Effects of UII/UT system on the expression of inflammatory signal molecules p38 MAPK and NF-κB in LPS-stimulated Kupffer cells

Abstract

Objective To investigate the effects of urotensin Ⅱ/urotensin Ⅱreceptor （ UⅡ/UT） system on the expression of inflammatory signal molecules p 38 mitogen-activated protein kinase （ p38 MAPK） and nuclear factor-κB （ NF-κB ） in lipopolysaccharide （ LPS ）-stimulated Kupffer cells （ KCs ） . Methods Rat KCs were isolated and purified by means of in situ perfusion and density gradient centrifuga-tion.The isolated cells were randomly divided into six treatment groups including group 1：UⅡ（-） urantide （-）LPS（-）, group 2：UⅡ（＋）urantide（-）LPS（-）, group 3： UⅡ（-）urantide（＋）LPS（-）, group 4：UⅡ（-）urantide（-）LPS（＋）, group 5：UⅡ（＋） urantide（-） LPS（＋） and group 6：UⅡ（-）urantide（＋） LPS（＋） .Western blot assay was performed to detect p 38 MAPK/p-p38 MAPK protein and NF-κB p65 sub-unit.The DNA-binding activity of NF-κB was tested by electrophoretic mobility shift assay （EMSA）.Re-sults There was no significant difference with the expression of p 38 MAPK protein in KCs among the six groups （P〉0.05）.The expression of p65 protein and p-p38 MAPK and the DNA-binding activity of NF-κB were significantly enhanced in LPS-stimulated KCs from groups 4, 5 and 6 in comparison with those in group 1 （P〈0.01）.No significant differences with the levels of p65 protein and phosphor-p38 MAPK and the DNA-binding activity of NF-κB were observed between UⅡ/urantide-treated cells （ group 2 or group 3） and untreated cells （group 1） （all P〉0.05）, but that were decreased in group 6 than those in group 4 （all P〈0.01）.Conclusion UⅡ/UT system participated in the activation of p38 MAPK and NF-κB signaling pathways in LPS-stimulated primary Kupffer cells . Key words: UrotensinⅡ; UrotensinⅡreceptor; Urantide; Kupffer cell; p38 MAPK; NF-κB