Attempts to produce astrocyte cultures devoid of oligodendrocyte generating potential by the use of antimitotic treatment reveal the presence of quiescent oligodendrocyte precursors

Abstract

The presence of oligodendrocyte precursor cells which cannot be removed from primary cultures by antibody-dependent techniques complicates the interpretation of transplantation experiments designed to examine the potential of astrocytes to influence remyelination (Blakemore et al.; Glia 13:79-91, 1995). In the present series of experiments we have investigated the use of the antimitotic cytosine arabinoside to eliminate oligodendrocyte precursors from mixed glial cell cultures following immunolytic removal of both oligodendrocytes and oligodendrocyte progenitors using A2B5 and O4 monoclonal antibodies. Our results indicate that not all oligodendrocyte precursors are involved during the subsequent regeneration of oligodendrocytes since a population of precursors survive 3-day and 12-day exposure to cytosine arabinoside. Maintaining immunolysed cultures in serum-free medium containing cytosine arabinoside for 23 days, removed the potential to generate large clones of oligodendrocytes both in vitro and following transplantation. However, a small number of oligodendrocyte precursors survived this treatment and generated single oligodendrocytes in vitro and isolated clusters of oligodendrocyte remyelination following transplantation. Overall, these results indicate that oligodendrocyte precursors have considerable potential to generate oligodendrocytes, but, since they can also survive for long periods in a quiescent state, their complete elimination from immunolysed astrocyte cultures by the use of an antimitotic is unreliable, if not impossible.

Sonic hedgehog promotes generation and maintenance of human forebrain Olig2 progenitors

“…These differences highlight the importance of distinct cellular support needed for OLs specification and differentiation that is present in mixed cell cultures and absent in enriched RGC culture. Indeed, the requirement of neurons and astrocytes to preserve OPCs proliferation and avoid their rapid loss in culture, as well as promote subsequent differentiation has been previously shown in multiple studies (Crang and Blakemore, 1997; Zhang et al, 2000; Filipovic and Zecevic, 2008; Emery, 2010; Monaco et al, 2012). …”

Response of the oligodendrocyte progenitor cell population (defined by NG2 labelling) to demyelination of the adult spinal cord

“…Although we have proposed that the responsive NG2ϩ cells represent oligodendrocyte progenitors, the identity of the nonresponsive cells is less clear, as our knowledge of the oligodendrocyte lineage is far from complete. Evidence for heterogeneity in the responsiveness of oligodendrocyte progenitors can be seen in studies which reveal both quiescent and mitotically active oligodendrocyte progenitor cells (Gard and Pfeiffer, 1989;Crang and Blakemore, 1997). Moreover, a recent study by Hardy and Freidricks (1996) illustrated the generation of oligodendrocytes from progenitor cells without cell division.…”

Proteolipid Promoter Activity Distinguishes Two Populations of NG2-Positive Cells throughout Neonatal Cortical Development

“…In studies in the adult rat spinal cord, two NG2-positive cell populations were termed responsive and nonresponsive based on their activity after GC antibody plus complement-induced demyelination (Keirstead et al, 1998). Other studies have also demonstrated both quiescent and mitotically active oligodendrocyte progenitors in adult brain (Gard and Pfeiffer,1989;Crang and Blakemore, 1997). Although Keirstead et al (1998) proposed that the responsive population represented oligodendrocyte progenitors, no role for the nonresponsive population was suggested.…”