Longitudinal Transcriptomic Analysis of the Hyperoxia-exposed Preterm Rabbit as a Model of BPD

Carlotta Boggi ¹ Nicola Casiraghi ² Xabier Murgia ³ Silvia Parolo ² Enrica Scalera ¹ Giorgio Aquila ¹ Chiara Catozzi ¹ Salomone Fabrizio ¹ Francesca Stretti ^1,4 Ilaria Minato ⁵ Francesca Ravanetti ⁴ Luisa Ragionieri ⁴ Roberta Ciccimarra ⁴ Matteo Zoboli ⁴ Gino Villetti ¹ BARBARA MONTANINI ^5* Francesca Ricci ⁶ Matteo Storti ^6*

• ¹ Department of Experimental Pharmacology and Translational Science. R&D, Chiesi Farmaceutici (Italy), Parma, Emilia-Romagna, Italy
• ² Fondazione The Microsoft Research, COSBI - Center for Computational and Systems Biology, University of Trento, Rovereto, Italy
• ³ Scientific Consultancy, Bilbao, Basque Country, Spain
• ⁴ Department of Veterinary Science, University of Parma, Parma, Emilia-Romagna, Italy
• ⁵ Laboratory of Biochemistry and Molecular Biology, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Emilia-Romagna, Italy
• ⁶ Department of Experimental Pharmacology and Translational Science. R&D,, Chiesi Farmaceutici (Italy), Parma, Emilia-Romagna, Italy

Bronchopulmonary dysplasia (BPD) is a multifactorial chronic lung disease of premature neonates. BPD development depends on prenatal and postnatal factors that induce inflammation, altering alveolar growth and pulmonary vascular development. Animal models are essential to investigate the precise molecular pathways leading to BPD. The preterm rabbit combines many advantages of small (e.g., rodents) and large BPD models (e.g., preterm lambs and baboons). Preterm rabbits display mild-to-moderate respiratory distress at delivery, which, along with continuous exposure to hyperoxia (95% O2), leads to functional and morphological lung changes resembling a BPD-like phenotype. Nevertheless, the molecular pathways leading to the BPD-like phenotype remain poorly understood. Here, we aimed to characterize the longitudinal gene expression in the lungs of preterm rabbits exposed to 95% O2, on postnatal days 3, 5, and 7. Histological analyses confirmed extensive lung injury and reduced lung development after 7 days of hyperoxia. Longitudinal transcriptomic analysis revealed different expression patterns for several genes and pathways. Over time, extracellular matrix organization and angiogenesis were increasingly downregulated. Apoptosis, RNA processing, and inflammation showed the opposite trend. We also investigated the expression of representative genes of these pathways, whose signatures could aid in developing pharmacological treatments in the context of BPD.