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HVCN1 contributes to superoxide production independent of intracellular pH regulation
Author(s) -
O'Connor Paul Michael,
Sun Jingping,
Mazer Benjamin Aaron
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1144.3
Subject(s) - superoxide , nigericin , nadph oxidase , intracellular , chemistry , intracellular ph , respiratory burst , extracellular , biophysics , oxidase test , biochemistry , reactive oxygen species , biology , enzyme , membrane
HVCN1 is a voltage‐gated ion channel, required for maximal superoxide (O 2 − ) production by NADPH oxidase during the respiratory burst in macrophages (MØ). During activation of NADPH oxidase, H + ions are produced resulting in cellular acidification. By extruding H + , HVCN1 maintains the respiratory burst by preventing feedback inhibition of the oxidase by low pH. Recent evidence from our laboratory indicates that HVCN1 may also contribute to superoxide formation by additional mechanisms. We hypothesized that ‘HVCN1 acts to enhance NADPH oxidase activity independent of its role in intracellular pH regulation’. Intracellular pH was clamped using nigericin (100μM)/K + (135μM) in isolated peritoneal MØ from the rat at pH 8.0, 7.5, 7.0 or 6.5. Maximal O 2 − production (L‐012 luminescence (AU)) in MØ in response to (PMA 100μM) was linearly related to intracellular pH (r 2 =0.97). Addition of Zn 2+ (100μM), to specifically inhibit HVCN1, significantly reduced maximal O 2 − production by >; 50% at all pH levels (Table 1). As these reductions in O 2 − production could not be explained by changes in intracellular pH, we conclude that HVCN1 enhances O 2 − production in MØ by pH independent mechanisms.