Basement membrane-like matrix sponge for the three-dimensional proliferation culture of differentiated retinal horizontal interneurons

As the neurons in the central nervous system (CNS) form a neuronal network in a three-dimensional (3D) manner, a 3D proliferation culture system for differentiated neurons has been desired. Although differentiated neurons were previously thought to never proliferate, differentiated horizontal interneurons of Rb–/–; p107+/−; p130−/− (p107-single) retina clonally proliferated without dedifferentiation in vivo [1]. In the present study, we developed a basement membrane-like matrix sponge (BM-sponge) for the 3D proliferation culture of differentiated horizontal interneurons. p107-single horizontal interneurons, but not other types of retinal neurons, proliferated in the BM-sponge in a 3D manner. These interneurons expressed presynaptic marker and developed synaptic vesicles. These data demonstrated that p107-single horizontal interneurons cultured in the BM-sponge proliferate while maintaining their differentiated features. We described here the 3D proliferation culture system for differentiated neurons.