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The ATP Receptors P2X7 and P2X4 Modulate High Glucose and Palmitate-Induced Inflammatory Responses in Endothelial Cells.

Sathanoori R, Swärd K, Olde B, Erlinge D - PLoS ONE (2015)

Bottom Line: Both P2X7 and P2X4 antagonists inhibited high glucose and palmitate-induced interleukin-6 levels with the former having a significant effect on interleukin-8 and cyclooxygenase-2.The effect of the antagonists was confirmed with siRNA knockdown of the receptors.In addition, P2X7 mediated both high glucose and palmitate-induced increase in reactive oxygen species levels and decrease in endothelial nitric oxide synthase.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden.

ABSTRACT
Endothelial cells lining the blood vessels are principal players in vascular inflammatory responses. Dysregulation of endothelial cell function caused by hyperglycemia, dyslipidemia, and hyperinsulinemia often result in impaired vasoregulation, oxidative stress, inflammation, and altered barrier function. Various stressors including high glucose stimulate the release of nucleotides thus initiating signaling via purinergic receptors. However, purinergic modulation of inflammatory responses in endothelial cells caused by high glucose and palmitate remains unclear. In the present study, we investigated whether the effect of high glucose and palmitate is mediated by P2X7 and P2X4 and if they play a role in endothelial cell dysfunction. Transcript and protein levels of inflammatory genes as well as reactive oxygen species production, endothelial-leukocyte adhesion, and cell permeability were investigated in human umbilical vein endothelial cells exposed to high glucose and palmitate. We report high glucose and palmitate to increase levels of extracellular ATP, expression of P2X7 and P2X4, and inflammatory markers. Both P2X7 and P2X4 antagonists inhibited high glucose and palmitate-induced interleukin-6 levels with the former having a significant effect on interleukin-8 and cyclooxygenase-2. The effect of the antagonists was confirmed with siRNA knockdown of the receptors. In addition, P2X7 mediated both high glucose and palmitate-induced increase in reactive oxygen species levels and decrease in endothelial nitric oxide synthase. Blocking P2X7 inhibited high glucose and palmitate-induced expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 as well as leukocyte-endothelial cell adhesion. Interestingly, high glucose and palmitate enhanced endothelial cell permeability that was dependent on both P2X7 and P2X4. Furthermore, antagonizing the P2X7 inhibited high glucose and palmitate-mediated activation of p38-mitogen activated protein kinase. These findings support a novel role for P2X7 and P2X4 coupled to induction of inflammatory molecules in modulating high glucose and palmitate-induced endothelial cell activation and dysfunction.

No MeSH data available.


Related in: MedlinePlus

P2X7 mediates high glucose and palmitate-induced increase in leukocyte adhesion.HUVEC monolayers seeded in 96-well plates were exposed to high glucose and palmitate in the presence or absence of receptor antagonists for 48 h. Leukocytes labeled with LeukoTracker were allowed to attach for 90 mins after which adherent cells were lysed and the fluorescence was measured at an excitation and emission wavelengths of 480 nm and 520 nm, respectively. n = 4 independent experiments each done in replicates; *p ≤ 0.05.
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pone.0125111.g008: P2X7 mediates high glucose and palmitate-induced increase in leukocyte adhesion.HUVEC monolayers seeded in 96-well plates were exposed to high glucose and palmitate in the presence or absence of receptor antagonists for 48 h. Leukocytes labeled with LeukoTracker were allowed to attach for 90 mins after which adherent cells were lysed and the fluorescence was measured at an excitation and emission wavelengths of 480 nm and 520 nm, respectively. n = 4 independent experiments each done in replicates; *p ≤ 0.05.

Mentions: Exposure of HUVECs to 48 h high glucose and palmitate significantly increased the leukocyte adherence by more than 1.7±0.07-fold (Fig 8; p = 0.0001), which was significantly attenuated by AZ11645373 (40.2±1.7%; p = 0.003; Fig 8). On the other hand exposure of the cells to PSB-12253 only resulted in a trend towards a decrease (20±7%; p = 0.07; Fig 8). This demonstrates high glucose and palmitate-induced endothelial dysfunction characterized by the increased adhesiveness in a mainly P2X7-dependent manner.


The ATP Receptors P2X7 and P2X4 Modulate High Glucose and Palmitate-Induced Inflammatory Responses in Endothelial Cells.

Sathanoori R, Swärd K, Olde B, Erlinge D - PLoS ONE (2015)

P2X7 mediates high glucose and palmitate-induced increase in leukocyte adhesion.HUVEC monolayers seeded in 96-well plates were exposed to high glucose and palmitate in the presence or absence of receptor antagonists for 48 h. Leukocytes labeled with LeukoTracker were allowed to attach for 90 mins after which adherent cells were lysed and the fluorescence was measured at an excitation and emission wavelengths of 480 nm and 520 nm, respectively. n = 4 independent experiments each done in replicates; *p ≤ 0.05.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4418812&req=5

pone.0125111.g008: P2X7 mediates high glucose and palmitate-induced increase in leukocyte adhesion.HUVEC monolayers seeded in 96-well plates were exposed to high glucose and palmitate in the presence or absence of receptor antagonists for 48 h. Leukocytes labeled with LeukoTracker were allowed to attach for 90 mins after which adherent cells were lysed and the fluorescence was measured at an excitation and emission wavelengths of 480 nm and 520 nm, respectively. n = 4 independent experiments each done in replicates; *p ≤ 0.05.
Mentions: Exposure of HUVECs to 48 h high glucose and palmitate significantly increased the leukocyte adherence by more than 1.7±0.07-fold (Fig 8; p = 0.0001), which was significantly attenuated by AZ11645373 (40.2±1.7%; p = 0.003; Fig 8). On the other hand exposure of the cells to PSB-12253 only resulted in a trend towards a decrease (20±7%; p = 0.07; Fig 8). This demonstrates high glucose and palmitate-induced endothelial dysfunction characterized by the increased adhesiveness in a mainly P2X7-dependent manner.

Bottom Line: Both P2X7 and P2X4 antagonists inhibited high glucose and palmitate-induced interleukin-6 levels with the former having a significant effect on interleukin-8 and cyclooxygenase-2.The effect of the antagonists was confirmed with siRNA knockdown of the receptors.In addition, P2X7 mediated both high glucose and palmitate-induced increase in reactive oxygen species levels and decrease in endothelial nitric oxide synthase.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden.

ABSTRACT
Endothelial cells lining the blood vessels are principal players in vascular inflammatory responses. Dysregulation of endothelial cell function caused by hyperglycemia, dyslipidemia, and hyperinsulinemia often result in impaired vasoregulation, oxidative stress, inflammation, and altered barrier function. Various stressors including high glucose stimulate the release of nucleotides thus initiating signaling via purinergic receptors. However, purinergic modulation of inflammatory responses in endothelial cells caused by high glucose and palmitate remains unclear. In the present study, we investigated whether the effect of high glucose and palmitate is mediated by P2X7 and P2X4 and if they play a role in endothelial cell dysfunction. Transcript and protein levels of inflammatory genes as well as reactive oxygen species production, endothelial-leukocyte adhesion, and cell permeability were investigated in human umbilical vein endothelial cells exposed to high glucose and palmitate. We report high glucose and palmitate to increase levels of extracellular ATP, expression of P2X7 and P2X4, and inflammatory markers. Both P2X7 and P2X4 antagonists inhibited high glucose and palmitate-induced interleukin-6 levels with the former having a significant effect on interleukin-8 and cyclooxygenase-2. The effect of the antagonists was confirmed with siRNA knockdown of the receptors. In addition, P2X7 mediated both high glucose and palmitate-induced increase in reactive oxygen species levels and decrease in endothelial nitric oxide synthase. Blocking P2X7 inhibited high glucose and palmitate-induced expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 as well as leukocyte-endothelial cell adhesion. Interestingly, high glucose and palmitate enhanced endothelial cell permeability that was dependent on both P2X7 and P2X4. Furthermore, antagonizing the P2X7 inhibited high glucose and palmitate-mediated activation of p38-mitogen activated protein kinase. These findings support a novel role for P2X7 and P2X4 coupled to induction of inflammatory molecules in modulating high glucose and palmitate-induced endothelial cell activation and dysfunction.

No MeSH data available.


Related in: MedlinePlus