Impact of isolated germline JAK2V617I mutation on human hematopoiesis.

Blood (2013-03-29)
Adam J Mead, Onima Chowdhury, Christian Pecquet, Alexandra Dusa, Petter Woll, Deborah Atkinson, Adam Burns, Joannah Score, Michelle Rugless, Ruth Clifford, Simon Moule, Nicola Bienz, Paresh Vyas, Nick Cross, Rosemary E Gale, Shirley Henderson, Stefan N Constantinescu, Anna Schuh, Sten Eirik W Jacobsen
ABSTRACT

The association between somatic JAK2 mutation and myeloproliferative neoplasms (MPNs) is now well established. However, because JAK2 mutations are associated with heterogeneous clinical phenotypes and often occur as secondary genetic events, some aspects of JAK2 mutation biology remain to be understood. We recently described a germline JAK2V617I mutation in a family with hereditary thrombocytosis and herein characterize the hematopoietic and signaling impact of JAK2V617I. Through targeted sequencing of MPN-associated mutations, exome sequencing, and clonality analysis, we demonstrate that JAK2V617I is likely to be the sole driver mutation in JAK2V617I-positive individuals with thrombocytosis. Phenotypic hematopoietic stem cells (HSCs) were increased in the blood and bone marrow of JAK2V617I-positive individuals and were sustained at higher levels than controls after xenotransplantation. In signaling and transcriptional assays, JAK2V617I demonstrated more activity than wild-type JAK2 but substantially less than JAK2V617F. After cytokine stimulation, JAK2V617I resulted in markedly increased downstream signaling compared with wild-type JAK2 and comparable with JAK2V617F. These findings demonstrate that JAK2V617I induces sufficient cytokine hyperresponsiveness in the absence of other molecular events to induce a homogeneous MPN-like phenotype. We also provide evidence that the JAK2V617I mutation may expand the HSC pool, providing insights into both JAK2 mutation biology and MPN disease pathogenesis.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
L-Isoleucine, reagent grade, ≥98% (HPLC)
Sigma-Aldrich
L-Isoleucine, from non-animal source, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%
Sigma-Aldrich
L-Valine, reagent grade, ≥98% (HPLC)
Sigma-Aldrich
L-Valine, from non-animal source, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%
SAFC
L-Isoleucine
SAFC
L-Valine
Supelco
L-Isoleucine, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
L-Valine, BioUltra, ≥99.5% (NT)
Supelco
L-Valine, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
L-Isoleucine, 99%, FCC, FG
Sigma-Aldrich
L-Isoleucine, BioUltra, ≥99.5% (NT)
Supelco
L-Valine, certified reference material, TraceCERT®
Supelco
L-Isoleucine, certified reference material, TraceCERT®