The myeloproliferative disease polycythemia vera (PV) driven by the JAK2 V617F mutation can transform into myelofibrosis (post-PV-MF). It remains an open question how JAK2 V617F in hematopoietic stem cells induces MF. Megakaryocytes are major players in murine PV models but are difficult to study in the human setting. We generated induced pluripotent stem cells (iPSCs) from JAK2 V617F PV patients and differentiated them into megakaryocytes. In differentiation assays, JAK2 V617F iPSCs recapitulated the pathognomonic skewed megakaryocytic and erythroid differentiation. JAK2 V617F iPSCs had a TPO-independent and increased propensity to differentiate into megakaryocytes. RNA sequencing of JAK2 V617F iPSC-derived megakaryocytes reflected a proinflammatory, profibrotic phenotype and decreased ribosome biogenesis. In three-dimensional (3D) coculture, JAK2 V617F megakaryocytes induced a profibrotic phenotype through direct cell contact, which was reversed by the JAK2 inhibitor ruxolitinib. The 3D coculture system opens the perspective for further disease modeling and drug discovery.

中文翻译：

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iPS 细胞衍生的 JAK2 V617F 巨核细胞的促炎表型诱导 3D 体外骨髓生态位纤维化

由 JAK2 V617F 突变驱动的骨髓增生性疾病真性红细胞增多症 (PV) 可转化为骨髓纤维化（PV-MF 后）。造血干细胞中的 JAK2 V617F 如何诱导 MF 仍然是一个悬而未决的问题。巨核细胞是小鼠 PV 模型的主要参与者，但很难在人类环境中进行研究。我们从 JAK2 V617F PV 患者中产生诱导多能干细胞 (iPSC)，并将其分化为巨核细胞。在分化测定中，JAK2 V617F iPSC 重现了特异的巨核细胞和红细胞分化。 JAK2 V617F iPSC 具有不依赖于 TPO 且分化为巨核细胞的倾向增加。 JAK2 V617F iPSC 衍生的巨核细胞的 RNA 测序反映了促炎、促纤维化表型和核糖体生物合成减少。在三维 (3D) 共培养中，JAK2 V617F 巨核细胞通过直接细胞接触诱导促纤维化表型，JAK2 抑制剂鲁索替尼可逆转这种表型。 3D 共培养系统为进一步的疾病建模和药物发现开辟了前景。