Wei Liu1, Shuang Liu, Ping Yao, Lie-gang Liu, Hua Qin. 1. Department of Gastroenterology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Abstract
OBJECTIVE: To investigate the possible molecular mechanisms of heme oxygenase-1 (HO-1) induction by quercetin using rat primary hepatocytes. METHODS: Sprague-Dawley rat primary hepatocytes were isolated using a two-step collagenase perfusion technique and treated with quercetin at various doses (25 - 200 mumol/L) and times (2 - 12 h). To investigate the roles of various signaling pathways, the hepatocytes were pre-treated with 50 mumol/L quercetin plus an extracellular signal-regulated kinase (ERK) inhibitor (PD98059 at 10 mumol/L), a p38 inhibitor (SB203580 at 10 mumol/L), a c-Jun N-terminal kinase inhibitor (SP600125 at 10 mumol/L) or a phosphatidylinositol 3-kinase inhibitor (Wortmannin at 1 mumol/L) for 12 h. Changes in the mRNA and protein levels of HO-1 and nuclear factor, E-2 related factor 2 (Nrf2) were detected by RT-PCR and western blotting. RESULTS: After 4 - 12 h of treatment with quercetin at all concentrations, the HO-1 mRNA level in hepatocytes had increased significantly (vs. untreated control cells; all P less than 0.01). The quercetin-induced HO-1 expression and Nrf2 translocation into the nucleolus was inhibited by PD98059. CONCLUSION: Quercetin may induce HO-1 expression via the ERK/Nrf2 signaling transduction pathway.
OBJECTIVE: To investigate the possible molecular mechanisms of heme oxygenase-1 (HO-1) induction by quercetin using rat primary hepatocytes. METHODS:Sprague-Dawley rat primary hepatocytes were isolated using a two-step collagenase perfusion technique and treated with quercetin at various doses (25 - 200 mumol/L) and times (2 - 12 h). To investigate the roles of various signaling pathways, the hepatocytes were pre-treated with 50 mumol/L quercetin plus an extracellular signal-regulated kinase (ERK) inhibitor (PD98059 at 10 mumol/L), a p38 inhibitor (SB203580 at 10 mumol/L), a c-Jun N-terminal kinase inhibitor (SP600125 at 10 mumol/L) or a phosphatidylinositol 3-kinase inhibitor (Wortmannin at 1 mumol/L) for 12 h. Changes in the mRNA and protein levels of HO-1 and nuclear factor, E-2 related factor 2 (Nrf2) were detected by RT-PCR and western blotting. RESULTS: After 4 - 12 h of treatment with quercetin at all concentrations, the HO-1 mRNA level in hepatocytes had increased significantly (vs. untreated control cells; all P less than 0.01). The quercetin-induced HO-1 expression and Nrf2 translocation into the nucleolus was inhibited by PD98059. CONCLUSION:Quercetin may induce HO-1 expression via the ERK/Nrf2 signaling transduction pathway.