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PI3 Kinase Inactivation in Myelodysplastic Syndrome

骨髓增生异常综合征中的 PI3 激酶失活

基本信息

批准号：
10476196
负责人：
Kira Gritsman
金额：
$ 10万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-17 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10476196
关键词：
1-Phosphatidylinositol 3-Kinase Abnormal Cell Address Alternative Splicing Anemia Animal Model Arginine Autophagocytosis Blood Blood Cells Bone Marrow Bone Marrow Transplantation CD34 gene Categories Cell Compartmentation Cell Line Cell Maturation Cells Chloroquine Clinical Cytokine Signaling Data Data Set Defect Development Dysmyelopoietic Syndromes Dysplasia Engineering Erythroid Erythropoiesis Event Excision Exons Flow Cytometry Gene Expression Profile Genes Genetic Genomic Instability Growth Factor Hematological Disease Hematopoiesis Hematopoietic Hematopoietic stem cells Histology Human IL3 Gene Impairment Knock-out Knockout Mice Lead Link Lipids Measures Mediating Messenger RNA Metformin Modeling Molecular Abnormality Morbidity - disease rate Mus Mutation Myelogenous NUP98 gene Nuclear PIK3CA gene PTEN gene Pancytopenia Pathogenesis Pathway interactions Patients Pattern Pharmaceutical Preparations Pharmacology Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Physiological Play Process Production Protein Isoforms Protein Kinase Proteins Proto-Oncogene Proteins c-akt Quality Control RNA Splicing RNA-Binding Proteins Regulation Reporting Reverse Transcriptase Polymerase Chain Reaction Role SRSF2 gene Sampling Serine Signal Transduction Spleen Spliceosomes TFRC gene Tamoxifen Testing Transplantation biological adaptation to stress cytokine cytopenia drug candidate erythroid differentiation exon skipping experimental study hematopoietic stem cell differentiation high risk improved inhibitor/antagonist mouse model mutant novel novel therapeutic intervention prevent progenitor stem cell biology stem cell function stem cell genes stem cell therapy stem cells therapeutic target

项目摘要

Regulation of Autophagy by PI3 Kinase in Myelodysplastic Syndrome Myelodysplastic Syndrome (MDS) is a blood disease driven by molecular abnormalities in hematopoietic stem cells (HSCs). Anemia is a common cause of morbidity in MDS patients. However, the mechanistic basis for the impaired HSC differentiation and erythroid maturation that leads to anemia in MDS patients is unclear. The PI3 kinase (PI3K) pathway is activated by many hematopoietic cytokines and growth factors, and is important for erythropoiesis. We generated a new triple knockout (TKO) mouse model in which deletion of the PI3K genes Pik3ca, Pik3cb, and Pik3cd in HSCs causes pancytopenia and myelodysplasia with impaired HSC differentiation. We observed that autophagic degradation is impaired in TKO HSCs, and that treatment with autophagy-inducing drugs improves HSC differentiation. We hypothesize that inactivation of PI3K dysregulates autophagic degradation in HSCs, leading to impaired HSC differentiation and erythropoiesis, which promotes MDS. Consistent with this, we observed that the phosphatase PTEN, which counteracts PI3K signaling, is upregulated in a subset of MDS patients. To more directly address the roles of PI3K in erythropoiesis, we plan to analyze erythropoiesis in the TKO;Mx1-Cre bone marrow transplant mouse model by performing CD71/Ter119 flow cytometry on the bone marrow and spleen. We will also generate the TKO;SCL-Cre-ERT mouse model, in which the PI3K genes can be deleted in HSCs after tamoxifen administration without transplantation. After Cre-mediated excision of Pik3ca, Pik3cb, and Pik3cd in HSCs, we will analyze blood counts, bone marrow histology, survival, and will perform CD71/Ter119 flow cytometry on the bone marrow and spleen to analyze erythropoiesis. To determine whether dysregulated autophagy plays a role in human MDS, we propose to examine autophagy in the stem cell compartment in MDS samples from the four different IPSSR categories (low, intermediate-1, intermediate-2, and high-risk). We will measure autophagy in HSCs and progenitors using intracellular flow cytometry for LC3II and P62 in cytokine-free media, with and without chloroquine treatment to measure autophagic flux. In addition, we will perform quantitative RT-PCR on CD34+ cells for PTEN expression from each MDS sample. We will also perform Western analysis for PTEN and phospho-AKT (pAKT), and will correlate PTEN and pAKT levels with autophagy induction in the same MDS samples. These experiments will better characterize the erythropoiesis defects that result from PI3K deletion and dysregulated autophagy in mouse HSCs, and will determine whether PI3K inactivation correlates with impaired autophagy in human MDS stem cells

PI3蛋白对骨髓增生异常综合征自噬的调节作用骨髓增生异常综合征(MDS)是一种由分子异常引起的血液疾病造血干细胞(HSC)。贫血是MDS患者发病的常见原因。然而，HSC分化和红系成熟受损的机制基础导致MDS患者贫血的原因尚不清楚。PI3激酶(PI3K)途径是由许多造血细胞因子和生长因子，对红血球的生成很重要。我们产生了一种新的三重敲除(TKO)小鼠模型，在该模型中PI3K基因缺失 HSC中的PIK3ca、Pik3cb和Pik3cd导致全血细胞减少和骨髓发育不良 HSC分化。我们观察到将军澳HSCs的自噬降解受到损害，并且用自噬诱导药物治疗可以促进HSC的分化。我们假设 PI3K失活导致肝星状细胞自噬降解失调，导致肝星状细胞受损分化和红细胞生成，促进MDS。与此一致，我们观察到抵消PI3K信号的磷酸酶PTEN在MDS的一个子集中上调病人。为了更直接地解决PI3K在红细胞生成中的作用，我们计划分析 TKO；Mx1-Cre小鼠骨髓移植模型中的红细胞生成骨髓和脾CD71/Ter119流式细胞仪检测。我们还将生成 TKO；SCL-CRE-ERT小鼠模型，在该模型中，PI3K基因可在HSCs中缺失他莫昔芬非移植用药。在Cre介导的PIK3ca、Pik3cb、和Pik3cd在HSCs中，我们将分析血细胞计数、骨髓组织学、存活率和对骨髓和脾进行CD71/Ter119流式细胞术分析红细胞生成情况。为了确定失调的自噬是否在人类MDS中起作用，我们建议检测来自四个不同IPSSR的MDS样本中干细胞间的自噬类别(低、中-1、中-2和高风险)。我们将测量自噬应用细胞内流式细胞术检测无细胞因子条件下肝星状细胞及其前体细胞中的LC3II和p62 用氯喹处理和不用氯喹处理来测量自噬通量。此外，我们还将对CD34+细胞进行定量RT-PCR，检测每个MDS样本中PTEN的表达。我们还将对PTEN和磷酸化AKT(PAKT)进行蛋白质分析，并将PTEN与在相同的MDS样本中，具有自噬诱导的PAKT水平。这些实验将更好地描述由PI3K缺失和调节失调引起的红细胞生成缺陷并将确定PI3K失活是否与人MDS干细胞自噬功能受损