TP53 modulates oxidative stress in Gata1+ erythroid cells. Danio rerio

In this report, we have found that gata1 expressing erythroid cells contribute to a significant proportion of total body oxidative stress when animals were exposed to a strong pro-oxidant. RNA-seq of zebrafish under oxidative stress revealed the induction of tp53. Zebrafish carrying tp53 with mutation in its DNA binding domain were acutely sensitive to pro-oxidant exposure and displayed significant reactive oxygen species (ROS) and tp53-independent erythroid cell death resulting in an edematous phenotype. We found that a major contributing factor to ROS was increased basal mitochondrial respiratory rate without reserve. These data add to the concept that tp53, while classically a tumor suppressor and cell cycle regulator, has additional roles in controlling cellular oxidative stress. Overall design: We performed RNA-seq in two experiments. (1) Wild-type zebrafish embryos were exposed to 1-naphthol (vs no exposure) from 24 - 72 hpf (n = 5/group). (2) tp53 mutant zebrafish embryos were exposed to 1-naphthol (vs no exposure) from 24 - 72 hpf (n = 5/group).

本研究报告显示，在动物暴露于强促氧化剂环境时，表达GATA1（gata1）的红细胞系细胞在全身总氧化应激中占比显著。对氧化应激下斑马鱼开展的RNA测序（RNA-seq）结果显示，tp53基因被诱导表达。携带tp53 DNA结合结构域突变的斑马鱼对促氧化剂暴露表现出急性敏感性，可出现显著的活性氧（ROS，reactive oxygen species）积累以及不依赖tp53的红细胞系细胞死亡，最终引发水肿表型。我们发现，活性氧产生的主要诱因之一是基础线粒体呼吸速率升高且缺乏呼吸储备能力。上述数据进一步丰富了相关认知：尽管tp53经典功能为肿瘤抑制因子与细胞周期调控因子，但其在调控细胞氧化应激方面还存在额外作用。总体实验设计：我们开展了两组RNA测序实验。(1) 野生型斑马鱼胚胎于受精后24~72小时（hpf，hours post-fertilization）暴露于1-萘酚，设置未暴露组作为对照，每组含5个生物学重复（n=5/group）。(2) tp53突变型斑马鱼胚胎于受精后24~72小时暴露于1-萘酚，设置未暴露组作为对照，每组含5个生物学重复（n=5/group）。