Assessing the role of lymphatic endothelial cell niche in intestinal regeneration

项目摘要 在小肠小生境中，血管和淋巴管的内皮细胞丰富。有趣的是，在 在过去的十年里，几个研究小组已经表明，内皮细胞的作用不仅仅是"管道"， 支持各种组织的干细胞维持和再生的旁分泌因子。虽然ISCs 淋巴管内皮细胞（LECs）在维持代谢健康中的作用， ISC利基尚未确立。值得注意的是，已知LEC表达高水平的Rsp 〇 3，其是WNT之一。 ISC自我更新所需的信号分子。在工作中，我进一步观察到 WNT调节剂Wls也由小肠中的LEC高度表达。除了假定的角色之外， 在稳态转换中，几条证据表明，内皮细胞在应答中被激活， 来促进上皮细胞的恢复。尽管有这方面的知识，LEC是否来源于WNT信号， 肠生态位对于细胞毒性损伤后ISC再生是必需的，这一点尚不清楚。基于此 在此前提下，我的目的是研究LEC在化疗诱导的肠损伤模型中的作用， 一种影响癌症患者的毁灭性炎症状态。 我的项目的首要目标是了解内皮细胞如何促进ISC再生， 提出，在某种程度上，这是通过LEC分泌WNT调节剂RSPO3和WLS来实现的。为 因此，我已经产生了杂交以获得小鼠模型，其中Rspo3或Wls被选择性地 从成年小鼠的LEC中敲除。我的初步数据表明，在Rspo3被删除的小鼠中， 从成年小鼠的LEC中，在5FU损伤后，ISC的恢复延迟。我打算进一步证实这些 结果在小鼠中Wls从LEC中缺失。此外，我将生成单细胞RNA测序数据， 在Rspo3被敲除的小鼠中测定5FU损伤后隐窝上皮细胞的转录变化 从LEC。最后，我将剖析LEC的变化，因为它们与5FU损伤后的上皮修复有关。在一起， 这些研究将明确淋巴生态位的信号如何促进ISC再生等 广泛地将确定一种潜在的新的肠道生态位成分，可以治疗靶向刺激 肠道修复

PROJECT SUMMARY Endothelial cells that line blood and lymphatic vessels are abundant in the small intestine niche. Interestingly, in the last decade, several groups have shown that endothelial cells have a role beyond “plumbing” and secrete paracrine factors supporting the stem cell maintenance and regeneration of various tissues. Although ISCs renew rapidly and continuously to sustain metabolic health, the role of lymphatic endothelial cells (LECs) in the ISC niche is not well-established. Notably, LECs are known to express high levels of Rspo3, one of the WNT signaling molecules required in the niche for ISC self-renewal. In my work, I have further made the observation that the WNT modulator Wls is also highly expressed by LECs in the small intestine. In addition to putative roles in homeostatic turnover, several lines of evidence suggest that endothelial cells become activated in response to intestinal injury to drive epithelial recovery. Despite this knowledge, whether LEC derived WNT signaling in the intestinal niche is essential for ISC regeneration after cytotoxic injury remains unknown. Based on this premise, I aim to study the role of LECs in a model of chemotherapy-induced intestinal injury, a frequent and devastating inflammatory condition that affects cancer patients. The overarching goal of my project is to understand how endothelial cells contribute to ISC regeneration and I propose that, in part, this is achieved through secretion of the WNT modulators RSPO3 and WLS by LECs. For this reason, I have generated crosses to obtain mouse models in which either Rspo3 or Wls are selectively knocked out from LECs in adult mice. My preliminary data indicate that in mice where Rspo3 has been deleted from LECs in adult mice, there is a delayed recovery of ISCs after 5FU injury. I plan to further corroborate these results in mice where Wls is deleted from LECs. Additionally, I will generate single cell RNA sequencing data to determine transcriptional changes in crypt epithelial cells after 5FU injury in mice where Rspo3 has been knocked out from LECs. Lastly, I will dissect changes in LECs as they relate to epithelial repair after 5FU injury. Together, the proposed studies will define how signals from the lymphatic niche contribute to ISC regeneration and more broadly will identify a potential novel intestinal niche component that can be therapeutically targeted to stimulate intestinal repair.