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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: 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.

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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Effect of PA and AA on protein expressionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. Expression of the p65 subunit of NF-κB, p47 of NADPH oxidase and iNOS was analysed by Western blotting after gel-based protein separation (A). The absorbances of the bands were measured and normalized to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) protein expression (B–D). Results are expressed as means±S.E.M., for three independent experiments. P<0.05 compared with cells incubated in the absence of fatty acid; #P<0.05 compared with the equivalent PA-only-treated cells.
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Figure 8: Effect of PA and AA on protein expressionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. Expression of the p65 subunit of NF-κB, p47 of NADPH oxidase and iNOS was analysed by Western blotting after gel-based protein separation (A). The absorbances of the bands were measured and normalized to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) protein expression (B–D). Results are expressed as means±S.E.M., for three independent experiments. P<0.05 compared with cells incubated in the absence of fatty acid; #P<0.05 compared with the equivalent PA-only-treated cells.

Mentions: The protein level of the enzyme responsible for NO generation, iNOS (inducible NO synthase), was increased following incubation in the presence of PA. A combination of AA and PA significantly decreased iNOS expression compared with PA-only-treated cells (Figure 8).


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)

Effect of PA and AA on protein expressionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. Expression of the p65 subunit of NF-κB, p47 of NADPH oxidase and iNOS was analysed by Western blotting after gel-based protein separation (A). The absorbances of the bands were measured and normalized to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) protein expression (B–D). Results are expressed as means±S.E.M., for three independent experiments. P<0.05 compared with cells incubated in the absence of fatty acid; #P<0.05 compared with the equivalent PA-only-treated cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 8: Effect of PA and AA on protein expressionBRIN-BD11 cells were incubated for 24 h in the presence of different concentrations of PA and 100 μM AA. Expression of the p65 subunit of NF-κB, p47 of NADPH oxidase and iNOS was analysed by Western blotting after gel-based protein separation (A). The absorbances of the bands were measured and normalized to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) protein expression (B–D). Results are expressed as means±S.E.M., for three independent experiments. P<0.05 compared with cells incubated in the absence of fatty acid; #P<0.05 compared with the equivalent PA-only-treated cells.
Mentions: The protein level of the enzyme responsible for NO generation, iNOS (inducible NO synthase), was increased following incubation in the presence of PA. A combination of AA and PA significantly decreased iNOS expression compared with PA-only-treated cells (Figure 8).

Bottom Line: 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.

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