Multiphoton Imaging of Regulatory T Cell and Oligodendrocyte Interactions During Neural Stem Cell Transplantation in Autoimmune Encephalitis 2308362

Abstract Introduction Multiple Sclerosis is an autoimmune disease of the central nervous system (CNS) characterized by demyelination and neuroinflammation. Regulatory T cells (Tregs) maintain self-tolerance, resolve inflammation, and are important for tissue repair in the CNS. Using experimental autoimmune encephalomyelitis (EAE), a model of immune-mediated demyelination, we have shown that transplantation of human neural stem cells (NSCs) in situ elevates Treg numbers and promotes tissue repair. In this study, we image cellular interactions among Tregs and oligodendrocytes (ODCs), the cells that produce myelin, to uncover the mechanisms of myelin repair. Methods We used quantitative multiphoton imaging (MPI) with NSC transplantation and fate-mapped reporter mice in the EAE model to elucidate the spatial organization of Treg cells relative to ODCs in the spinal cord. Treg cell therapy and flow cytometry were used to evaluate ex vivo expansion of Tregs using an NSC-derived antigen and homing of adoptively transferred Tregs into the CNS to promote functional recovery during EAE. Results During EAE, NSC transplantation resulted in a two-fold higher Treg density in the spinal cord. Time-lapse MPI revealed that NSC-expanded Treg cells migrate in slightly straighter trajectories while maintaining their velocities, contributing to their local spread in the spinal cord. Tissue-wide imaging revealed EAE-specific loss of ODCs in the lumbar region, which was restored by NSC transplantation. Moreover, NSC-expanded Treg cells were observed in proximity to ODCs. Finally, NFM (neurofilament medium), an NSC-derived antigen, expanded Tregs ex vivo, and adoptive transfer of NFM-expanded Tregs reduced EAE severity. Conclusion Our results show that NSC-expanded Treg cells promote tissue repair during EAE, in part by restoring regional ODC numbers. Our study highlights the strength of direct imaging of neuro-immune interactions and the therapeutic potential of Treg expansion strategies for autoimmune demyelinating diseases of the CNS. Funding Source Supported by NIH/NIAID grants R01AI168063 and U01AI160397 Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)