Rapidly renewable tissues adapt different strategies to cope with environmental insults. While tissue repair is associated with increased intestinal stem cell (ISC) proliferation and accelerated tissue turnover rates, reduced calorie intake triggers a homeostasis-breaking process causing adaptive resizing of the gut. Here we show that activins are key drivers of both adaptive and regenerative growth. Activin-β (Actβ) is produced by stem and progenitor cells in response to intestinal infections and stimulates ISC proliferation and turnover rates to promote tissue repair. Dawdle (Daw), a divergent Drosophila activin, signals through its receptor, Baboon, in progenitor cells to promote their maturation into enterocytes (ECs). Daw is dynamically regulated during starvation-refeeding cycles, where it couples nutrient intake with progenitor maturation and adaptive resizing of the gut. Our results highlight an activin-dependent mechanism coupling nutrient intake with progenitor-to-EC maturation to promote adaptive resizing of the gut and further establish activins as key regulators of adult tissue plasticity.

快速再生的组织采用不同的策略来应对环境侵害。虽然组织修复与肠干细胞（ISC）增殖增加和组织更新率加快有关，但热量摄入减少会引发破坏体内平衡​​的过程，导致肠道适应性调整大小。在这里，我们证明激活素是适应性和再生性生长的关键驱动因素。激活素-β (Actβ) 由干细胞和祖细胞响应肠道感染而产生，刺激 ISC 增殖和周转率，从而促进组织修复。 Dawdle (Daw) 是一种不同的果蝇激活素，通过其受体 Baboon 在祖细胞中发出信号，促进其成熟为肠上皮细胞 (EC)。 Daw 在饥饿-再进食周期中受到动态调节，它将营养摄入与祖细胞的成熟和肠道的适应性调整结合起来。我们的结果强调了激活素依赖性机制，将营养摄入与祖细胞到 EC 的成熟结合起来，以促进肠道的适应性调整，并进一步确立激活素作为成体组织可塑性的关键调节剂。