The Children's Research Center, Our Lady's Children's Hospital, Dublin 12, Ireland.
J Pediatr Surg. 2010 Feb;45(2):366-71. doi: 10.1016/j.jpedsurg.2009.10.075.
The pathogenesis of pulmonary hypoplasia in congenital diaphragmatic hernia (CDH) is not fully understood. The serine/threonine protein kinase B (AKT) plays important roles for lung morphogenesis through epithelial-mesenchymal interaction in phosphatidylinositide 3-kinase (PI3K)-dependent manner. It has been reported that the lung explant morphogenesis in mice is interfered by inhibitors of the PI3K-AKT pathway. We hypothesized that PI3K and AKT gene and protein expression/distribution are altered during epithelial morphogenesis in the nitrofen-induced hypoplastic lung.
Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs were harvested on D15, D18, and D21 and divided into 3 groups as follows: control, nitrofen with CDH (CDH[-]), and nitrofen without CDH (CDH[+]) (n = 8 at each time-point, respectively). Reverse transcription polymerase chain reaction and immunohistochemistry were performed.
Messenger RNA expression levels of PI3K at D21 was significantly decreased in CDH(-) and CDH(+) group (5.71 +/- 0.85 and 6.80 +/- 0.88, respectively) compared to controls (8.95 +/- 3.22; P < .05). Messenger RNA levels of AKT were also significantly decreased at D18 in CDH(-) and CDH(+) lungs (1.21 +/- 0.16 and 1.20 +/- 0.32, respectively) compared to controls (1.62 +/- 0.14; P < .01). The PI3K immunoreactivity was diminished in the distal epithelium at D18 and decreased in the overall intensity at D21 in hypoplastic lungs compared to controls. The AKT immunoreactivity was decreased in mesenchyme at D18 and decreased overall intensity at D21 in CDH lungs compared to controls.
Spatiotemporal alteration of pulmonary PI3K and AKT gene and protein expression during epithelial morphogenesis may interfere with epithelial-mesenchymal interaction, causing pulmonary hypoplasia in CDH by disrupting PI3K-AKT signaling pathway.
先天性膈疝（CDH）中肺发育不全的发病机制尚未完全阐明。丝氨酸/苏氨酸蛋白激酶 B（AKT）通过磷脂酰肌醇 3-激酶（PI3K）依赖性上皮-间充质相互作用在肺形态发生中发挥重要作用。据报道，PI3K-AKT 通路抑制剂会干扰小鼠肺培养物的形态发生。我们假设在硝呋酚诱导的发育不全肺中，上皮形态发生过程中，PI3K 和 AKT 基因和蛋白的表达/分布会发生改变。
妊娠大鼠于妊娠第 9 天（D9）接受橄榄油或硝呋酚处理。在 D15、D18 和 D21 时收获胎肺，并分为以下 3 组：对照组、有 CDH 的硝呋酚组（CDH[-]）和无 CDH 的硝呋酚组（CDH[+]）（每个时间点分别为 8 只）。进行逆转录聚合酶链反应和免疫组织化学。
D21 时，CDH（-）和 CDH（+）组的 PI3K 信使 RNA 表达水平明显低于对照组（分别为 5.71 ± 0.85 和 6.80 ± 0.88 比 8.95 ± 3.22；P <.05）。AKT 的信使 RNA 水平在 D18 时在 CDH（-）和 CDH（+）肺中也明显降低（分别为 1.21 ± 0.16 和 1.20 ± 0.32 比 1.62 ± 0.14；P <.01）。与对照组相比，在 D18 时，远端上皮中的 PI3K 免疫反应性减弱，在 D21 时整体强度降低。在 CDH 肺中，D18 时间充质中的 AKT 免疫反应性降低，D21 时整体强度降低。
在肺上皮形态发生过程中，PI3K 和 AKT 基因和蛋白表达的时空改变可能会干扰上皮-间充质相互作用，通过破坏 PI3K-AKT 信号通路导致 CDH 中的肺发育不全。
