The currently accepted intestinal epithelial cell organization model proposes that Lgr5⁺ crypt-base columnar (CBC) cells represent the sole intestinal stem cell (ISC) compartment. However, previous studies have indicated that Lgr5⁺ cells are dispensable for intestinal regeneration, leading to two major hypotheses: one favoring the presence of a quiescent reserve ISC and the other calling for differentiated cell plasticity. To investigate these possibilities, we studied crypt epithelial cells in an unbiased fashion via high-resolution single-cell profiling. These studies, combined with in vivo lineage tracing, show that Lgr5 is not a specific ISC marker and that stemness potential exists beyond the crypt base and resides in the isthmus region, where undifferentiated cells participate in intestinal homeostasis and regeneration following irradiation (IR) injury. Our results provide an alternative model of intestinal epithelial cell organization, suggesting that stemness potential is not restricted to CBC cells, and neither de-differentiation nor reserve ISC are drivers of intestinal regeneration.

目前公认的肠上皮细胞组织模型提出，Lgr5 ⁺隐窝基底柱状（CBC）细胞代表唯一的肠干细胞（ISC）区室。然而，之前的研究表明，Lgr5 ⁺细胞对于肠道再生来说是可有可无的，这导致了两个主要假设：一个支持静态储备 ISC 的存在，另一个则呼吁分化的细胞可塑性。为了研究这些可能性，我们通过高分辨率单细胞分析以公正的方式研究了隐窝上皮细胞。这些研究与体内谱系追踪相结合，表明Lgr5不是特定的 ISC 标记，并且干细胞潜力存在于隐窝基底之外并存在于峡部区域，其中未分化细胞参与辐照 (IR) 损伤后的肠道稳态和再生。我们的结果提供了肠上皮细胞组织的另一种模型，表明干细胞潜力不仅限于CBC细胞，并且去分化和储备ISC都不是肠再生的驱动因素。