IGF-1 Accelerates Cell Aging by Inhibiting POLD1 Expression.

The individual cascades of the insulin-like growth factor-1 (IGF-1) signaling pathway and the molecular mechanism of aging have not been fully clarified. In the current study, we explored the effect of DNA polymerase delta 1 (POLD1) on the IGF-1 signaling pathway in cell aging.First, we analyzed the relationship between IGF-1 and POLD1 expression in aging. To investigate the effect of IGF-1 on POLD1 expression and aging, the 2BS cells were incubated with young-age or old-age human serum, IGF-1 protein, or linsitinib. Next, the effect of IGF-1 on aging was examined in the 2BS cells with increased or decreased POLD1 expression to clarify the molecular mechanism.In this study, we found that IGF-1 expression increased and POLD1 expression decreased with aging in human serum and hippocampal tissues of SAMP8 mice, and a negative relationship between IGF-1 and POLD1 expression was observed. Furthermore, the cells cultured with old-age human serum or IGF-1 showed lower POLD1 expression and more pronounced senescence characteristics, and the effect could be reversed by treatment with linsitinib or overexpression of POLD1, while the effect of linsitinib on cell aging could be reversed with the knockdown of POLD1.Taken collectively, our findings demonstrate that IGF-1 promotes aging by binding to IGF-1R and inhibiting the expression of POLD1. These findings offer a new target for anti-aging strategies.