Implications of PARP1 in myelodysplastic syndromes and targeted therapy

PARP1 在骨髓增生异常综合征和靶向治疗中的意义

• 批准号: 10624340
• 负责人: Dang Hai Nguyen
• 金额: $ 48.36万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-20 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10624340
• 关键词: ADP ribosylation; Address; Biological Markers; Biology; Blood; Blood typing procedure; Bone Marrow; CD34 gene; Cell Death; Cells; Clinic; Clonal Hematopoietic Stem Cell; DNA; DNA Damage; Data; Disease; Dysmyelopoietic Syndromes; Enzymes; FDA approved; Genes; Genetic Predisposition to Disease; Genetic Transcription; Genome; Genomic Instability; Genomics; Hematological Disease; Hematopoietic; Heterozygote; Human; Hybrids; In Vitro; Ineffective Hematopoiesis; Laboratories; Lead; Link; Modality; Modeling; Molecular; Monitor; Mononuclear; Mus; Mutate; Mutation; Myelogenous; PTPRC gene; Patients; Play; Poly(ADP-ribose) Polymerase Inhibitor; Poly(ADP-ribose) Polymerases; Prevalence; Production; Prognosis; Proteins; Proteomics; RNA; RNA Splicing; Regulation; Route; SRSF2 gene; SS DNA BP; Secondary acute myeloid leukemia; Secondary to; Signal Transduction; Single-Stranded DNA; Site; Source; Spliceosomes; Structure; Testing; Therapeutic; Translating; Transplantation; acquired bone marrow failure; bone marrow failure syndrome; cytopenia; efficacy evaluation; established cell line; genome-wide; high risk; in vivo; mouse model; mutant; novel therapeutics; overexpression; peripheral blood; pre-clinical; progenitor; progression risk; public health relevance; recruit; replication factor A; response; sensor; stem cells; targeted treatment

PROJECT SUMMARY/ABSTRACT Myelodysplastic syndromes (MDS), a heterogenous group of clonal hematopoietic stem cell disorders, are an acquired bone marrow failure syndrome. MDS is characterized by ineffective hematopoiesis resulting in peripheral blood cytopenia and progenitor expansion. Genes encoding for RNA splicing factors (U2AF1, SF3B1, SRSF2, and ZRSR2) are frequently mutated and occur in the founding clones of MDS, representing a unique class of genetic vulnerability for targeted therapy. However, despite the prevalence of spliceosome mutations, how such mutations impact different cellular mechanisms are largely unclear. Recent studies by us and others suggest that R-loops, a group of transcription intermediates containing RNA:DNA hybrids and displaced single- stranded DNA, are a source of genomic instability induced by different spliceosome mutants. In the preliminary studies leading to this application, we find that PARP1 is activated by R-loops and it plays a key role in suppressing R-loop-associated DNA damage. Furthermore, we show that MDS-associated RNA splicing factor mutations promote R-loop accumulation and render cells sensitive to PARP inhibition. These exciting findings lead us to hypothesize that PARP1 is a key sensor of R-loops and a critical suppressor of R-loop-associated DNA damage. Furthermore, aberrant R-loop accumulation represents a new targetable vulnerability in MDS- associated splicing factor mutant cells, making PARP inhibition an attractive way to target R-loop vulnerability in MDS. Finally, since PARP inhibitors achieved limited FDA approval in different diseases, repurposing PARP inhibitors to treat MDS patients harboring RNA splicing factor mutations may provide the fastest route to translate our findings to the clinics. To test these hypotheses, in Aim 1, we will elucidate mechanisms by which PARP1 is activated by R-loops. In Aim 2, we will identify global PARP1 substrates and R-loop distribution landscape in U2AF1-mutant cells, providing a proteomic and genomic view of how PARP1 regulates R-loops. In Aim 3, we will evaluate whether PARP inhibitor, olaparib, can selectively eliminate MDS-associated splicing mutant cells in vitro and in vivo. Together, these studies will mechanistically explain how R-loops are sensed by PARP1 in splicing mutant cells, reveal how PARP1 guards cells against R-loop-associated genomic instability, and address whether R-loop-associated vulnerability in spliceosome-mutant MDS cells can be exploited by PARP inhibitors as targeted MDS therapy. The combined expertise in R-loops, PARP1, DNA damage response and spliceosome mutations in MDS (Nguyen laboratory), PARP regulation by proteomic approach (Leung laboratory, co-I), and MDS GEMM mouse models of U2AF1 and SRSF2 mutations (Lee laboratory, co-I) provides us the unique opportunity to characterize PARP1 function in cells expressing MDS-associated mutations. These studies will not only significantly advance our understanding of R-loop biology and PARP1 signaling, but also repurpose the use of FDA-approved PARP inhibitors in targeted therapy for MDS patients harboring RNA splicing factor mutations by exploiting R-loop-associated vulnerability.

项目摘要/摘要 骨髓塑性综合征（MDS）是一组异源性克隆造血干细胞疾病，是一种 获得的骨髓衰竭综合征。 MD的特征是无效的造血作用，导致 外周血细胞质和祖细胞扩张。编码RNA剪接因子的基因（U2AF1，SF3B1， SRSF2和ZRSR2）经常突变并发生在MDS的创始克隆中，代表独特 靶向治疗的遗传脆弱性类别。然而，尽管剪接体突变的流行率，但 这种突变如何影响不同的细胞机制在很大程度上不清楚。我们和其他人最近的研究 建议R-loops，一组含有RNA的转录中间体：DNA杂交和移位 滞留的DNA是由不同的剪接体突变体诱导的基因组不稳定性的来源。在初步 导致该应用的研究，我们发现PARP1被R-Loops激活，并且在 抑制与R环相关的DNA损伤。此外，我们表明与MDS相关的RNA剪接因子 突变会促进R环的积累，并使细胞对PARP抑制敏感。这些令人兴奋的发现 导致我们假设PARP1是R环的关键传感器，也是与R环相关的临界抑制剂 DNA损伤。此外，异常的R环积累代表了MDS-的新目标脆弱性 相关的剪接因子突变细胞，使PARP抑制成为靶向R环脆弱性的有吸引力的方式 MDS。最后，由于PARP抑制剂在不同疾病中获得了有限的FDA批准，因此重新利用PARP 治疗带有RNA剪接因子突变的MDS患者的抑制剂可能会提供最快的翻译途径 我们向诊所的发现。为了检验这些假设，在AIM 1中，我们将阐明PARP1为的机制 由R-loops激活。在AIM 2中，我们将确定全球PARP1基材和R-loop分配环境 U2AF1突变细胞，提供了PARP1如何调节R环的蛋白质组学和基因组观点。在AIM 3中，我们 将评估PARP抑制剂Olaparib是否可以选择性地消除与MDS相关的剪接突变细胞 体内和体内。这些研究将共同​​解释R-loops如何通过PARP1在 剪接突变细胞，揭示PARP1如何应对与R-loop相关的基因组不稳定性的细胞，并解决 PARP抑制剂是否可以利用与R-loop相关的MDS细胞中与R环相关的脆弱性 作为目标MDS疗法。 R环，PARP1，DNA损伤响应和剪接体的组合专业知识 MDS（NGUYEN实验室）的突变，蛋白质组学方法（Leung Laboratory，CO-I）的PARP调节，以及 U2AF1和SRSF2突变（Lee Laboratory，Co-I）的MDS Gemm鼠标模型为我们提供了独特的 在表达与MDS相关突变的细胞中表征PARP1功能的机会。这些研究会 不仅显着提高了我们对R环生物学和PARP1信号传导的理解，还可以重新利用 在具有RNA剪接因子的MDS患者的靶向治疗中使用FDA批准的PARP抑制剂 通过利用与R环相关的脆弱性来进行突变。