Association of increased autophagic inclusions labeled for β-galactosidase with fibroblastic aging
Association of increased autophagic inclusions labeled for β-galactosidase with fibroblastic aging
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DOI：
10.1016/s0531-5565(03)00132-3
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发表时间：
2003-08-01
影响因子：
3.9
通讯作者：
Ffrench, M
中科院分区：
文献类型：
--
作者：
Gerland, LM;Peyrol, S;Ffrench, M
复制性衰老在有限次数的细胞分裂后出现。增殖停止后，衰老细胞仍能长期存活，并观察到代谢改变，例如脂褐素积累。为了理解这种现象，我们检查了 MRC5 正常人成纤维细胞中与自噬相对应的亚细胞修饰的出现。与年轻成纤维细胞相比，衰老过程中观察到单丹磺酰尸胺荧光（自噬的特定标记）增加（p < 0.0001）。电子显微镜证实了衰老成纤维细胞中自噬泡的增加。我们比较了年轻和衰老的成纤维细胞，结果表明，年轻细胞中已经存在的自噬泡在衰老的成纤维细胞中变得更大，并且包涵体面积相对于测量的细胞面积显着相对增加（p = 0.0041）。然而，与年轻成纤维细胞相比，衰老细胞中自噬相关基因的表达保持稳定，表明自噬过程本身并未增强。与此同时，透射电子显微镜分析表明，β-半乳糖苷酶活性分布因衰老而改变：β-半乳糖苷酶（一种与溶酶体相关的酶）分散在年轻成纤维细胞中，但在衰老成纤维细胞中聚集在自噬液泡水平，表明此阶段自噬溶酶体占主导地位。这些结果支持这样的假设：在成纤维细胞衰老过程中，自噬空泡以及β-半乳糖苷酶活性的增加可能与溶酶体质量的增加以及具有脂褐素的降解自溶酶体的积累有关。这种现象可能与衰老成纤维细胞的死亡有关。 (C) 2003 Elsevier Inc. 保留所有权利。
Replicative senescence appears after a finite number of cell divisions. After proliferation has ceased, senescent cells remain viable for long periods and metabolic modifications are observed such as lipofuscin accumulation. In order to understand this phenomenon, we examined the emergence of subcellular modifications corresponding to autophagy in MRC5 normal human fibroblasts. An increase of monodansylcadaverine fluorescence, a specific marker of autophagy, in aging compared to young fibroblasts was observed (p < 0.0001). The increase of autophagic vacuoles in aging fibroblasts was confirmed by electron microscopy. We compared young versus senescent fibroblasts and showed that autophagic vacuoles, already present in young cells, became larger in senescent fibroblasts with a significant relative increase of inclusion area with respect to measured cell area (p = 0.0041). However, autophagy-associated-gene expression remained stable in senescent compared to young fibroblasts, suggesting that the autophagy process per se is not enhanced. In parallel, transmission electron microscopy analysis showed that beta-galactosidase activity distribution was modified by aging: beta-galactosidase (an enzyme linked to lysosome) was scattered in young fibroblasts, but clustered at the level of autophagic vacuoles in senescent fibroblasts, suggesting a predominance of autolysosomes at this stage. These results support the hypothesis that, during fibroblast aging, the increase of autophagic vacuoles, as well as that of beta-galactosidase activity, may be associated to an increase of lysosomal mass and to an accumulation of degradative autolysosomes with lipofuscin. This phenomenon could be involved in the death of senescent fibroblasts. (C) 2003 Elsevier Inc. All rights reserved.