BMPR2-expressing bone marrow-derived endothelial-like progenitor cells alleviate pulmonary arterial hypertension in vivo

Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the distal pulmonary arteries, ultimately leading to right heart failure and, despite the available therapeutics, survival remains poor. Reduced expression of bone morphogenetic protein receptor type 2 (BMPR2) is strongly associated with PAH. Cell therapies are of interest in PAH, but whether this approach can upregulate BMPR2 is not known. Our objective was to evaluate a preclinical cell therapy approach based on upregulation of BMPR2.

We assessed the therapeutic effect of intravenously injected BMPR2-augmented rat bone marrow-derived endothelial-like progenitor cells (BMPR2-BM-ELPC) on PAH in the rat monocrotaline (MCT) model.

The cells accumulate in the lungs with negligible systemic distribution, but the vast majority are lost from the lungs by 24 h. Lungs from rats treated with BMPR2-BM-ELPC exhibited an immediate increase in BMPR2 and related intracellular signalling proteins. Treatment with BMPR2-BM-ELPC attenuated PAH as demonstrated by a reduction in right ventricular hypertrophy as well as right ventricular systolic and mean pulmonary arterial pressures. In addition, this treatment reversed PAH-induced vascular remodelling with a significant reduction in vessel thickness and muscularization. In view of the short retention time of injected cells in the lungs, the mechanism for the effects seen may be intracellular communication via exosomes. In support of this hypothesis, we demonstrate that BMPR2-transduced outgrowth endothelial progenitor cells (OECs) release BMPR2-expressing exosomes.

BMPR2-augmented ELPC demonstrate therapeutic benefits in the rat model and may have clinical translation potential.