Figure 5. A potential SIRT1/HO-1 signaling under the NMN-treated oxidative stress model. Both NMN (A) and SRT2104 (B) administration significantly increased HO-1 protein levels after ROS insult. N = 4 per group. Statistical significance was analyzed with the unpaired Student's t-test. *p<0.05. **p<0.01. ***p<0.001. Data are mean ± SEM. (C) Silencing SIRT1 by siRNA almost abolished the induced HO-1 expression by NMN after ROS insult. (D) HO-1 siRNA didn’t alter the expression of SIRT1 by NMN after ROS insult.