College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.
Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina.
Am J Physiol Gastrointest Liver Physiol. 2021 Nov 1;321(5):G588-G602. doi: 10.1152/ajpgi.00165.2021. Epub 2021 Sep 22.
Intestinal ischemia is a life-threatening emergency with mortality rates of 50%-80% due to epithelial cell death and resultant barrier loss. Loss of the epithelial barrier occurs in conditions including intestinal volvulus and neonatal necrotizing enterocolitis. Survival depends on effective epithelial repair; crypt-based intestinal epithelial stem cells (ISCs) are the source of epithelial renewal in homeostasis and after injury. Two ISC populations have been described: ) active ISC [aISC; highly proliferative; leucine-rich-repeat-containing G protein-coupled receptor 5 (LGR5)-positive or sex-determining region Y-box 9 -antigen Ki67-positive (SOX9Ki67)] and ) reserve ISC [rISC; less proliferative; homeodomain-only protein X positive (HOPX)]. The contributions of these ISCs have been evaluated both in vivo and in vitro using a porcine model of mesenteric vascular occlusion to understand mechanisms that modulate ISC recovery responses following ischemic injury. In our previously published work, we observed that rISC conversion to an activated state was associated with decreased expression during in vitro recovery. In the present study, we wanted to evaluate the direct role of on cellular proliferation during recovery after injury. Our data demonstrated that during early in vivo recovery, injury-resistant HOPX cells maintain quiescence. Subsequent early regeneration within the intestinal crypt occurs around 2 days after injury, a period in which HOPX expression decreased. When was silenced in vitro, cellular proliferation of injured cells was promoted during recovery. This suggests that HOPX may serve a functional role in ISC-mediated regeneration after injury and could be a target to control ISC proliferation. This paper supports that rISCs are resistant to ischemic injury and likely an important source of cellular renewal following near-complete epithelial loss. Furthermore, we have evidence that controls ISC activity state and may be a critical signaling pathway during ISC-mediated repair. Finally, we use multiple novel methods to evaluate ISCs in a translationally relevant large animal model of severe intestinal injury and provide evidence for the potential role of rISCs as therapeutic targets.
肠缺血是一种危及生命的紧急情况，死亡率为 50%-80%，原因是上皮细胞死亡和由此导致的屏障丧失。上皮屏障的丧失发生在肠扭转和新生儿坏死性小肠结肠炎等情况下。生存取决于有效的上皮修复；隐窝基肠上皮干细胞（ISC）是在稳态和损伤后上皮更新的来源。已经描述了两种 ISC 群体：）活跃的 ISC[aISC；高度增殖；富含亮氨酸重复的 G 蛋白偶联受体 5（LGR5）阳性或性别决定区 Y 盒 9-抗原 Ki67 阳性（SOX9Ki67）]和）储备 ISC[rISC；增殖较少；同源域蛋白 X 阳性（HOPX）]。使用猪肠系膜血管闭塞模型在体内和体外评估了这些 ISC 的贡献，以了解调节 ISC 恢复反应的机制缺血性损伤后。在我们之前发表的工作中，我们观察到 rISC 向激活状态的转化与体外恢复过程中 表达的减少有关。在本研究中，我们希望评估 在损伤后恢复期间对细胞增殖的直接作用。我们的数据表明，在体内早期恢复过程中，耐损伤的 HOPX 细胞保持静止。损伤后肠道隐窝内的早期再生发生在损伤后 2 天左右，在此期间 HOPX 表达下降。在体外沉默 时，损伤细胞的细胞增殖在恢复过程中得到促进。这表明 HOPX 可能在损伤后 ISC 介导的再生中发挥功能作用，并且可能是控制 ISC 增殖的靶点。本文支持 rISC 对缺血性损伤具有抗性，并且可能是近完全上皮丢失后细胞更新的重要来源。此外，我们有证据表明 控制 ISC 活性状态，并且可能是 ISC 介导的修复过程中的关键信号通路。最后，我们使用多种新方法在严重肠损伤的翻译相关大型动物模型中评估 ISC，并提供 rISC 作为治疗靶点的潜在作用的证据。
