Hematopoietic Stem Cell Heterogeneity Is Linked to the Initiation and Therapeutic Response of Myeloproliferative Neoplasms

The implications of stem cell heterogeneity for disease pathogenesis and therapy are poorly defined. JAK2V617F(+) myeloproliferative neoplasms (MPNs), harboring the same mutation in hematopoietic stem cells (HSCs), display diverse phenotypes, including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). These chronic malignant disorders are ideal models to analyze the pathological consequences of stem cell heterogeneity. Single-cell gene expression profiling with parallel mutation detection demonstrated that themegakaryocyte (Mk)-primed HSC subpopulation expanded significantly with enhanced potential in untreated individuals with JAK2V617F(+) ET, driven primarily by the JAK2mutation and elevated interferon signaling. During treatment, mutant HSCs were targeted preferentially in the Mk-primed HSC subpopulation. Interestingly, homozygous mutant HSCs were forced to re-enter quiescence, whereas their heterozygous counterparts underwent apoptosis. This study provides important evidence for the association of stem cell heterogeneity with the pathogenesis and therapeutic response of a malignant disease.

Automated summary

This study demonstrates that in JAK2V617F(+) ET patients, the Mk-primed HSC subpopulation significantly expands with enhanced potential, and during treatment, mutant HSCs are preferentially targeted in this subpopulation. Homozygous mutant HSCs are forced to re-enter quiescence, while their heterozygous counterparts undergo apoptosis.