Abstract
Systemic sclerosis (SSc) is a complex and heterogeneous condition characterized by progressive fibrosis in multiple organs. Recent studies implicate plasminogen activator inhibitor-1 (PAI-1) in the pathogenesis of SSc, and PAI-1 is considered as a potential target for therapy. Here, using single-cell and spatial RNA-seq analysis of skin biopsies from 18 healthy individuals and 22 SSc patients, we found elevated PAI-1 colocalizing to myofibroblasts with enriched extracellular matrix–associated biological processes. Treatment of SSc dermal fibroblasts with the small-molecule PAI-1 inhibitor MDI-2517 reduced the expression of the profibrotic markers COL1A1 and ACTA2. To investigate the therapeutic potential of MDI-2517, we evaluated its efficacy in reducing fibrosis in a preclinical model of SSc. Treatment of mice with MDI-2517 significantly reduced both skin and lung fibrosis and was superior to treatment with either pirfenidone or mycophenolate mofetil. Additionally, MDI-2517 attenuated weight loss and significantly reduced the expression of key profibrotic markers. Compared with tiplaxtinin, another PAI-1 inhibitor previously shown to be effective in a model of SSc, MDI-2517 was found to have superior efficacy at a 10-fold lower dose. These findings highlight the role of PAI-1 in the pathogenesis of SSc, and the potential of MDI-2517 for the treatment of SSc.
Authors
Enming J. Su, Pei-Suen Tsou, Mark Warnock, Natalya Subbotina, Kris Mann, Sirapa Vichaikul, Alyssa Rosek, Lisa Leung, Xianying Xing, Enze Xing, Olesya Plazyo, Rachael Bogle, Lam C. Tsoi, Cory D. Emal, Dinesh Khanna, John Varga, Thomas H. Sisson, Johann E. Gudjonsson, Daniel A. Lawrence
Figure 7
Lung trichrome staining from the comparator study of MDI-2517, MMF, and combined MMF plus MDI-2517.
