Journal: Redox Biology
Article Title: Methylation reader MBD2-mediated GPX4 transcriptional repression drives ovarian granulosa cell ferroptosis in PCOS
doi: 10.1016/j.redox.2026.104034
Figure Lengend Snippet: GPX4 suppression is regulated by a repressive complex containing MBD2, MAZ, HDAC3 and NCoR. (a) Peak plot showing the ATAC-seq peak at the Gpx4 locus (Chr10: 80051488–80056439) in ovarian tissues from control (Ctrl, blue) and DHEA-treated (DHEA, red) mice. Orange boxes and asterisks denote regions with increased chromatin accessibility. (b) A heatmap displays the top six transcription factors (TFs) binding to the Gpx4 promoter region in the ATAC-seq analysis, along with the mRNA expression identified by RNA-seq analysis, and the predicted TF motifs and E-values are shown on the right. (c) Schematic representation of the Gpx4 promoter region showing the MAZ binding motif relative to the transcription start site (TSS). (Below) MAZ binding footprint enrichment at the Gpx4 locus in Ctrl (blue) and DHEA-treated (red) mice. Primary ovarian granulosa cells (GCs) were treated with 50 μM DHEA for 48 h in vitro to establish the PCOS model. (d) Western blot analysis of MAZ, NCoR and HDAC3 protein expression in DHEA-treated GCs. GAPDH served as a loading control. Blots are representative of one sample per group. Quantification was presented as means ± SEM, n = 3. ∗ P < 0.05, Student's t-test. (e) Co-immunoprecipitation (Co-IP) assay. Cell lysates were immunoprecipitated (IP) with isoform-matched immunoglobulin (Ig) or antibodies (IP Ab) to MBD2, MAZ, HDAC3, or NCoR, and then immunoprecipitants were assessed for MBD2, MAZ, HDAC3, or NCoR by western blotting reciprocally (the upper panel). The non-IP lysates (Input) were assayed for GAPDH as input controls. (f) Immunofluorescence co-staining was used to determine the expression and localization of MAZ (green), NCoR (red), and HDAC3 (magenta) within GCs. (g) Quantification of protein co-localization from the magnified region in ( f ). (h) Chromatin immunoprecipitation (ChIP) assay. DHEA-treated GCs were in presence or absence of KCC-07 (KCC, 10 μM, 48 h), and the cell lysates were immunoprecipitated with isoform-matched immunoglobulin or antibodies to MBD2, MAZ, NCoR, HDAC3, or pan-acetylated lysine (Pan-Ace), respectively. The genomic DNA (Input) and the antibody-bound DNAs were PCR-amplified with primers covering the MAZ motif on Gpx4 promoter. The PCR products of representative sample per group were analyzed on 1.5 % agarose gels. Quantitative analysis was shown on the right. Data were presented as mean ± SEM, n = 4. ∗ P < 0.05, one-way ANOVA. (i) Western blot analysis. (Left) HDAC3 and GPX4 protein expression in DHEA-treated GCs in the presence or absence of the HDAC3 inhibitor RGFP966 (RGFP, 10 μM, 48 h). (Middle) MAZ and GPX4 protein expression in GCs transfected with negative- (si-Ctrl) or MAZ-targeting (si-MAZ) siRNA, followed by treatment with or without DHEA. (Right) NCoR and GPX4 protein expression in GCs transfected with negative- (si-Ctrl) or NCoR-targeting (si-NCoR) siRNA, followed by DHEA treatment. GAPDH was as a loading control. (j) Quantifications of ( i ). Data were presented as mean ± SEM, n = 3. ∗ P < 0.05, one-way ANOVA. (k) Schematic model of Gpx4 transcriptional repression. A transcriptional repressive complex orchestrated by MBD2, MAZ, HDAC3, and NCoR binds to the hypermethylated Gpx4 promoter, leading to transcriptional suppression.
Article Snippet: To further confirm GPX4 as a critical target for MBD2-driven GC ferroptosis, pharmacologic GPX4 inhibition with RSL3 (5 mg/kg, intraperitoneal injection for 10 days; HY-100218A, MCE, USA) or GC-specific Gpx4 deletion mice were used to establish the PCOS model.
Techniques: Control, Binding Assay, Expressing, RNA Sequencing, In Vitro, Western Blot, Co-Immunoprecipitation Assay, Immunoprecipitation, Immunofluorescence, Staining, Chromatin Immunoprecipitation, Amplification, Transfection