A large animal model of heritable pulmonary arterial hypertension using BMPR2 gene-edited sheep.

Pulmonary arterial hypertension (PAH) is a rare vascular disorder characterized by elevated pressure in pulmonary arteries, eventually leading to right ventricular failure. Approximately 50% of pediatric disease and 20% of adult disease can be linked to a genetic mutation, with nearly 70% of these cases involving mutations in the bone morphogenetic protein receptor type 2 (BMPR2) locus. Investigations using rodent models have made substantial advances in our understanding of BMPR2 signaling; however, limited data exist regarding the onset and course of PAH, and etiologies for phenotypic expression in these patients remain unknown. In this work, we describe the development of an ovine model of heritable PAH. Because homozygous disruption of BMPR2 is embryonic lethal, we developed heterozygous BMPR2-edited (BMPR2+/-) sheep by using a PAM-disrupting synonymous single-stranded oligodeoxyribonucleotide alongside a single guide RNA and Cas9-mediated gene editing strategy. The resulting BMPR2+/- lambs demonstrated cardiac and pulmonary vascular pathology that are consistent with BMPR2 mutation-driven PAH observed in humans. Given the genetic and physiological similarities of BMPR2+/- sheep to humans with heritable PAH, this large animal model will serve as a vital platform for mechanistic molecular studies and will provide a much-needed preclinical model for extensive treatment evaluations.