Neural stem cells express RET, produce nitric oxide, and survive transplantation in the gastrointestinal tract.

Transplantation of neural stem cells (NSC) has been shown to be successful in a variety of experimental models of nongastrointestinal diseases. The aim of this study was to assess the potential of NSC transplantation as a therapeutic strategy for neuronal replacement in disorders of the enteric nervous system. Central nervous system-derived NSC (CNS-NSC) were obtained from the subventricular zone of rat brain (E17). Expression of RET, GFRalpha1, and neuronal nitric oxide synthase (nNOS) was assessed by Western blot and immunocytochemistry. Nitric oxide (NO) production was assessed using the NO-sensitive fluorescent indicator DAF-2. CNS-NSC (labeled with CM-DiI) were transplanted into the pylorus of mice and fluorescent double-labeling immunostaining for betaIII-tubulin or PGP 9.5 and nNOS was performed at 2, 4, and 8 weeks after transplantation. Our results show that CNS-NSC express both the receptors (RET and GFRalpha1) for the enteric neurotrophin, GDNF; GDNF, in turn, induces expansion of the RET-expressing CNS-NSC population. Furthermore, CNS-NSC express nNOS and produce NO in vitro. When transplanted into the gut, CNS-NSC differentiate into neurons, continue to express nNOS and survive at least 8 weeks. We conclude that transplantation of CNS-NSC bears promise as a potential cellular replacement strategy for enteric neurons.