Gonçalves Ana N, Correia-Pinto Jorge, Nogueira-Silva Cristina
Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.
ICVS/3B's - PT Government Associate Laboratory, Guimarães, Portugal.
Front Pediatr. 2022 May 6;10:836591. doi: 10.3389/fped.2022.836591. eCollection 2022.
Recent studies identified a great diversity of cell types in precise number and position to create the architectural features of the lung that ventilation and respiration at birth depend on. With damaged respiratory function at birth, congenital diaphragmatic hernia (CDH) is one of the more severe causes of fetal lung hypoplasia with unspecified cellular dynamics.
To characterize the epithelial cell tissue in hypoplastic lungs, a careful analysis regarding pulmonary morphology and epithelial cell profile was conducted from pseudoglandular-to-saccular phases in normal versus nitrofen-induced CDH rat lungs.
Our analysis comprises three experimental groups, control, nitrofen (NF) and CDH, in which the relative expression levels (western blot) by group and developmental stage were analyzed in whole lung. Spatiotemporal distribution (immunohistochemistry) was revealed by pulmonary structure during normal and hypoplastic fetal lung development. Surfactant protein-C (SP-C), calcitonin gene-related peptide (CGRP), clara cell secretory protein (CCSP), and forkhead box J1 (FOXJ1) were the used molecular markers for alveolar epithelial cell type 2 (AEC2), pulmonary neuroendocrine, clara, and ciliated cell profiles, respectively.
Generally, we identified an aberrant expression of SP-C, CGRP, CCSP, and FOXJ1 in nitrofen-exposed lungs. For instance, the overexpression of FOXJ1 and CGRP in primordia of bronchiole defined the pseudoglandular stage in CDH lungs, whereas the increased expression of CGRP in bronchi; FOXJ1 and CGRP in terminal bronchiole; and SP-C in BADJ classified the canalicular and saccular stages in hypoplastic lungs. We also described higher expression levels in NF than CDH or control groups for both FOXJ1 in bronchi, terminal bronchiole and BADJ at canalicular stage, and SP-C in bronchi and terminal bronchiole at canalicular and saccular stages. Finally, we report an unexpected expression of FOXJ1 in BADJ at canalicular and saccular stages, whereas the multi cilia observed in bronchi were notably absent at embryonic day 21.5 in induced-CDH lungs.
The recognized alterations in the epithelial cell profile contribute to a better understanding of neonatal respiratory insufficiency in induced-CDH lungs and indicate a problem in the epithelial cell differentiation in hypoplastic lungs.
最近的研究发现，肺的结构特征取决于精确数量和位置的多种细胞类型，而出生时的通气和呼吸依赖于这些结构特征。先天性膈疝（CDH）是出生时呼吸功能受损的原因之一，是导致胎儿肺发育不全且细胞动力学不明确的较为严重的病因之一。
为了描述发育不全肺中的上皮细胞组织，我们对正常大鼠肺和硝芬诱导的CDH大鼠肺从假腺期到囊状期的肺形态和上皮细胞特征进行了仔细分析。
我们的分析包括三个实验组，即对照组、硝芬（NF）组和CDH组，分析了全肺中各实验组和发育阶段的相对表达水平（蛋白质免疫印迹法）。通过正常和发育不全胎儿肺发育过程中的肺结构揭示时空分布（免疫组织化学法）。表面活性物质蛋白-C（SP-C）、降钙素基因相关肽（CGRP）、克拉拉细胞分泌蛋白（CCSP）和叉头框J1（FOXJ1）分别用作2型肺泡上皮细胞（AEC2）、肺神经内分泌细胞、克拉拉细胞和纤毛细胞特征的分子标记物。
一般来说，我们在硝芬暴露的肺中发现了SP-C、CGRP、CCSP和FOXJ1的异常表达。例如，在CDH肺的假腺期，细支气管原基中FOXJ1和CGRP的过度表达有明确界定；而在发育不全肺中，支气管中CGRP表达增加；终末细支气管中FOXJ1和CGRP表达增加；肺泡管和肺泡囊中BADJ区域的SP-C表达增加，这些分别界定了小管期和囊状期。我们还描述了在小管期，支气管、终末细支气管和BADJ区域的FOXJ1，以及在小管期和囊状期支气管和终末细支气管中的SP-C，NF组的表达水平高于CDH组或对照组。最后，我们报告了在小管期和囊状期BADJ区域意外出现FOXJ1表达，而在诱导CDH肺中，胚胎第21.5天时支气管中观察到的多纤毛显著缺失。
上皮细胞特征中公认的改变有助于更好地理解诱导CDH肺中的新生儿呼吸功能不全，并表明发育不全肺中上皮细胞分化存在问题。
