Characterization of Human Liver Stromal Cells

Abstract

The liver is a highly immunologic, metabolic organ in the body with many functions including but not limited to amino acid and carbohydrate metabolism, synthesis of plasma proteins, metabolism of pharmaceuticals, defense against pathogens, and more. There are two types of stromal cells in the liver: liver sinusoidal endothelial cells and hepatic stellate cells. The goal of this thesis is to determine markers that can be used to identify human stromal cells. I investigated the expression of cellular surface and intracellular molecules on human stromal cells isolated from human livers. The cellular markers for this work in human samples were modeled after published data in mice. In order to test the stability of the expression of these markers in vitro, multiple stromal cell lines were generated from the human stromal cells, and different passage numbers of each cell line tested using flow cytometry. Phenotypic and morphological changes were found across multiple passage numbers where the stromal cells start to lose their strict structure. In addition to morphological changes, changes in expression of cellular markers were also identified. VCAM-1 (CD106) is changed across different passages and also reproduced across numerous cell lines. Cellular adhesion marker CD146 expression is also altered, and when coupled with antigen uptake of Ova via scavenger receptors on LSECs there is a strong shift in populations from single positive for each marker, scavenger receptor and CD146, to double positive across subsequent passages. Our identification of stromal cell markers can be used for further experiments for cellular sorting and functional studies of stromal cells.