Rat Endothelin 1 protein, His tag (active)

Endothelins (EDN) are small (21 amino acids) vasoactive peptides produced by many cell types including endothelial and epithelial cells, macrophages and fibroblasts. By binding to G-protein-linked transmembrane receptors, EDNs participate in vasoconstriction modulation and cell growth regulation. It has been proven that EDN1 has chemotaxis active on monocytes, thus chemotaxis assay used 24-well microchemotaxis system was undertaken to detect the chemotactic effect of EDN1 on the human monocytic cell line THP-1. Briefly, THP-1 cells were seeded into the upper chambers (100 μl cell suspension, 1x10⁶cells/ml in RPMI-1640 with 0. 5% FBS) and EDN1 (20 ng/ml, 40 ng/ml and 80 ng/ml diluted separately in serum free RPMI-1640) was added in lower chamber with a polycarbonate filter (8μm pore size) used to separate the two compartments. After incubation at 37ºC with 5% CO₂ for 3h, the filter was removed, then cells in low chamber were observed by inverted microscope at low magnification (×100) and the number of migrated cells were counted at high magnification (×400) randomly. EDN1 is able to induce migration of THP-1 cells, and the optimum chemotaxis of EDN1 occurs at 80 ng/ml.