Apoptotic inducers activate the release of D-aspartate through a hypotonic stimulus-triggered mechanism in PC12 cells.
We have characterized release of D-aspartate (D-Asp), a regulator of hormone synthesis and secretion, via a volume-sensitive organic anion channel (VSOC) in PC12 cells by studying its response to apoptotic stimuli. PC12 cells have been demonstrated to endogenously synthesize D-Asp. Apoptotic inducers, including staurosporin (STS), tumor necrosis factor (TNF)-alpha, H(2)O(2), and C2-ceramide, activate the release of D-Asp through a hypotonic stimulus-triggered mechanism. Putative blockers of the anion channel, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and 4,4'-diisothiocyanostilbene-2,2'-sulphonic acid (DIDS), significantly inhibited stress-induced D-Asp release under hypotonic conditions following the application of apoptotic inducers. Hypotonic conditions are essential for activation by apoptotic inducers. Phorbol 12-mirystate 13-acetate and the Ca(2+) ionophore A23187 increased D-Asp efflux via the VSOC, implying the involvement of intracellular Ca(2+) in the activation of the D-Asp efflux. However, hypotonic stress and STS had no effect on the concentration of intracellular Ca(2+) in PC12 cells. Furthermore, an unknown EGTA-sensitive factor(s), other than Ca(2+), and peroxynitrite may play pivotal roles in STS-enhanced D-Asp release.
Furuchi
Takemitsu
T
Laboratory of Biomolecular Science, Department of Pharmaceutical Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
Suzuki
Toshiyuki
T
Sekine
Masae
M
Katane
Masumi
M
Homma
Hiroshi
H
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007038:Hypotonic Solutions; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D007476:Ionophores / Q000494:pharmacology; D009579:Nitrobenzoates / Q000494:pharmacology; D016716:PC12 Cells; D051381:Rats; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D013237:Stereoisomerism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014527:Uric Acid / Q000494:pharmacology
D007038:Hypotonic Solutions; D007473:Ion Channels; D007476:Ionophores; C064769:N-acetylsphingosine; D009579:Nitrobenzoates; D014409:Tumor Necrosis Factor-alpha; D014527:Uric Acid; D001224:Aspartic Acid; D000001:Calcimycin; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D006861:Hydrogen Peroxide; D019311:Staurosporine; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate