Fate of immortalized human neuronal progenitor cells transplanted in rat spinal cord.
BACKGROUND
Replacement of neurons and glia by transplantation has been proposed as a therapy for neurodegenerative diseases, including amyotrophic lateral sclerosis. This strategy requires using human motor neuronal progenitor cells or xenografts of animal cells, but there is little evidence that xenografted neuronal cells can survive in spinal cord despite immunosuppression.


OBJECTIVE
To clarify the mechanisms responsible for the death of xenografted neurons in spinal cord.


METHODS
Cells from an immortalized, neuronally committed, human embryonic spinal cord-derived cell line (HSP1) that expresses motor neuronal properties in vitro were transplanted into adult rat spinal cord. The rats were killed at intervals up to 8 weeks and serial sections through the graft sites were processed for immunofluorescence using primary antibodies against human nuclear and mitochondrial antigens, microtubule-associated protein 2, TUJ1, CD5, natural killer cells, and activated microglia-macrophages, caspase-3 and caspase-9.


RESULTS
Grafted cells did not migrate and underwent partial differentiation along a neuronal pathway. They were rejected after 4 weeks despite cyclosporine immunosuppression. Cells died by apoptosis via the cytochrome c/caspase-9/caspase-3 pathway. The host response included natural killer cells and activated microglia-macrophages but few T cells.


CONCLUSIONS
Intraspinal neuronal xenotransplantation failed because of apoptotic cell death. Neither T cells nor the spinal cord environment, which favors gliogenesis, are likely to have been responsible, but natural killer cells may have been involved.
Li
Peiying
P
Department of Neurology and the David Mahoney Institute of Neurological Sciences, University of Pennsylvania Medical Center, Philadelphia 19104-4283, USA.
Tessler
Alan
A
Han
Steve S W
SS
Fischer
Itzhak
I
Rao
Mahendra S
MS
Selzer
Michael E
ME
D000818:Animals; D001324:Autoantigens / Q000378:metabolism; D018956:CD5 Antigens / Q000378:metabolism; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D051047:Dihydrolipoyllysine-Residue Acetyltransferase; D004318:Doxycycline / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007211:Indoles; D019394:Ki-67 Antigen / Q000378:metabolism; D007694:Killer Cells, Natural / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000637:transplantation*; D051381:Rats; D013116:Spinal Cord / Q000166:cytology*; D033581:Stem Cell Transplantation / Q000379:methods*; D014183:Transplantation, Heterologous / Q000379:methods; D014404:Tubulin / Q000378:metabolism
D001324:Autoantigens; D018956:CD5 Antigens; D007211:Indoles; D019394:Ki-67 Antigen; C489788:MAP2 protein, human; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D014404:Tubulin; C007293:DAPI; C052359:DLAT protein, human; D051047:Dihydrolipoyllysine-Residue Acetyltransferase; C505407:CASP3 protein, human; C506433:CASP9 protein, human; C505410:Casp3 protein, rat; C506435:Casp9 protein, rat; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D004318:Doxycycline