Endothelial JAK2V617F mutation leads to thrombosis, vasculopathy, and cardiomyopathy in a murine model of myeloproliferative neoplasm

Rational: The myeloproliferative neoplasms (MPNs) are clonal hematological malignancies characterized by hematopoietic stem cell expansion and overproduction of mature blood cells. Cardiovascular complications are the leading cause of morbidity and mortality in patients with MPNs. The acquired kinase mutation JAK2V617F plays a central role in these disorders. Mechanisms responsible for cardiovascular dysfunction in MPNs are not fully understood, limiting the effectiveness of current treatment. Objective: Vascular endothelial cells (ECs) play critical roles in the regulation of hemostasis and thrombosis. ECs carrying the JAK2V617F mutation can be detected in patients with MPNs. The goal of this study was to test the hypothesis that the JAK2V617F mutation alters endothelial function to promote cardiovascular complications in patients with MPNs. Methods and Results: We employed murine models of MPN in which the JAK2V617F mutation is expressed in specific cell lineages. When JAK2V617F is expressed in both blood cells and vascular ECs, the mice developed MPN and spontaneous, age-related dilated cardiomyopathy with an increased risk of sudden death as well as a prothrombotic and vasculopathy phenotype on histology evaluation. We showed that JAK2V617F-mutant ECs are required for this cardiovascular disease phenotype and the mutation can alter endothelial cell function. Finally, in a more therapeutically oriented approach, we demonstrated that transplantation with wild-type donor marrow cells can improve cardiac function by reversing the left ventricle remodeling process in this JAK2V617F-positive MPN murine model. Conclusions: These findings suggest that the JAK2V617F mutation alters vascular endothelial function to promote cardiovascular complications in MPNs. Therefore, targeting the MPN vasculature represents a promising new therapeutic strategy for patients with MPNs.