WP4: TBI and Repair: There are two approaches which we will take: a) we will look at late-stage treatment (TBI that has occurred beyond 4 hours) and b) once the in vivo model is validated, the effects of early treatment (less than 4 hours after TBI has occurred) will then be studied. We have already identified some compounds that prevent necroptosis, which can minimize lesion size and prevent the early stage cascade effects of TBI. Epidermal neural crest stem cells (EPI-NCSCs) derived from the bulge of autologous hair follicles and N2 Euro cells, a neural progenitor stem cell line, will be studied for their migration and differentiation properties in the cryogenic brain injury model. These cells will be transplanted into animals with induced-cryogenic injury, followed by multi-modality (MRI, fMRI, MSOTTM and near infra-red fluorescent [NIRF] optical) imaging and these data will be confirmed by histology / immunohistochemistry, fluorescent microscopy and MSI. NEO-STEM dual modality (paramagnetic and NIRF) nanoparticles will be used for the cell migration studies. For cell differentiation, we will use the in vivo dual-colour bioluminescence technique recently developed in Leiden. WP3 will be led by Prof. Lowik with one incoming and one outgoing scientist plus collaborations with MPI, Medres, PERC, AMOLF and TUM. The process will allow for the development and opening-up of scientific career opportunities for many non-tenure staff. Moreover, this will ensure cross-fertilisation of ideas to help develop a causal-based treatment strategy based upon optimisation of cell type, time and location after TBI, degree of pre-differentiation prior to implantation, etc. Furthermore, with such knowledge available, and with imaging reporters of functional cell status developed, the cells’ dynamics after implantation can be monitored. We can then determine the highest impact for success of such cell replacement therapy and / or anti-necroptosis treatment by determining whether there is a decline or cessation in cell death. We would follow the migration and differentiation of transplanted EPI-NCSCs and N2 Euro cells in this model to demonstrate the feasibility of such cells to be used for the treatment of TBI. The intention is that the scientists within the consortium would move between labs to align all the tools and techniques required to ensure optimal monitoring of cell activity.