Intrathecal transplantation of neural stem/precursor cells derived from induced pluripotent stem cells is safe and promotes clinical recovery in experimental autoimmune encephalomyelitis

Neural stem/precursor cell (NPC) transplantation promotes recovery in experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS). However, clinical translation is limited by the lack of safe sources of autologous NPCs. Induced pluripotent stem cells (iPSCs) represent an expandable autologous source that may overcome this limitation. We investigated whether NPCs derived from iPSCs (miPSC-NPCs) could represent a safe and effective source of NPCs for transplantation in EAE. Methods: miPSC-NPCs were obtained according to established protocols. Expression of CXC receptor 4 (CXCR4), Very Late Antigen-4 (VLA4) and CD44 was assessed by flow cytometry. EAE was induced in C57BL/6 mice by immunization with myelin oligodendrocyte glycoprotein 35-55. At the peak of disease severity 106 miPSC-NPCs were transplanted intrathecally in the cisterna magna. Sham-treated mice were used as controls. Clinical score was assessed daily. Neuropathology was performed at 40, 80 and 170 days post immunization (dpi). Results: transplanted miPSC-NPCs distributed with a diffusion gradient from the injection site in the subarachnoid spaces of the cisterna magna, IV ventricle and spinal cord. Most miPSC-NPCs, thanks to the expression of CXCR4, VLA4 and CD44, reached pathologically relevant sites, i.e. perivascular infiltrates and demyelinated areas. A small quota (6,7%) of miPSC-NPCs retained proliferation capacity; however, no tumour formation was detected in the central nervous system and peripheral organs up to 170 dpi. EAE mice treated with miPSC-NPCs showed a significant, persistent clinical amelioration with a mean clinical score at 80 dpi of 1.0 and 2.0 in the miPSC-NPC and sham group, respectively (p<0,0001). The clinical amelioration was confirmed by histopathology with a significant reduction in demyelination (p<0,05) and axonal loss (p<0,01) at 80 dpi in the miPSC-NPC-treatment group. Notably, miPSC-NPC treatment reduced inflammatory infiltration (p<0,02) and blood brain barrier disruption (p<0,05) as well as increased oligodendrocyte density within demyelinated areas (p