Role of ASK1 and PKR in Fancc hematopoiesis

ASK1 和 PKR 在 Fancc 造血中的作用

• 批准号: 6918154
• 负责人: Laura S Haneline
• 金额: $ 30.3万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6918154
• 关键词: apoptosis; biological signal transduction; cell population study; congenital aplastic anemia; cytokine; cytoprotection; gene mutation; hematopoiesis; hematopoietic stem cells; laboratory mouse; protein kinase

DESCRIPTION (provided by applicant): Our long-term goal is to identify the mechanism(s) that Fanconi anemia (FA) proteins have in protecting hematopoietic stem/progenitor cells (HS/Ps) from apoptosis in order to design targeted therapies for prevention/treatment of bone marrow failure in FA. 80% of FA patient deaths are a direct result of a progressive marrow failure. Thus, understanding mechanisms involved in the apoptotic predisposition of FA HS/Ps is of critical importance and clinically relevant. Currently, little is known regarding the function(s) that individual FA proteins have in maintaining HS/Ps survival. Using a murine model of FA type C, we previously showed that Fancc -/- stem cells have a marked reduction in repopulating ability and Fame -/- progenitors exhibit enhanced inhibitory cytokine-induced apoptosis. Preliminary data also show that Fancc /- progenitors are hypersensitive to oxidants. Our central hypothesis is that loss of IIS/Ps via altered inhibitory cytokine and oxidant apoptotic signaling has a crucial role in the development of marrow failure in FA-C patients. Previous structure-function studies in cell lines demonstrated 2 FANCC functions, separable by FANCC" mutants. One (1) function was to protect from genotoxins, and the other was to enhance survival after IFN-y/TNF-a treatment by inhibiting double-stranded RNA-dependent kinase (PKR)-mediated apoptosis. While these studies begin to clarify distinct FANCC functions in cell lines, a critical yet unanswered question is whether these 2 functions exhibit equally important roles in enhancing the survival of primary HS/Ps. Furthermore, our preliminary data suggest that FANCC may protect cells from TNF-a and oxidant induced apoptosis through an apoptosis signal-regulating kinase 1 (ASK1) dependent pathway. We hypothesize that Fancc -/- cells exhibit both altered ASK1 and PKR apoptotic signaling, which contribute to the pro-apoptotic phenotype of Fancc -/ HS/Ps after oxidant or inhibitory cytokine treatment. The goals of this application are, 1) to determine whether PKR-dependent and -independent FANCC functions enhance Fancc -/- stem cell repopulating ability and protect from inhibitory cytokine and genotoxin treatment in vivo, 2) to determine whether ASK1 participates in Fancc -/- HS/Ps hypersensitivity to apoptotic stimuli and repopulating ability, and 3) to investigate whether inhibitory cytokine hypersensitivity in primary Fancc -/- cells involves alterations in both ASK1 and PKR apoptotic signaling.

描述（由申请人提供）：我们的长期目标是确定Fanconi贫血（FA）蛋白在保护造血干/祖细胞（HS/PS）免受凋亡中具有的机制，以设计靶向疗法，以预防FA中的骨髓骨髓衰竭。 80％的FA患者死亡是进行性骨髓衰竭的直接结果。因此，了解FA HS/PS凋亡易感性涉及的机制至关重要，并且在临床上具有相关性。目前，关于单个FA蛋白在维持HS/PS存活方面具有的功能知之甚少。使用FA型C型鼠模型，我们先前表明FANCC - / - 干细胞的重塑能力显着降低，名声 - / - 祖细胞表现出增强的抑制性细胞因子诱导的凋亡。初步数据还表明，FANCC / - 祖细胞对氧化剂过敏。我们的中心假设是，通过改变的抑制性细胞因子和氧化剂凋亡信号传导丧失IIS/PS，在FA-C患者的骨髓衰竭发展中至关重要。在细胞系中先前的结构功能研究表明了2种FANCC功能，可以通过FANCC“突变体分离。一个（1）的功能是防止遗传毒素，而另一个功能是在IFN-Y/TNF-A处理后增强生存率，通过抑制双链RNA的RNA依赖性激酶（PKR）的差异范围，而一定的fintive clarlive clarl in IS clarl carlan clarl carlan carlan carlan carlaine则可以澄清。这两个功能是否在增强原代HS/PS的存活中表现出同样重要的作用，我们的初步数据表明，FANCC可能会保护细胞免受TNF-A的侵害，而氧化剂诱导的凋亡是通过凋亡信号调节的凋亡。氧化剂或抑制性细胞因子处理后的fancc-/hs/ps的促凋亡表型。 HS/PS对凋亡刺激和重塑性能力的超敏反应，以及3）研究原代FANCC - / - 细胞中抑制性细胞因子的超敏性是否涉及ASK1和PKR凋亡信号的改变。