Neural stem cells display an inherent mechanism for rescuing dysfunctional neurons.
We investigated the hypothesis that neural stem cells (NSCs) possess an intrinsic capacity to "rescue" dysfunctional neurons in the brains of aged mice. The study focused on a neuronal cell type with stereotypical projections that is commonly compromised in the aged brain-the dopaminergic (DA) neuron. Unilateral implantation of murine NSCs into the midbrains of aged mice, in which the presence of stably impaired but nonapoptotic DA neurons was increased by treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), was associated with bilateral reconstitution of the mesostriatal system. Functional assays paralleled the spatiotemporal recovery of tyrosine hydroxylase (TH) and dopamine transporter (DAT) activity, which, in turn, mirrored the spatiotemporal distribution of donor-derived cells. Although spontaneous conversion of donor NSCs to TH(+) cells contributed to nigral reconstitution in DA-depleted areas, the majority of DA neurons in the mesostriatal system were "rescued" host cells. Undifferentiated donor progenitors spontaneously expressing neuroprotective substances provided a plausible molecular basis for this finding. These observations suggest that host structures may benefit not only from NSC-derived replacement of lost neurons but also from the "chaperone" effect of some NSC-derived progeny.
Ourednik
Jitka
J
Department of Neurobiology, Swiss Federal Institute of Technology, Hoenggerberg, CH-8093, Switzerland. joured@iastate.edu
Ourednik
Václav
V
Lynch
William P
WP
Schachner
Melitta
M
Snyder
Evan Y
EY
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000375:Aging; D000818:Animals; D002452:Cell Count; D002470:Cell Survival; D003913:Dextroamphetamine / Q000494:pharmacology; D005260:Female; D020267:MPTP Poisoning / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009416:Nerve Regeneration / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000473:pathology*; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D020127:Recovery of Function; D012016:Reference Values; D015398:Signal Transduction; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D013378:Substantia Nigra / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
C048977:1-methyl-4-(2'-methylphenyl)-1,2,3,6-tetrahydropyridine; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D014446:Tyrosine 3-Monooxygenase; D003913:Dextroamphetamine