Requirement of polysialic acid for the migration of the O-2A glial progenitor cell from neurohypophyseal explants

Abstract

While the capacity of O-2A oligodendrocyte progenitors to migrate in cell culture and during in vivo myelin formation is well documented, little is known about factors that regulate the motility of these cells. Here, we report on an in vitro model that allowed us to evaluate the contribution of alpha 2-8 linked polysialic acid (PSA) to O-2A cell motility. Using explant cultures of newborn rat neurohypophysis, we observed that individual glial fibrillary acidic protein (GFAP)-positive cells rapidly disperse from the explants, and that cells of the O-2A lineage predominate in the migratory cell pool. Presumed O-2A progenitor cells had a round or bipolar morphology and presented both A2B5 and GFAP immunoreactivity. When cultured in medium containing 10% fetal calf serum, these cells differentiated into stellate-shaped, A2B5/GFAP-positive type 2 astrocytes. In serum-free medium most of them developed into O4/galactocerebroside-positive oligodendrocytes. O-2A lineage cells were found only in a specific developmental period extending from embryonic day 21 to postnatal day 3. A monoclonal antibody, which recognizes the alpha 2-8 linked PSA, characteristic of the embryonic form of NCAM, revealed immunoreactivity on the surface of O-2A progenitor cells, whereas mature oligodendrocytes, type 2, type 1 astrocytes as well as flat GFAP-negative cells were negative. Treatment of the explants with endoneuraminidase purified from phage K1, which specifically removes PSA from the surface of the cell, resulted in a complete blockade of the dispersion of O-2A lineage population from the explant. The effects of the enzymatic treatment were both selective and reversible: migration of GFAP-negative fibroblast-like cells that are normally PSA negative was not influenced, and upon removal of the enzyme, cells of the O-2A lineage were readily detectable in the migrating population. These results provide direct evidence that alpha 2-8 linked PSA contribute to the motility of O-2A, glial progenitor cells.

A nude mice model of human rhabdomyosarcoma lung metastases for evaluating the role of polysialic acids in the metastatic process

“…The spatiotemporal pattern of PSA-NCAM expression correlates well with such roles during histogenesis (Rougon and Marshat, 1986;Lackie et al, 1990;Figarella-Branger et al, 1992). There is direct evidence both for the contribution of PSA to the mobility of O-2A glial progenitor cells from neurohypophyseal explants (Wang et al, 1994) and for the migration of olfactory bulb interneuron precursors in the subventricular zone (Hu et al, 1996).…”

“…Endo-N, which speci®-cally removes PSA polymers from the cell surface after in vitro (Wang et al, 1994) and in vivo (Ono et al, 1994) injections, was instrumental in our study. First, we showed that in vitro a single Endo-N addition was su cient to completely remove PSA on NCAM on TE 671 cell surface for up to 72 h without a ecting the viability nor the proliferation rate of TE 671 cells.…”

“…tumors. It is likely that because the enzyme is active under a trimeric or tetrameric form (Wang et al, 1994), it cannot di use through the serous peritoneal barrier (Gokal, 1992). In contrast, i.p.…”

Increased Neurogenesis in Adult mCD24-Deficient Mice

“…The explants were mixed with 70% Matrigel in HBSS medium (Becton Dickinson, Mountain View, CA) and cultured in four-well dishes. After polymerization for 10 min, the gel was overlaid with 2 ml of serum-free medium containing B-27 supplement (Invitrogen), in presence or absence of 70 U of Endoneuraminidase (EndoN) prepared in our laboratory (Wang et al, 1994). Cultures were maintained in a humidified, 5% CO 2 , 37°C incubator.…”

Polysialyltransferase expression is linked to neuronal migration in the developing and adult zebrafish

“…It has been shown to be involved in regulating embryonic neurogenesis (Ponti et al, 2006), neuronal migration (Ono et al, 1994;Wang et al, 1994;Hu et al, 1996), axonal pathfinding (Tang et al, 1992;Daston et al, 1996;Cremer et al, 1997;Marx et al, 2001), as well as synaptogenesis (Seki and Rutishauser, 1998). Furthermore, in the mature brain, NCAM has been implicated in regulating adult neurogenesis (Vutskits et al, 2006), neuronal migration (Cremer et al, 1994), survival of neural stem cell derived neuronal progenitors (Gascon et al, 2007), synaptic plasticity, and learning (Becker et al, 1996;Muller et al, 1996).…”