Chondroitin sulfate, a major niche substance of neural stem cells, and cell transplantation therapy of neurodegeneration combined with niche modification.

Chondroitin sulfate (CS), a polysaccharide moiety of proteoglycans, is one of the major components of the extracellular matrix in the central nervous system and is involved in various cellular events in the formation and maintenance of the neural network. In the developing brain, CS in the milieu of neural stem/progenitor cells (NSPCs) is believed to participate in the regulation of their functions such as proliferation and differentiation. NSPCs are expected to act as a potent cell type in cell replacement therapy for neurodegeneration in various neurological diseases. Recently, it has been shown that transplantation of NSPCs combined with removal of extracellular CS from the host nervous tissues gives a satisfactory outcome in some animal models of nervous tissue injuries including neonatal hypoxic-ischemic injury and adult spinal cord injury. The combination of cell transplantation with modification of the extracellular matrix of the host tissue could be a novel strategy for the treatment of incurable neurodegenerative diseases.