Department of Medical Sciences and Public Health, Division of Pathology, AOU of Cagliari, Cagliari, Italy.
Eur Rev Med Pharmacol Sci. 2022 Jun;26(12):4346-4353. doi: 10.26355/eurrev_202206_29073.
L1 cell adhesion molecule (L1CAM) is a member of the immunoglobulin superfamily of cell adhesion molecules. The present study investigated the expression of L1CAM during the development in the fetal human kidney at different gestational ages, to reach a better knowledge on the role of L1CAM in renal morphogenesis.
The immunohistochemical analysis for L1CAM was performed in 24 fetal kidneys of different gestational ages, ranging from 10 to 38 weeks. L1CAM expression was observed in all 24 kidneys examined.
Immunoreactivity for L1CAM was restricted to the collecting tubules, of the developing fetal kidneys. Moreover, L1CAM was detected in the ureteric bud tips, near the subcapsular metanephric mesenchymal stem/progenitor cells. L1CAM was also expressed in the collecting tubules undergoing fusion with the distal tubules of the developing nephrons. L1CAM was mainly expressed along the cell membrane. In fetal kidneys in which the renal pelvis was observed, epithelial cells of the renal pelvis showed strong membranous reactivity for L1CAM.
Our study shows that L1CAM is expressed in all stages of human kidney nephrogenesis, being restricted to the renal structures derived from the ureteric bud. The expression of L1CAM in the cells of the ureteric bud tips suggests a major role for this adhesion molecule in the induction of metanephric mesenchymal cells to undergo mesenchymal-to-epithelial transition and differentiation into new nephrons. The interindividual variability in L1CAM expression observed in this study might be related to different levels of nephrogenesis, suggesting L1CAM involvement in the fetal programming of adult kidney diseases.
L1 细胞黏附分子（L1CAM）是免疫球蛋白超家族细胞黏附分子的成员。本研究调查了 L1CAM 在不同胎龄的人胎儿肾脏发育过程中的表达，以更好地了解 L1CAM 在肾脏形态发生中的作用。
对 24 例不同胎龄（10 至 38 周）的胎儿肾脏进行了 L1CAM 的免疫组织化学分析。在检查的 24 个肾脏中均观察到 L1CAM 表达。
L1CAM 的免疫反应性仅限于发育中的胎儿肾脏的集合管。此外，L1CAM 存在于输尿管芽尖端，靠近被膜下肾间充质干细胞/祖细胞附近。L1CAM 也在与发育中的肾单位远端小管融合的集合管中表达。L1CAM 主要表达在细胞膜上。在观察到肾盂的胎儿肾脏中，肾盂的上皮细胞对 L1CAM 表现出强烈的膜反应性。
我们的研究表明，L1CAM 在人类肾脏发生的所有阶段都有表达，仅限于输尿管芽衍生的肾脏结构。在输尿管芽尖端细胞中表达 L1CAM 表明该黏附分子在诱导间充质细胞经历间充质上皮转化并分化为新的肾单位中起主要作用。在这项研究中观察到的 L1CAM 表达的个体间变异性可能与不同水平的肾发生有关，表明 L1CAM 参与了成人肾脏疾病的胎儿编程。
