Genomic dissection of platelet production

血小板产生的基因组解剖

• 批准号: 7278584
• 负责人: WARREN S ALEXANDER
• 金额: $ 23.6万
• 依托单位: WALTER AND ELIZA HALL INST MEDICAL RES
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-17 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7278584
• 关键词: Acute; Adverse effects; Animal Model; Autoimmune Process; Binding; Biochemical; Biochemical Pathway; Biological; Biological Assay; Blood Platelets; Bone Marrow Transplantation; CSF3 gene; Characteristics; Complex; Condition; Cytotoxic agent; Data; Development; Disease; Disruption; Dissection; Down-Regulation; Dysmyelopoietic Syndromes; E1A-associated p300 protein; EP300 gene; Elevation; Erythrocytes; Ethylnitrosourea; Exhibits; Gene Expression; Gene Targeting; Genes; Genetic; Genetic Screening; Genome; Genomics; Goals; Half-Life; Hematological Disease; Hematopoiesis; Hematopoietic stem cells; Hemorrhage; Homozygote; Infection; Interleukin-11; Intervention; Investigation; Knowledge; Lead; Life; Living Wills; MYB gene; Megakaryocytes; Modeling; Molecular; Morbidity - disease rate; Mus; Mutagenesis; Mutant Strains Mice; Mutate; Mutation; Numbers; Operative Surgical Procedures; Outcome; Pathway interactions; Patients; Pattern; Pharmaceutical Preparations; Physiological; Platelet Count measurement; Platelet Transfusion; Production; Proteins; Proto-Oncogene Proteins c-myb; Purpura; Recovery; Regulation; Research; Research Personnel; Resources; Risk; Role; Signal Transduction; Testing; Thrombocytopenia; Thrombopoietin; Transactivation; Transfusion; Vertebrates; base; cancer therapy; chemotherapy; concept; cytokine; cytotoxic; drug discovery; experience; gene function; human MPL protein; loss of function mutation; mortality; mouse model; mutant; novel; novel therapeutics; programs; protein expression; response; therapeutic target; thrombocytosis; tool; transcription factor

DESCRIPTION (provided by applicant): Thrombocytopenia, or low platelet count, is a life threatening condition associated with cytotoxic cancer treatments and other disorders. Platelet transfusion is the only current effective treatment for severe thrombocytopenia. Although effective, transfusion is associated with immunohematological side effects and infections. The aim of this project is to better understand the molecular regulation of platelet production with the ultimate goal of discovering novel targets for the development of new therapeutics for thrombocytopenia. We propose that forward genetic screens using random mutagenesis provide an unbiased, genome-wide discovery tool for regulators of circulating platelet numbers that do not rely on pre-existing knowledge of potential gene function and thus have the capacity to discover hitherto unanticipated modulators of platelet numbers. Moreover, mutagenesis screens using a murine model of thrombocytopenia will uncover genes in which loss-of function mutations lead to amelioration of disease. Since drugs overwhelmingly inhibit their targets, the proteins normally encoded by these suppressors of thrombocytopenia should provide biologically validated targets for therapeutic discovery. In preliminary studies, we have isolated several suppressors of thrombocytopenia (PIt mutants) including three that have mutations in the c-Myb transcription factor (Plt3 and Plt4) or the p300 transcriptional co-regulator/c-Myb partner protein (Plt6). Mice heterozygous for these mutations display amelioration of the thrombocytopenia inherent in mice lacking c-MpI, the receptor for thrombopoietin (TPO) and homozygotes exhibit supra-physiological platelet counts characterized by excessive megakaryocytopoiesis. We hypothesize that c-Myb/p300 activity is normally required to keep megakaryocytopoiesis in appropriate check and that pharmacological disruption of c-Myb/p300 may provide a novel therapeutic strategy to treat thrombocytopenia. The aims of this application are to fully define the biological consequences of c-Myb/p300 mutation in Plt3, Plt4 and Plt6 mice, to determine the effects of these mutations on the transcriptional regulatory functions of c-Myb/p300, to define the key target genes of this complex that control megakaryocyte and platelet production and to begin to test the potential of inhibiting c- Myb/p300 clinically by studying the responses of mice bearing c-Myb/p300 mutations in animal models of chemotherapy or bone marrow transplant-induced thrombocytopenia.

描述(申请人提供)：血小板减少，或低血小板计数，是一种与细胞毒性癌症治疗和其他疾病相关的危及生命的疾病。血小板输注是目前治疗严重血小板减少症的唯一有效方法。尽管输血有效，但它与免疫血液学副作用和感染有关。该项目的目的是更好地了解血小板产生的分子调控，最终目的是为开发新的治疗血小板减少症的药物寻找新的靶点。我们认为，使用随机突变的正向遗传筛选为循环中的血小板数量的调节者提供了一种公正的、全基因组的发现工具，这些工具不依赖于潜在基因功能的预先存在的知识，因此有能力发现迄今为止未曾预料到的血小板数量调节器。此外，使用小鼠血小板减少模型进行突变筛选将发现功能丧失突变导致疾病改善的基因。由于药物压倒性地抑制他们的靶点，通常由这些血小板减少抑制因子编码的蛋白质应该为治疗发现提供生物学上有效的靶点。在初步研究中，我们分离到了几个血小板减少的抑制因子(PIT突变体)，其中包括三个具有c-Myb转录因子(Plt3和Plt4)或p300转录辅助调节/c-Myb伙伴蛋白(Plt6)突变的基因。这些突变的杂合子小鼠表现出缺乏c-MPI的小鼠固有的血小板减少的改善，c-MPI是血小板生成素受体(TPO)的受体，纯合子小鼠表现出以巨核细胞生成过多为特征的超生理血小板计数。我们假设通常需要c-Myb/p300活性来适当地抑制巨核细胞的生成，而药物干扰c-Myb/p300可能为治疗血小板减少症提供一种新的治疗策略。本应用的目的是全面确定c-Myb/p300突变在Plt3、Plt4和Plt6小鼠中的生物学后果，确定这些突变对c-Myb/p300转录调控功能的影响，确定该复合体控制巨核细胞和血小板产生的关键靶基因，并通过研究携带c-Myb/p300突变的小鼠在化疗或骨髓移植诱导的血小板减少动物模型中的反应，开始测试临床抑制c-Myb/p300的可能性。