Gene expression of senescent and non-senescent AL1 cells. Gene expression of senescent and non-senescent AL1 cells

Axolotl limb regeneration proceeds through the formation of a blastema, a mound of progenitor cells that accumulate at the end of the amputated stump. These progenitor cells expand and later undergo patterning to regenerate the missing limb, restoring both form and function. A subset of cells within the blastema become senescent, a state of permanent growth arrest. Here, we address the functional relevance of cellular senescence to axolotl limb regeneration, through a combination of gain- and loss-of-function assays. Using transcriptomic analyses on in vitro and in vivo senescent cells, we gain insights into the basis of the senescent phenotype, cell-cycle arrest, and molecular mediators involved in axolotl regeneration at the molecular level. Overall design: AL1 cells were treated with either etoposide and nutlin-3a to trigger senescence induction, or DMSO to generate proliferating controls. Their transcriptomes were analyzed through RNA-seq to obtain insights into the molecular basis of senescence induction in axolotl AL1 cells, as well as to uncover common features between in vitro and in vivo senescennce in the axolotl.

美西钝口螈（Axolotl）的肢体再生通过芽基（blastema）的形成启动，芽基是一类在截肢残端末端聚集的祖细胞团块。此类祖细胞会发生增殖扩增，后续再经历模式形成过程以再生出缺失的肢体，同时恢复其形态与功能。芽基内的一部分细胞会进入衰老状态，即永久性的生长阻滞状态。本研究通过功能获得与功能丧失实验相结合的手段，探究细胞衰老对美西钝口螈肢体再生的功能相关性。我们通过对体外及体内的衰老细胞开展转录组分析，从分子层面解析美西钝口螈再生过程中衰老表型、细胞周期阻滞的发生基础，以及相关的分子介导因子。

整体实验设计：将AL1细胞分为两组，一组经依托泊苷（etoposide）与Nutlin-3a处理以诱导细胞衰老，另一组经二甲基亚砜（DMSO）处理以构建增殖型对照组。通过RNA-seq对两组细胞的转录组进行分析，一方面阐明美西钝口螈AL1细胞中衰老诱导的分子基础，另一方面揭示美西钝口螈体内与体外衰老过程的共通特征。