Finding degrees of separation: Experimental approaches for astroglial and oligodendroglial cell isolation and genetic targeting

Abstract

The study of CNS glial cell function requires experimental methods to detect, purify, and manipulate each cell population with fidelity and specificity. With the identification and cloning of cell- and stage-specific markers, glial cell analysis techniques have grown beyond physical methods of tissue dissociation and cell culture, and become highly specific with immunoselection of cell cultures in vitro and genetic targeting in vivo. The unique plasticity of glial cells offers the potential for cell replacement therapies in neurological disease that utilize neural cells derived from transplanted neural stem and progenitor cells. In this mini-review, we outline general physical and genetic approaches for macroglial cell generation. We summarize cell culture methods to obtain astrocytes and oligodendrocytes and their precursors, from developing and adult tissue, as well as approaches to obtain human neural progenitor cells through the establishment of stem cells. We discuss popular targeting rodent strains designed for cell-specific detection, selection and manipulation of neuroglial cell progenitors and their committed progeny. Based on shared markers between astrocytes and stem cells, we discuss genetically modified mouse strains with overlapping expression, and highlight SOX-expressing strains available for targeting of stem and progenitor cell populations. We also include recently established mouse strains for detection, and tag-assisted RNA and miRNA analysis. This discussion aims to provide a brief overview of the rapidly expanding collection of experimental approaches and genetic resources for the isolation and targeting of macroglial cells, their sources, progeny and gene products to facilitate our understanding of their properties and potential application in pathology.

Lineage, fate, and fate potential of NG2-glia

“…Collectively, these studies are in agreement that NG2 cells throughout all stages of development can self-renew and generate oligodendrocytes. They provided direct confirmation that NG2 cells in the postnatal CNS are indeed OPCs (reviewed in Nishiyama et al, 2009; Richardson et al, 2011; Chew et al, 2014), although it remains unknown whether all NG2 cells are equivalent in their potential to give rise to oligodendrocytes.…”

Targeting human oligodendrocyte progenitors for myelin repair

“…Various methods have been described for the isolation of glial cells and OPCs from rodent tissues, and were recently reviewed elsewhere (Chew et al, 2014). However, the majority of these techniques do not readily translate to human tissues, likely due to differences in enzymatic dissociation methods and species- and tissue-dependent antibody specificities.…”

In vitro Models of Neurodegenerative Diseases

“…These are preferred because they have the ability to differentiate and generate myelin in vitro in the absence of signals from axons (Bechler et al, 2015). Protocols based on OPCs have been particularly successful because they can generate mature myelinating oligodendrocytes (Dugas and Emery, 2013;Barateiro and Fernandes, 2014;Chew et al, 2014). Mouse, rat and human OPCs differ in terms of their longevity in culture, with rat OPCs proving the easiest to isolate and maintain whereas human OPCs take the longest to develop the classical mature oligodendrocyte phenotype.…”