Physiologic Regulation of Hematopoiesis by Notch

描述(由申请人提供)：对以下机制知之甚少 在细胞水平上调节造血细胞自我更新的过程 和分化，特别是在对压力的生理反应期间，如 炎症和感染。这个项目的总体目标是 Notch受体在维持骨髓中的生理作用研究 动态平衡，尤其是在炎症应激期间。的主要假设 在我们的研究中被测试的是：i)Notch激活是否有利于 在干细胞和祖细胞水平上的自我更新超过分化，以及2) 这是否代表了骨髓过程中的一项重要调节功能 对炎症和感染的生理反应。我们假设诺奇 激活可能平衡炎症的前分化作用 细胞因子，允许祖细胞增殖池的扩张 需要对生理应激做出反应并防止干细胞库 因为精疲力竭。具体目标：为了检验这些假设，我们计划：(1) 确定凹槽功能增益和(2)凹槽功能损失的影响， 干细胞和祖细胞的自我更新和扩增潜能； 炎症过程中骨髓细胞Notch通路激活水平的研究 应力；(4)确定Notchi在骨骼中丧失功能的后果 骨髓对炎性应激的反应。研究设计和方法：我们将 使用不同和互补的体内模型：a)异种移植 人类细胞实验，设计表达Notch 1的组成形式 或配体J2，将其植入NOD/S CID小鼠；b)转基因小鼠 被设计来表达Notch反义的将被用于评估效果 C)“小鼠皮肤全层烧伤模型” (脓毒症模型)将作为炎症模型来评估骨髓反应 和Notch功能。意义：这些研究旨在产生洞察力 研究调节成人造血的生理机制。我们相信 更好地理解这些事件对于理解 血液系统疾病的生物学及其发展所必需的 新的治疗策略，特别是那些针对体外扩张的策略 人类的造血干细胞。

DESCRIPTION (provided by applicant): Little is known about the mechanisms that regulate, at the cellular level, the process of hematopoietic cell self-renewal and differentiation, in particular during physiologic responses to stress, such as inflammation and infection. The overall objective of this project is to study the physiologic role of Notch receptors in maintaining bone marrow homeostasis, in particular during inflammatory stress. The main hypotheses to be tested in our study are: I) whether Notch activation favors the decision of self-renewal over differentiation at the stem and progenitor cell level, and 2) whether this represents an important regulatory function during bone marrow physiologic response to inflammation and infection. We hypothesize that Notch activation may balance the prodifferentiative effects of inflammatory cytokines, permitting expansion of the proliferating pool of progenitor cells required to respond to physiologic stress and preventing the stem cell pool from exhaustion. Specific Aims: to test these hypotheses we plan to: (1) determine the impact of Notch gain-of function and (2) Notch loss-of function, on self-renewal and expansion potential of stem and progenitor cells; (3) evaluate the level of Notch pathway activation in BM cells during inflammatory stress; (4) determine the consequences of Notchi loss-of function during bone marrow response to inflammatory stress. Research Design and Methods: We will use different and complementary in vivo models: a) xenotransplantation experiments of human cells, engineered to express constitutive forms of Notch 1 or the ligand J2, will be carried out into NOD/S CID mice; b) transgenic mice engineered to express the Notch antisense will be used to evaluate the effects of Notch loss-of function; c) the "mouse full skin thickness burn model" (sepsis model) will be used as a model of inflammation to evaluate BM response and Notch function. Significance: These studies are intended to yield insight into the physiologic mechanisms that regulate adult hematopoiesis. We believe that a better comprehension of these events is crucial for the understanding of the biology of hematopoietic disorders and essential for the development of novel therapeutic strategies, in particular those targeted to ex-vivo expansion of human hematopoietic stem cells.