Anagliptin prevented interleukin 1β (IL-1β)-induced cellular senescence in vascular smooth muscle cells through increasing the expression of sirtuin1 (SIRT1)

Abstract

Vascular smooth muscle cell senescence plays a pivotal role in the pathogenesis of atherosclerosis. Anagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor for the treatment of hyperglycemia. Recent progress indicates that DPP-4 inhibitors show a wide range of cardiovascular benefits. We hypothesize that Anagliptin plays a role in vascular smooth muscle cell senescence and this may imply its modulation of atherosclerosis. Here, the beneficial effect of Anagliptin against interleukin 1β (IL-1β)-induced cell senescence in vascular smooth muscle cells was studied to learn the promising therapeutic capacity of Anagliptin on atherosclerosis. Firstly, we found that Anagliptin treatment ameliorated the elevated secretions of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and macrophage chemoattractant protein-1 (MCP-1). Secondly, our findings indicate that exposure to IL-1β reduced telomerase activity from 26.7 IU/L to 15.8 IU/L, which was increased to 20.3 and 24.6 IU/L by 2.5 and 5 μM Anagliptin, respectively. In contrast, IL-1β stimulation increased senescence- associated β-galactosidase (SA-β-gal) staining to 3.1- fold compared to the control group, it was then reduced to 2.3- and 1.6- fold by Anagliptin dose-dependently. Thirdly, Anagliptin dramatically reversed the upregulated p16, p21, and downregulated sirtuin1 (SIRT1) in IL-1β-treated vascular smooth muscle cells. Lastly, the protective effect of Anagliptin against cellular senescence in vascular smooth muscle cells was abolished by silencing of SIRT1. In conclusion, Anagliptin protects vascular smooth muscle cells from cytokine-induced senescence, and the action of Anagliptin in vascular smooth muscle cells requires SIRT1 expression.

Keywords: Anagliptin; atherosclerosis; cell senescence; il-1β; sirt1; vascular smooth muscle cells.

Graphical abstract

Figure 1.

The effects of Anagliptin on cell viability of vascular smooth muscle cells. Cells were stimulated with Anagliptin at the concentrations of 0.1, 0.25, 0.5, 2.5, 5, 25, and 50 μM for 24 hours. (a). Molecular structure of Anagliptin; (b). Cell viability; (c). Release of LDH (*, **, P < 0.05, 0.01 vs. vehicle group)

Figure 2.

Anagliptin reduced IL-1β- induced pro-inflammatory cytokines. (a-c). mRNA of TNF-α, IL-6, and MCP-1; (d-f). Secretions of TNF-α, IL-6, and MCP-1 (****, P < 0.0001 vs. vehicle group, ##, ###, P < 0.1, 0.001 vs. IL-1β group)

Figure 3.

Anagliptin restored IL-1β-induced reduction of telomerase activity. Telomerase activity was measured using a commercial kit (****, P < 0.0001 vs. vehicle, ##, ###, P < 0.1, 0.001 vs. IL-1β)

Figure 4.

Anagliptin prevented IL-1β-induced cellular senescence. Cellular senescence was assayed using SA-β-gal staining. Scale bar, 100 μM (****, P < 0.0001 vs. vehicle, ##, ###, P < 0.1, 0.001 vs. IL-1β)

Figure 5.

Anagliptin prevented IL-1β-induced p16 and p21. (a). mRNA of p16 and p21; (b). Protein of p16 and p21 (****, P < 0.0001 vs. vehicle group, ##, ###, P < 0.1, 0.001 vs. IL-1β group)

Figure 6.

Anagliptin restored IL-1β-induced expression of SIRT1. (a). mRNA of SIRT1; (b). Protein of SIRT1 (****, P < 0.0001 vs. vehicle, ##, ###, P < 0.1, 0.001 vs. IL-1β)

Figure 7.

Silencing of SIRT1 abolished the protective effects of Anagliptin against IL-1β- induced cellular senescence. (a). Successful knockdown of SIRT1; (b). Telomerase activity; (c). Cellular senescence (****, P < 0.0001 vs. vehicle, ###, P < 0.001 vs. IL-1β; $$$, P < 0.001 vs. IL-1β+ Anagliptin group)