关键词: 皮肤衰老, 细胞衰老, 自噬, 成纤维细胞, 环状RNA, circIGF2BP3

Abstract: 【Abstract】 Objective To preliminarily investigate the effect of circIGF2BP3 on autophagy in photoaged dermal fibroblasts. Methods Human dermal fibroblasts were isolated from circumcised foreskin tissues from 6 children in the Department of Urological Surgery, Third Affiliated Hospital of Sun Yat-sen University. An ultraviolet A （UVA）-induced photoaged human dermal fibroblast model （UVA radiation group） was established by repeated UVA radiation at a dose of 10 J/cm2 for 14 consecutive days, and human dermal fibroblasts receiving no treatment served as control group. The photoaged cell model was verified by β-galactosidase staining, Western blot analysis for determining P21 protein expression, and cell counting kit-8 （CCK8） assay for evaluating cell viability. Moreover, Western blot analysis was performed to determine the protein expression of autophagy-related proteins P62, microtubule-associated protein 1 light chain 3 （LC3）-Ⅰand LC3-Ⅱ in photoaged human dermal fibroblasts, and real-time quantitative RCR （qRT-PCR） to verify the differential expression of circIGF2BP3 between photoaged and normal human dermal fibroblasts. Furthermore, circIGF2BP3 was biologically annotated. Some cultured primary human dermal fibroblasts were divided into 4 groups: empty vector group transfected with an empty vector, UVA + empty vector group transfected with an empty vector followed by repeated UVA radiation, circIGF2BP3 group transfected with a circIGF2BP3-overexpressing lentiviral vector, UVA + circIGF2BP3 group transfected with a circIGF2BP3-overexpressing lentiviral vector followed by repeated UVA radiation. Western blot analysis was performed to determine the expression of autophagy-related proteins. Statistical analysis was carried out by using t test, one-way analysis of variance and least significant difference-t test. Results Compared with the control group, the UVA radiation group showed significantly increased proportions of β-galactosidase-positive cells （61.33% ± 5.78% vs. 6.37% ± 0.32%, t = 9.49, P < 0.01） and P21 expression（1.25 ± 0.03 vs. 1.00 ± 0.05, t = 4.26, P < 0.05）, but significantly decreased cell viability （74.33% ± 3.48% vs. 100%, t = 7.38, P < 0.01）. Moreover, the P62 expression and LC3-Ⅱ/Ⅰ ratio were significantly higher in the UVA radiation group than in the control group （both P < 0.05）. The relative expression of circIGF2BP3 was 0.72 ± 0.04 in the photoaged human dermal fibroblasts, which was significantly lower than that in the normal human dermal fibroblasts （1.00 ± 0.03, t = 5.46, P < 0.01）. The P62 expression and LC3-Ⅱ/Ⅰ ratio were significantly lower in the circIGF2BP3 group （0.60 ± 0.01, 0.71 ± 0.01, respectively） than in the empty vector group （1.00 ± 0.02, 1.00 ± 0.01, t = 16.25, 2.75, P < 0.01, < 0.05, respectively）, and lower in the UVA + circIGF2BP3 group （1.05 ± 0.02, 2.04 ± 0.05, respectively） than in the UVA + empty vector group （1.31 ± 0.02, 2.72 ± 0.14, t = 10.493, 6.472, respectively, both P < 0.01）. Conclusion circIGF2BP3 can regulate autophagy in UVA-induced photoaged dermal fibroblasts, which provides a new potential therapeutic target for the prevention and treatment of skin photoaging.

Key words: Skin aging, Cell aging, Autophagy, Fibroblasts, Circular RNA, circIGF2BP3