3.5. Effects of MQL on ROS generation in CD4+ T
cells
Phytochemicals have been well-known as antioxidants that can directly
scavenge ROS, and are used to protect against
inflammation36,37. Whereas phytochemicals can generate
appropriate intracellular ROS, resulting in up-regulation of HO-1
expression38. Furthermore, intracellular ROS have been
linked to ERK1/2 as cAMT-mediated ROS production can induce ERK1/2
phosphorylation via Ras activation39. Thus, we
investigated intracellular ROS generated by MQL in
CD4+ T cells using DCFH-DA or
MitoSOXTM Red, and found that MQL increased
intracellular and mitochondrial ROS levels (Fig. 5A and B) .
Next, to investigate effects of intracellular ROS generated by MQL on
the C-Raf-ERK1/2 signaling pathway, CD4+ T cells were
cultured with MQL in the presence and absence of the antioxidant
N-acetylcysteine (NAC). We found that MQL-induced C-Raf and ERK1/2
phosphorylation, as well as HO-1 expression, were suppressed by NAC
treatment (Fig. 5C and D) . Taken together, these results
suggest that MQL-induced ROS mediate Ras-Raf-ERK activation and HO-1
expression in CD4+ T cells.