Hyperglycemia mediated myeloproliferative disease

项目摘要/摘要 糖尿病(DM)是癌症发生的重要危险因素。然而，目前还不清楚糖尿病是否也是一种风险 白血病前期干细胞转化为急性髓系白血病等成熟白血病的因子 白血病(AML)、慢性粒单核细胞白血病(CMML)或严重形式的骨髓增生性肿瘤 (MPN)。为此，对2万多个外周血(PB)细胞进行了广泛的外显子组全序列测定 对未被选为血液学表型的人进行了160个复发基因的检查 在白血病中发生突变。发现的两个突变最多的基因是表观遗传调节基因：1011易位 甲基胞嘧啶双加氧酶2(TET2)和DNA胞嘧啶甲基转移酶3A(DNMT3A)。值得注意的是，这两个 在MPNS和AML患者中，基因突变的频率非常高。重要的是，流行病学调查结果 证明患有糖尿病的人比没有糖尿病的人更有可能有这些突变。然而， 在我们对DM在MPN和MPN中的致病作用的理解上存在着显著的差距 白血病的发生。利用小鼠TET2功能丧失模型(TET2-/-)的研究表明，TET2缺乏 造血干细胞(HSCs)具有异常的全局5-羟甲基胞嘧啶(5-HMC)水平和局部5-羟甲基胞嘧啶(5-HMC)水平. 负责造血干细胞自我更新的基因中的HMC水平。此外，TET2-/-HSC显示出具有竞争力的 与正常的HSCs相比具有优势(即克隆性造血)，但不会发展为AML。此外， TET2(TET2/-)半缺乏的小鼠只有在衰老时才表现出较温和的这些表型， 提示TET2可能是一种肿瘤抑制因子。我们发现TET2缺陷小鼠表现出 对急性炎症和衰老幼稚TET2-/-小鼠的持续反应显示一系列 编码先天免疫/促炎途径成分的基因包括S100A8/9、TLR4、NFκB1 和IL-6。随着糖尿病患者出现慢性炎症并增加S100A8/A9的表达， 这一建议的中心假设是，携带单一遗传病变形式的糖尿病患者 在他们的HSCs中的TET2(没有任何血液恶性肿瘤)将更容易发展为严重的 MPN和/或髓系白血病，部分原因是过度活跃的促炎细胞因子信号级联或前向 喂养正信号环和部分高血糖(HG)诱导5-HMC进一步整体降低 携带TET2缺失的前LSCs的水平，从而模拟缺少所有形式的TET的前LSCs。事实上，通过引入 TET2突变进入糖尿病小鼠模型(Ins2Akita/)，我们的初步数据表明，糖尿病 TET2单倍体缺乏的小鼠(Ins2Akita/；TET2/-)逐渐发展为致死性AML/严重MPN。重要的是 用抗炎分子治疗暴露在急性炎症挑战中的TET2-/-小鼠， APX3330逆转了这一表型。根据这些初步结果，我们假设进行性糖尿病 是将前LSCs和/或克隆性造血转化为血红素恶性肿瘤的重要危险因素 以年龄相关的方式。

PROJECT SUMMARY/ABSTRACT Diabetes mellitus (DM) is a strong risk factor for cancer development. However, it is unclear if DM is also a risk factor for transforming pre-leukemic stem cells (pre-LSCs) into full-blown leukemia such as acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML) or severe form of myeloproliferative neoplasm (MPN). To this end, extensive whole exome sequencing on peripheral blood (PB) cells of more than 20 thousand persons who were unselected for hematologic phenotypes were examined for 160 genes that are recurrently mutated in leukemia. Two most mutated genes found were epigenetic regulators: Ten eleven translocation methylcytosine dioxygenase 2 (TET2) and DNA cytosine-methyltransferase 3A (DNMT3A). Notably, both these genes are mutated at very high frequency in patients with MPNs and AML. Importantly, epidemiological findings demonstrate that persons with DM are more likely to have these mutations than those without DM. However, there is a significant gap in knowledge regarding our understanding of DMs causative role in MPN and leukemogenesis. Studies using murine models of loss of Tet2 function (Tet2-/-) show that Tet2-deficient hematopoietic stem cells (HSCs) have abnormal global 5-hydroxymethylcytosine (5-hmC) levels and local 5- hmC levels in genes responsible for self-renewal of HSCs. In addition, Tet2-/- HSCs show a competitive advantage (i.e. clonal hematopoiesis) over normal HSCs but do not progress to AML development. Moreover, mice with haplo-insufficiency of Tet2 (Tet2+/-) manifest milder form of these phenotypes only when aged, indicating that Tet2 functions as a putative tumor suppressor. We discovered that Tet2-deficient mice manifest a sustained response to acute inflammation and aged naïve Tet2-/- mice show elevated expression of a series of genes encoding the innate immune/pro-inflammatory pathway components including S100A8/9, TLR4, NFκB1 and IL-6. As patients with DM develop chronic inflammation and have increased expression of S100A8/A9, the central hypothesis of this proposal is that diabetic individuals that carry a single genetic lesion in the form of TET2 in their HSCs (in absence of any hematologic malignancies), will be more susceptible to developing severe MPN and/or myeloid leukemia, in part to an overactive pro-inflammatory cytokine signaling cascade or a forward feeding positive signaling loop and in part to hyperglycemia (HG) induced further global reduction in 5-hmC levels in pre-LSCs bearing loss of Tet2, thus mimicking pre-LSCs lacking all forms of TET. Indeed, by introducing Tet2 mutation into a murine model of diabetes (Ins2Akita/+), our preliminary data demonstrate that the diabetic mice haploinsufficient for Tet2 (Ins2Akita/+;Tet2+/-) progressively develop lethal AML/severe MPN. Importantly, treatment of Tet2-/- mice exposed to an acute inflammatory challenge with an anti-inflammatory molecule, APX3330, reverses this phenotype. Based on these preliminary results, we hypothesize that progressive DM acts as a significant risk factor for transforming pre-LSCs and/or clonal hematopoiesis into heme malignancies in an age-dependent manner.