[Protein kinase C-nuclear factor-erythroid 2-related factor 2 regulating the expression of heme oxygenase-1 in rat airway epithelial cells].

OBJECTIVE: To observe the effect of the signaling pathway of protein kinase C (PKC)-nuclear factor-erythroid 2-related factor 2 (Nrf2) on the expression of heme oxygenase -1 (HO-1) induced by cigarette smoke extract in rat airway epithelial cells.

METHODS: The airway epithelial cells of 25 male SD rats were randomly divided into a control group, a CSE3h group, a RO318220 group (PKC inhibitor), a Nrf2 siRNA group and a Nrf2 siRNA+RO318220 group, 5 rats in each group. The control group was incubated with DMEM/F12 alone. The CSE3h group was treated with 10% CSE for 3 h. The RO318220 group was pretreated with 3 μmol/L RO318220 for 0.5 h and subsequently treated with 10% CSE for 3 h. The Nrf2 siRNA group was pretreated with Nrf2 siRNA, and then treated with 10% CSE for 3 h. The Nrf2 siRNA+RO318220 group was pretreated with Nrf2 siRNA and 3 μmol/L RO318220 for 0.5 h, and then treated with 10% CSE for 3 h. The protein levels of Nrf2 in the nucleus and cytoplasm, and HO-1 and PKC in the whole cells were semi-quantified by Western blot. The protein expression of HO-1 was measured by immunocytochemistry. HO-1 mRNA expression was detected by RTPCR. Immunofluorescence staining was used to observe the nuclear translocatin of Nrf2.

RESULTS: CSE markedly induced Nrf2 nuclear translocation in the rat airway epithelial cells, and RO318220 pretreatment blocked the CSE induced Nrf2 nuclear translocation. Immunocytochemistry showed that HO-1 protein expression was strongly positive in the CSE3h group, weakly positive in the other 4 groups. The expression of PKC protein, HO-1 mRNA and protein significantly increased in the CSE3h group, and HO-1 activity markedly improved in the CSE group (P<0.05). The level of PKC protein expression was not significantly different in the Nrf2 siRNA group compared with that in the CSE3h group (P>0.05).

CONCLUSION: CSE induces the nuclear translocation of Nrf2 by PKC signaling pathway, thus upregulating the HO-1 expression in the rat airway epithelial cells.