Abstract 18284: Inhibition of Sulfatase-1 Prevents Pulmonary Arterial Hypertension in Animal Models of Disease

Abstract

Introduction: Sulfatase-1 (Sulf1) is an extracellular enzyme that removes 6-O-sulfate groups from heparan sulfate and is implicated in cardiovascular disease. In human pulmonary artery endothelial cells (HPAECs), Sulf1 mRNA and protein levels are regulated by the fibroproliferative protein NEDD9 involved in PAH. Hypothesis: Sulf1 regulates migration and profibrotic potential of HPAECs and its downregulation prevents the development of PAH. Methods: HPAECs were transfected with Sulf1 siRNA or adenovirus expressing Sulf1 and cell migration was analyzed by scratch assay. In a PAH disease prevention treatment protocol, rats received intratracheal injection of Sulf1 siRNA (si-Sulf1) (1mg/kg of body weight, once a week for 3 weeks) beginning one day following the administration of monocrotaline (MCT). In a disease reversal protocol, injection of si-Sulf1 (1mg/kg of body weight, once every 5 days for a total of 3 doses) began 14 days following initiation of SU-5416/Hypoxia (SU/Hypox) PAH model. Results: Overexpression of Sulf1 in HPAECs resulted in a significant reduction in migration compared to empty vector (wound size 506 ± 39 vs 353 ± 19 μm, P<0.01), whereas transfection with si-Sulf1 increased migration significantly compared to si-Scrambled control (wound size 212 ± 30 vs 295 ± 31 μm, P<0.01). Overexpression of Sulf1 also increased extracellular collagen III deposition in cultured HPAECs compared to empty vector (15.4 ± 5 vs. 7 ± 1 arb. units, P<0.01). Immunostaining of HPAECs for Sulf1 showed strong expression at focal adhesions. In both in vivo PAH models, si-Sulf1 treatment significantly decreased right ventricular (RV) systolic pressure compared to si-Scrambled control (MCT: 41 ± 5 vs 58 ± 6 mm Hg, P<0.05; SU/Hypox: 40 ± 5 vs 75 ± 15 mm Hg, P<0.05) and RV mass measured by Fulton index (MCT: 0.33 ± 0.06 vs 0.56 ± 0.06, P<0.01; SU/Hypox: 0.32 ± 0.02 vs 0.41 ± 0.02, P<0.05). Conclusions: These data demonstrate that pulmonary endothelial expression of Sulf1 is increased at focal adhesions and regulates cellular migration. Inhibition of Sulf1 significantly reduced the severity of PAH in vivo, which, taken together, identifies Sulf1 as a potential therapeutic target by which to improve proliferative vascular remodeling and pulmonary hypertension in PAH.