The tracking of cellular senescence usually depends on the detection of senescence‐associated β‐galactosidase (SA‐β‐gal). Previous probes for SA‐β‐gal with this purpose only cover a single dimension: the accumulation of this enzyme in lysosomes. However, this is insufficient to determine the destiny of senescence because endogenous β‐gal enriched in lysosomes is not only related to senescence, but also to some other physiological processes. To address this issue, we introduce our fluorescent probes including a second dimension: lysosomal pH, since de‐acidification is a unique feature of the lysosomes in senescent cells. With this novel design, our probes achieved excellent discrimination of SA‐β‐gal from cancer‐associated β‐gal, which enables them to track cellular senescence as well as tissue aging more precisely. Our crystal structures of a model enzyme E. coli β‐gal mutant (E537Q) complexed with each probe further revealed the structural basis for probe recognition.

中文翻译：

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构建用于精确跟踪衰老的智能荧光探针的二维设计策略

细胞衰老的追踪通常取决于衰老相关β-半乳糖苷酶（SA-β-gal）的检测。以前用于此目的的 SA-β-gal 探针仅涵盖一个维度：该酶在溶酶体中的积累。然而，这不足以确定衰老的命运，因为富含溶酶体的内源性 β-gal 不仅与衰老有关，还与其他一些生理过程有关。为了解决这个问题，我们引入了我们的荧光探针，包括第二个维度：溶酶体 pH 值，因为脱酸是衰老细胞中溶酶体的独特特征。通过这种新颖的设计，我们的探针实现了 SA-β-gal 与癌症相关 β-gal 的出色区分，这使它们能够更精确地跟踪细胞衰老和组织衰老。与每个探针复合的大肠杆菌β-gal 突变体（E537Q）进一步揭示了探针识别的结构基础。