Olfactory ensheathing cells from the nasal mucosa and olfactory bulb have distinct membrane properties

Abstract

Transplantation of Olfactory Ensheathing Cells (OECs) is a potential therapy for the regeneration of damaged neurons. While they maintain tissue homeostasis in the olfactory mucosa (OM) and olfactory bulb (OB), their regenerative properties also support the normal sense of smell by enabling continual turnover and axonal regrowth of olfactory sensory neurons (OSNs). However, the molecular physiology of OECs is not fully understood, especially that of OECs from the mucosa. Here, we carried out whole-cell patch clamp recordings from individual OECs cultured from the OM and OB of the adult rat, and from the human OM. A subset of OECs from the rat OM cultured 1-3 days in vitro (DIV) had large weakly rectifying K+ currents, which were sensitive to Ba2+ and desipramine, blockers of Kir4-family channels. Kir4.1 immunofluorescence was detectable in OM cells co-labelled for the OEC marker S100, and found adjacent to axons of OSNs. OECs cultured from rat OB had distinct properties though, displaying strongly rectifying inward currents at hyperpolarized membrane potentials and strongly rectifying outward currents at depolarized potentials. Kir4.1 immunofluorescence was not evident in OECs adjacent to axons of OSNs in the OB. A subset of human OECs cultured from the OM of adults had membrane properties comparable to those of the rat OM, i.e. dominated by Ba2+-sensitive weak inwardly rectifying currents. The membrane properties of peripheral OECs are different to those in central OECs, suggesting they may play distinct roles during olfaction.\n\nTable of Contents Image\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=169 SRC=\"FIGDIR/small/640839v2_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (39K):\norg.highwire.dtl.DTLVardef@7bc4edorg.highwire.dtl.DTLVardef@1bdc7c1org.highwire.dtl.DTLVardef@85851corg.highwire.dtl.DTLVardef@1e620b8_HPS_FORMAT_FIGEXP M_FIG C_FIG Main pointsO_LIPeripheral and central OECs are functionally distinct\nC_LIO_LIPeripheral OECs have large weak inward rectifier currents\nC_LIO_LICentral OECs have strong inward and outward rectifier currents\nC_LI