Loss of Function Mouse Models Reveal a Novel Regulatory Function for ULK1 in Myeloproliferative Neoplasms.

Defining the mechanisms that promote development and progression of myeloproliferative neoplasms (MPNs) is important for understanding the mechanisms of malignant hematopoiesis and critical development of new treatment approaches. We provide evidence for a key and essential role of the kinase ULK1 in MPN pathophysiology. Our studies demonstrate that genetic or pharmacological targeting of ULK1 delays substantially disease development in Jak2V617F-mutant MPN models in vivo and establish that ULK1 activity is required for transcription of genes that control hematopoietic stem cell differentiation. Pharmacological targeting of ULK1 exhibits potent therapeutic effects, resulting in reduction of early stage erythroid progenitors in spleen and bone marrow, decreased levels of hemoglobin, and reduced spleen size in MPN mouse models in vivo. Taken together, these findings provide the first evidence for a novel protumorigenic role for ULK1 downstream of the hyperactive JAK2 signaling in MPNs and raise the potential of ULK1 as a new therapeutic target for the treatment of MPNs.