FIGURE 4.

Involvement of p38 signaling pathways and Nrf-2 in NHE1-stimulated HO-1 expression. A, cells were pretreated with SB203580 (SB, p38 inhibitor), LY294002 (LY, Akt/PI3K inhibitor), BAY11-7082 (BAY, NF-κB inhibitor), PD98059 (PD, MEK1 inhibitor), and SP600125 (SP, JNK inhibitor) for 1 h. Whole cell lysates and mRNA were prepared and subjected to Western blot analysis with antibodies against anti-HO-1 and β-actin and real-time PCR to assess HO-1 mRNA expression level. Con, control. B, K562R cells were treated by p38 inhibitor SB203580 at different concentrations (0, 5, and 10 μm) for 2 h, and total protein and mRNA were extracted from cells to detect HO-1 protein and mRNA expression levels. C, the relationship between NHE1 and p38 was assessed. K562R cells were treated by cariporide with increasing dose, and p-p38 and p38 were detected by Western blot. D, Nrf-2 siRNA was successfully transduced into K562R cells, and total protein was isolated to detect HO-1 expression by Western blot. E–G, K562R cells were treated by cariporide (0.4 μm), LY333531 (10 μm), and SB203580 (10 μm) alone or in combination with each other for 2 h. Nuclear Nrf-2, HO-1, p-p38/p38, and p-PKC-β/PKC-β were measured by quantifying p-Akt from immunoblots. ** indicates p < 0.01, and * indicates p < 0.05.