Immortalized Human Skin Fibroblast-SV40

Screening of Active Molecules to Prevent UVA-Induced Senescence of HDF Cells

Cellular senescence plays a critical role in repeated ultraviolet (UV) exposure-induced skin photoaging. Currently, from the perspective of regulating senescent cells, potent compounds or reliable protein targets that could effectively prevent skin photoaging have not yet been reported.

Candidate compounds against UVA-induced photoaging were screened from 27 natural products at a concentration of 10 μM. The immortalized human dermis skin fibroblasts (HDF) were treated with UVA irradiation for 30 min to induce senescence, and 10 μM natural products were added to the medium and incubated with the cells for 24 h, as Fig. 1a depicted. Senescent cells were characterized by elevated SA-β-gal activity, SASP secretion and increased p16 and p21 protein expression.

The results indicated that chlorogenic acid (CGA) could effectively reduce the proportion of SA-β-gal positive cells induced by UVA treatment. The ELISA data confirmed that CGA exhibited the best biologic activity in inhibiting the senescence of HDF, supported by the decreased TNF-α and IL-6 secretion in treated groups. Furthermore, CGA is just as effective as rapamycin (RA, a positive drug that suppress senescence, concentration in 5 nM) in preventing UVA-induced senescence of HDF cells (Fig. 1b, c). Flow cytometry results showed that CGA also inhibited UVA-induced elevation of ROS level (Fig. 1d). And western blot analysis further showed that CGA could effectively inhibit the expression levels of p16 and p21 proteins in UVA-induced HDF cells (Fig. 1e). Moreover, CGA can also significantly suppressed the expression levels of inflammatory factors TNF-α and IL-6 proteins in UVA-treated HDF cells (Fig. 1f). In conclusion, these results demonstrated that CGA effectively prevented UVA induced senescence of HDF in vitro.