The long-temri objective of this research project is to define the molecular basis of polycythemia vera (PV). PV represents the ultimate phenotype of the mutant kinase, JAK2 V617F, through its effects on committed hematopoietic progenitor cells but we hypothesize that while JAK2 V617F expression is responsible for the clinical phenotype of PV, the underlying molecular mechanisms responsible for the disease reside in the hematopoietic stem cell (HSC), which does not require JAK2, and that the thrombopoietin (TPO) receptor, Mpl, is integrally Involved In these mechanisms. This hypothesis, which is based on our discovery of impaired Mpl expression in PV with an attendant increase in plasma TPO, and our observation that absence of the MPL gene abrogated the PV phenotype in a JAK2 V617F transgenic (tg) mouse model of PV, provides a mechanistic basis for understanding the pathophysiology of PV at the stem cell level and a rational approach to therapy To this end, we propose to use genetic techniques to dissect the influence of the MPL:TPO axis, and also the roles of specific genes up regulated in human PV CD34+ cells, on the behavior of HSC in the murine JAK2 V617F tg model of PV.
In Specific Aim 1, we will examine the effect of abrogation of the TPO gene on the phenotype of the JAK2 V617F tg mouse, on the size of its HSC pool and the HSC gene expression profile, by breeding with a TPO-/- mouse. Control experiments will employ mice in which Mpl function was abrogated by a point mutation or a gene knockout independent of MPL that impairs platelet production, while a neutralizing Mpl antiserum will be examined as a model of targeted therapy.
In Specific Aim 2, we will create a tg mouse expressing a PV Mpl splice variant and assess its phenotype in the presence and absence of JAK2 V617F. We also examine by crossbreeding, the effect of knocking out SPARC or LCN2, two genes that are up regulated in PV, on the phenotype of the JAK2 V617F tg mouse. Finally, in Specific Aim 3, we will use xenotranslantation in NOG mice to examine the in vivo behavior of genetically-defined PV CD34 + cells from clinically distinct PV patient populations that we have identified by gene expression profiling and unsuoervised hierarchical clustering.

Public Health Relevance

Polycythemia vera (PV) is a hematopoietic stem cell (HSC) disorder in which there is overproduction of blood cells, leading to thrombosis, marrow fibrosis, splenic enlargement and acute leukemia, at varying frequencies. We propose to define the mechanisms causing PV by focusing on the behavior of genes required by PV HSC for their survival and function, inhibition of which could provide the basis for targeted therapy in this disorder.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Program Projects (P01)
Project #
Application #
Study Section
Special Emphasis Panel (ZCA1-RPRB-J)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Icahn School of Medicine at Mount Sinai
New York
United States
Zip Code
Gilles, Laure; Arslan, Ahmet Dirim; Marinaccio, Christian et al. (2017) Downregulation of GATA1 drives impaired hematopoiesis in primary myelofibrosis. J Clin Invest 127:1316-1320
Varricchio, Lilian; Falchi, Mario; Dall'Ora, Massimiliano et al. (2017) Calreticulin: Challenges Posed by the Intrinsically Disordered Nature of Calreticulin to the Study of Its Function. Front Cell Dev Biol 5:96
Zingariello, M; Sancillo, L; Martelli, F et al. (2017) The thrombopoietin/MPL axis is activated in the Gata1(low) mouse model of myelofibrosis and is associated with a defective RPS14 signature. Blood Cancer J 7:e572
Falchi, Mario; Varricchio, Lilian; Martelli, Fabrizio et al. (2017) The Calreticulin control of human stress erythropoiesis is impaired by JAK2V617F in polycythemia vera. Exp Hematol 50:53-76
Lanikova, Lucie; Reading, N Scott; Hu, Hao et al. (2017) Evolutionary selected Tibetan variants of HIF pathway and risk of lung cancer. Oncotarget 8:11739-11747
Sergueeva, Adelina; Miasnikova, Galina; Shah, Binal N et al. (2017) Prospective study of thrombosis and thrombospondin-1 expression in Chuvash polycythemia. Haematologica 102:e166-e169
Wang, Linghua; Wheeler, David A; Prchal, Josef T (2016) Acquired uniparental disomy of chromosome 9p in hematologic malignancies. Exp Hematol 44:644-52
Klionsky, Daniel J (see original citation for additional authors) (2016) Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition). Autophagy 12:1-222
Migliaccio, Anna Rita (2016) To condition or not to condition-That is the question: The evolution of nonmyeloablative conditions for transplantation. Exp Hematol 44:706-12
Spangrude, Gerald J; Lewandowski, Daniel; Martelli, Fabrizio et al. (2016) P-Selectin Sustains Extramedullary Hematopoiesis in the Gata1 low Model of Myelofibrosis. Stem Cells 34:67-82

Showing the most recent 10 out of 181 publications