Haematologica. 2013 Oct;98(10):1517-24. doi: 10.3324/haematol.2012.082560. Epub 2013 Aug 23.
Myeloproliferative disorders are associated with increased risk of thrombosis and vascular complications. The pathogenesis of these complications is not completely known. Reactive oxygen species produced by the neutrophil NADPH oxidase could have a role in this process. The aim of this study was to evaluate reactive oxygen species production by neutrophils of myeloproliferative disorder patients. Patients with or without the JAK2 V617F mutation were characterized. Reactive oxygen species production was assessed by chemiluminescence, and phosphorylation of the NADPH oxidase subunit p47phox was analyzed by Western blots. In a comparison of controls and myeloproliferative disorder patients without the JAK2 V617F mutation, reactive oxygen species production by neutrophils from patients with the JAK2 V617F mutation was dramatically increased in non-stimulated and in stimulated conditions. This increase was associated with increased phosphorylation of the p47phox on Ser345 and of the uspstream kinase ERK1/2. In neutrophils from healthy donors, JAK2 can be activated by GM-CSF. GM-CSF-induced p47phox phosphorylation and priming of reactive oxygen species production are inhibited by the selective JAK2 inhibitors AG490 and lestaurtinib (CEP-701), supporting a role for JAK2 in the upregulation of NADPH oxidase activation. These findings show an increase in reactive oxygen species production and p47phox phosphorylation in neutrophils from myeloproliferative disorder patients with the JAK2 V617F mutation, and demonstrate that JAK2 is involved in GM-CSF-induced NADPH oxidase hyperactivation. As neutrophil hyperactivation could be implicated in the thrombophilic status of patients with myeloproliferative disorders, aberrant activation of JAK2 V617F, leading to excessive neutrophil reactive oxygen species production might play a role in this setting.
骨髓增殖性疾病与血栓形成和血管并发症的风险增加有关。这些并发症的发病机制尚不完全清楚。中性粒细胞 NADPH 氧化酶产生的活性氧可能在这个过程中起作用。本研究旨在评估骨髓增殖性疾病患者中性粒细胞的活性氧产生。对伴有或不伴有 JAK2 V617F 突变的患者进行了特征描述。通过化学发光法评估活性氧的产生，并用 Western blot 分析 NADPH 氧化酶亚基 p47phox 的磷酸化。在比较对照和无 JAK2 V617F 突变的骨髓增殖性疾病患者时，伴有 JAK2 V617F 突变的患者中性粒细胞在非刺激和刺激条件下的活性氧产生明显增加。这种增加与 p47phox 在 Ser345 的磷酸化以及上游激酶 ERK1/2 的激活有关。在健康供体的中性粒细胞中，GM-CSF 可以激活 JAK2。GM-CSF 诱导的 p47phox 磷酸化和活性氧产生的“启动”被选择性 JAK2 抑制剂 AG490 和 lestaurtinib（CEP-701）抑制，这支持 JAK2 在 NADPH 氧化酶激活的上调中的作用。这些发现表明骨髓增殖性疾病患者中 JAK2 V617F 突变的中性粒细胞中活性氧产生和 p47phox 磷酸化增加，并证明 JAK2 参与 GM-CSF 诱导的 NADPH 氧化酶过度激活。由于中性粒细胞的过度激活可能与骨髓增殖性疾病患者的血栓形成状态有关，因此异常激活 JAK2 V617F 导致中性粒细胞产生过多的活性氧可能在这种情况下发挥作用。
