Wnt signaling and hematopoietic stem cells

Wnt信号传导与造血干细胞

• 批准号: 7875243
• 负责人: ROBERT O'Mara RYAN
• 金额: $ 18.71万
• 依托单位: CHILDREN'S HOSPITAL & RES CTR AT OAKLAND
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7875243
• 关键词: Affect; Apolipoprotein A-I; Apolipoprotein E; Apolipoproteins; Binding; Biological; Biological Assay; Cell Nucleus; Cell Surface Receptors; Cells; Cholates; Complex; Dialysis procedure; Disease; Gel Chromatography; Gene Targeting; Genetic Transcription; Goals; Hematopoietic stem cells; Hydrophobicity; Immunoprecipitation; LDL-Receptor Related Protein 1; Lipid Binding; Lipids; Lipoproteins; Liposomes; Mediating; Methods; Molecular Conformation; Nature; Outcome; Protein Family; Public Health; Recombinants; Regulation; Reporter; Research; Scaffolding Protein; Signal Transduction; Signal Transduction Pathway; Stem cells; Surface; System; TCF Transcription Factor; Testing; Therapeutic; Tissues; Tretinoin; Wnt proteins; aqueous; cell type; fatty acylation; gel electrophoresis; member; morphogens; mutant; nanoparticle; nanoscale; novel; particle; protein function; public health relevance; receptor; self-renewal; stem cell fate; stem cell therapy

DESCRIPTION (provided by applicant): Stem cells hold great therapeutic promise for a variety of diseases. These cells are unique in that they are capable of self-renewal or differentiation into various tissue cell types. Factors that regulate the ultimate fate of stem cells include members of the Wnt protein family. Wnt proteins function by binding to cell surface receptors of the frizzled and low-density lipoprotein receptor-related protein families. Following binding, a signal is transduced to ss-catenin, which then enters the nucleus and forms a complex with T cell factor / lymphoid enhancer factor, activating transcription of Wnt target genes. The goal of proposed research is to generate a soluble, active Wnt protein for use in studies of signaling and stem cell self-renewal. In Aim 1 it is hypothesized that nanoscale bilayer disk particles, termed nanodisks (ND), will provide a lipid surface for Wnt fatty acyl chain insertion, thereby anchoring Wnt to the particle in a biologically active conformation. In Aim 2 it is hypothesized that Wnt3a-ND will possess biological activity in signal transduction and colony forming cell assays using hematopoietic stem cells. The hypothesis that inclusion of apolipoprotein E as ND scaffold protein will affect Wnt3a-ND activity through binding to the Wnt co-receptor LRP5 will be tested. The effect of including all trans retinoic acid as a component of Wnt3a-ND will be evaluated to determine if additive or synergistic stem cell self renewal activity will be observed. Execution of these studies will provide new results on a potential aqueous soluble Wnt3a binding complex that preserves the potent biological activity of members of this protein family. Defining conditions to induce expansion of HSC will have profound effects on disease treatment options and outcomes. PUBLIC HEALTH RELEVANCE: Stem cells hold exceptional promise as therapy for disease. A critical aspect related to the application of stem cells for therapy is an ability to regulate their fate, in terms of differentiation versus proliferation. An important signal transduction pathway involved in stem cell regulation is mediated by the "Wnt" protein. Studies to be undertaken will establish an optimized Wnt signaling system and evaluate stem cell responsiveness as a function Wnt association with specialized nanoparticles.

描述（申请人提供）：干细胞对多种疾病具有巨大的治疗前景。这些细胞的独特之处在于它们能够自我更新或分化成各种组织细胞类型。调控干细胞最终命运的因子包括Wnt蛋白家族成员。Wnt蛋白通过与卷曲和低密度脂蛋白受体相关蛋白家族的细胞表面受体结合而起作用。结合后，信号被转导到ss-catenin，然后进入细胞核，与T细胞因子/淋巴细胞增强因子形成复合物，激活Wnt靶基因的转录。提出的研究目标是产生一种可溶的、活性的Wnt蛋白，用于信号传导和干细胞自我更新的研究。在Aim 1中，假设纳米级双层磁盘颗粒，称为纳米磁盘（ND），将为Wnt脂肪酰基链插入提供脂质表面，从而以生物活性构象将Wnt锚定在颗粒上。在Aim 2中，假设Wnt3a-ND将在使用造血干细胞的信号转导和集落形成细胞检测中具有生物活性。我们将检验载脂蛋白E作为ND支架蛋白通过与Wnt共受体LRP5结合而影响Wnt3a-ND活性的假设。将评估所有反式维甲酸作为Wnt3a-ND成分的效果，以确定是否会观察到添加性或增效性干细胞自我更新活性。这些研究的实施将为潜在的水溶性Wnt3a结合复合物提供新的结果，该复合物保留了该蛋白家族成员的有效生物活性。确定诱导HSC扩增的条件将对疾病治疗方案和结果产生深远影响。