SURVIVAL AND MATURATION OF HUMAN NEURONAL PROGENITOR CELLS IN HUMAN CORTICAL ORGANOTYPIC SLICE CULTURES

Organotypic slice cultures derived from postoperative human brain tissue combined with stem cells offer a unique long-term model for studying neuronal development and integration under near-physiological conditions. This system supports tissue viability for several weeks, enabling investigations of optogenetic tools and stem cell integration.
In this study, GFP-expressing human induced pluripotent stem cell (iPSC) derived neural progenitor cells (NPCs) were injected into human cortical organotypic slices. To enhance integration, we optimised the culturing medium composition, method, and timing of the injection. Their survival, differentiation, and integration into the existing neuronal network were analysed using light, confocal, and electron microscopy. The differentiation state of NPCs and the effect on the tissue were assessed by immunohistochemistry.
In most cases, the NPCs initiated neuronal polarisation by growing neuronal protrusions; however, round cells with glial morphology were also observed after 14 days in vitro. NPCs mainly survived at the tissue margins and injection site, while some migrated deeper into the tissue. Neuron-specific marker, MAP2, showed their maturation, whereas the astroglial and microglial markers GFAP and IBA1, respectively, demonstrated the presence of a strong glial response in the slices.
These findings demonstrate that NPCs can survive and develop neuronal phenotypes in human cortical slice cultures for up to 5 weeks, depending on environmental factors, without the need for additional trophic factors. Based on our preliminary findings, this system appears to be a promising platform for studying cell integration and circuit formation in stem cell-based therapies.