The mechanism of NRF2 inhibiting ROS induced autophagy to reduce ovarian granulosa cells damage

Abstract

This study explores the effects and possible mechanisms of nuclear factor E2 related factor 2 (NRF2) on ovarian granulosa cells, providing a scientific basis to prevent premature ovarian failure. An ovarian cell injury model was constructed by treating human ovarian granulosa cell (KGN cell) with 4-Vinylcyclohexene dioxide (VCD). Firstly, KGN cells were treated with different concentrations of VCD, and cell counting kit 8 (CCK-8) was used to detect ovarian cell proliferation. After determining IC50 by CCK8, the levels of estradiol and progesterone in the cell supernatant were detected using enzyme-linked immunosorbent assay (ELISA), reactive oxygen species (ROS) assay kit was used to detect the content of ROS in ovarian cells, real-time fluorescence quantitative polymerase chain reaction (qRT PCR) was used to detect the mRNA expression level of NRF2, and Western blot was used to detect the protein expression level of NRF2. Further, NRF2 silence (siNRF2) and overexpression (NRF2-OE) cell models were constructed through lentivirus transfection, and the effects of regulating NRF2 on VCD treated cell models were investigated by detecting hormone levels, oxidative stress indicators (ROS, SOD, GSH-Px), and autophagy (LC3B level). The results showed that VCD intervention inhibited the proliferation of ovarian granulosa cells in a time-dependent and dose-dependent manner (F>100, P<0.05), with an IC50 of 1.2 mmol/L at 24 hours. After VCD treatment, the level of estradiol in the cell supernatant decreased from (56.32±10.18) ng/ml to (24.59±8.75) ng/ml (t=5.78, P<0.05). Progesterone decreased from (50.25±7.03) ng/ml to (25.13±6.67) ng/ml (t=6.54, P<0.05). After VCD treatment, the SOD of cells decreased from (44.47±7.71) ng/ml to (30.92±4.97) ng/ml (t=3.61, P<0.05). GSH-Px decreased from (68.51±10.17) ng/ml to (35.19±6.59) ng/ml (t=5.73, P<0.05). Simultaneously accompanied by an increase in autophagy and a decrease in NRF2. This study successfully constructed KGN cell models that silenced NRF2 and overexpressed NRF2. Subsequently, this study treated each group of cells with VCD and found that the cell proliferation activity of the siNRF2 group was significantly reduced (t=8.37, P<0.05), while NRF2-OE could reverse the cell activity damage caused by VCD (t=3.37, P<0.05). The siNRF2 group had the lowest level of estradiol (t=5.78, P<0.05), while NRF2-OE could reverse the decrease in cellular estradiol levels caused by VCD (t=5.58, P<0.05). The siNRF2 group had the lowest progesterone levels (t=3.02, P<0.05), while NRF2-OE could reverse the decrease in cellular progesterone levels caused by VCD (t=2.41, P<0.05). The ROS level in the siNRF2 group was the highest (t=2.86, P<0.05), NRF2-OE could reverse the increase in ROS caused by VCD (t=3.14, P<0.05), the SOD enzyme content in the siNRF2 group was the lowest (t=2.98, P<0.05), and NRF2-OE could reverse the decrease in SOD enzyme content caused by VCD (t=4.72, P<0.05). The GSH-Px enzyme content in the siNRF2 group was the lowest (t=3.67, P<0.05), and NRF2-OE could reverse the decrease in antioxidant enzyme content caused by VCD (t=2.71, P<0.05). The LC3B level was highest in the siNRF2 group (t=2.45, P<0.05), and NRF2-OE was able to reverse the LC3B elevation caused by VCD (t=9.64, P<0.05). In conclusion, NRF2 inhibits ROS induced autophagy, thereby playing a role in reducing ovarian granulosa cell damage, which may be a potential target for premature ovarian failure.