Regulation of cell lineage specificity in the liver

肝脏细胞谱系特异性的调节

• 批准号: 6740157
• 负责人: SUM P LEE
• 金额: $ 23.7万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6740157
• 关键词: bile ducts; cell differentiation; cell growth regulation; cell population study; epithelium; genetically modified animals; laboratory mouse; liver cells; liver failure; polymerase chain reaction; stem cell transplantation; stem cells; tissue /cell culture

DESCRIPTION (provided by applicant): Classical stochastic view of cell growth and differentiation insists on a specific progenitor cell origin, a process of growth resulting in a mature (terminally differentiated) cell which cannot further divide. In the liver, a pluripotential stem (oval) cell gives rise to both hepatocytes and biliary ductal cells. A bone marrow derived progenitor cell also contributes to the growth and differentiation of liver and biliary ductal cells. Recent emphasis has focused on the plasticity of stem cells. The concept of 'plasticity' of the well differentiated cell has been largely ignored. This proposal examines the provocative hypothesis that it is possible to have transdifferentiation between the mature cells of the hepatocyte and biliary epithelial cell lineages. Mature hepatocytes and biliary duct epithelia divide actively in vivo and in vitro. Culture conditions in vitro (growth factors, cytokines, extracellular matrix) can induce phenotypic transdifferentiation of hepatocytes into biliary cells and vice versa. Experiments are designed to (1) further characterize a biliary cell line which we have established from the MT-lacZ mouse, with a transgene encoding Beta-galactosidase (X-gal) driven by an albumin promoter and hence only hepatocytes will stain blue. (2) induce transdifferentiation of biliary cells into hepatocytes in vitro, Cells will be studied with lineage-specific and maturation-dependant markers, albumin secretion, and X-gal positivity. The potential role of Notch gene in regulating cell lineage decision will be studied. Notch pathway gene expression during cell growth and differentiation will be determined using semi-quantitative RT-PCR. In addition, the functional role in cell lineage commitment and differentiation will be studied by inducing Notch signalling using exogenous Notch ligands (Jagged 1, Delta 1). (3) study the in vivo propagation of transdifferentiated cells by implanting them into the omental compartment of congenic mice, and (4) to use transdifferentiated cells of biliary origin in cell transplantation to repopulate and rescue the dying livers of Albu-PA mice (carrying a cytotoxic transgene resulting in liver failure). The results of these experiments will yield new, important information on cell lineage specificity, regulation of cell commitment and cell fate, and the effect of instructive transdifferentiation. It potentially can open up a new field of using mature cells of the same embryonic origin to mediate gene.

描述（由申请人提供）：细胞生长和分化的经典随机观点坚持特定的祖细胞来源，这是一种导致成熟（终末分化）细胞不能进一步分裂的生长过程。在肝脏中，多能干细胞（卵圆）产生肝细胞和胆管细胞。骨髓来源的祖细胞也有助于肝和胆管细胞的生长和分化。最近的重点集中在干细胞的可塑性。分化良好的细胞的“可塑性”的概念在很大程度上被忽视了。该提议检验了具有挑衅性的假设，即肝细胞和胆管上皮细胞谱系的成熟细胞之间可能存在转分化。成熟肝细胞和胆管上皮细胞在体内和体外分裂活跃。体外培养条件（生长因子、细胞因子、细胞外基质）可诱导肝细胞表型转分化为胆管细胞，反之亦然。设计实验以（1）进一步表征我们从MT-lacZ小鼠建立的胆管细胞系，其具有由白蛋白启动子驱动的编码β-半乳糖苷酶（X-gal）的转基因，因此只有肝细胞将染成蓝色。(2)在体外诱导胆管细胞转分化为肝细胞，用谱系特异性和成熟依赖性标志物、白蛋白分泌和X-gal阳性研究细胞。Notch基因在调控细胞谱系决定中的潜在作用将被研究。将使用半定量RT-PCR测定细胞生长和分化期间的Notch途径基因表达。此外，将通过使用外源Notch配体（Jagged 1、Delta 1）诱导Notch信号传导来研究细胞谱系定型和分化中的功能作用。(3)通过将转分化细胞植入同类小鼠的网膜区室来研究转分化细胞的体内增殖，以及（4）在细胞移植中使用胆管来源的转分化细胞来重新填充和挽救Albu-PA小鼠（携带导致肝功能衰竭的细胞毒性转基因）的垂死肝脏。这些实验的结果将产生新的，重要的信息，细胞谱系特异性，调节细胞的承诺和细胞的命运，和指导性转分化的影响。这为利用同一胚胎来源的成熟细胞介导基因表达开辟了新的领域。