Selenoprotein P attenuates oxidative senescence and ferroptosis-associated lipid peroxidation in dental pulp stem cells through a FOXM1-dependent program

Figure 6 Aging human dental pulp exhibits depletion of selenoprotein P and forkhead box protein M1 and reduced expression of selenium-dependent antioxidant genes. A: Representative hematoxylin and eosin staining of human dental pulp tissues from young and aging groups. Scale bars = 50 μm; B: Western blot analysis of forkhead box protein M1 (FOXM1) and selenoprotein P (SEPP1) in human dental pulp tissues (young vs aging); ACTB was used as the loading control; C: Densitometric quantification of FOXM1 and SEPP1 protein expression normalized to ACTB (n = 3); D: Representative immunofluorescence images of SEPP1 (green) and THY1 (red) in young dental pulp tissues; nuclei were counterstained with DAPI (blue). Scale bars = 50 μm; E: Representative immunofluorescence images of SEPP1 (green) and THY1 (red) in aging dental pulp tissues. Scale bars = 50 μm; F: Quantification of SEPP1 fluorescence intensity; G: Pearson’s correlation coefficient analysis of SEPP1 and THY1 colocalization; H: Representative immunofluorescence images of FOXM1 (green) and THY1 (red) in young dental pulp tissues. Scale bars = 50 μm; I: Representative immunofluorescence images of FOXM1 (green) and THY1 (red) in aging dental pulp tissues. Scale bars = 50 μm; J: Quantification of FOXM1 fluorescence intensity; K: Pearson’s correlation coefficient analysis of FOXM1 and THY1 colocalization; L: Quantitative real-time polymerase chain reaction (qPCR) analysis of glutathione peroxidase 4 mRNA in young and aging pulp tissues; M: QPCR analysis of thioredoxin reductase 1 mRNA in young and aging pulp tissues; N: QPCR analysis of DIO2 mRNA in young and aging pulp tissues. Data are presented as mean ± SD. ^aP < 0.05. FOXM1: Forkhead box protein M1; SEPP1: Selenoprotein P; GPX4: Glutathione peroxidase 4; TXNRD1: Thioredoxin reductase 1.