Abstract
If all distinct cell types of the body could be clonally isolated and stocked, similar to cDNA or genomic DNA libraries, they would be very invaluable for studying the tissue and cellular functions. We developed new method to establish conditionally immortalized cell lines that retain the differentiated cell functions similar to the original tissues, using the temperature-sensitive simian virus 40 large tumor antigen gene transgenic mouse. We successfully established many functional cell lines including hepatocyte, renal tubule cell, vascular smooth muscle cell, gastric surface mucous cell and various bone marrow stromal cells. We developed in vitro hematopoietic microenvironment to support growth and differentiation of hematopoietic stem cells and their progenitors by coculture with bone marrow stromal cells. In addition, we showed that bone marrow stromal cell lines have properties of mesenchymal stem cells that differentiate towards osteoblast, skeletal muscle cell, endothelial cell, adipocyte, smooth muscle cell and cardiomyocyte. Using newly developed transgenic rat, we established various endothelial cell lines from brain capillary, retinal capillary, bone marrow, and choroid plexus, which can be used for a novel in vitro system to investigate transport functions at the blood-tissue fluid barrier and to develop high throughput screening systems. Our transgenic mouse and rat will be useful to develop new types of cell lines with differentiation potentials. The established cell lines will be useful to study tissue functions at cellular and molecular levels and may be applicable to high throughput drug screening, toxicity test, and to develop the alternatives to animal experiments.
