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Mechanism of Cytosolic Phospholipase A(2) Activation in Ghrelin Protection of Salivary Gland Acinar Cells against Ethanol Cytotoxicity.

Slomiany BL, Slomiany A - Adv Pharmacol Sci (2010)

Bottom Line: The protective effect of ghrelin was associated with the increase in NO and PGE2, and upregulation in cytosolic phospholipase A(2) (cPLA(2)) activity and arachidonic acid (AA) release.The loss in countering effect of ghrelin occurred with cNOS inhibitor, L-NAME, as well as indomethacin and COX-1 inhibitor, SC-560, while COX-2 inhibitor, NS-398, and iNOS inhibitor, 1400W, had no effect.The effect of L-NAME was reflected in the inhibition of ghrelin-induced cell capacity for NO production, cPLA(2) activation and PGE2 generation, whereas indomethacin caused only the inhibition in PGE2.

View Article: PubMed Central - PubMed

Affiliation: Research Center, University of Medicine and Dentistry of New Jersey, 110 Bergen Street, P.O. Box 1709, Newark, NJ 07103 - 2400, USA.

ABSTRACT
Ghrelin, a peptide hormone, newly identified in oral mucosal tissues, has emerged recently as an important mediator of the processes of mucosal defense. Here, we report on the mechanism of ghrelin protection against ethanol cytotoxicity in rat sublingual salivary gland cells. The protective effect of ghrelin was associated with the increase in NO and PGE2, and upregulation in cytosolic phospholipase A(2) (cPLA(2)) activity and arachidonic acid (AA) release. The loss in countering effect of ghrelin occurred with cNOS inhibitor, L-NAME, as well as indomethacin and COX-1 inhibitor, SC-560, while COX-2 inhibitor, NS-398, and iNOS inhibitor, 1400W, had no effect. The effect of L-NAME was reflected in the inhibition of ghrelin-induced cell capacity for NO production, cPLA(2) activation and PGE2 generation, whereas indomethacin caused only the inhibition in PGE2. Moreover, the ghrelin-induced up-regulation in AA release was reflected in the cPLA(2) phosphorylation and S-nitrosylation. Inhibition in ghrelin-induced S-nitrosylation was attained with L-NAME, whereas the ERK inhibitor, PD98059, caused the blockage in cPLA(2) protein phosphorylation as well as S-nitrosylation. Thus, ghrelin protection of salivary gland cells against ethanol involves cNOS-derived NO induction of cPLA(2) activation through S-nitrosylation for the increase in AA release at the site of COX-1 action for PGE2 synthesis.

No MeSH data available.


Related in: MedlinePlus

Effect of nitric oxide synthase (a) and cyclooxygenase (b) inhibitors on the ghrelin (Gh)-induced protection of sublingual salivary gland acinar cells against ethanol (Et) cytotoxicity. The cells, preincubated with the indicated concentrations of L-NAME (LN), 200 μM D-NAME (DN) and 30 μM 1400W (14W) or indomethacin (In), SC-560 (SC) and NS-398 (NS), were treated with Gh at 0.7 μg/ml and incubated for 2 h in the presence of 3% Et. The cell-free aliquots of the medium were assayed for lactate dehydrogenase release. Values represent the means ± SD of five experiments. *P < .05 compared with that of control. **P < .05 compared with that of Et alone. ***P < .05 compared with that of Gh + Et.
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fig2: Effect of nitric oxide synthase (a) and cyclooxygenase (b) inhibitors on the ghrelin (Gh)-induced protection of sublingual salivary gland acinar cells against ethanol (Et) cytotoxicity. The cells, preincubated with the indicated concentrations of L-NAME (LN), 200 μM D-NAME (DN) and 30 μM 1400W (14W) or indomethacin (In), SC-560 (SC) and NS-398 (NS), were treated with Gh at 0.7 μg/ml and incubated for 2 h in the presence of 3% Et. The cell-free aliquots of the medium were assayed for lactate dehydrogenase release. Values represent the means ± SD of five experiments. *P < .05 compared with that of control. **P < .05 compared with that of Et alone. ***P < .05 compared with that of Gh + Et.

Mentions: Our results furthermore revealed that a concentration-dependent loss in the protective effect of ghrelin on the ethanol-induced salivary gland acinar cell toxicity was attained with cNOS inhibitor, L-NAME (Figure 2(a)) as well as cyclooxygenase (COX-1 and COX-2) inhibitor, indomethacin, and a specific COX-1 inhibitor, SC-560 (Figure 2(b)), while selective iNOS inhibitor, 1400W and a specific COX-2 inhibitor, NS-398 had no effect (Figure 2).


Mechanism of Cytosolic Phospholipase A(2) Activation in Ghrelin Protection of Salivary Gland Acinar Cells against Ethanol Cytotoxicity.

Slomiany BL, Slomiany A - Adv Pharmacol Sci (2010)

Effect of nitric oxide synthase (a) and cyclooxygenase (b) inhibitors on the ghrelin (Gh)-induced protection of sublingual salivary gland acinar cells against ethanol (Et) cytotoxicity. The cells, preincubated with the indicated concentrations of L-NAME (LN), 200 μM D-NAME (DN) and 30 μM 1400W (14W) or indomethacin (In), SC-560 (SC) and NS-398 (NS), were treated with Gh at 0.7 μg/ml and incubated for 2 h in the presence of 3% Et. The cell-free aliquots of the medium were assayed for lactate dehydrogenase release. Values represent the means ± SD of five experiments. *P < .05 compared with that of control. **P < .05 compared with that of Et alone. ***P < .05 compared with that of Gh + Et.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2990110&req=5

fig2: Effect of nitric oxide synthase (a) and cyclooxygenase (b) inhibitors on the ghrelin (Gh)-induced protection of sublingual salivary gland acinar cells against ethanol (Et) cytotoxicity. The cells, preincubated with the indicated concentrations of L-NAME (LN), 200 μM D-NAME (DN) and 30 μM 1400W (14W) or indomethacin (In), SC-560 (SC) and NS-398 (NS), were treated with Gh at 0.7 μg/ml and incubated for 2 h in the presence of 3% Et. The cell-free aliquots of the medium were assayed for lactate dehydrogenase release. Values represent the means ± SD of five experiments. *P < .05 compared with that of control. **P < .05 compared with that of Et alone. ***P < .05 compared with that of Gh + Et.
Mentions: Our results furthermore revealed that a concentration-dependent loss in the protective effect of ghrelin on the ethanol-induced salivary gland acinar cell toxicity was attained with cNOS inhibitor, L-NAME (Figure 2(a)) as well as cyclooxygenase (COX-1 and COX-2) inhibitor, indomethacin, and a specific COX-1 inhibitor, SC-560 (Figure 2(b)), while selective iNOS inhibitor, 1400W and a specific COX-2 inhibitor, NS-398 had no effect (Figure 2).

Bottom Line: The protective effect of ghrelin was associated with the increase in NO and PGE2, and upregulation in cytosolic phospholipase A(2) (cPLA(2)) activity and arachidonic acid (AA) release.The loss in countering effect of ghrelin occurred with cNOS inhibitor, L-NAME, as well as indomethacin and COX-1 inhibitor, SC-560, while COX-2 inhibitor, NS-398, and iNOS inhibitor, 1400W, had no effect.The effect of L-NAME was reflected in the inhibition of ghrelin-induced cell capacity for NO production, cPLA(2) activation and PGE2 generation, whereas indomethacin caused only the inhibition in PGE2.

View Article: PubMed Central - PubMed

Affiliation: Research Center, University of Medicine and Dentistry of New Jersey, 110 Bergen Street, P.O. Box 1709, Newark, NJ 07103 - 2400, USA.

ABSTRACT
Ghrelin, a peptide hormone, newly identified in oral mucosal tissues, has emerged recently as an important mediator of the processes of mucosal defense. Here, we report on the mechanism of ghrelin protection against ethanol cytotoxicity in rat sublingual salivary gland cells. The protective effect of ghrelin was associated with the increase in NO and PGE2, and upregulation in cytosolic phospholipase A(2) (cPLA(2)) activity and arachidonic acid (AA) release. The loss in countering effect of ghrelin occurred with cNOS inhibitor, L-NAME, as well as indomethacin and COX-1 inhibitor, SC-560, while COX-2 inhibitor, NS-398, and iNOS inhibitor, 1400W, had no effect. The effect of L-NAME was reflected in the inhibition of ghrelin-induced cell capacity for NO production, cPLA(2) activation and PGE2 generation, whereas indomethacin caused only the inhibition in PGE2. Moreover, the ghrelin-induced up-regulation in AA release was reflected in the cPLA(2) phosphorylation and S-nitrosylation. Inhibition in ghrelin-induced S-nitrosylation was attained with L-NAME, whereas the ERK inhibitor, PD98059, caused the blockage in cPLA(2) protein phosphorylation as well as S-nitrosylation. Thus, ghrelin protection of salivary gland cells against ethanol involves cNOS-derived NO induction of cPLA(2) activation through S-nitrosylation for the increase in AA release at the site of COX-1 action for PGE2 synthesis.

No MeSH data available.


Related in: MedlinePlus