Analysis on the mechanisms of growth, differentiation, and survival of megakaryocytic cells

巨核细胞生长、分化和存活机制分析

基本信息

批准号：
16209033
负责人：
KANAKURA Yuzuru
金额：
$ 29.2万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16209033/
关键词：
FLT3 Notch HOXB4 Anamorsin c-myc hematopoietic Stem Cell apoptosis アナモルシン増殖分化造血器腫瘍

项目摘要

1.To explore activation mechanism of FLT3 TKD mutation, we analysed critical tyrosine residues for the constitutive activation and downstream signaling of the mutant by generating a series of single Tyr→Phe substitution mutant of all 22 cytoplasmic tyrosine residues of murine FLT3 TKD-mutant (mFLT3Asp838Val). Tyr845Phe, Tyr892Phe and Tyr922Phe substitutions suppressed the phosphorylation of mFLT3Asp838Val itself, the activation of Erk1/2,STAT3 and STAT5, and the factor-independent cell proliferation and survival. In contrast, these three Tyr→Phe mutations partially suppressed but maintained the ligand-dependent activation and anti-apoptotic activity of wild-type FLT3, suggesting that these tyrosine residues were more critical for the constitutive activation and signaling of mFLT3Asp838Val.2.We examined the expression of cell cycle regulatory molecules during Notch- and HOXB4-induced self-renewal of hematopoietic stem cells, and found that both molecules induce the expression of c-myc. … More In addition, we determined that HOXB4 activated the c-my promoter through the element between -195 and -161 bp. We also proved that the induction of c-myc activity alone was sufficient for enhancing self-renewal of hematopoietic stem cells in the presence of appropriate cytokines using Myc/ERT, which reveals c-myc activity in response to 4-hydroxytamoxifen. These results indicated that Notch and HOXB4 induce self-renewal of hematopoietic stem cells through the induction of c-myc.3.We generated knock out mice for Anamorsin. Anamorsin^<-/-> mice are embryonic lethal due to the failure of definitive hematopoiesis in the fetal liver, Although the number of hematopoietic stem/progenitor cells in the fetal liver did not decrease in these mice, myeloid and particularly erythroid colony formation was severely disrupted. Also, Anamorsin^<-/-> erythroid cells initiated apoptosis during terminal maturation. As for the mechanism of Anamorsin-mediated cell survival, a microarray analysis revealed that the expression of Bcl-xL and Jak2 was severely impaired in the fetal liver of Anamorsin^<-/-> mice. Less

1.探索FLT3 TKD突变的激活机制，我们通过生成一系列的22个单个Tyr→PHE取代突变体，分析了突变体组成型酪氨酸残留物，以进行组成型和下游信号传导。 Tyr845Phe，Tyr892Phe和Tyr922PHE取代抑制了Mflt3asp838Val本身的磷酸化，ERK1/2，STAT3和STAT5的激活以及与因子无关的细胞增殖和生存。相反，这三个Tyr→Phe突变部分抑制了野生型FLT3的配体依赖性激活和抗凋亡活性，这表明这些酪氨酸保留的保留更为重要。造血干细胞，发现这两个分子都会影响c-myc的表达。 …此外，我们确定HOXB4通过-195和-161 bp之间的元素激活了C -MY启动子。我们还规定，仅使用MYC/ERT存在适当的细胞因子，仅诱导C-MYC活性就足以增强造血干细胞的自我更新，这揭示了C-MYC活性以响应4-羟基氧莫莫昔芬。这些结果表明，Notch和Hoxb4通过诱导C-Myc诱导造血干细胞的自我更新。3。我们生成的anamorsin敲出小鼠。由于胎儿肝脏中确定的造血性失败，胎儿肝脏中的造血性造血症的失败，胎儿肝中的造血/祖细胞的数量并未减少这些小鼠，髓样本和成类菌落的形成，但在eRy-er rap中均引起了序列，因此在胎儿肝脏/祖细胞中的数量并没有减少，但在胎儿肝脏中的造血干细胞的数量并未降低，在胎儿肝脏中的造血/祖细胞的数量并未降低，在胎儿肝脏中的造血/祖细胞的数量并未降低，在胎儿肝脏中，namorsin^< - / - >小鼠是胚胎致死性的。至于Anamorsin介导的细胞存活的机理，微阵列分析表明，在Anamorsin^< - / - >小鼠的胎儿肝脏中，Bcl-XL和JAK2的表达严重受损。较少的