Investigation of the impact of pegylated Interferon on clonal trajectory and inflammatory cytokine production in MPN patients

项目摘要 骨髓增生性肿瘤（MPN）包括真性红细胞增多症（PV）、原发性 血小板增多症（ET）和骨髓纤维化（MF）是造血干细胞克隆性疾病 其特征在于JAK-STAT信号通路的异常激活。JAK-STAT途径最常见于 JAK 2、CALR或MPL突变激活。在生物学上，这些疾病的特征是增殖 成熟的髓系和红系细胞，以及炎性细胞因子的过度产生。临床上，这些疾病 导致血栓形成和出血事件的风险增加，进行性骨髓纤维化，高度 症状负担，最终转化为急性白血病。细胞减灭治疗，包括 羟基脲（HU）和聚乙二醇化干扰素（pegINF）是用于控制疾病的常用药剂 ET和PV患者的临床表现。值得注意的是，pegINF已经证明了获得临床 缓解（包括ET和PV患者的血液学和病理学缓解）。此外，外围 成熟中性粒细胞和单核细胞的血液DNA测序研究表明， 可以导致JAK 2 V617 F等位基因负荷的降低，在某些情况下降低至低于JAK 2 V617 F等位基因的检测限的水平。 使用的分析。然而，INF在MPN中发挥作用的机制，包括其对 MPN造血干细胞和祖细胞（HSPCs），仍有待解决。 观察到pegINF治疗可以使外周血计数正常化，减少突变型JAK 2 MPN患者外周血中等位基因负荷和血清中细胞因子表达的改变表明， pegINF可能通过耗尽JAK 2突变型HSPC，改变JAK 2突变型HSC的适应性，或 改变HSPC的转录谱以减少巨核细胞/红系细胞谱系偏倚。但没有 综合分析pegINF治疗对MPN患者突变型和野生型HPSC的影响， 被举报。我们假设pegINF治疗通过以下方式导致血液学和分子学应答： 减少JAK 2 mut HSPC的克隆输出并通过以下方式减弱炎性细胞因子的产生： 减少来源于JAKmut HSPC的成熟和未成熟髓系和红系细胞的数量 以及每个细胞的细胞因子产生。 使用主要患者样本进行最近报告的ET和PV患者中pegINF的II期研究 （MPD-RC 111研究）和在未经治疗的PV和ET患者中比较羟基脲与INF的III期试验（MPD-RC 111研究）。 RC 112研究），我们将采用单细胞方法来确定pegINF对谱系的影响 JAK 2突变体HSPC的轨迹、HSPC的转录输出以及这些HSPC对细胞因子产生的影响 人口。我们的实验将揭示pegINF如何改变造血和炎症的见解， MPN患者的骨髓，并确定疾病反应的预测因子。

PROJECT SUMMARY The myeloproliferative neoplasms (MPNs) which include Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Myelofibrosis (MF) are clonal hematopoietic stem cell disorders molecularly characterized by aberrant activation of the JAK-STAT signaling pathway. The JAK-STAT pathway is most often activated by mutations in JAK2, CALR, or MPL. Biologically, theses disease are characterized by proliferation of mature myeloid and erythroid cells, and overproduction of inflammatory cytokines. Clinically, these diseases result in increased risk of thrombotic and hemorrhagic events, progressive bone marrow fibrosis, a high degree of symptom burden, and ultimately transformation to acute leukemia. Cytoreductive therapy, including hydroxyurea (HU) and pegylated Interferon (pegINF) are commonly used agents used to control disease manifestations in patients with ET and PV. Notably, pegINF has demonstrated the ability to procure clinical response (including hematologic and pathologic response in patients with ET and PV). Further, peripheral blood DNA sequencing studies of mature neutrophils and mononuclear cells have demonstrated that pegINF can results in decreases of JAK2V617F allele burden, in some cases to levels below the limits of detection of employed assays. However, the mechanisms by which INF exerts its effects in MPN, including its effects on MPN hematopoietic stem and progenitor cells (HSPCs), remains to be resolved. The observation that pegINF therapy can normalize peripheral blood counts, decrease mutant JAK2 allele burden in the peripheral blood, and alter cytokine expression in the serum of MPN patients suggests the possibility that pegINF may work by depleting JAK2 mutant HSPCs, alter the fitness of JAK2 mutant HSCs, or alter the transcriptional profile of HSPCs to reduce megakaryocyte/erythroid lineage bias. However, no comprehensive analysis of the impact of pegINF therapy on mutant and wildtype HPSCs in MPN patients has been reported. We hypothesize that pegINF therapy results in hematologic and molecular responses by reducing the clonal output of JAK2mut HSPCs and attenuates inflammatory cytokine production by reducing the number of mature and immature myeloid and erythroid cells derived from JAKmut HSPCs as well as the cytokine production per cell. Using primary patient samples for the recently reported phase II study of pegINF in ET and PV patients (MPD-RC 111 study) and the Phase III trial of hydroxyurea versus INF in untreated PV and ET patients (MPD- RC 112 study) we will undertake single-cell approaches to determine the impact of pegINF on the lineage trajectory of JAK2 mutant HSPCs, the transcriptional output of HSPCs, and on cytokine production by these populations. Our experiments will reveal insights into how pegINF alters hematopoiesis and inflammation in the bone marrow of MPN patients, and identify predictors of disease response.