Cathepsin D contributes to the accumulation of advanced glycation end products during photoaging
Cathepsin D contributes to the accumulation of advanced glycation end products during photoaging
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组织蛋白酶 D 有助于光老化过程中晚期糖基化终产物的积累
DOI：
10.1016/j.jdermsci.2018.02.009
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发表时间：
2018-06-01
影响因子：
4.6
通讯作者：
Xu, Qingfang
中科院分区：
文献类型：
--
作者：
Xu, Xinya;Zheng, Yue;Xu, Qingfang
背景：晚期糖基化终末产物(AGEs)的沉积在光老化皮肤中加速，但其潜在机制仍不清楚。最近，细胞内降解被认为在AGEs的去除中起着重要的作用。尽管溶酶体组织蛋白酶D(CatD)、B(CatB)、L(CATL)和蛋白酶体可降解内化AGEs，但目前尚不清楚人真皮成纤维细胞(HDF)内化AGEs的降解机制，以及细胞内AGEs降解的减少是否有助于光老化皮肤AGEs沉积的增加。目的：研究在光老化皮肤中参与降解细胞内AGEs的特异性蛋白酶，调节AGEs的积累。用流式细胞仪、酶联免疫吸附试验和共聚焦显微镜检测和比较光老化和非光老化成纤维细胞对AGE-BSA的摄取和降解。对光老化和非光老化成纤维细胞的蛋白酶体和溶酶体活性、CatD、CatB和CATL的表达进行了研究。进一步分析了慢病毒转导的蛋白酶抑制剂和CatD过表达对AGE-BSA降解的影响。最后，用免疫组织化学方法研究了不同年龄段皮肤中CatD的表达与AGEs蓄积的相关性。结果：反复UVA照射后成纤维细胞在体外发生光老化。AGE-BSA被光老化和非光老化成纤维细胞摄取，但光老化细胞的降解明显低于非光老化细胞。与非光老化细胞相比，光老化成纤维细胞中蛋白酶体、CatB、Cat Land Cat D的活性显著降低，CatB、CATL和CatD的表达显著减弱，但抑制蛋白酶体、CatB和CATL不影响HDFS中AGE-BSA的降解。相反，抑制CatD活性可剂量依赖性地降低AGE-BSA的降解，而过表达CatD则显著增加AGE-BSA的降解。重要的是，AGEs在体内光损伤皮肤中的积累与CatD的表达呈负相关。结论：CatD在细胞内AGEs的降解中起主要作用。在光老化的成纤维细胞中，CatD的表达和活性降低会损害细胞内AGEs的降解，这可能是光老化皮肤中AGEs沉积加速的原因之一。本研究为抗光老化治疗提供了一个潜在的新的分子基础。(C)2018年日本皮肤病研究学会。爱思唯尔出版，版权所有。
Background: The deposition of advanced glycation end products (AGEs) is accelerated in photoaged skin, but the underlying mechanisms remain elusive. Intracellular degradation has been recently considered to play an important role in AGEs removal. Although lysosomal cathepsin D (CatD), B (CatB), L(CatL) and proteasomes are found to degrade internalized AGEs, it remains unknown which protease degrades internalized AGEs in human dermal fibroblasts (HDFs), and whether a decrease in intracellular degradation contributes to enhanced AGEs deposition in photoaged skin.Objective: This study aims to investigate the specific proteases that contribute to intracellular AGEs degradation in HDFs and regulate AGEs accumulation in photoaged skin.Methods: Repetitive UVA irradiation was used to induce primary HDF photoaging in vitro. Uptake and degradation of AGE-BSA were verified and compared between photoaged and non-photoaged fibroblasts with flow cytometry, ELISA and confocal microscopy. Proteasomal and lysosomal activity, expression of CatD, CatB and CatL were also investigated between photoaged and non-photoaged fibroblasts. Further, the effect of protease inhibitors and CatD overexpression via lentiviral transduction on AGE-BSA degradation was analyzed. Finally, the correlation between CatD expression and AGEs accumulation in sun-exposed and sun-protected skin of people from different age was studied with immunohistochemistry.Results: Fibroblasts underwent photoaging in vitro after repetitive UVA irradiation. AGE-BSAwas taken up by both photoaged and non-photoaged fibroblasts, but its degradation was significantly decreased in photoaged cells than that of non-photoaged cells. Although the activity of proteasome, CatB, Cat Land Cat D was significantly reduced in photoaged fibroblasts compared to that of non-photoaged cells, and the expression of CatB, CatL and CatD was profoundly attenuated in photoaged fibroblasts, inhibiting proteasome, CatB and CatL did not affect AGE-BSA degradation in HDFs. In contrast, inhibiting CatD activity dose-dependently decreased AGE-BSA degradation; whereas CatD overexpression significantly increased AGE-BSA degradation. Importantly, AGEs accumulation in photo-damaged skin in vivo was inversely correlated with CatD expression.Conclusion: CatD plays a major role in intracellular AGEs degradation. Decreased CatD expression and activity impairs intracellular AGEs degradation in photoaged fibroblasts, which may contribute to accelerated AGEs deposition in photoaged skin. The present study provides a potentially novel molecular basis for antiphotoaging therapy. (C) 2018 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.