PKC-NOTCH-DEPENDENT NEUROGENESIS ACTIVATION IN HUMAN CORTICAL ORGANOIDS AS A STRATEGY FOR BRAIN REPAIR

Strategies to restore human cortical neurons after injury are limited. Human cortical organoids (hCOs) derived from embryonic and induced pluripotent stem cells offer a human-relevant platform to explore neurogenesis and regenerative mechanisms. Here, we use hCOs to explore the potential of diterpene compounds to boost neurogenesis as a treatment for brain repair. We report that diterpene treatment robustly enhanced organoid growth and progenitor expansion, leading to increased neurogenesis in early-stage hCOs. Mechanistically, we showed that these effects are PKC and Notch dependent, as their pharmacological inhibition abolished the pro-neurogenic response. Interestingly, PKC or Notch inhibition of untreated organoids also reduced basal growth, uncovering their role in human cortical development. Transcriptomic profiling further revealed diterpene-induced upregulation of genes controlling extracellular matrix organization, cell adhesion, and growth factor signaling-key processes for neurogenic niche remodeling. Further, we established an ischemia-like model coupled to an organoid-to-organoid transplantation paradigm to study the potential of cell transplantation under pro-neurogenic conditions following ischemic stroke. Under these injury-mimicking conditions, diterpene treatment enhanced graft integration and sustained neurogenic activity, demonstrating a pro-regenerative effect in an in vitro human cortical damage model. Together, our results identify diterpenes as potent modulators of human cortical neurogenesis via PKC- and Notch-dependent mechanisms and provide proof-of-concept evidence for their regenerative potential in human injury-mimicking organoid systems, highlighting PKC-targeting diterpenes as promising candidates for brain repair strategies.