Department of Medicine, Samsung Medical Center, Sungkyunwan University School of Medicine, Seoul 06351, Korea.
Department of Radiation Oncology, Samsung Medical Center, Seoul 06351, Korea.
Int J Mol Sci. 2019 Sep 2;20(17):4297. doi: 10.3390/ijms20174297.
Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) affords stem cell protection and links microbes to intestinal epithelial regeneration. We investigated whether NOD2 status is associated with crypt survival and intestinal epithelial regeneration independent of microbiota-derived molecules. To assess crypt survival, a clonogenic microcolony assay was performed with 15 Gy of X-ray irradiation. The fractional crypt survival rate (46.0 ± 15.5% vs. 24.7 ± 9.2%, < 0.01) and fractional EdU-positive crypt survival rate (29.8 ± 14.5% vs. 9.79 ± 4.37%, = 0.015) were significantly decreased in the NOD2 mice compared with the wild-type (WT) mice at 3.5 days after irradiation. To evaluate intestinal epithelial regeneration capability, organoid reconstitution assays were performed. Small bowel crypts of the WT and NOD2 mice were isolated and seeded into Matrigel for 3D culture. In the organoid reconstitution assays, the number of organoids formed did not differ between the NOD2 and WT mice. Organoid formation ability was also assessed after exposure to 5 Gy irradiation. Organoid formation ability was significantly decreased in the NOD2 mice compared with the WT ones after exposure to 5 Gy irradiation (33.2 ± 5.9 vs. 19.7 ± 8.8/well, < 0.01). NOD2 supports crypt survival after potentially lethal irradiation damage and is associated with intestinal epithelial regeneration.
核苷酸结合寡聚化结构域蛋白 2（NOD2）为干细胞提供保护，并将微生物与肠道上皮细胞再生联系起来。我们研究了 NOD2 状态是否与微生物衍生分子无关，与隐窝存活和肠道上皮细胞再生有关。为了评估隐窝的存活，我们用 15Gy 的 X 射线照射进行了克隆微集落测定。照射后 3.5 天，NOD2 小鼠的克隆微集落存活率（46.0±15.5%比 24.7±9.2%，<0.01）和 EdU 阳性克隆微集落存活率（29.8±14.5%比 9.79±4.37%，=0.015）明显低于野生型（WT）小鼠。为了评估肠道上皮细胞再生能力，我们进行了类器官重建实验。分离 WT 和 NOD2 小鼠的小肠隐窝并种植在 Matrigel 中进行 3D 培养。在类器官重建实验中，NOD2 和 WT 小鼠形成的类器官数量没有差异。还评估了暴露于 5Gy 照射后类器官的形成能力。暴露于 5Gy 照射后，NOD2 小鼠的类器官形成能力明显低于 WT 小鼠（33.2±5.9 比 19.7±8.8/孔，<0.01）。NOD2 支持潜在致死性照射损伤后的隐窝存活，并与肠道上皮细胞再生有关。
