The S52F FOXF1 Mutation Inhibits STAT3 Signaling and Causes Alveolar Capillary Dysplasia.

Area of Science:

• Genetics and Developmental Biology
• Pulmonary Medicine
• Molecular Biology

Background:

• Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a fatal congenital disorder causing severe respiratory issues and pulmonary hypertension in newborns.
• Current treatments for ACDMPV are limited to lung transplantation, highlighting the urgent need for novel therapeutic strategies.
• While mutations in the FOXF1 gene are associated with ACDMPV, the precise molecular mechanisms driving the disease remain largely unknown.

Purpose of the Study:

• To elucidate the molecular mechanisms by which specific FOXF1 mutations, such as S52F, contribute to the pathogenesis of ACDMPV.
• To investigate the role of FOXF1 in regulating pulmonary vasculature development and function.
• To explore potential therapeutic interventions for ACDMPV based on identified molecular pathways.

Main Methods:

• Generation of a mouse model mimicking ACDMPV by introducing the S52F FOXF1 mutation using CRISPR/Cas9 gene editing.
• Histopathological analysis, whole-lung imaging, and biochemical assays to assess lung vasculature and molecular changes in mutant mice.
• Investigation of protein-protein interactions between FOXF1 and STAT3, and assessment of STAT3 signaling pathways in both mouse models and human ACDMPV lung samples.

Main Results:

• The S52F FOXF1 mutation was found to disrupt interactions with STAT3, inhibiting STAT3 transcription and subsequently reducing STAT3 signaling and endothelial proliferation critical for angiogenesis.
• The mutant FOXF1 protein demonstrated impaired chromatin binding and transcriptional activity.
• Neonatal nanoparticle-mediated delivery of STAT3 cDNA successfully restored endothelial proliferation and promoted lung angiogenesis in the ACDMPV mouse model.

Conclusions:

• FOXF1 plays a crucial role in stimulating neonatal lung angiogenesis through its interaction with STAT3.
• Decreased STAT3 signaling is a key molecular defect in ACDMPV.
• Nanoparticle delivery of STAT3 represents a promising therapeutic approach for ACDMPV patients with compromised STAT3 signaling.