-PKC pathway, either U73122 (phospholipase C inhibitor) or chelerythrine (protein kinase C inhibitor), curcumin-stimulated contraction in urinary bladder was markedly reduced. In conclusion, the obtained results suggest that curcumin can activate M(1)-mAChR at concentrations lower than to scavenge free radicals to increase of muscle tone in urinary bladder through PLC-PKC pathway.

Topics: Animals; Benzophenanthridines; Curcumin; Estrenes; In Vitro Techniques; Male; Muscarinic Agonists; Muscle Contraction; Muscle, Smooth; Protein Kinase C; Pyrrolidinones; Radioligand Assay; Rats; Rats, Wistar; Receptor, Muscarinic M1; Type C Phospholipases; Urinary Bladder

Human esophageal epithelial cells play a key role in esophageal inflammation in response to acidic pH during gastroesophageal reflux disease (GERD), increasing secretion of IL-6 and IL-8. The mechanisms underlying IL-6 and IL-8 expression and secretion in esophageal epithelial cells after acid stimulation are not well characterized. We investigated the role of PKC, MAPK, and NF-kappaB signaling pathways and transcriptional regulation of IL-6 and IL-8 expression in HET-1A cells exposed to acid. Exposure of HET-1A cells to pH 4.5 induced NF-kappaB activity and enhanced IL-6 and IL-8 secretion and mRNA and protein expression. Acid stimulation of HET-1A cells also resulted in activation of MAPKs and PKC (alpha and epsilon). Curcumin, as well as inhibitors of NF-kappaB (SN-50), PKC (chelerythrine), and p44/42 MAPK (PD-098059) abolished the acid-induced expression of IL-6 and IL-8. The JNK inhibitor SP-600125 blocked expression/secretion of IL-6 but only partially attenuated IL-8 expression. The p38 MAPK inhibitor SB-203580 did not inhibit IL-6 expression but exerted a stronger inhibitory effect on IL-8 expression. Together, these data demonstrate that 1) acid is a potent inducer of IL-6 and IL-8 production in HET-1A cells; 2) MAPK and PKC signaling play a key regulatory role in acid-mediated IL-6 and IL-8 expression via NF-kappaB activation; and 3) the anti-inflammatory plant compound curcumin inhibits esophageal activation in response to acid. Thus IL-6 and IL-8 expression by acid may contribute to the pathobiology of mucosal injury in GERD, and inhibition of the NF-kappaB/proinflammatory cytokine pathways may emerge as important therapeutic targets for treatment of esophageal inflammation.

Topics: Anthracenes; Anti-Inflammatory Agents; Benzophenanthridines; Cell Line; Curcumin; Enzyme Activation; Epithelial Cells; Esophagus; Flavonoids; Humans; Hydrogen-Ion Concentration; Imidazoles; Interleukin-6; Interleukin-8; Mitogen-Activated Protein Kinases; Mucous Membrane; NF-kappa B; Peptides; Protein Kinase C; Protein Kinase Inhibitors; Pyridines; Signal Transduction; Telomerase; Time Factors; Transcription, Genetic; Up-Regulation

Many infants who undergo cardiac surgery have a congenital cyanotic defect where the heart is chronically perfused with hypoxemic blood. Infant hearts adapt to chronic hypoxemia by activation of intracellular protein kinase signal transduction pathways. However, the involvement of heat shock protein 70 in adaptation to chronic hypoxemia and its role in protein kinase signaling pathways is unknown. We determined expression of message and subcellular protein distribution for inducible (Hsp70i) and constitutive heat shock protein 70 (Hsc70) in chronically hypoxic and normoxic infant human and rabbit hearts and their relationship to protein kinases. In chronically hypoxic human and rabbit hearts message levels for Hsp70i were elevated 4- to 5-fold compared with normoxic hearts, Hsp70i protein was redistributed from the particulate to the cytosolic fraction. In normoxic infants Hsp70i protein was distributed almost equally between the cytosolic and particulate fractions. Hsc70 message and subcellular distribution of Hsc70 protein were unaffected by chronic hypoxia. We then determined if protein kinases influence Hsp70i protein subcellular distribution. In rabbit hearts SB203580 and chelerythrine reduced Hsp70i message levels, whereas SB203580, chelerythrine, and curcumin reversed the subcellular redistribution of Hsp70i protein caused by chronic hypoxia, with no effect in normoxic hearts, indicating regulation of Hsp70i message and subcellular distribution of Hsp70i protein in chronically hypoxic rabbit hearts is influenced by protein kinase C and mitogen-activated protein kinases, specifically p38 MAPK and JNK. We conclude the Hsp70 signal transduction pathway plays an important role in adaptation of infant human and rabbit hearts to chronic hypoxemia.

Topics: Alkaloids; Animals; Benzophenanthridines; Blotting, Western; Curcumin; Electrophoresis, Polyacrylamide Gel; Enzyme Inhibitors; Female; Heart; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; HSC70 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Humans; Hypoxia; Imidazoles; Immunohistochemistry; Infant; Infant, Newborn; Ischemia; Male; MAP Kinase Signaling System; Membrane Proteins; Myocardium; Phenanthridines; Protein Kinase C; Pyridines; Rabbits; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Time Factors