NEDD9 Is a Novel and Modifiable Mediator of Platelet–Endothelial Adhesion in the Pulmonary Circulation
George A. Alba, Andriy O. Samokhin, Rui‐Sheng Wang, Yingyi Zhang, Bradley M. Wertheim, Elena Arons, Edward Greenfield, Martina H. Lundberg Slingsby, Julia R. Ceglowski, Kathleen J. Haley, Frederick P. Bowman, Yen‐Rei Yu, John C. Haney, George Eng, Richard N. Mitchell, Anthony R. Sheets, Sara O. Vargas, Sachiko Seo, Richard N. Channick, Peter J. Leary, Sudarshan Rajagopal, Joseph Loscalzo, Elisabeth M. Battinelli, Bradley A. Maron
Abstract
Abstract Rationale Data on the molecular mechanisms that regulate platelet–pulmonary endothelial adhesion under conditions of hypoxia are lacking, but may have important therapeutic implications. Objectives To identify a hypoxia-sensitive, modifiable mediator of platelet–pulmonary artery endothelial cell adhesion and thrombotic remodeling. Methods Network medicine was used to profile protein–protein interactions in hypoxia-treated human pulmonary artery endothelial cells. Data from liquid chromatography–mass spectrometry and microscale thermophoresis informed the development of a novel antibody (Ab) to inhibit platelet–endothelial adhesion, which was tested in cells from patients with chronic thromboembolic pulmonary hypertension (CTEPH) and three animal models in vivo. Measurements and Main Results The protein NEDD9 was identified in the hypoxia thrombosome network in silico. Compared with normoxia, hypoxia (0.2% O2) for 24 hours increased HIF-1α (hypoxia-inducible factor-1α)–dependent NEDD9 upregulation in vitro. Increased NEDD9 was localized to the plasma-membrane surface of cells from control donors and patients with CTEPH. In endarterectomy specimens, NEDD9 colocalized with the platelet surface adhesion molecule P-selectin. Our custom-made anti-NEDD9 Ab targeted the NEDD9–P-selectin interaction and inhibited the adhesion of activated platelets to pulmonary artery endothelial cells from control donors in vitro and from patients with CTEPH ex vivo. Compared with control mice, platelet–pulmonary endothelial aggregates and pulmonary hypertension induced by ADP were decreased in NEDD9−/− mice or wild-type mice treated with the anti-NEDD9 Ab, which also decreased chronic pulmonary thromboembolic remodeling in vivo. Conclusions The NEDD9–P-selectin protein–protein interaction is a modifiable target with which to inhibit platelet–pulmonary endothelial adhesion and thromboembolic vascular remodeling, with potential therapeutic implications for patients with disorders of increased hypoxia signaling pathways, including CTEPH.