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oxLDL downregulates the dendritic cell homing factors CCR7 and CCL21.

Nickel T, Pfeiler S, Summo C, Kopp R, Meimarakis G, Sicic Z, Lambert M, Lackermair K, David R, Beiras-Fernandez A, Kaczmarek I, Weis M - Mediators Inflamm. (2012)

Bottom Line: CCL21- and CCR7-mRNA levels were significantly downregulated in atherosclerotic plaques versus non-atherosclerotic controls [90% for CCL21 and 81% for CCR7 (P < 0.01)].In vitro, oxLDL reduced CCR7 mRNA levels on DCs by 30% and protein levels by 46%.Furthermore, mRNA expression of CCL21 was significantly reduced by 50% (P < 0.05) and protein expression by 24% in HMECs by oxLDL (P < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Medizinische Klinik und Poliklinik I, Campus Grosshadern, Ludwig-Maximilians University, 81377 Munich, Germany. tsnickel@web.de

ABSTRACT

Introduction: Dendritic cells (DCs) and oxLDL play an important role in the atherosclerotic process with DCs accumulating in the plaques during plaque progression. Our aim was to investigate the role of oxLDL in the modulation of the DC homing-receptor CCR7 and endothelial-ligand CCL21.

Methods and results: The expression of the DC homing-receptor CCR7 and its endothelial-ligand CCL21 was examined on atherosclerotic carotic plaques of 47 patients via qRT-PCR and immunofluorescence. In vitro, we studied the expression of CCR7 on DCs and CCL21 on human microvascular endothelial cells (HMECs) in response to oxLDL. CCL21- and CCR7-mRNA levels were significantly downregulated in atherosclerotic plaques versus non-atherosclerotic controls [90% for CCL21 and 81% for CCR7 (P < 0.01)]. In vitro, oxLDL reduced CCR7 mRNA levels on DCs by 30% and protein levels by 46%. Furthermore, mRNA expression of CCL21 was significantly reduced by 50% (P < 0.05) and protein expression by 24% in HMECs by oxLDL (P < 0.05).

Conclusions: The accumulation of DCs in atherosclerotic plaques appears to be related to a downregulation of chemokines and their ligands, which are known to regulate DC migration. oxLDL induces an in vitro downregulation of CCR7 and CCL21, which may play a role in the reduction of DC migration from the plaques.

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mRNA expression of CCL21/19 and protein expression of CCL21 on HMECs-1 after stimulation with oxLDL. (a) Fold increase in mRNA expression levels of CCL21/19 in human microvascular endothelial cells after 48 h of stimulation with oxLDL (10 μg/mL) analyzed by real-time PCR. *P < 0.05, (n = 9) versus unstimulated controls. (b) Corresponding protein expression of CCL21 measured by immunofluorescence analysis. The green staining represents CCL21 positive structures (α-CCL21/6Ckine-Alexa488), red represents the plasma membrane (Vybrand DiD). Scale bar 10 μm. (c) The fluorescence intensity was quantified showing a significant change for oxLDL. *P < 0.05, (n = 8) versus unstimulated control.
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fig4: mRNA expression of CCL21/19 and protein expression of CCL21 on HMECs-1 after stimulation with oxLDL. (a) Fold increase in mRNA expression levels of CCL21/19 in human microvascular endothelial cells after 48 h of stimulation with oxLDL (10 μg/mL) analyzed by real-time PCR. *P < 0.05, (n = 9) versus unstimulated controls. (b) Corresponding protein expression of CCL21 measured by immunofluorescence analysis. The green staining represents CCL21 positive structures (α-CCL21/6Ckine-Alexa488), red represents the plasma membrane (Vybrand DiD). Scale bar 10 μm. (c) The fluorescence intensity was quantified showing a significant change for oxLDL. *P < 0.05, (n = 8) versus unstimulated control.

Mentions: For HMECs-1, stimulation with oxLDL led to a significant reduction of CCL21 mRNA expression (50%; ΔΔct = 0.5; P < 0.05, Figure 4(a)). These results correspond with the results of the immunofluorescence analysis, where we found a 24% down-regulation of CCL21 receptor expression (n = 9; 34.00 ± 8.53 versus control 44.54 ± 6.23 intensity/mm2; P < 0.05; Figures 4(b) and 4(c). oxLDL had no significant impact on protein or mRNA expression of CCL19 (Figure 4(a)).


oxLDL downregulates the dendritic cell homing factors CCR7 and CCL21.

Nickel T, Pfeiler S, Summo C, Kopp R, Meimarakis G, Sicic Z, Lambert M, Lackermair K, David R, Beiras-Fernandez A, Kaczmarek I, Weis M - Mediators Inflamm. (2012)

mRNA expression of CCL21/19 and protein expression of CCL21 on HMECs-1 after stimulation with oxLDL. (a) Fold increase in mRNA expression levels of CCL21/19 in human microvascular endothelial cells after 48 h of stimulation with oxLDL (10 μg/mL) analyzed by real-time PCR. *P < 0.05, (n = 9) versus unstimulated controls. (b) Corresponding protein expression of CCL21 measured by immunofluorescence analysis. The green staining represents CCL21 positive structures (α-CCL21/6Ckine-Alexa488), red represents the plasma membrane (Vybrand DiD). Scale bar 10 μm. (c) The fluorescence intensity was quantified showing a significant change for oxLDL. *P < 0.05, (n = 8) versus unstimulated control.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3350855&req=5

fig4: mRNA expression of CCL21/19 and protein expression of CCL21 on HMECs-1 after stimulation with oxLDL. (a) Fold increase in mRNA expression levels of CCL21/19 in human microvascular endothelial cells after 48 h of stimulation with oxLDL (10 μg/mL) analyzed by real-time PCR. *P < 0.05, (n = 9) versus unstimulated controls. (b) Corresponding protein expression of CCL21 measured by immunofluorescence analysis. The green staining represents CCL21 positive structures (α-CCL21/6Ckine-Alexa488), red represents the plasma membrane (Vybrand DiD). Scale bar 10 μm. (c) The fluorescence intensity was quantified showing a significant change for oxLDL. *P < 0.05, (n = 8) versus unstimulated control.
Mentions: For HMECs-1, stimulation with oxLDL led to a significant reduction of CCL21 mRNA expression (50%; ΔΔct = 0.5; P < 0.05, Figure 4(a)). These results correspond with the results of the immunofluorescence analysis, where we found a 24% down-regulation of CCL21 receptor expression (n = 9; 34.00 ± 8.53 versus control 44.54 ± 6.23 intensity/mm2; P < 0.05; Figures 4(b) and 4(c). oxLDL had no significant impact on protein or mRNA expression of CCL19 (Figure 4(a)).

Bottom Line: CCL21- and CCR7-mRNA levels were significantly downregulated in atherosclerotic plaques versus non-atherosclerotic controls [90% for CCL21 and 81% for CCR7 (P < 0.01)].In vitro, oxLDL reduced CCR7 mRNA levels on DCs by 30% and protein levels by 46%.Furthermore, mRNA expression of CCL21 was significantly reduced by 50% (P < 0.05) and protein expression by 24% in HMECs by oxLDL (P < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Medizinische Klinik und Poliklinik I, Campus Grosshadern, Ludwig-Maximilians University, 81377 Munich, Germany. tsnickel@web.de

ABSTRACT

Introduction: Dendritic cells (DCs) and oxLDL play an important role in the atherosclerotic process with DCs accumulating in the plaques during plaque progression. Our aim was to investigate the role of oxLDL in the modulation of the DC homing-receptor CCR7 and endothelial-ligand CCL21.

Methods and results: The expression of the DC homing-receptor CCR7 and its endothelial-ligand CCL21 was examined on atherosclerotic carotic plaques of 47 patients via qRT-PCR and immunofluorescence. In vitro, we studied the expression of CCR7 on DCs and CCL21 on human microvascular endothelial cells (HMECs) in response to oxLDL. CCL21- and CCR7-mRNA levels were significantly downregulated in atherosclerotic plaques versus non-atherosclerotic controls [90% for CCL21 and 81% for CCR7 (P < 0.01)]. In vitro, oxLDL reduced CCR7 mRNA levels on DCs by 30% and protein levels by 46%. Furthermore, mRNA expression of CCL21 was significantly reduced by 50% (P < 0.05) and protein expression by 24% in HMECs by oxLDL (P < 0.05).

Conclusions: The accumulation of DCs in atherosclerotic plaques appears to be related to a downregulation of chemokines and their ligands, which are known to regulate DC migration. oxLDL induces an in vitro downregulation of CCR7 and CCL21, which may play a role in the reduction of DC migration from the plaques.

Show MeSH
Related in: MedlinePlus