Involvement of Src kinase in T-type calcium channel-dependent neuronal differentiation of NG108-15 cells by hydrogen sulfide

J. Neurochem. (2010) 114, 512-519. Hydrogen sulfide (H₂S), a gasotransmitter, induces neuronal differentiation characterized by neuritogenesis and functional up-regulation of high voltage-activated Ca²⁺ channels, via activation of T-type Ca²⁺ channels in NG108-15 cells. We thus analyzed signaling mechanisms for the H₂S-evoked neuronal differentiation. NaHS, a donor for H₂S, facilitated T-type Ca²⁺ channel-dependent membrane currents, an effect blocked by ascorbic acid that selectively inhibits Cav3.2 among three T-type channel isoforms. NaHS, applied once at a high concentration (13.5 mM) or repetitively at a relatively low concentration (1.5 mM), as well as ionomycin, a Ca²⁺ ionophore, evoked neuritogenesis. The neuritogenesis induced by NaHS, but not by ionomycin, was abolished by mibefradil, a T-type Ca²⁺ channel blocker. PP2, a Src kinase inhibitor, completely suppressed the neuritogenesis caused by NaHS or ionomycin, while it only partially blocked neuritogenesis caused by dibutyryl cAMP, a differentiation inducer. NaHS, but not dibutyryl cAMP, actually caused phosphorylation of Src, an effect blocked by 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl, an intracellular Ca²⁺ chelator, mibefradil or ascorbic acid. The up-regulation of high voltage-activated currents in the cells treated with NaHS was also inhibited by PP2. Together, our data reveal that Src kinase participates in the T-type Ca²⁺ channel-dependent neuronal differentiation caused by NaHS/H₂S in NG108-15 cells.