Top2b regulates morphological and migratory properties of retinal progenitor cells in vivo and upon transplantable matrix substrates.

AIM: This study evaluated the impact of retinal extracellular matrix (ECM) and key biomaterial substrates on the motility of transplantable retinal cells with genomic manipulation, using the therapeutic molecule, Topoisomerase II beta (Top2b), as a model. METHODS: Tests first applied in ovo electroporation to examine the effects of a pharmacological Top2b inhibitor (ICRF-193) on progenitor motility and development of embryonic retina. Complementary qRT-PCR tests measured changes in select cadherin molecules in response to treatment. In vitro transfection produced cultured retinal progenitor cell groups with Top2b overexpression and Top2b knockdown. Differences in the adhesion and motility of Top2b altered groups, compared to wildtype cells, were measured upon biomaterial substrates used in emerging transplantation matrixes. RESULTS: Data illustrated significant differences in the number and spacing of retinal ganglion cells when retina was treated with ICRF-193, as well as downregulation of several key cadherin molecules. Cultured retinal progenitors with Top2b knockdown and Top2b overexpression exhibited different expression of chemotactic receptors, adhesion parameters, and modalities of migration upon substrates of laminin, poly-L-lysine, and collagen IV. Significant changes in cell morphology and surface area were also measured compared to wildtype cells. CONCLUSIONS: Corroborating in vivo and in vitro data support Top2b as a therapeutic target for retinal progenitor motility but indicate significant differences in the migration of Top2b altered cells upon substrates used in transplantation. These data highlight the therapeutic advantages of bioinspired materials developed to aid the motility of replacement cells with modified genetic expression to improve transplantation outcomes across the nervous system.