Neural stem cells from protein tyrosine phosphatase sigma knockout mice generate an altered neuronal phenotype in culture.
BACKGROUND
The LAR family Protein Tyrosine Phosphatase sigma (PTPsigma) has been implicated in neuroendocrine and neuronal development, and shows strong expression in specific regions within the CNS, including the subventricular zone (SVZ). We established neural stem cell cultures, grown as neurospheres, from the SVZ of PTPsigma knockout mice and sibling controls to determine if PTPsigma influences the generation and the phenotype of the neuronal, astrocyte and oligodendrocyte cell lineages.


RESULTS
The neurospheres from the knockout mice acquired heterogeneous developmental characteristics and they showed similar morphological characteristics to the age matched siblings. Although Ptprs expression decreases as a function of developmental age in vivo, it remains high with the continual renewal and passage of the neurospheres. Stem cells, progenitors and differentiated neurons, astrocytes and oligodendrocytes all express the gene. While no apparent differences were observed in developing neurospheres or in the astrocytes and oligodendrocytes from the PTPsigma knockout mice, the neuronal migration patterns and neurites were altered when studied in culture. In particular, neurons migrated farther from the neurosphere centers and the neurite outgrowth exceeded the length of the neuronal processes from age matched sibling controls.


CONCLUSIONS
Our results imply a specific role for PTPsigma in the neuronal lineage, particularly in the form of inhibitory influences on neurite outgrowth, and demonstrate a role for tyrosine phosphatases in neuronal stem cell differentiation.
Kirkham
David L
DL
Department of Pathology and Molecular Medicine, McMaster University, Hamilton Ontario, L8N 3Z5, Canada. doering@mcmaster.ca.
Pacey
Laura K K
LK
Axford
Michelle M
MM
Siu
Roberta
R
Rotin
Daniela
D
Doering
Laurie C
LC
D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D007527:Isoenzymes / Q000172:deficiency / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D016501:Neurites / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D010641:Phenotype; D017027:Protein Tyrosine Phosphatases / Q000172:deficiency / Q000502:physiology*; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D018874:Spheroids, Cellular; D013234:Stem Cells / Q000166:cytology / Q000201:enzymology / Q000502:physiology*
D007527:Isoenzymes; D017027:Protein Tyrosine Phosphatases; C516885:Ptprs protein, mouse; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2