As for the mechanisms by which VDR reduces ROS generation, a recent study reported that active vitamin D inhibited ROS production in mesenchymal stem cells (MSCs) by activating the VDR-Bmi1 signal pathway, and then inhibited cell oxidative stress, DNA damage, as well as cellular senescence, and finally achieved the effect of anti-osteoporosis (Sun et al., 2020). The gene discussed is BMI1; the disease is osteoporosis.