Figure 4.

(a) Effect of MAPK kinase (MEK) inhibitor (U0126) on the augmentation of AGT mRNA expression by H₂O₂ treatment. Primary rat mesangial cells were treated with 10⁻⁴ M H₂O₂ and an MEK inhibitor (U0126) for 30 min (n=4 in each). After the treatment AGT mRNA was measured by qRT-PCR. The data are expressed as relative values compared with the control condition (column A). *P<0.0001 vs. column A; ^#P<0.0001 vs. column B. (b) Effect of MEK inhibitor (U0126) on the augmentation of AGT protein expression in the supernatants by H₂O₂ treatment. Primary rat mesangial cells were treated with 5×10⁻⁵ M H₂O₂ and 10 μM MEK inhibitor (U0126) for 7 h (n=3 in each). H₂O₂ was administered every hour. After the treatment the supernatants were concentrated and measured by western blotting. The data are expressed as relative values compared with the 7-h H₂O₂ stimulation alone (column E). The stippled bars show AGT protein expression with H₂O₂ alone and the hatched bar shows AGT protein expression with co-administration of H₂O₂ and U0126. *P<0.0001 vs. column E. (c) Effect of JNK inhibitor (SP600125) on the augmentation of AGT mRNA expression by H₂O₂ treatment. Primary rat mesangial cells were treated with 10⁻⁴ M H₂O₂ and an inhibitor of JNK (SP600125) for 30 min (n=4 in each). After the treatment AGT mRNA was measured by qRT-PCR. The data are expressed as relative values compared with the control condition (column A). *P<0.01; **P<0.001; ***P<0.0001 vs. column A; and ^#P<0.01 vs. column B. (d) Effect of JNK inhibitor (SP600125) on the augmentation of AGT protein expression in the supernatants by H₂O₂ treatment. Primary rat mesangial cells were treated with 5×10⁻⁵ M H₂O₂ and 40 μM JNK inhibitor (SP600125) for 7 h (n=3 in each). H₂O₂ was administered every hour. After the treatment the supernatants were concentrated and measured by western blotting. The data are expressed as relative values compared with the 7-h H₂O₂ stimulation alone (column E). The stippled bars show AGT protein expression with H₂O₂ alone and the hatched bar shows AGT protein expression with co-administration of H₂O₂ and SP600125. *P<0.001; **P<0.0001 vs. column E. (e) Effect of p38 MAPK inhibitor (SB203580) on the augmentation of AGT mRNA expression by H₂O₂ treatment. Primary rat mesangial cells were treated with 10⁻⁴ M H₂O₂ and an inhibitor of p38 MAPK (SB203580) for 30 min (n=4 in each). After the treatment AGT mRNA was measured by qRT-PCR. The data are expressed as relative values compared with the control condition (column A). *P<0.0001 vs. column A. (f) Effect of p38 MAPK inhibitor (SB203580) on the augmentation of AGT protein expression in the supernatants by H₂O₂ treatment. Primary rat mesangial cells were treated with 5×10⁻⁵ M H₂O₂ and 10 μM p38 MAPK inhibitor (SB203580) for 7 h (n=3 in each). H₂O₂ was administered every hour. After the treatment the supernatants were concentrated and measured by western blotting. The data are expressed as relative values compared with the 7-h H₂O₂ stimulation alone (column E). The stippled bars show AGT protein expression with H₂O₂ alone and the hatched bar shows AGT protein expression with co-administration of H₂O₂ and SB203580. *P<0.0001 vs. column E. AGT, angiotensinogen; H₂O₂, hydrogen peroxide; JNK, c-Jun N-terminal kinase; MAPK, mitogen-activated protein kinase; MEK, MAPK kinase; ND, not detected; qRT-PCR, quantitative real-time RT-PCR.