UVA-induced photoaging inhibits autophagic degradation by impairing lysosomal function in dermal fibroblasts
UVA-induced photoaging inhibits autophagic degradation by impairing lysosomal function in dermal fibroblasts
复制标题
UVA 诱导的光老化通过损害真皮成纤维细胞的溶酶体功能来抑制自噬降解。
DOI：
10.1016/j.bbrc.2019.08.103
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发表时间：
2019-10-22
影响因子：
3.1
通讯作者：
Xu, Qingfang
中科院分区：
文献类型：
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作者：
Huang, Yunfen;Li, Yuying;Xu, Qingfang
自噬与多种疾病特别是衰老有关。人真皮成纤维细胞（HDFs）可以内化并降解溶酶体中的弹性蛋白、胶原蛋白和晚期糖基化终产物（AGEs），这在真皮细胞外基质稳态和AGEs去除中起着重要作用。尽管有报道称光老化成纤维细胞的自噬减少，但其潜在机制及其与光老化的相关性尚不清楚。我们发现，与非光老化对照相比，uva诱导的光老化成纤维细胞中每个细胞的GFP-LC3点、LC3I/II转换和p62表达显著增加，而beclinl表达没有改变。此外，氯喹处理对光老化成纤维细胞的自噬通量没有显著影响，但雷帕霉素处理显著诱导了自噬通量，这表明uva诱导的光老化可能抑制了降解阶段的自噬。进一步的溶酶体功能研究表明，光老化成纤维细胞中形成的自噬体、lc3i蛋白和DQ-Green BSA的降解都显著降低。LysoSensor黄/蓝DND 160染色和流式细胞术检测显示光老化明显减弱溶酶体酸化。光老化成纤维细胞中组织蛋白酶B、L和D的表达减少。这些数据表明，溶酶体酸度的降低和组织蛋白酶表达的减少可能有助于抑制自噬降解，这可能是通过损害细胞内降解而发生光老化的关键。(C) 2019 Elsevier Inc.版权所有。
Autophagy has been associated with a variety of diseases especially aging. Human dermal fibroblasts (HDFs) can internalize and then degrade elastin, collagen and advanced glycation end products (AGEs) in lysosomes, which plays prominent roles in extracellular matrix homeostasis and AGEs removal in the dermis. Although autophagy has been reported to be decreased in photoaged fibroblasts, the underlying mechanism and its relevance to photoaging remain elusive. Here, we showed that GFP-LC3 puncta per cell, LC3I/II conversion and p62 expression were significantly increased, whereas beclinl expression was not altered in UVA-induced photoaged fibroblasts compared with non-photoaged control. Moreover, autophagic flux was not significantly affected by chloroquine treatment, but was remarkably induced by rapamycin treatment in photoaged fibroblasts, suggesting that UVA-induced photoaging might inhibit autophagy at the degradation stage. Further lysosomal function studies demonstrated that degradation of formed autophagosomes, LC3IIprotein and DQ-Green BSA was all dramatically decreased in photoaged fibroblasts. LysoSensor yellow/blue DND 160 staining and flow cytometry assays demonstrated that photoaging obviously attenuated lysosomal acidification. Also, decreased expression of cathepsin B, L and D was found in photoaged fibroblasts. These data suggest that lowered lysosomal acidity and decreased cathepsins expression might contribute to the inhibition of autophagic degradation, which might be crucial in the development of photoaging through impairing intracellular degradation. (C) 2019 Elsevier Inc. All rights reserved.