A major barrier to the impact of genomic diagnosis in patients with congenital malformations is the lack of understanding regarding how sequence variants contribute to disease pathogenesis and whether this information could be used to generate patient-specific therapies. Congenital diaphragmatic hernia (CDH) is among the most common and severe of all structural malformations; however, its underlying mechanisms are unclear. We identified loss-of-function sequence variants in the epigenomic regulator geneSIN3Ain two patients with complex CDH. Tissue-specific deletion ofSin3ain mice resulted in defects in diaphragm development, lung hypoplasia, and pulmonary hypertension, the cardinal features of CDH and major causes of CDH-associated mortality. Loss of SIN3A in the lung mesenchyme resulted in reduced cellular differentiation, impaired cell proliferation, and increased DNA damage. Treatment of embryonicSin3amutant mice with anacardic acid, an inhibitor of histone acetyltransferase, reduced DNA damage, increased cell proliferation and differentiation, improved lung and pulmonary vascular development, and reduced pulmonary hypertension. These findings demonstrate that restoring the balance of histone acetylation can improve lung development in theSin3amouse model of CDH.

Congenital diaphragmatic hernia (CDH) is a common and severe malformation associated with abnormal lung and pulmonary vascular development. This study investigates GATA4 haploinsufficiency, a common CDH-associated variant linked to higher morbidity and mortality. We establish mechanical compression as the mechanism leading to abnormal lung and pulmonary vascular development, which differs from other CDH-associated variants. Findings support using patient genotype to identify those most likely to benefit from fetal procedures that improve lung growth and survival.

Background/Objectives: Acetaminophen (APAP) is used during 50–60% of pregnancies in the U.S. and has been associated with childhood respiratory morbidity, though the underlying mechanism remains unclear. APAP-induced injury is dependent on cell-specific expression of CYP2E1, the enzyme that metabolizes APAP into the mitochondrial toxin NAPQI. In mice, pulmonary Cyp2e1 expression peaks during the saccular stage of lung development on embryonic day 18 (E18). We investigated whether this developmental surge in Cyp2e1 triggers a pulmonary transcriptional response to maternal APAP exposure in embryonic lungs. Methods: Pregnant dams were exposed to APAP on E17 or E18 (150 or 250 mg/kg, IP) using doses derived from prior studies. We assessed the induction of NRF2 target genes and genes associated with inflammation, apoptosis and cellular stress due to their roles in APAP-induced oxidative and cellular stress. Results: At E17, maternal treatment with APAP induced pulmonary Cyp2e1 but resulted in inconsistent transcriptional changes. In contrast, maternal APAP at E18 triggered a robust transcriptional induction of Cyp2e1, NRF2 targets and markers of apoptosis, inflammation and cellular stress. Histopathology at birth after E18 APAP exposure revealed no acute pulmonary injury. Conclusions: We demonstrate a developmentally regulated, dose-dependent transcriptional response to maternal APAP in the embryonic murine lung. Importantly, transcriptional responses do not directly indicate lung injury; thus, future studies should assess protein-level changes following APAP exposure. This study underscores the need for further investigation into the role of developmentally regulated Cyp2e1 expression in APAP-induced toxicity and long-term respiratory morbidity.

Summary: The mesothelium is a squamous monolayer that ensheathes internal organs, lines the body cavity, and the diaphragm. It serves as a protective barrier, coated in glycocalyx, and secretes lubricants to facilitate tissue movement. How the mesothelium forms is poorly understood. Here, we investigate Myrf , a transcription factor gene expressed in the mesothelium, because it carries variants in patients with Congenital Diaphragmatic Hernia (CDH), a disorder that affects the diaphragm, lung, and other organs. In mice, inactivation of Myrf early in organogenesis resulted in CDH and defective mesothelial specification, compromising its function as a signaling center for lung growth. Inactivation of Myrf later led to enhanced mesothelium differentiation into mesenchymal cell types through partial epithelial-to-mesenchymal transition (EMT), resulting in a unique accumulation of smooth muscle encasing the lung. In this role, MYRF functions in parallel with YAP/TAZ. Together, these findings establish MYRF as a critical regulator of mesothelium development, and when mutated, causes CDH.

SCIEPublish is an international open-access journal publishing service provider run by SCIE Publishing Limited, dedicated to supporting and inspiring scientists or institutions/societies who aspire to publish high-quality journals.