Figure 2. SENP1 depletion promotes the SUMOylation of peroxisome proliferator-activated receptor-γ (PPARγ) in BV-2 cells and neuronal apoptosis under intermittent hypoxia (IH) condition. (A) The qRT-PCR, (B, C) western blot analysis, and (D) cellular immunofluorescence analysis showed the downregulation of SENP1 in BV-2 cells after transfection. Untreated BV-2 cells were used as controls. Scale bar, 20 μm. ***p < 0.001 versus LV-Ctrl. (E) Data are presented as the percentage of SENP1 positive BV-2 cells. ***p < 0.001 versus LV-Ctrl. (F–H) The effects of IH on the SUMOylation of PPARγ (F, G) and the level of PPARγ (F, H) were detected by co-immunoprecipitation followed by western blot analysis. **p < 0.01, ***p < 0.001 versus LV-Ctrl. (I) The expression of IL-1β and TNF-α in BV-2 cells with or without SENP1 knockdown under IH condition were detected using ELISA. ***p < 0.001 versus LV-Ctrl. (J, K) The expression of NF-κB p65 in BV-2 cells and Bcl-2, Bax, Cleaved caspase-3 in HT-22 cells were detected by western blot analysis. *p < 0.05, **p < 0.01, ***p < 0.001 versus LV-Ctrl or HT-22 cocultured with the medium of LV-Ctrl BV-2 cells under IH condition. SENP1, small ubiquitin-related modifier protein-specific protease 1; LV, Lentivirus; qRT-PCR, quantitative reverse transcriptase polymerase chain reaction.