| Gene name: | DPP4 |
| Aging type: | Accelerate |
| Aging characteristic: |
| Tissue type: | -- |
| Cell name: | HUVECs |
| Experiment: | SA-β-gal activity assay//Western blot//Immunochemical staining |
| Description: | The fraction of senescence-associated β-galactosidase (SA-β-gal) positive cells was increased with aging, whereas DPP4 inhibition mitigated this enhancement. In addition, immunohistochemical staining and western blot analysis revealed that the aging markers, including p53 and p21, were increased with advancing age, whereas DPP4 inhibition reversed these changes. Taken together, these data demonstrated that inhibiting DPP4 activity partly prevented vascular aging. Small interfering RNA (SiRNA) for DPP4 silencing was used. After exposure to H2O2, the fraction of cells that stained positive for SA-β-gal was markedly increased, accompanied with augmented p53 and p21 expression. DPP4 knockdown significantly reversed H2O2-induced increase in SA-β-gal + cell numbers, and p53, p21 expression. Inhibiting DPP4 with saxagliptin repressed both the activity and expression of DPP4 in endothelial cells, and inhibiting DPP4 reversed H2O2-induced augmentation of SA-β-gal + cell numbers, as well as p53 and p21 expression. |
| Regulatory pathway: | AMPK-SIRT1-NRF2 |
| R-AG-Pathway: | Activation |
| Pathway experiment: | Immunochemical staining//Western blot//Immunofluorescence |
| Pathway description: | Immunohistochemical staining and western blot analysis revealed that SIRT1 and AMPKα expression, as well as phosphorylation level of AMPKα, was decreased with aging, and that DPP4 inhibition was able to restore these changes in aging aortas. As observed in in vivo studies, SIRT1 and AMPKα expression, as well as - phosphorylation level of AMPKα, was also decreased in H2O2-induced senescent endothelial cells, whereas DPP4 knockdown, or inhibition with saxagliptin, significantly reversed these changes. Our data from immunofluorescence staining revealed that SIRT1 activation and DPP4 silencing promoted the translocation of Nrf2 into the nucleus. However, inhibiting SIRT1 reversed the effect of DPP4 knockdown on Nrf2 translocation. Moreover, Nrf2 expression was decreased with cell senescence, whereas DPP4 silencing or SIRT1 activation reversed Nrf2 expression. The results from western blot analysis demonstrated that Nrf2 expression was decreased with vascular aging, while DPP4 inhibition markedly abolished this change. Similarly, Nrf2 expression was reduced in senescent endothelial cells, while DPP4 silencing reversed this change. |
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