P050 Up-regulation of interleukin 8 and CXC chemokine ligand 1 by cold stimulation in human dermal microvascular endothelial cells: A role in winter ulceration and cold urticaria
Introduction Cold is one of several important pathogenic factors in conditions such as livedo reticularis with winter ulceration (LRWU) [1] , cold urticaria [2] , [3] . As yet however, the effects resulting from cold stimulation remain poorly understood. Methods In the present study, using DNA microarray analysis, we investigated gene expression profiles in cultured human normal dermal microvascular endothelial cells (dHMVECs) exposed to different temperatures (10, 20 and 37 °C). Quantitative real-time polymerase chain reaction (qPCR) was used to confirm gene expression results obtained from DNA microarray. ELISA assay was used to evaluate protein expression in culture medium of dHMVECs, mice and patients’ sera. Results By DNA microarray analysis, differential transcriptional expressions of 137 genes were identified compared to 37 °C. 21 genes were both regulated at 10 degrees C and 20 °C, 19.05% (4 in 21) of which encode proteins which are related to the immune response (cytokines, chemokines, their receptors, cytokine/chemokines-related genes). Under cold stimulation, the production of the neutrophil chemokine interleukin (IL)-8 and CXC chemokine ligand (CXCL)1 was found remarkably up-regulated by both DNA microarray and qPCR analyses. IL-8 and CXCL1 mRNA were present at detectable levels even in the nontreated control dHMVECs and significantly up-regulated (Ratio 10 centigrade C/37 degrees C: IL8, 1.46 ± 0.13-fold, p  = 0.0122; CXCL1, 2.40 ± 0.35-fold, p  = 0.0100) within 2 h after cold stimulation and remained elevated for up to 12-h. Up-regulated protein expressions of IL8 and CXCL1 were found in culture medium of dHMVECs and mouse serum after cold stimulation, and also in sera from patients, who suffer from LRWU and cold urticaria. Neutrophil migration in the presence of conditional medium from cold-stimulated dHMVECs is currently under investigation. Conclusion Our results showed that cold induced expression of different genes. This is the first time to show that cold can affect the expression profile of chemokines in dHMVECs, which may contribute to the accumulation of neutrophils and inflammation in dermal vascular. They might be candidate biomarkers of diseases resulting from exposure to cold.