Santos Marta, Nogueira-Silva Cristina, Baptista Maria J, Soares-Fernandes João, Moura Rute S, Correia-Pinto Jorge
Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, 4709-057 Braga, Portugal.
J Pediatr Surg. 2007 Jul;42(7):1231-7. doi: 10.1016/j.jpedsurg.2007.02.014.
BACKGROUND/AIM: In congenital diaphragmatic hernia (CDH), there is pulmonary neuroendocrine cell (PNEC) hyperplasia and Clara (nonendocrine) cell hypoplasia, the meaning of which remains unknown. In embryonic/fetal lung, an intricate cross talk between Notch pathway and basic helix-loop-helix transcription factors Mash1 and Hes1 determines the balance between endocrine and nonendocrine epithelial cell fate. Differences at the molecular level in pulmonary epithelial cell differentiation between control and CDH hypoplastic lungs were investigated.
The nitrofen-induced CDH rat model was used. At 15.5 days postconception (dpc), fetuses were assigned to 2 experimental groups: control and nitrofen (exposed to nitrofen, without CDH), whereas at 17.5, 19.5, and 21.5 dpc, fetuses were assigned to 3 experimental groups: control, nitrofen, and CDH (exposed to nitrofen, with CDH). The fetal lungs were processed for expression quantification of CC10, Hes1, Mash1, and Dll1 by real-time polymerase chain reaction.
In control fetuses, expression of all studied genes increased with gestational age. In nitrofen-exposed fetal lungs, endocrine cell marker Mash1 was downregulated only at the earliest studied gestational age, whereas Dll1 expression levels were significantly increased in the CDH group at 19.5 and 21.5 dpc. Regarding nonendocrine markers, Hes1 presented increased expression at 15.5 and 19.5 dpc, whereas CC10 was downregulated at 17.5 and 19.5 dpc but not at term.
This study suggests that PNEC hyperplasia in CDH fetal lung is likely because of Notch signaling deregulation, whereas Clara cell hypoplasia in CDH lungs could be a consequence of protein synthesis delay, reflecting a functional maturation hindrance and not a cell fate commitment problem.
背景/目的：在先天性膈疝（CDH）中，存在肺神经内分泌细胞（PNEC）增生和克拉拉（非内分泌）细胞发育不全，其意义尚不清楚。在胚胎/胎儿肺中，Notch信号通路与碱性螺旋-环-螺旋转录因子Mash1和Hes1之间复杂的相互作用决定了内分泌和非内分泌上皮细胞命运之间的平衡。本研究调查了对照和CDH发育不全肺之间肺上皮细胞分化在分子水平上的差异。
采用硝呋烯腙诱导的CDH大鼠模型。在受孕后15.5天（dpc），将胎儿分为2个实验组：对照组和硝呋烯腙组（暴露于硝呋烯腙，无CDH），而在17.5、19.5和21.5 dpc时，将胎儿分为3个实验组：对照组、硝呋烯腙组和CDH组（暴露于硝呋烯腙，有CDH）。通过实时聚合酶链反应对胎儿肺进行CC10、Hes1、Mash1和Dll1表达定量分析。
在对照胎儿中，所有研究基因的表达均随胎龄增加。在暴露于硝呋烯腙的胎儿肺中，内分泌细胞标记物Mash1仅在最早研究的胎龄时下调，而在19.5和21.5 dpc时，CDH组的Dll1表达水平显著升高。关于非内分泌标记物，Hes1在15.5和19.5 dpc时表达增加，而CC10在17.5和19.5 dpc时下调，但足月时未下调。
本研究表明，CDH胎儿肺中的PNEC增生可能是由于Notch信号失调，而CDH肺中的克拉拉细胞发育不全可能是蛋白质合成延迟的结果，反映了功能成熟障碍而非细胞命运决定问题。
