CNS Schwann cells display oligodendrocyte precursor-like potassium channel activation and antigenic expression in vitro

Central nervous system (CNS) injury triggers production of myelinating Schwann cells from endogenous oligodendrocyte precursors (OLPs). These CNS Schwann cells may be attractive candidates for novel therapeutic strategies aiming to promote endogenous CNS repair. However, CNS Schwann cells have been so far mainly characterized in situ regarding morphology and marker expression, and it has remained enigmatic whether they display functional properties distinct from peripheral nervous system (PNS) Schwann cells. Potassium channels (K⁺) have been implicated in progenitor and glial cell proliferation after injury and may, therefore, represent a suitable pharmacological target. In the present study, we focused on the function and expression of voltage-gated K⁺ channels K_v1–12 and accessory β-subunits in purified adult canine CNS and PNS Schwann cell cultures using electrophysiology and microarray analysis and characterized their antigenic phenotype. We show here that K⁺ channels differed significantly in both cell types. While CNS Schwann cells displayed prominent K _D-mediated K⁺ currents, PNS Schwann cells elicited K _D- and K_A-type K⁺ currents. Inhibition of K⁺ currents by TEA and Ba²⁺ was more effective in CNS Schwann cells. These functional differences were not paralleled by differential mRNA expression of K_v1–12 and accessory β-subunits. However, O4/A2B5 and GFAP expressions were significantly higher and lower, respectively, in CNS than in PNS Schwann cells. Taken together, this is the first evidence that CNS Schwann cells display specific properties not shared by their peripheral counterpart. Both K_v currents and increased O4/A2B5 expression were reminiscent of OLPs suggesting that CNS Schwann cells retain OLP features during maturation.