The Postnatal Human Filum Terminale Is a Source of Autologous Multipotent Neurospheres Capable of Generating Motor Neurons

Abstract

BACKGROUND: Neural progenitor cells (NPCs) are undifferentiated and mitotic and can be induced to differentiate into neurons and glia, the building blocks of the nervous system. NPCs have great therapeutic potential for nervous system trauma and degenerative disorders. They have been identified in the mammalian central nervous system, but current sources are difficult to access surgically and come from regions that are critical for normal brain function. OBJECTIVE: To identify and characterize in detail a novel source of human NPCs in the filum terminale (FT), a vestigial structure at the caudal end of the spinal cord, which is easily accessed and plays no functional role in the postnatal nervous system. METHODS: Cells were isolated and cultured in vitro from the FT of terminated fetuses and from children and adolescents who had undergone surgical resections for tethered spinal cords. Cell culture techniques, immunohistochemistry, and immunocytochemistry were applied to examine FT cells. RESULTS: FT cells gave rise to neurospheres that proliferated over extended periods of time in culture. These neurospheres were positive for neural stem/progenitor cell markers by immunocytochemical staining. The neurospheres were able to be induced to differentiate in vitro into neurons and glial cells, which were confirmed by the use of antibodies against the cell type-specific markers. Moreover, they have been induced to form motor neurons capable of innervating striated muscle in vitro. CONCLUSION: Multipotent NPC cells from the FT are both accessible and expendable. They may allow autologous cell-based transplantation therapy that circumvents immunological rejection. ABBREVIATIONS: BDNF, brain-derived neurotrophic factor CNTF, ciliary neurotrophic factor DMEM, Dulbecco modified Eagle medium FT, filum terminale GDNF, glial cell–derived neurotrophic factor GFAP, glial fibrillary acidic protein MN, motor neuron MNR, motor neuron restricted-2 NPC, neural progenitor cell RA, retinoic acid Shh, sonic hedgehog