Objective: The hematopoietic system is nurtured by a supportive stroma environment allowing maintenance and differentiation of hematopoietic stem cells (HSC). However, only a limited number of these stromal cell clones support hematopoiesis in the absence of cytokine supplementation. So far, only two bone marrow-derived stromal cell lines (OP9 and S17) are capable of inducing hematopoietic differentiation of totipotent murine and human embryonic stem cells (ESC). Here, the potential of more than 100 stromal cell lines developed from the aorta-gonado-mesonephros (AGM) region was investigated in supporting adult and embryonic hematopoiesis. In addition, extensive phenotypic analysis should elucidate possible mechanisms involved in maintenance of hematopoietic stem cell function.
Methods: More than 100 stromal cell clones derived from the AGM region of E10.5 mouse embryos were isolated. Hematopoietic stem cell support was tested for adult murine and human cord blood hematopoietic stem cells and hematopoietic cells derived from murine ESC. Genotypic and phenotypic characterization was performed including gene array analysis.
Results: It was demonstrated that multiple clones showed high efficiency in supporting maintenance and expansion of primitive murine and human hematopoietic progenitors. In addition, we demonstrated for the first time that AGM stromal cell lines are also potent inducers of hematopoietic differentiation of murine ESC. Microarray analysis of AGM lines revealed a characteristic genotype with expression of genes involved in regulating hematopoiesis as well as mesodermal and early B cell development.
Conclusion: These AGM stromal cell lines may be of value in elucidating molecular mechanisms regulating early stem cell development and hematopoietic differentiation from ES-derived mesoderm.