The RNA-binding protein quaking is upregulated in nitrofen-induced congenital diaphragmatic hernia lungs at the end of gestation.

BACKGROUND: The RNA-binding protein Quaking (QKI) increases during epithelial-to-mesenchymal transition and its expression is controlled by microRNA-200 family members. Here, we aimed to describe the expression of QKI in the developing lungs of control and nitrofen-induced congenital diaphragmatic hernia lungs (CDH). METHODS: To investigate the expression of QKI, we dissected lungs from control and nitrofen-induced CDH rats on embryonic day 15, 18, 21 (E15, E18, E21). We performed immunofluorescence (IF) and quantitative reverse transcription PCR (RT-qPCR) for QKI expression. Additionally, we assessed Interleukin-6 (IL-6) abundance using IF. RESULTS: On E21, IF showed that the abundance of all three QKI isoforms and IL-6 protein was higher in CDH lungs compared to control lungs (QKI5: p = 0.023, QKI6: p = 0.006, QKI7: p = 0.014, IL-6: p = 0.045, respectively). Furthermore, RT-qPCR data showed increased expression of QKI5, QKI6, and QKI7 mRNA in E21 nitrofen lungs by 1.63 fold (p = 0.001), 1.63 fold (p = 0.010), and 1.48 fold (p = 0.018), respectively. CONCLUSIONS: Our data show an increase in the abundance and expression of QKI at the end of gestation in nitrofen-induced CDH lungs. Therefore, a disruption in the regulation of QKI during the late stage of pregnancy could be associated with the pathogenesis of abnormal lung development in CDH.

Dysregulation of CITED2 in abnormal lung development in the nitrofen rat model.

PURPOSE: CITED2 both modulates lung, heart and diaphragm development. The role of CITED2 in the pathogenesis of congenital diaphragmatic hernia (CDH) is unknown. We aimed to study CITED2 during abnormal lung development in the nitrofen model. METHODS: Timed-pregnant rats were given nitrofen on embryonic day (E) 9 to induce CDH. Fetal lungs were harvested on E15, 18 and 21. We performed RT-qPCR, RNAscope™ in situ hybridization and immunofluorescence staining for CITED2. RESULTS: We observed no difference in RT-qPCR (control: 1.09 ± 0.22 and nitrofen: 0.95 ± 0.18, p = 0.64) and in situ hybridization (1.03 ± 0.03; 1.04 ± 0.03, p = 0.97) for CITED2 expression in E15 nitrofen and control pups. At E18, CITED2 expression was reduced in in situ hybridization of nitrofen lungs (1.47 ± 0.05; 1.14 ± 0.07, p = 0.0006), but not altered in RT-qPCR (1.04 ± 0.16; 0.81 ± 0.13, p = 0.33). In E21 nitrofen lungs, CITED2 RNA expression was increased in RT-qPCR (1.04 ± 0.11; 1.52 ± 0.17, p = 0.03) and in situ hybridization (1.08 ± 0.07, 1.29 ± 0.04, p = 0.02). CITED2 protein abundance was higher in immunofluorescence staining of E21 nitrofen lungs (2.96 × 109 ± 0.13 × 109; 4.82 × 109 ± 0.25 × 109, p < 0.0001). CONCLUSION: Our data suggest that dysregulation of CITED2 contributes to abnormal lung development of CDH, as demonstrated by the distinct spatial-temporal distribution in nitrofen-induced lungs.