Online Methods and Data Supplement
Creators: name: Stepanova, Victoria
Publisher: name: figshare
Year: 2024
Subjects: classificationCode: 320101
subject: Cardiology (incl. cardiovascular diseases)
classificationCode: 320103
subject: Respiratory diseases

description: <b>PAI-1 Deficiency Drives Pulmonary Vascular Smooth Muscle Remodeling and Pulmonary Hypertension</b><br>Tatiana V. Kudryashova<sup>1#</sup>, Sergei V. Zaitsev<sup>2,3#</sup>, Lifeng Jiang<sup>4#</sup>, Benjamin J. Buckley<sup>5</sup>, Joshua P. McGuckin<sup>6</sup>, Dmitry Goncharov<sup>4</sup>, Iryna Zhyvylo<sup>4</sup>, Derek Lin<sup>4</sup>, Geoffrey Newcomb<sup>7</sup>, Bryce Piper<sup>7</sup>, Srimathi Bogamuwa<sup>7</sup>, Aisha Saiyed<sup>4</sup>, Leyla Teos<sup>4</sup>, Andressa Pena<sup>1</sup>, Marie Ranson<sup>5</sup>, John R. Greenland<sup>8,9</sup>, Paul J. Wolters<sup>8</sup>, Michael J. Kelso<sup>5</sup>, Mortimer Poncz<sup>3</sup>, Horace M. DeLisser<sup>10</sup>, Douglas B. Cines<sup>2</sup>, Elena A. Goncharova<sup>4&amp;</sup>, Laszlo Farkas<sup>7&amp;</sup>, and Victoria Stepanova<sup>2&amp;</sup>*<br><sup>1</sup>University of Pittsburgh Heart, Blood, and Vascular Medicine Institute, Pittsburgh, PA, USA; <sup>2</sup>University of Pennsylvania Department of Pathology and Laboratory Medicine, Philadelphia, PA, USA; <sup>3</sup>Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA; <sup>4</sup>Department of Internal Medicine, University of California, Davis, Davis, CA, USA; <sup>5</sup>School of Chemistry and Molecular Bioscience and Molecular Horizons Institute, University of Wollongong, Wollongong, New South Wales, Australia; <sup>6</sup>School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA; <sup>7</sup>Division of Pulmonary, Critical Care &amp; Sleep Medicine, Department of Internal Medicine, Davis Heart &amp; Lung Research Institute, The Ohio State University, Columbus, OH, USA; <sup>8</sup>University of California, San Francisco School of Medicine; <sup>9</sup>San Francisco Veterans Affairs Health Care System, San Francisco, CA, USA; <sup>10</sup>University of Pennsylvania Department of Medicine, Philadelphia, PA, USA.<br><sup>#</sup>equally contributed as first authors; <sup>&amp;</sup>equally contributed as senior authors<b>*</b>Correspondence to:<b> </b>Victoria Stepanova, 513B Stellar Chance Bld, 422 Curie Blvd, Philadelphia, 19104 PA, USA; email: vstepano@pennmedicine.upenn.edu<br><br><br><b>ABSTRACT</b>Pulmonary arterial hypertension (PAH) is a progressive disease characterized by vasoconstriction and remodeling of small pulmonary arteries (PAs). Central to the remodeling process is a switch of pulmonary vascular cells to a proliferative, apoptosis-resistant phenotype. Plasminogen activator inhibitors-1 and -2 (PAI-1 and PAI-2) are the primary physiological inhibitors of urokinase-type and tissue-type plasminogen activators (uPA and tPA), but their roles in PAH are unsettled. Here, we report that: (1) PAI-1, but not PAI-2, is deficient in remodeled small PAs and in early-passage PA smooth muscle and endothelial cells (PASMCs and PAECs) from subjects with PAH compared to controls; (2) PAI-1<sup>-/-</sup><i> </i>mice spontaneously develop pulmonary vascular remodeling associated with up-regulation of mTORC1 signaling, pulmonary hypertension (PH), and right ventricle (RV) hypertrophy; and (3) pharmacological inhibition of uPA in human PAH PASMCs suppresses pro-proliferative mTORC1 and SMAD3 signaling, restores PAI-1 levels, reduces proliferation and induces apoptosis <i>in vitro</i>, and prevents the development of SU5416/hypoxia-induced PH and RV hypertrophy <i>in vivo</i> in mice. These data strongly suggest that down-regulation of PAI-1 in small PAs promotes vascular remodeling and PH due to unopposed activation of uPA and consequent up-regulation of mTOR and TGF-b signaling in PASMCs, and call for further studies to determine the potential benefits of targeting the PAI-1/uPA imbalance to attenuate and/or reverse pulmonary vascular remodeling and PH.