Low salt induces the expression of cyclooxygenase-2 in a mouse macula densa cells through the activation of ERK、AP-1 pathways / 基础医学与临床

ABSTRACT

Objective To identify the effect of low salt medium on P44/42 kinase(ERK)、AP-1 in the expression of cyclooxygenase-2 (COX-2) in a mouse macula densa derived cell line (MMDD1 cells). Methods MMDD1 cells were transfected with luciferase reporter plasmid containing AP-1. Luciferase reporter assay were studied in normal salt(NS) and low salt(LS) medium; the expression of C-JUN、C-FOS were analyzed as well by Western Blotting. RT-PCR and Western Blotting were used to detect the mRNA and protein expression of COX-2. Expression of total and phosphorylated ERK was analyzed by Western Blotting in LS solution. The content of PGE2 in the supernatant was examined by ELISA. Results Phosphorylated ERK were markedly increased by LS treatment. The up-regulated COX-2 protein expression with LS was reduced with PD-98059 (ERK inhibitiors) at 20 ?mmol/L, PGE2 release was down-regulated as well. Luciferase activity of AP-1 was stimulated in LS, the up-regulated luciferase activity of AP-1 was attenuated by curcumin at 20 ?mmol/L (AP-1 inhibitor). The expression of C-JUN、C-FOS were increased as well. Low salt medium changed COX-2 mRNA abundance and protein expression was decreasedin medium with curcumin at 20 ?mmol/L.Conclusion Low salt induces the expression of COX-2 in MMDD1 cells through the activation of ERK、AP-1 pathways.