Effect of hypoxia on HIF-1α and NOS3 expressions in CD34+ cells of JAK2V617F-positive myeloproliferative neoplasms

Purpose

Myeloproliferative neoplasms (MPN) are a heterogeneous group of hematopoietic stem-cell diseases with excessive proliferation of one or more blood cell lines. In this study, we evaluated the effect of different oxygen concentrations on HIF-1α and NOS3 gene expression to determine the effect of the bone marrow microenvironment on JAK2V617F positive Philadelphia chromosome negative (Ph⁻) MPNs.

Patients and methods

Peripheral blood mononuclear cells (MNC) of 12 patients with Ph⁻ MPN were collected. The presence of JAK2V617F allele status was determined with allele-specific nested PCR analysis. MPN CD34⁺ and CD34^depleted populations were isolated from MNC by magnetic beads. Separate cell cultures of CD34^+/depleted populations were managed at different oxygen concentrations including anoxia (∼0%), hypoxia (∼3%), and normoxia (∼20%) conditions for 24 ​h. HIF-1α and NOS3 gene expression changes were examined in each population related to JAK2V617F status with real time RT-PCR.

Result

It was revealed that relative HIF-1α and NOS3 expressions were significantly increased in response to decreased oxygen concentration in all samples. Relative HIF-1α and NOS3 expressions were found to be higher especially in CD34⁺ and CD34^depleted populations carrying JAK2V617F mutations compared to MPN patients carrying wild-type JAK2.

Conclusion

JAK2V617F might have specific role in HIF-1α and NOS3 regulations with respect to low oxygen concentrations in Ph⁻ MPN. Further evaluations might reveal the effect of JAK2V617F on Ph⁻ MPN pathogenesis in bone marrow microenvironment.