Liang Ang, Liu Jinglong, Zhang Zhiyuan, Xiao Jing, Liu Dezeng, Dong Zimei, Chen Guangwen
College of Life Science, Henan Normal University, Xinxiang, Henan, China.
School of Nursing, Xinxiang Medical University, Xinxiang, Henan, China.
J Transl Med. 2025 Jan 30;23(1):137. doi: 10.1186/s12967-025-06134-w.
Regeneration plays a key role in energy recycling and homeostasis maintenance. Planarians, as ideal model animals for studying regeneration, stem cell proliferation, and apoptosis, have the strong regenerative abilities. Considerable evidence suggests that ubiquitin plays an important role in maintaining homeostasis and regulating regeneration, but the function of Ubiquitin specific proteases 7 (Usp7) on regeneration in planarians remains elusive.
We identified an evolutionarily conserved gene, Usp7, and utilized RNA interference (RNAi), Quantitative real-time PCR (qRT-PCR), Whole-mount immunofluorescence, Tunnel, Whole-mount in situ hybridization (WISH), and western blotting to detect the function of Usp7 during the planarian regeneration.
In this study, we found that the regenerative trunk fragments in the Usp7 RNAi worms could not regenerate missing tails; meanwhile, the level of cell proliferation was decreased, while cell apoptosis was increased. Furthermore, the expression of Islet was inhibited in the Usp7 RNAi worms during planarian regeneration. The hybridization signal of wnt1/P-1 exhibited the dot-like pattern at the posterior of the regenerating planarians after Usp7 RNAi at regenerative 1 day (R 1 d). However, the concentrated expression pattern wnt1/P-1 dramatically declined at regenerative 3 days (R 3 d) and disappeared at regenerative 7 days (R 7 d). In addition, activating the Wnt pathway partially rescued regenerative defects induced by inhibition of Usp7.
Collectively, Usp7 is necessary for tissue regeneration and tail blastema formation partially by regulating the cell proliferation and apoptosis during planarian regeneration. It could also promote the posterior polarity reconstruction of the regenerative planarians via the Islet/Wnt1 axis.
再生在能量循环和体内平衡维持中起着关键作用。涡虫作为研究再生、干细胞增殖和凋亡的理想模式动物，具有强大的再生能力。大量证据表明泛素在维持体内平衡和调节再生中发挥重要作用，但泛素特异性蛋白酶7（Usp7）在涡虫再生中的功能仍不清楚。
我们鉴定了一个进化上保守的基因Usp7，并利用RNA干扰（RNAi）、定量实时PCR（qRT-PCR）、全组织免疫荧光、Tunnel、全组织原位杂交（WISH）和蛋白质免疫印迹法来检测Usp7在涡虫再生过程中的功能。
在本研究中，我们发现Usp7 RNAi蠕虫的再生躯干片段无法再生缺失的尾巴；同时，细胞增殖水平降低，而细胞凋亡增加。此外，在涡虫再生过程中，Usp7 RNAi蠕虫中胰岛（Islet）的表达受到抑制。在再生第1天（R 1 d）进行Usp7 RNAi后，再生涡虫后部的wnt1/P-1杂交信号呈点状模式。然而，在再生第3天（R 3 d），wnt1/P-1的集中表达模式显著下降，并在再生第7天（R 7 d）消失。此外，激活Wnt信号通路部分挽救了因抑制Usp7而导致的再生缺陷。
总体而言，Usp7对于组织再生和尾芽基形成是必需的，部分原因是其在涡虫再生过程中调节细胞增殖和凋亡。它还可以通过Islet/Wnt1轴促进再生涡虫的后部极性重建。
