Viable, Proliferating Progenitor Cells

Abstract

Objective: Compare conditions and outcomes of otosphere suspension cultures from dissociated organ of Corti of either mouse or guinea pig at postnatal day 3 (P3), and to evaluate the guinea pig as a potential cochlea donor for preclinical cell therapy. Method: Organs of Corti were isolated from P3 guinea pig or mouse cochlea, dissociated, and cultivated under nonadherent conditions as cell clusters (otospheres), in DMEM:F12 medium, supplemented with epidermal growth factor (EGF), plus either basic fibroblast growth factor (bFGF) or transforming growth factor alpha (TGFα), and submitted to immunofluorescence assays. Results: Otospheres from mouse and guinea pig organ of Corti cultivated in vitro retained properties of inner ear progenitor cells, such as self-renewal, proliferation, and differentiation into hair cells or supporting cells. The best culture outcome was observed when mouse-derived cells were cultivated in the presence of TGFα instead of bFGF. Otosphere cell sorting will be additionally tested by flow cytometry of dissociated mouse cells. These ongoing experiments will be useful for the phenotype characterization of the progenitor cells presenting the best proliferating index. Conclusion: The expression of sox2 and nestin in guinea pig and mouse otosphere is supporting evidence for the presence of inner ear progenitor cells in P3 guinea pig. However, the proliferation and differentiation potential of mouse-derived cells place this organism as a better model for studying early postnatal progenitor cell dynamics.