Inhibition of lysophosphatidic acid receptor 2 attenuates neonatal chronic lung disease in mice by preserving vascular and alveolar development

Aim: Bronchopulmonary dysplasia (BPD) is a common morbidity in extremely premature infants. Previous studies demonstrated the important role of lysophosphatidic acid (LPA) in inflammation in BPD. However, the role of LPA and its receptors in hyperoxia-induced vascular malformations in BPD remains to be elucidated.

Methods and results: Elevated plasma LPA levels were observed in mice with BPD compared to controls (792 vs. 607 ng/mL, p < 0.05). Inhibition of LPA signaling protected against hyperoxia-induced lung injury in neonatal mice, demonstrated by a 2.8-fold increase in pulmonary vascular density and a 14% reduction in alveolar enlargement. In vitro studies showed that LPA suppressed tube formation in human umbilical vein endothelial cells (HUVECs) by approximately 50%. LPA receptor 2 (LPA₂) was identified as a functional LPA receptor in primary endothelial cells from the lungs of hyperoxic mice and in HUVECs under hyperoxic conditions. The LPA₂ antagonist H2L5186303 enhanced the tube formation ability of HUVECs exposed to LPA, both under normoxia (4-fold) and hyperoxia (5-fold). Moreover, H2L5186303 significantly protected against hyperoxia-induced vascular malformation (2-fold) and improved alveolarization in neonatal mice (12% decrease in mean linear intercept, MLI). Early growth response 1 (EGR1) was characterized as a downstream target of LPA₂, silencing EGR1 restored tube formation in HUVECs exposed to LPA and hyperoxia.

Conclusions: Our in vitro and in vivo findings demonstrate that the inhibition of LPA/LPA₂ signaling mitigates hyperoxia-induced pulmonary vascular malformations, suggesting the LPA/LPA₂-dependent signaling pathway has therapeutic potential for extremely premature infants with BPD.

Angiogenesis; Bronchopulmonary dysplasia; Early growth response 1; Vascularization.