Abstract 19333: Ectonucleoside Triphosphate Diphosphohydrolase-1 (ENTDP-1/CD39) Regulates the Inflammatory Response in a Murine Model of Venous Thrombosis

Abstract

Background: Deep vein thrombosis (DVT) is a major health concern in the United States, carrying significant morbidity, mortality and socioeconomic cost. CD39 (ectonucleoside triphosphate diphosphohydrolase 1) is a circulating and membrane-spanning protein on the surface of endothelial and some leukocyte populations that is responsible for the phospohydrolysis of ATP to ADP and ADP to AMP. We hypothesized that CD39 plays a protective role in modulating inflammatory responses in a murine model of DVT. Methods: C57BL/6 (WT) and CD39-/- mice underwent inferior vena cava (IVC) ligation. IVCs were harvested at 48h and 6 days post IVC ligation. Vena cava and thrombi were characterized. Leukocytes infiltrating the vein wall were quantified per high power field (hpf) by H&E. Additionally, gene expression of macrophage markers was evaluated using qRT-PCR. Results: Thrombosed IVC weights were higher six days post IVC ligation in CD39-/- mice compared to IVC-ligated WT mice (35.6 mg ± 4.0 vs. 19.5 ± 2.6, n=3 per group, p<0.05, respectively). Additionally, CD39-/- mice had a trend toward increased leukocyte infiltration into the vessel wall at all timepoints with an 80% increase in total leukocytes at 48h (225 ± 26 cells/hpf, n=3 vs. 124 ± 29 cells/hpf n=4, p=0.061, respectively), driven by neutrophilic (PMN) predominance (181 ± 15 cells/hpf, n=3 vs. 103 ± 23 cells/hpf, n=4, p 0.046, respectively) followed by a later trend toward increased macrophage and lymphocyte infiltration in CD39-/- mice. Consistent with these findings, CD39 gene-deletion was associated with a >40-fold increase in mRNA expression of CCR2 (52.35 ± 0.73 vs. 1.17 ± 0.10, n=2 per group, p<0.0002, respectively), a marker of pro-inflammatory macrophages, in the vessel wall compared to WT 6 days post IVC ligation. CD39-/- mice also had 15-fold increased expression (9.62 ± 0.43 vs. 0.62 ± 0.56, n=2 per group, p=0.006, respectively) of CD301b versus WT mice 6 days post IVC ligation. Conclusion: CD39 appears to be a critical regulator of the early and late inflammatory responses in murine DVT with increased thrombus burden, leukocyte infiltration and inflammation-related gene expression in CD39 gene-deleted mice. CD39 may serve a previously unexplored, protective role in the pathophysiology of DVT.