Release of CXC-chemokines by human lung microvascular endothelial cells (LMVEC) compared with macrovascular umbilical vein endothelial cells

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Abstract
In the present study, the sensitivity of LMVEC and human umbilical vein endothelial cells (HUVEC) to lipopolysaccharide (LPS) and the proinflammatory cytokines IL-1, tumour necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) was compared. To this end, the production of the CC- (MCP-1), CXC- (IL-8, ENA-78, Groα, NAP-2, GCP-2) and CX3C (fractalkine) chemokines was studied. A low basal production of these chemokines was observed in both cell types. TNF-α, IL-1 and LPS up-regulated all chemokines tested. IFN-γ however was only able to up-regulate MCP-1 production. LMVEC were more sensitive to IL-1 and LPS compared with HUVEC, since LMVEC produced significantly more MCP-1, ENA-78 and Groα (P < 0.01) under these conditions. Maximal production of MCP-1 in LMVEC was achieved with TNF-α (28.4 ng/ml, P < 0.01), whereas IL-1 was the most potent stimulator of ENA-78 (2.78 ng/ml, P < 0.001) and Groα (29.2 ng/ml, P < 0.001). IL-8 production in LMVEC cells was maximal after LPS stimulation (28.4 ng/ml), but lower than on HUVEC (P < 0.01). LPS, TNF-α and IL-1 stimulation strongly up-regulated all chemokine mRNA. No quantitative differences in mRNA expression between LMVEC and HUVEC were detected for MCP-1 and Groα after LPS stimulation. mRNA expression of ENA-78, GCP-2, CX3C and NAP-2 was however higher in LMVEC under LPS stimulation. In contrast, IL-8 mRNA was slightly more expressed in HUVEC under these conditions. These results further support the hypothesis that the microvascular lung endothelium plays an active role in the induction and perpetuation of acute lung injury.