背景:溶酶体组织蛋白酶D(CTSD)可以降解真皮成纤维细胞中内化的晚期糖基化终产物(AGEs)。光老化成纤维细胞中CTSD表达降低,这有助于细胞内AGEs沉积并进一步在光老化皮肤的AGEs积累中起作用。CTSD表达下调的机制尚不清楚。
目的:探讨光老化成纤维细胞CTSD表达调控的可能机制。
方法:反复紫外线A(UVA)照射诱导真皮成纤维细胞光老化。构建竞争性内源RNA(ceRNA)网络以预测与CTSD表达相关的候选circRNAs或miRNA。用流式细胞术研究成纤维细胞对AGEs-BSA的降解,ELISA,和共聚焦显微镜。通过慢病毒转导过表达circRNA-406918对CTSD表达的影响,自噬,在光老化的成纤维细胞中分析AGE-BSA降解。研究了circRNA-406918与晒太阳和防晒皮肤中CTSD表达或AGEs积累之间的相关性。
结果:CTSD表达,自噬,光老化成纤维细胞中AGEs-BSA降解显著降低。CircRNA-406918被鉴定为调节CTSD表达,自噬,和光老化成纤维细胞的衰老。过表达circRNA-406918能有效降低衰老和增加CTSD表达,自噬通量,和AGEs-BSA在光老化成纤维细胞中的降解。此外,circRNA-406918水平与CTSDmRNA表达呈正相关,与光损伤皮肤中AGEs积累呈负相关。Further,预测circRNA-406918通过形成八个miRNA来介导CTSD表达。
结论:这些发现表明,circRNA-406918在UVA诱导的光老化成纤维细胞中调节CTSD表达和AGEs降解,并可能在光老化皮肤中AGEs积累中发挥作用。
BACKGROUND: Lysosomal cathepsin D (CTSD) can degrade internalized advanced glycation end products (AGEs) in dermal fibroblasts. CTSD expression is decreased in photoaged fibroblasts, which contributes to intracellular AGEs deposition and further plays a role in AGEs accumulation of photoaged skin. The mechanism under downregulated CTSD expression is unclear.
OBJECTIVE: To explore possible mechanism of regulating CTSD expression in photoaged fibroblasts.
METHODS: Dermal fibroblasts were induced into photoaging with repetitive ultraviolet A (UVA) irradiation. The competing endogenous RNA (ceRNA) networks were constructed to predict candidate circRNAs or miRNAs related with CTSD expression. AGEs-BSA degradation by fibroblasts was studied with flow cytometry, ELISA, and confocal microscopy. Effects of overexpressing circRNA-406918 via lentiviral transduction on CTSD expression, autophagy, AGE-BSA degradation were analyzed in photoaged fibroblasts. The correlation between circRNA-406918 and CTSD expression or AGEs accumulation in sun-exposed and sun-protected skin was studied.
RESULTS: CTSD expression, autophagy, and AGEs-BSA degradation were significantly decreased in photoaged fibroblasts. CircRNA-406918 was identified to regulate CTSD expression, autophagy, and senescence in photoaged fibroblasts. Overexpressing circRNA-406918 potently decreased senescence and increased CTSD expression, autophagic flux, and AGEs-BSA degradation in photoaged fibroblasts. Moreover, circRNA-406918 level was positively correlated with CTSD mRNA expression and negatively associated with AGEs accumulation in photodamaged skin. Further, circRNA-406918 was predicted to mediate CTSD expression through sponging eight miRNAs.
CONCLUSIONS: These findings suggest that circRNA-406918 regulates CTSD expression and AGEs degradation in UVA-induced photoaged fibroblasts and might exert a role in AGEs accumulation in photoaged skin.