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 catalase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the catalase. *p < 0.05, **p < 0.01, ***p < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4537507&req=5

Fig6: The influence of LPS, exenatide, exendin 9-39, and H89 (for Western blot only) on the expression of catalase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the catalase. *p < 0.05, **p < 0.01, ***p < 0.001

Mentions: LPS reduced mRNA and protein expression for glutathione peroxidase by 25 and 40 %, respectively. These findings were accompanied by a decrease in GSH-Px activity by 20 %. Exenatide did not influence the expression of GSH-Px mRNA and protein, but it elevated the GSH-Px activity by 61 %. Cells treated with LPS plus exenatide increased the expression of GSH-Px mRNA by 42 % and protein by 79 %. In this setting, the activity of GSH-Px was higher than in control (by 21 %) and cells treated with LPS (by 33 %). On the other hand, it was lower than in cells treated with exenatide (by 22 %). GLP-1 antagonist reduced the impact of LPS plus exenatide on the expression of GSH-Px mRNA (by 25 %) and protein (by 34 %), but the expression levels remained higher than in cells treated with LPS (by 39 % for mRNA and 102 % for protein). Furthermore, exendin 9-39 reduced the activity of GSH-Px in macrophages treated with LPS plus exenatide (by 41 %). These findings showed that exenatide elevated the activity of GSH-Px without influencing the level of expression of the enzyme. LPS treatment was associated with a decrease in enzymatic activity and GSH-Px expression. Co-stimulation with LPS and exenatide was associated with an increase in enzymatic activity connected with a rise in mRNA and protein expression, which supports the idea of an improvement of antioxidative potential of macrophages followed by exenatide.


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 catalase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the catalase. *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

Fig6: The influence of LPS, exenatide, exendin 9-39, and H89 (for Western blot only) on the expression of catalase assessed by a RT-QPCR and b Western blot analysis and c on the activity of the catalase. *p < 0.05, **p < 0.01, ***p < 0.001
Mentions: LPS reduced mRNA and protein expression for glutathione peroxidase by 25 and 40 %, respectively. These findings were accompanied by a decrease in GSH-Px activity by 20 %. Exenatide did not influence the expression of GSH-Px mRNA and protein, but it elevated the GSH-Px activity by 61 %. Cells treated with LPS plus exenatide increased the expression of GSH-Px mRNA by 42 % and protein by 79 %. In this setting, the activity of GSH-Px was higher than in control (by 21 %) and cells treated with LPS (by 33 %). On the other hand, it was lower than in cells treated with exenatide (by 22 %). GLP-1 antagonist reduced the impact of LPS plus exenatide on the expression of GSH-Px mRNA (by 25 %) and protein (by 34 %), but the expression levels remained higher than in cells treated with LPS (by 39 % for mRNA and 102 % for protein). Furthermore, exendin 9-39 reduced the activity of GSH-Px in macrophages treated with LPS plus exenatide (by 41 %). These findings showed that exenatide elevated the activity of GSH-Px without influencing the level of expression of the enzyme. LPS treatment was associated with a decrease in enzymatic activity and GSH-Px expression. Co-stimulation with LPS and exenatide was associated with an increase in enzymatic activity connected with a rise in mRNA and protein expression, which supports the idea of an improvement of antioxidative potential of macrophages followed by exenatide.

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