THE GENERATION OF FETAL LIVER HEMATOPOIETIC PROGENITOR CELLS: A MODEL SYSTEM TO STUDY HEMATOPOIESIS IN LETHAL GENE DELETIONS

Abstract

Recent discoveries in hematopoiesis have shed light on the process of development of mature blood lineages, but still many aspects of lineage commitment are unknown. Due to the rarity of hematopoietic stem cells (HSCs) in vivo, it is difficult to purify and sustain cultures of HSCs in vitro. The Erythroid-Myeloid-Lymphoid (EML) cell line is a primitive HSC cell line that was immortalized by infecting bone marrow from mice previously treated with 5 fluorouracil (5-FU) (increases progenitor cell cycling) with a retrovirus containing a dominant negative retinoic acid receptor a (dnRARa). This cell line has the phenotype of a primitive hematopoietic progenitor and has been used as a cell model for the study of hematopoiesis. The protocol to develop EML-like HSC lines cannot be used to derive HSC lines from mice that, as a consequence of gene ablation, do not survive after birth. Since the fetal liver is the main area of embryonic hematopoietic development in the mouse, I have hypothesized that fetal liver HSCs could be immortalized using the dnRARa containing retrovirus. Testing the hypothesis has indicated that EML-like cell lines can be established using murine fetal liver as a source of stem/progenitor cells. Studies examining morphology, antigen expression, proliferation, and neutrophil differentiation have illustrated that fetal liver hematopoietic progenitor (FLHP) cell lines derived from both wild type and CCAAT enhancer binding protein deleted mice are comparable to their 5-FU treated bone marrow derived EML counterparts.