Fig 2: Effects of Srsf1 knockdown on GC-induced OB apoptosis.A qPCR to verify the knockdown efficiency of Srsf1 (n = 4), CV279: the control lentivirus vector, KD-Srsf1: knockdown of Srsf1. B, C Western Blot detection of SRSF1 knockdown efficiency (n = 4). D, E TUNEL/DAPI staining detection of OBs TUNEL* cell number (n = 3). F–H Expression levels of cleaved-CASP3 and cleaved-CASP9 were detected by western blot (n = 3). I, J Apoptosis detected by Annexin V-FITC/PI staining (n = 4). In (A, C, D, G, H, and J), the data were expressed as mean ± SD, and statistical significance was calculated using one-way ANOVA with Tukey post hoc test. *P < 0.05, **P < 0.01, ***P < 0.001, nsP > 0.05.

Fig 3: SRSF1 regulates alternative splicing of Bmf pre-mRNA and participates in GC-induced OB apoptosis.A qPCR was utilized to detect the expression changes in Bmf variants (n = 4). B, C Structure diagram of human and mouse BMF protein subtypes. D The knockdown efficiency of Bmf was detected by qPCR (n = 4), sh-Bmf: knockdown of Bmf. E, F Western Blot detection of BMF knockdown efficiency (n = 3). G, H Apoptosis detected by Annexin V-FITC/PI staining (n = 4). I, J TUNEL/DAPI staining detection of OBs TUNEL* cell number (n = 3). K–M Expression levels of cleaved-CASP3 and cleaved-CASP9 were detected by western blot (n = 3). In (A, D, F, H, I, L, M), the data were expressed as mean ± SD, and statistical significance was calculated using one-way ANOVA with Tukey post hoc test. *P < 0.05, **P < 0.01, ***P < 0.001, nsP > 0.05.

Fig 4: Screening and identification of splicing factors associated with GC-induced OB apoptosis.A Heat map showing differentially expressed genes (n = 3). B Gene ontology (GO) analysis (n = 3). C Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis (n = 3). D Heat map showing differentially expressed apoptosis-related genes (n = 3). E Heat map showing differentially expressed RNA splice-related genes (n = 3). F–K The relative expression of Srsf1, Srsf2, Srsf3, Srsf7, Bmf, and Bcl2l1 was detected by qPCR (n = 4). L–M The expression level of SRSF1 was detected by western blot (n = 4). N The correlation between SRSF1 expression and OB apoptosis rate was analyzed by Pearson correlation (n = 4). In (F–K, M), the data are expressed as mean ± SD, where statistical significance was calculated using Student’s t test in (F–K) and using one-way ANOVA with Tukey post hoc test in (M). Control control group, GC glucocorticoid treatment group. *P < 0.05, **P < 0.01, ***P < 0.001, nsP > 0.05.

Fig 5: Overview of the involvement of Srsf1 in OB apoptosis induced by GC.GC induces the upregulation of Hdac4 and decreases the level of H3K9ac and H3K27ac in the Foxc1 promoter region to inhibit the expression of FOXC1, thereby reducing the expression of Srsf1. SRSF1 can bind to the 7807–8006 nucleotide sites of Bmf pre-mRNA to regulate the alternative splicing of Bmf. Overexpression of Srsf1 reduced the expression of Bmf V2 and Bmf V3 variants, thereby inhibiting GC-induced OB apoptosis; conversely, knockdown of Srsf1 increased the expression of Bmf V2 and V3 variants, thereby promoting GC-induced OB apoptosis.