ACTRIIA-Fc rebalances activin/GDF versus BMP signaling in pulmonary hypertension

• Published in: Science translational medicine Vol. 12; no. 543
• Main Authors: Yung, Lai-Ming, Yang, Peiran, Joshi, Sachindra, Augur, Zachary M, Kim, Stephanie S J, Bocobo, Geoffrey A, Dinter, Teresa, Troncone, Luca, Chen, Po-Sheng, McNeil, Megan E, Southwood, Mark, Poli de Frias, Sergio, Knopf, John, Rosas, Ivan O, Sako, Dianne, Pearsall, R Scott, Quisel, John D, Li, Gang, Kumar, Ravindra, Yu, Paul B
• Format: Journal Article
• Language: English
• Published: United States 13.05.2020
• ISSN: 1946-6242
• DOI: 10.1126/scitranslmed.aaz5660

Human genetics, biomarker, and animal studies implicate loss of function in bone morphogenetic protein (BMP) signaling and maladaptive transforming growth factor-β (TGFβ) signaling as drivers of pulmonary arterial hypertension (PAH). Although sharing common receptors and effectors with BMP/TGFβ, the function of activin and growth and differentiation factor (GDF) ligands in PAH are less well defined. Increased expression of GDF8, GDF11, and activin A was detected in lung lesions from humans with PAH and experimental rodent models of pulmonary hypertension (PH). ACTRIIA-Fc, a potent GDF8/11 and activin ligand trap, was used to test the roles of these ligands in animal and cellular models of PH. By blocking GDF8/11- and activin-mediated SMAD2/3 activation in vascular cells, ACTRIIA-Fc attenuated proliferation of pulmonary arterial smooth muscle cells and pulmonary microvascular endothelial cells. In several experimental models of PH, prophylactic administration of ACTRIIA-Fc markedly improved hemodynamics, right ventricular (RV) hypertrophy, RV function, and arteriolar remodeling. When administered after the establishment of hemodynamically severe PH in a vasculoproliferative model, ACTRIIA-Fc was more effective than vasodilator in attenuating PH and arteriolar remodeling. Potent antiremodeling effects of ACTRIIA-Fc were associated with inhibition of SMAD2/3 activation and downstream transcriptional activity, inhibition of proliferation, and enhancement of apoptosis in the vascular wall. ACTRIIA-Fc reveals an unexpectedly prominent role of GDF8, GDF11, and activin as drivers of pulmonary vascular disease and represents a therapeutic strategy for restoring the balance between SMAD1/5/9 and SMAD2/3 signaling in PAH.