Abstract
Lung maturation is hallmarked by the appearance of surfactantโproducing alveoli during transition from the saccular to alveolar stage of lung development. Inflammation can disrupt this process and accelerate lung maturity following intrauterine amniotic infection (chorioamnionitis). Nuclear factor kB (NFโkB) is a transcription factor central to multiple inflammatory and developmental pathways, including dorsalโventral patterning in fruit flies, limb and mammary and submandibular gland development in mice, and branching morphogenesis in chick lungs. Given its shared role in inflammation and developmental signaling, we hypothesized that overexpression of NFโkB targeted to the lung epithelium would exert maturational effects on alveolar development. We generated transgenic mice with lungโspecific overexpression of the RelA subunit of NFโkB using a surfactant protein C promoter construct. Our results showed that RelA overexpression in the lung yields increased alveolar type I and type II cells. These findings are consistent with a model whereby NFโkB may induce maturation of lung development through decreased apoptosis of epithelial cells. Developmental Dynamics 237:328โ338, 2008. ยฉ 2007 WileyโLiss, Inc.