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Arachidonic acid actions on functional integrity and attenuation of the negative effects of palmitic acid in a clonal pancreatic β-cell line.

Keane DC, Takahashi HK, Dhayal S, Morgan NG, Curi R, Newsholme P - Clin. Sci. (2011)

Bottom Line: Experiments using specific COX and LOX (lipoxygenase) inhibitors demonstrated the importance of COX-1 activity for acute (20 min) stimulation of insulin secretion, suggesting that AA metabolites may be responsible for the insulinotropic effects.AA decreased the protein expression of iNOS (inducible NO synthase), the p65 subunit of NF-κB (nuclear factor κB) and the p47 subunit of NADPH oxidase in PA-treated cells.These findings indicate that AA has an important regulatory and protective β-cell action, which may be beneficial to function and survival in the 'lipotoxic' environment commonly associated with Type 2 diabetes mellitus.

View Article: PubMed Central - PubMed

Affiliation: UCD School of Biomolecular and Biomedical Science, UCD Conway Institute and UCD Institute of Sport and Health, UCD Dublin, Belfield, Dublin 4, Ireland.

ABSTRACT
Chronic exposure of pancreatic β-cells to saturated non-esterified fatty acids can lead to inhibition of insulin secretion and apoptosis. Several previous studies have demonstrated that saturated fatty acids such as PA (palmitic acid) are detrimental to β-cell function compared with unsaturated fatty acids. In the present study, we describe the effect of the polyunsaturated AA (arachidonic acid) on the function of the clonal pancreatic β-cell line BRIN-BD11 and demonstrate AA-dependent attenuation of PA effects. When added to β-cell incubations at 100 μM, AA can stimulate cell proliferation and chronic (24 h) basal insulin secretion. Microarray analysis and/or real-time PCR indicated significant AA-dependent up-regulation of genes involved in proliferation and fatty acid metabolism [e.g. Angptl (angiopoietin-like protein 4), Ech1 (peroxisomal Δ3,5,Δ2,4-dienoyl-CoA isomerase), Cox-1 (cyclo-oxygenase-1) and Cox-2, P<0.05]. Experiments using specific COX and LOX (lipoxygenase) inhibitors demonstrated the importance of COX-1 activity for acute (20 min) stimulation of insulin secretion, suggesting that AA metabolites may be responsible for the insulinotropic effects. Moreover, concomitant incubation of AA with PA dose-dependently attenuated the detrimental effects of the saturated fatty acid, so reducing apoptosis and decreasing parameters of oxidative stress [ROS (reactive oxygen species) and NO levels] while improving the GSH/GSSG ratio. AA decreased the protein expression of iNOS (inducible NO synthase), the p65 subunit of NF-κB (nuclear factor κB) and the p47 subunit of NADPH oxidase in PA-treated cells. These findings indicate that AA has an important regulatory and protective β-cell action, which may be beneficial to function and survival in the 'lipotoxic' environment commonly associated with Type 2 diabetes mellitus.

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Influence of PA and AA on oxidative stress and nitrite productionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. (A) ROS production was quantified using the H2DFCH probe. Results are expressed as means±S.E.M., for three independent experiments. (B) Superoxide production was measured using the DHE probe. Results are expressed as means±S.E.M., for five independent experiments.#P<0.0001 compared with the no-fatty-acid control. (C) Nitrite production was measured using the Griess Reagent kit according to the manufacturer's instructions. Results are expressed as means±S.E.M., for n=5 independent experiments. #P<0.0001 compared with the no-fatty-acid control. *P<0.0001 compared with the respective group without 100 μM AA.
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Figure 7: Influence of PA and AA on oxidative stress and nitrite productionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. (A) ROS production was quantified using the H2DFCH probe. Results are expressed as means±S.E.M., for three independent experiments. (B) Superoxide production was measured using the DHE probe. Results are expressed as means±S.E.M., for five independent experiments.#P<0.0001 compared with the no-fatty-acid control. (C) Nitrite production was measured using the Griess Reagent kit according to the manufacturer's instructions. Results are expressed as means±S.E.M., for n=5 independent experiments. #P<0.0001 compared with the no-fatty-acid control. *P<0.0001 compared with the respective group without 100 μM AA.

Mentions: An increase in the production of total ROS and superoxide was observed in BRIN-BD11 cells following incubation with 100 or 150 μM PA for 24 h. Incubation with 100 μM AA alone did not alter either the production of ROS or superoxide when compared with control. AA, however, when added in combination with 100 or 150 μM PA, significantly decreased the level of superoxide and, at 150 μM PA, significantly decreased the level of ROS (Figures 7A and 7B).


Arachidonic acid actions on functional integrity and attenuation of the negative effects of palmitic acid in a clonal pancreatic β-cell line.

Keane DC, Takahashi HK, Dhayal S, Morgan NG, Curi R, Newsholme P - Clin. Sci. (2011)

Influence of PA and AA on oxidative stress and nitrite productionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. (A) ROS production was quantified using the H2DFCH probe. Results are expressed as means±S.E.M., for three independent experiments. (B) Superoxide production was measured using the DHE probe. Results are expressed as means±S.E.M., for five independent experiments.#P<0.0001 compared with the no-fatty-acid control. (C) Nitrite production was measured using the Griess Reagent kit according to the manufacturer's instructions. Results are expressed as means±S.E.M., for n=5 independent experiments. #P<0.0001 compared with the no-fatty-acid control. *P<0.0001 compared with the respective group without 100 μM AA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2990202&req=5

Figure 7: Influence of PA and AA on oxidative stress and nitrite productionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. (A) ROS production was quantified using the H2DFCH probe. Results are expressed as means±S.E.M., for three independent experiments. (B) Superoxide production was measured using the DHE probe. Results are expressed as means±S.E.M., for five independent experiments.#P<0.0001 compared with the no-fatty-acid control. (C) Nitrite production was measured using the Griess Reagent kit according to the manufacturer's instructions. Results are expressed as means±S.E.M., for n=5 independent experiments. #P<0.0001 compared with the no-fatty-acid control. *P<0.0001 compared with the respective group without 100 μM AA.
Mentions: An increase in the production of total ROS and superoxide was observed in BRIN-BD11 cells following incubation with 100 or 150 μM PA for 24 h. Incubation with 100 μM AA alone did not alter either the production of ROS or superoxide when compared with control. AA, however, when added in combination with 100 or 150 μM PA, significantly decreased the level of superoxide and, at 150 μM PA, significantly decreased the level of ROS (Figures 7A and 7B).

Bottom Line: Experiments using specific COX and LOX (lipoxygenase) inhibitors demonstrated the importance of COX-1 activity for acute (20 min) stimulation of insulin secretion, suggesting that AA metabolites may be responsible for the insulinotropic effects.AA decreased the protein expression of iNOS (inducible NO synthase), the p65 subunit of NF-κB (nuclear factor κB) and the p47 subunit of NADPH oxidase in PA-treated cells.These findings indicate that AA has an important regulatory and protective β-cell action, which may be beneficial to function and survival in the 'lipotoxic' environment commonly associated with Type 2 diabetes mellitus.

View Article: PubMed Central - PubMed

Affiliation: UCD School of Biomolecular and Biomedical Science, UCD Conway Institute and UCD Institute of Sport and Health, UCD Dublin, Belfield, Dublin 4, Ireland.

ABSTRACT
Chronic exposure of pancreatic β-cells to saturated non-esterified fatty acids can lead to inhibition of insulin secretion and apoptosis. Several previous studies have demonstrated that saturated fatty acids such as PA (palmitic acid) are detrimental to β-cell function compared with unsaturated fatty acids. In the present study, we describe the effect of the polyunsaturated AA (arachidonic acid) on the function of the clonal pancreatic β-cell line BRIN-BD11 and demonstrate AA-dependent attenuation of PA effects. When added to β-cell incubations at 100 μM, AA can stimulate cell proliferation and chronic (24 h) basal insulin secretion. Microarray analysis and/or real-time PCR indicated significant AA-dependent up-regulation of genes involved in proliferation and fatty acid metabolism [e.g. Angptl (angiopoietin-like protein 4), Ech1 (peroxisomal Δ3,5,Δ2,4-dienoyl-CoA isomerase), Cox-1 (cyclo-oxygenase-1) and Cox-2, P<0.05]. Experiments using specific COX and LOX (lipoxygenase) inhibitors demonstrated the importance of COX-1 activity for acute (20 min) stimulation of insulin secretion, suggesting that AA metabolites may be responsible for the insulinotropic effects. Moreover, concomitant incubation of AA with PA dose-dependently attenuated the detrimental effects of the saturated fatty acid, so reducing apoptosis and decreasing parameters of oxidative stress [ROS (reactive oxygen species) and NO levels] while improving the GSH/GSSG ratio. AA decreased the protein expression of iNOS (inducible NO synthase), the p65 subunit of NF-κB (nuclear factor κB) and the p47 subunit of NADPH oxidase in PA-treated cells. These findings indicate that AA has an important regulatory and protective β-cell action, which may be beneficial to function and survival in the 'lipotoxic' environment commonly associated with Type 2 diabetes mellitus.

Show MeSH
Related in: MedlinePlus