Limits...
Exenatide (a GLP-1 agonist) improves the antioxidative potential of in vitro cultured human monocytes/macrophages.

Bułdak Ł, Łabuzek K, Bułdak RJ, Machnik G, Bołdys A, Okopień B - Naunyn Schmiedebergs Arch. Pharmacol. (2015)

Bottom Line: According to our findings, exenatide reduced ROS and malondialdyhyde (MDA) level by decreasing the expression of ROS-generating NADPH oxidase and by increasing the expression and activities of SOD and GSH-Px.We also showed that this effect was significantly inhibited by exendin 9-39 (a GLP-1 antagonist) and blocked by H89.This effect relied on the stimulation of GLP-1 receptor.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Medykow 18, 40-752, Katowice, Poland, lbuldak@gmail.com.

ABSTRACT
Macrophages are dominant cells in the pathogenesis of atherosclerosis. They are also a major source of reactive oxygen species (ROS). Oxidative stress, which is particularly high in subjects with diabetes, is responsible for accelerated atherosclerosis. Novel antidiabetic drugs (e.g., glucagon-like peptide-1 (GLP-1) agonists) were shown to reduce ROS level. Therefore, we conceived a study to evaluate the influence of exenatide, a GLP-1 agonist, on redox status in human monocytes/macrophages cultured in vitro, which may explain the beneficial effects of incretin-based antidiabetic treatment. Human macrophages obtained from 10 healthy volunteers were in vitro subjected to the treatment with GLP-1 agonist (exenatide) in the presence of lipopolysaccharide (LPS), antagonist of GLP-1 receptors (exendin 9-39), or protein kinase A inhibitor (H89). Afterwards, reactive oxygen species, malondialdehyde level, NADPH oxidase, and antioxidative enzymes [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase] expression was evaluated. Finally, we estimated the activity of the abovementioned enzymes in the presence of H89. According to our findings, exenatide reduced ROS and malondialdyhyde (MDA) level by decreasing the expression of ROS-generating NADPH oxidase and by increasing the expression and activities of SOD and GSH-Px. We also showed that this effect was significantly inhibited by exendin 9-39 (a GLP-1 antagonist) and blocked by H89. Exenatide improved the antioxidative potential and reduced oxidative stress in cultured human monocytes/macrophages, and this finding may be responsible for the pleiotropic effects of incretin-based therapies. This effect relied on the stimulation of GLP-1 receptor.

No MeSH data available.


Related in: MedlinePlus

The influence of LPS, exenatide, exendin 9-39, and H89 (for Western blot only) on the expression of glutathione peroxidase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the glutathione peroxidase. *p < 0.05, **p < 0.01, ***p < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4537507&req=5

Fig5: The influence of LPS, exenatide, exendin 9-39, and H89 (for Western blot only) on the expression of glutathione peroxidase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the glutathione peroxidase. *p < 0.05, **p < 0.01, ***p < 0.001

Mentions: LPS increased the quantity of mRNA and protein of SOD by 30 and 41 % without affecting its activity. This discrepancy between the expression level and lack of enzymatic activity may result from the decrease in antioxidative potential during LPS stimulation, which is antagonized in cells by an increase in the production of enzymes. Exenatide alone showed only a trend toward an increase in the expression of mRNA and protein but modestly increased the activity of SOD by 15 %. The most interesting results were observed in macrophages treated with exenatide plus LPS. Compared to cells treated only with LPS, a minute increase in mRNA level was seen (by 18 %), accompanied by a strong increase in protein synthesis (by 36 %), resulting in doubling the activity of SOD. Exendin 9-39 prevented a rise in mRNA and protein level in macrophages treated with LPS and exenatide compared to cells exposed only to LPS. SOD activity was reduced by exendin 9-39 (by 38 %) in cells subjected to LPS plus exenatide but remained elevated by 25 % compared to cultures treated with LPS. The incomplete inhibition of the activity by exendin 9-39 may result from the insufficient blockade of GLP-1 receptors (i.e., competition between agonist and antagonist).


Exenatide (a GLP-1 agonist) improves the antioxidative potential of in vitro cultured human monocytes/macrophages.

Bułdak Ł, Łabuzek K, Bułdak RJ, Machnik G, Bołdys A, Okopień B - Naunyn Schmiedebergs Arch. Pharmacol. (2015)

The influence of LPS, exenatide, exendin 9-39, and H89 (for Western blot only) on the expression of glutathione peroxidase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the glutathione peroxidase. *p < 0.05, **p < 0.01, ***p < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4537507&req=5

Fig5: The influence of LPS, exenatide, exendin 9-39, and H89 (for Western blot only) on the expression of glutathione peroxidase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the glutathione peroxidase. *p < 0.05, **p < 0.01, ***p < 0.001
Mentions: LPS increased the quantity of mRNA and protein of SOD by 30 and 41 % without affecting its activity. This discrepancy between the expression level and lack of enzymatic activity may result from the decrease in antioxidative potential during LPS stimulation, which is antagonized in cells by an increase in the production of enzymes. Exenatide alone showed only a trend toward an increase in the expression of mRNA and protein but modestly increased the activity of SOD by 15 %. The most interesting results were observed in macrophages treated with exenatide plus LPS. Compared to cells treated only with LPS, a minute increase in mRNA level was seen (by 18 %), accompanied by a strong increase in protein synthesis (by 36 %), resulting in doubling the activity of SOD. Exendin 9-39 prevented a rise in mRNA and protein level in macrophages treated with LPS and exenatide compared to cells exposed only to LPS. SOD activity was reduced by exendin 9-39 (by 38 %) in cells subjected to LPS plus exenatide but remained elevated by 25 % compared to cultures treated with LPS. The incomplete inhibition of the activity by exendin 9-39 may result from the insufficient blockade of GLP-1 receptors (i.e., competition between agonist and antagonist).

Bottom Line: According to our findings, exenatide reduced ROS and malondialdyhyde (MDA) level by decreasing the expression of ROS-generating NADPH oxidase and by increasing the expression and activities of SOD and GSH-Px.We also showed that this effect was significantly inhibited by exendin 9-39 (a GLP-1 antagonist) and blocked by H89.This effect relied on the stimulation of GLP-1 receptor.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Medykow 18, 40-752, Katowice, Poland, lbuldak@gmail.com.

ABSTRACT
Macrophages are dominant cells in the pathogenesis of atherosclerosis. They are also a major source of reactive oxygen species (ROS). Oxidative stress, which is particularly high in subjects with diabetes, is responsible for accelerated atherosclerosis. Novel antidiabetic drugs (e.g., glucagon-like peptide-1 (GLP-1) agonists) were shown to reduce ROS level. Therefore, we conceived a study to evaluate the influence of exenatide, a GLP-1 agonist, on redox status in human monocytes/macrophages cultured in vitro, which may explain the beneficial effects of incretin-based antidiabetic treatment. Human macrophages obtained from 10 healthy volunteers were in vitro subjected to the treatment with GLP-1 agonist (exenatide) in the presence of lipopolysaccharide (LPS), antagonist of GLP-1 receptors (exendin 9-39), or protein kinase A inhibitor (H89). Afterwards, reactive oxygen species, malondialdehyde level, NADPH oxidase, and antioxidative enzymes [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase] expression was evaluated. Finally, we estimated the activity of the abovementioned enzymes in the presence of H89. According to our findings, exenatide reduced ROS and malondialdyhyde (MDA) level by decreasing the expression of ROS-generating NADPH oxidase and by increasing the expression and activities of SOD and GSH-Px. We also showed that this effect was significantly inhibited by exendin 9-39 (a GLP-1 antagonist) and blocked by H89. Exenatide improved the antioxidative potential and reduced oxidative stress in cultured human monocytes/macrophages, and this finding may be responsible for the pleiotropic effects of incretin-based therapies. This effect relied on the stimulation of GLP-1 receptor.

No MeSH data available.


Related in: MedlinePlus