A Large Animal Model of Heritable Pulmonary Arterial Hypertension Using Gene-edited BMPR2 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 significant 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 a novel ovine model of heritable PAH. Because homozygous disruption of BMPR2 is embryonic lethal, we developed heterozygous 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 pre-clinical model for extensive treatment evaluations.