Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
OU Cancer Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Sci Rep. 2016 Nov 23;6:37667. doi: 10.1038/srep37667.
Crypt epithelial survival and regeneration after injury require highly coordinated complex interplay between resident stem cells and diverse cell types. The function of Dclk1 expressing tuft cells regulating intestinal epithelial DNA damage response for cell survival/self-renewal after radiation-induced injury is unclear. Intestinal epithelial cells (IECs) were isolated and purified and utilized for experimental analysis. We found that small intestinal crypts of Villin;Dclk1 mice were hypoplastic and more apoptotic 24 h post-total body irradiation, a time when stem cell survival is p53-independent. Injury-induced ATM mediated DNA damage response, pro-survival genes, stem cell markers, and self-renewal ability for survival and restitution were reduced in the isolated intestinal epithelial cells. An even greater reduction in these signaling pathways was observed 3.5 days post-TBI, when peak crypt regeneration occurs. We found that interaction with Dclk1 is critical for ATM and COX2 activation in response to injury. We determined that Dclk1 expressing tuft cells regulate the whole intestinal epithelial cells following injury through paracrine mechanism. These findings suggest that intestinal tuft cells play an important role in regulating the ATM mediated DNA damage response, for epithelial cell survival/self-renewal via a Dclk1 dependent mechanism, and these processes are indispensable for restitution and function after severe radiation-induced injury.
在损伤后，隐窝上皮细胞的存活和再生需要驻留干细胞和多种细胞类型之间高度协调的复杂相互作用。表达 Dclk1 的微绒毛细胞调节肠道上皮细胞 DNA 损伤反应以促进辐射损伤后细胞存活/自我更新的功能尚不清楚。我们分离和纯化了肠道上皮细胞（IECs），并用于实验分析。我们发现，Villin;Dclk1 小鼠的小肠隐窝在全身照射后 24 小时体积减小，凋亡增加，此时干细胞存活不依赖于 p53。损伤诱导的 ATM 介导的 DNA 损伤反应、促生存基因、干细胞标志物和自我更新能力对于存活和修复的能力在分离的肠道上皮细胞中降低。在 TBI 后 3.5 天，即隐窝再生的高峰期，这些信号通路的减少更为明显。我们发现，与 Dclk1 的相互作用对于损伤后 ATM 和 COX2 的激活至关重要。我们确定，表达 Dclk1 的微绒毛细胞通过旁分泌机制调节损伤后的整个肠道上皮细胞。这些发现表明，肠道微绒毛细胞通过依赖 Dclk1 的机制在调节 ATM 介导的 DNA 损伤反应、上皮细胞存活/自我更新方面发挥重要作用，这些过程对于严重辐射诱导损伤后的修复和功能是不可或缺的。
