Autophagy inducer activates Nrf2-ARE pathway to attenuate aberrant alveolarization in neonatal rats with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a severe respiratory complication in preterm infants. This study reveals the molecular mechanism of autophagic agonists regulating the Nrf2-ARE pathway via p62 to improve alveolar development in BPD rats. Newborn Sprague-Dawley rats were randomly exposed to a hyperoxic environment (FiO 2 = 0.85) for 14 days and rapamycin (RAPA) was intraperitoneally injected on alternate days into hyperoxia-exposed mice. Alveolar development was assessed using HE and RAC values. Markers associated with the p62-Keap1-Nrf2-ARE pathway were detected by western blot, immunohistochemistry, and RT-PCR. Co-localization of proteins was determined using double immunofluorescence staining. At the levels of lung tissue and primary type II alveolar epithelial cells, the enhanced binding between phosphorylated p62 and Keap1 disrupted the nuclear transport of Nrf2. The activated Nrf2 was insufficient to reverse alveolar simplification. The autophagy agonist was able to inhibit p62 phosphorylation, promote Keap1 degradation, increase Nrf2 nuclear transport, augment downstream antioxidant enzyme expression, and enhance antioxidant capacity, thereby improving the simplification of alveolar structure in BPD rats. The use of autophagy agonists to enhance the Nrf2-ARE pathway activity and promote alveolar development could be a novel target in antioxidant therapy for BPD.