STAT5 Structure-Function in Hematopoiesis

STAT5 在造血中的结构-功能

• 批准号: 8133428
• 负责人: Kevin D Bunting
• 金额: $ 29.05万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8133428
• 关键词: 1-Phosphatidylinositol 3-Kinase; Adverse effects; Attenuated; Autoimmunity; Back; Benign; Biology; Blood Vessels; Bone Marrow Purging; Cell Death; Cell Proliferation; Cell Surface Receptors; Cell physiology; Cells; Clinical; Cues; Data; Defect; Development; Disease; Engraftment; Fetal Liver; Financial compensation; Future; Gene Expression; Genes; Goals; Growth; Hematological Disease; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Immunologic Deficiency Syndromes; Individual; Knockout Mice; Lead; Malignant Neoplasms; Measures; Multipotent Stem Cells; Mus; Mutant Strains Mice; Myeloproliferative disease; N Domain; Oncogenes; Physiological; Post-Translational Protein Processing; Recovery; Regimen; Regulation; Research; Research Project Grants; Role; STAT3 gene; STAT5A gene; Saint Jude Children' s Research Hospital; Signal Pathway; Signal Transduction; Site; Stem cell transplant; Stem cells; Stress; Structure; Structure-Activity Relationship; Therapeutic; Transgenic Mice; Transplantation; United States National Institutes of Health; Work; base; cell type; chemokine; conditioning; cytokine; insight; leukemia; leukemogenesis; migration; mouse model; mutant; novel; novel strategies; novel therapeutic intervention; novel therapeutics; prevent; programs; protein expression; receptor; response; retroviral transduction; self-renewal; stem cell biology

DESCRIPTION (provided by applicant): Hematopoietic stem cells (HSCs) can respond to microenvironmental cues that modulate cell proliferation, differentiation, survival, self-renewal, and migration. These responses are critical for the HSC to contribute to hematopoiesis long-term during steady-state and during stress. Defects in these responses can lead to hematologic disease. The most durable and complete cure for many diseases would be stem cell replacement, however stem cell transplant is currently not warranted for many benign disorders. Understanding the basic biology of HSCs may lead to novel approaches for stem cell transplant and for promoting endogenous hematopoietic recovery following myeloablation. These goals may have significant clinical benefit. Furthermore, the same mechanisms of HSC regulation may be involved in leukemic stem cell biology. Our research during the first cycle of this R01 was focused on defining the role of JAK/STAT signaling in normal HSC biology. This work uncovered roles for STAT5 activation in growth, long-term competitive repopulating activity, and self-renewal of HSCs. We showed that deficiencies in HSCs were almost identical to c-Mpl knockout mice but deficiencies in multipotent progenitor differentiation were considerably greater, illustrating a broad requirement for STAT5 in hematopoiesis. We were surprised to find that a Balb/c derived modifier locus that included the Gab2 gene modulated the steady- state engraftment ability as measured in W/Wv hosts. We now provide preliminary evidence that Gab2 is also required for normal hematopoiesis and it cooperates with STAT5 through a direct interaction. Furthermore, we show that Gab2 and STAT5 cooperate in normal HSC engraftment and that myeloproliferative disease resulting from constitutive activation of STAT5 is attenuated by Gab2 deficiency. We propose the following specific aims to further explore the role of STAT5 activation in hematopoiesis: 1) Explore novel non-myeloablative conditioning based on STAT5/PI3-kinase inhibition using STAT5/Gab2 compound mutant mice. 2) Establish the structure-function relationship for STAT5 in normal hematopoiesis using the complete null STAT5 knockout mouse background as a template. Our preliminary data has established feasibility for this approach using fetal liver retroviral transduction to add back STAT5 mutants lacking specific domain functions. 3) Determine whether survival signaling is the Achilles' heel of constitutive STAT5 activation in leukemic hematopoiesis. We will define mechanisms by which STAT5 acquires survival signals such as Bcl-2 to promote leukemogenesis. This work is expected to significantly advance our understanding of the pivotal role of STAT5 signaling in normal and leukemic hematopoiesis and potentially uncover new therapeutic strategies with fewer side effects based on suppression of specific STAT5 domain functions. It is now unequivocal that the JAK/STAT signaling pathway is defective in many blood diseases including immunodeficiency, autoimmunity, and cancer. We believe that a better understanding of the structure-function mechanisms of STAT5 signaling may have broad application for development of novel therapeutics with fewer side effects.

描述（由申请人提供）：造血干细胞（HSC）可以对调节细胞增殖、分化、存活、自我更新和迁移的微环境线索做出反应。这些反应对于 HSC 在稳态和应激期间长期促进造血至关重要。这些反应的缺陷可能导致血液系统疾病。许多疾病最持久、最彻底的治愈方法是干细胞替代，但目前对于许多良性疾病来说，干细胞移植并不适用。了解造血干细胞的基本生物学可能会带来干细胞移植和清髓后促进内源性造血恢复的新方法。这些目标可能具有显着的临床益处。此外，白血病干细胞生物学可能涉及相同的 HSC 调节机制。我们在 R01 第一个周期的研究重点是定义 JAK/STAT 信号传导在正常 HSC 生物学中的作用。这项工作揭示了 STAT5 激活在 HSC 生长、长期竞争性增殖活动和自我更新中的作用。我们发现，HSC 的缺陷几乎与 c-Mpl 敲除小鼠相同，但多能祖细胞分化的缺陷要大得多，说明造血过程中对 STAT5 的广泛需求。我们惊讶地发现，Balb/c 衍生的包含 Gab2 基因的修饰基因座调节了在 W/Wv 宿主中测量的稳态植入能力。我们现在提供初步证据表明Gab2也是正常造血所必需的，并且它通过直接相互作用与STAT5合作。此外，我们发现 Gab2 和 STAT5 在正常 HSC 植入中协同作用，并且 Gab2 缺陷可减轻由 STAT5 组成型激活引起的骨髓增殖性疾病。我们提出以下具体目标，以进一步探索 STAT5 激活在造血中的作用：1）使用 STAT5/Gab2 复合突变小鼠探索基于 STAT5/PI3 激酶抑制的新型非清髓性调节。 2) 以完全无效的STAT5敲除小鼠背景为模板，建立STAT5在正常造血过程中的结构-功能关系。我们的初步数据已经确定了这种方法的可行性，即使用胎儿肝脏逆转录病毒转导来添加缺乏特定结构域功能的 STAT5 突变体。 3) 确定生存信号传导是否是白血病造血过程中 STAT5 组成型激活的致命弱点。我们将定义 STAT5 获取 Bcl-2 等生存信号以促进白血病发生的机制。这项工作预计将显着增进我们对 STAT5 信号在正常和白血病造血中关键作用的理解，并有可能发现基于抑制特定 STAT5 结构域功能的副作用更少的新治疗策略。现在已经明确，JAK/STAT 信号通路在许多血液疾病（包括免疫缺陷、自身免疫和癌症）中存在缺陷。我们相信，更好地了解 STAT5 信号传导的结构功能机制可能对开发副作用更少的新型疗法具有广泛的应用。