PI3 Kinase Inactivation in Myelodysplastic Syndrome

骨髓增生异常综合征中的 PI3 激酶失活

• 批准号: 10518821
• 负责人: Kira Gritsman
• 金额: $ 51.86万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10518821
• 关键词: 1-Phosphatidylinositol 3-Kinase; Abnormal Cell; Affect; Alternative Splicing; Animal Model; Arginine; Autophagocytosis; Biological Models; Cells; Clinical; Cytokine Signaling; DNA Damage; Data; Data Set; Defect; Dependence; Development; Disease; Dysmyelopoietic Syndromes; Dysplasia; Event; Exons; Gene Expression; Gene Expression Profile; Genes; Genomic Instability; Growth Factor; Hematopoiesis; Hematopoietic; Hematopoietic Cell Growth Factors; Hematopoietic stem cells; Hemorrhage; Human; Impairment; Infection; Knock-out; Knockout Mice; Lead; Link; Lipids; Maintenance; Messenger RNA; Metformin; Modeling; Mus; Mutation; Myelogenous; Nuclear; PTEN gene; Pathogenesis; Pathway interactions; Patients; Pattern; Persons; Pharmacology; Phenotype; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiological; Play; Process; Protein Isoforms; Protein Kinase; Proteins; Proto-Oncogene Proteins c-akt; Quality Control; RNA Splicing; RNA-Binding Proteins; Recycling; Reporting; Role; SRSF2 gene; Sampling; Serine; Signal Transduction; Spliceosomes; Testing; Therapeutic; Transfusion; aging population; biological adaptation to stress; cytopenia; drug candidate; erythroid differentiation; exon skipping; hematopoietic stem cell differentiation; improved; inhibitor; mortality; mouse model; mutant; novel therapeutic intervention; prevent; public health relevance; stem cell biology; stem cell function; stem cell genes; stem cells; therapeutic target

Myelodysplastic Syndrome (MDS) affects at least 10,000 people each year in the U.S., and is particularly prevalent in the aging population. MDS is a clonal disorder arising in hematopoietic stem cells (HSCs), characterized by impaired myeloid and erythroid differentiation and genomic instability. There are currently few therapeutic approaches available to improve cytopenias in MDS patients. Mutations in RNA splicing factors are observed in 50% of MDS cases, and are important contributors to MDS initiation and progression. Most hematopoietic growth factors and cytokines signal through the PI3 kinase (PI3K)/AKT pathway. We have found that compound deletion of the three PI3K isoforms P110a, b, and d in mouse hematopoietic cells leads to a phenotype resembling MDS, with cytopenias, impaired HSC differentiation and genomic instability. Interestingly, we observed enrichment of our TKO HSC expression signature in an MDS patient gene expression dataset. Furthermore, a subset of MDS samples have elevated expression levels of the negative regulator PTEN, suggesting functional inactivation of PI3K in these MDS patients. Our preliminary data reveals that HSCs in PI3K triple knockout (TKO) mice have a defect in autophagy, an intracellular recycling mechanism that is important for the maintenance of HSC differentiation. We found that pharmacologic induction of autophagy can improve differentiation of TKO HSCs. We also observed widespread alterations in mRNA splicing in TKO HSCs. Therefore, PI3K TKO mice are a valuable new model system to study the mechanisms of MDS initiation and progression. We hypothesize that maintenance of PI3K signaling in HSCs is required to maintain HSC differentiation and to protect HSCs from DNA damage. We propose to (1) determine whether induction of autophagy can improve myeloid and erythroid differentiation in MDS patient samples, (2) delineate the mechanism by which PI3K and its downstream kinase AKT control mRNA splicing in HSCs and in MDS, and (3) determine whether MDS cells with splicing factor mutations are more sensitive to inhibition of PI3K/AKT signaling. These approaches will further our understanding of how growth factor and cytokine signaling regulates autophagy and mRNA splicing through PI3K/AKT in MDS initiation. We also plan to test several therapeutic approaches to improve differentiation in MDS, including induction of autophagy and inhibition of PI3K/AKT in MDS with splicing factor mutations.

在美国，骨髓增生异常综合征 (MDS) 每年影响至少 10,000 人，并且在老龄化人口中尤为普遍。 MDS 是一种起源于造血干细胞 (HSC) 的克隆性疾病，其特征是骨髓和红系分化受损以及基因组不稳定。目前可用于改善 MDS 患者血细胞减少症的治疗方法很少。 RNA剪接因子的突变是 在 50% 的 MDS 病例中观察到，并且是 MDS 发生和进展的重要因素。大多数造血生长因子和细胞因子通过 PI3 激酶 (PI3K)/AKT 途径发出信号。我们发现，小鼠造血细胞中三种 PI3K 同工型 P110a、b 和 d 的复合缺失会导致类似于 MDS 的表型，伴有血细胞减少、HSC 分化受损和基因组不稳定。有趣的是，我们在 MDS 患者基因表达数据集中观察到 TKO HSC 表达特征的丰富。此外，MDS 样本的一个子集负调节因子 PTEN 的表达水平升高，表明这些 MDS 患者中 PI3K 功能失活。我们的初步数据表明，PI3K 三重敲除 (TKO) 小鼠中的 HSC 存在自噬缺陷，自噬是一种细胞内回收机制，对于维持 HSC 分化非常重要。我们发现自噬的药理学诱导可以改善 TKO HSC 的分化。我们还观察到 TKO HSC 中 mRNA 剪接的广泛变化。因此，PI3K TKO小鼠是研究MDS发生和进展机制的有价值的新模型系统。我们假设 HSC 中 PI3K 信号传导的维持是 维持 HSC 分化并保护 HSC 免受 DNA 损伤所必需的。我们建议(1)确定自噬的诱导是否可以改善MDS患者样本中的骨髓和红细胞分化，(2)描绘PI3K及其下游激酶AKT控制HSC和MDS中mRNA剪接的机制，以及(3)确定具有剪接因子突变的MDS细胞是否对PI3K/AKT信号传导的抑制更敏感。这些方法将进一步了解生长因子和细胞因子信号传导如何在 MDS 起始过程中通过 PI3K/AKT 调节自噬和 mRNA 剪接。我们还计划测试几种改善 MDS 分化的治疗方法，包括在具有剪接因子突变的 MDS 中诱导自噬和抑制 PI3K/AKT。