Intracellular ion signaling influences myelin basic protein synthesis in oligodendrocyte precursor cells. Issue 5 (November 2016)

• Record Type: Journal Article
• Authors: Friess, Maike; Hammann, Jens; Unichenko, Petr; Luhmann, Heiko J.; White, Robin; Kirischuk, Sergei
• Is Part Of: Cell calcium. Volume 60:Issue 5(2016)
• Page Start: 322
• Page End: 330
• Publication Date: 2016-11
• Subjects: [Ca2+]i intracellular free Ca2+ ion concentration -- CNS central nervous system -- DIV day in vitro -- MBP myelin basic protein -- [Na+]i intracellular free Na+ ion concentration -- NCX Na+-Ca2+ exchanger -- NKA Na+-K+-ATPase -- OPC oligodendrocyte precursor cell -- OGB1 Oregon Green BAPTA 1 -- SBFI Sodium-binding benzofuran isophthalate; Intracellular Na+ concentration -- Intracellular Ca2+ concentration -- Na+-Ca2+ exchanger -- Na+, K+-ATPase -- Reversal potential -- Myelination; Calcium -- Metabolism -- Periodicals; Vertebrates -- Physiology -- Periodicals; Calcium -- Physiological effect -- Periodicals; Cell physiology -- Periodicals; Calcium in the body -- Periodicals; 572.516
• DOI: 10.1016/j.ceca.2016.06.009
• Languages: English
• ISSNs: 0143-4160

Abstract

Graphical abstract: Oligodendrocyte precursor cell, presumably in distal part of their processes, can sense neuronal activity by means of Na + /K + -ATPase and Na + /Ca 2+ exchanger which cause [Na + ]i and [Ca 2+ ]i transients, modulating in turn myelin basic protein (MBP) synthesis. Highlights: [Ca 2+ ]i and [Na + ]i in OPCs demonstrate developmental changes. NCX operating in reverse mode potentiates MBP synthesis. Increase in [K + ]e or elevation of [Na + ]i potentiate NCX-dependent MBP synthesis. Neuronal activity via [K + ]e changes may influence myelination. Abstract: Myelination in the central nervous system depends on axon-oligodendrocyte precursor cell (OPC) interaction. We suggest that myelin synthesis may be influenced by [Na + ]i and [Ca 2+ ]i signaling in OPCs. Experiments were performed in mouse cultured OPCs at day in vitro (DIV) 2–6 or acute slices of the corpus callosum at postnatal days (P) 10–30. Synthesis of Myelin Basic Protein (MBP), an "executive molecule of myelin", was used as readout of myelination. Immunohistological data revealed that MBP synthesis in cultured OPCs starts around DIV4. Transient elevations of resting [Ca 2+ ]i and [Na + ]i levels were observed in the same temporal window (DIV4-5). At DIV4, but not at DIV2, both extracellular [K + ] ([K + ]e) elevation (+5 mM) and partial Na +, K + -ATPase (NKA) inhibition elicited [Na + ]i and [Ca 2+ ]i transients. These responses were blocked with KB-R7943 (1 μM), a blocker of Na + -Ca 2+ exchanger (NCX), indicating an involvement of NCX which operates in reverse mode. Treatment of OPCs with culture medium containing elevated [K + ] (+5 mM, 24 h) or ouabain (500 nM, 24 h) increased resting [Ca 2+ ]i and facilitated MBP synthesis. Blockade of NCX with KB-R7943 (1 μM, 12 h) reduced resting [Ca 2+ ]i and decreased MBP synthesis. Similar to the results obtained in OPC cultures, OPCs in acute callosal slices demonstrated an increase in resting [Ca 2+ ]i and [Na + ]i levels during development. NCX blockade induced [Ca 2+ ]i and [Na + ]i responses in OPCs at P20-30 but not at P10. We conclude that local [Na + ]i and/or membrane potential changes can modulate Ca 2+ influx through NCX and in turn MBP synthesis. Thus neuronal activity-induced changes in [K + ]e may via NCX and NKA modulate myelination.