LIVER REPOPULATION FOR LIVER INJURY AND GENE THERAPY

描述(由申请人提供)：我们的一般假设是，移植的肝细胞将在允许的微环境中存活并发挥作用，最好的例子是肝脏。微环境因素、其他类型的肝细胞和可溶性因子之间的各种相互作用可以调节移植细胞在肝脏中的植入。此外，细胞治疗需要在肝脏中产生足够数量的移植细胞。为了证明移植细胞是否可以在特定的疾病中植入和增殖，有必要对合适的动物模型进行研究。这类研究需要包括对人类细胞的分析以及对干细胞/祖细胞的分析，以建立适当的临床策略。在过去的几年里，我们实验室的进步导致了移植细胞在肝脏中植入和增殖的工作模型的发展。已确定了几种重要的机制来调节移植细胞进入肝实质，并进一步决定移植细胞是否会增殖。宿主肝脏中促进细胞植入的特定扰动包括对肝窦内细胞的分析、肝脏微环境的调节以及移植细胞本身的生物学特性方面。天然肝细胞的遗传毒性损伤使移植细胞免受损伤，似乎在促进移植细胞增殖方面非常有效。我们在这一领域继续研究的一个主要目标是开发肝脏再繁殖的新机制。我们建议进行一系列研究，以进一步确定细胞在正常和病变动物肝脏中的植入。我们将研究人类肝细胞在免疫缺陷小鼠中的命运，以建立更多的动物模型。在细胞移植之前，我们将确定移植细胞是否会按照新的方法在受体动物的肝脏中诱导基因毒性损伤而增殖。我们将利用这些原则，通过肝脏导向细胞疗法来纠正动物体内的代谢和遗传障碍。我们研究的完成将在肝脏再生、干细胞生物学和细胞治疗领域提供新的知识。我们的研究将为细胞疗法在人类中的最终应用提供有价值的临床前信息。

DESCRIPTION (provided by applicant): Our general hypothesis is that transplanted liver cells will survive and function in the context of a permissive microenvironment, best exemplified by the liver. A variety of interactions between microenvironmental factors, other types of liver cells, and soluble factors could regulate engraftment of transplanted cells in the liver. Also, cell therapy requires creation of an adequate mass of transplanted cells in the liver. To demonstrate whether transplanted cells can engraft and proliferate in specific disorders, studies in suitable animal models are necessary. Such studies need to include analysis of human cells as well as assays of stem/progenitor cells for establishing appropriate clinical strategies. Progress in our laboratory over the past several years has led to the development of working models of transplanted cell engraftment and proliferation in the liver. Several important mechanisms have been identified that regulate the entry of transplanted cells in the liver parenchyma and further determine whether transplanted cells will proliferate or not. Specific perturbations in the host liver that promote cell engraftment include analysis of cells in liver sinusoids, modulations in the liver microenvironment and aspects of the biological properties of transplanted cells themselves. Genotoxic injury in native hepatocytes that spare transplanted cells from injury appears to be highly effective in promoting transplanted cell proliferation. A major goal of our continuing studies in this area concerns development of novel mechanisms in liver repopulation. We propose a series of studies to further define cell engraftment in the normal and the diseased liver of animals. We will study the fate of human liver cells in immunodeficient mice to generate further animal models. We will determine whether transplanted cells will proliferate following novel ways to induce genotoxic injury in the liver of recipient animals prior to cell transplantation. We will use these principles to approach correction of metabolic and genetic disorders in animals by liver-directed cell therapy. Completion of our studies will provide new knowledge in the areas of liver repopulation, stem cell biology and cell therapy. Our studies will provide valuable preclinical information for eventual applications of cell therapy in people.