Regulation of zinc homeostasis by inducible NO synthase-derived NO: nuclear metallothionein translocation and intranuclear Zn2+ release.
Zn2+ is critical for the functional and structural integrity of cells and contributes to a number of important processes including gene expression. It has been shown that NO exogenously applied via NO donors resulting in nitrosative stress leads to cytoplasmic Zn2+ release from the zinc storing protein metallothionein (MT) and probably other proteins that complex Zn2+ via cysteine thiols. We show here that, in cytokine-activated murine aortic endothelial cells, NO derived from the inducible NO synthase (iNOS) induces a transient nuclear release of Zn2+. This nuclear Zn2+ release depends on the presence of MT as shown by the lack of this effect in activated endothelial cells from MT-deficient mice and temporally correlates with nuclear MT translocation. Data also show that NO is an essential but not sufficient signal for MT-mediated Zn2+ trafficking from the cytoplasm into the nucleus. In addition, we found that, endogenously via iNOS, synthesized NO increases the constitutive mRNA expression of both MT-1 and MT-2 genes and that nitrosative stress exogenously applied via an NO donor increases constitutive MT mRNA expression via intracellular Zn2+ release. In conclusion, we here provide evidence for a signaling mechanism based on iNOS-derived NO through the regulation of intracellular Zn2+ trafficking and homeostasis.
Spahl
Daniela U
DU
Institute of Molecular Medicine, Research Group Immunobiology, Medical Department, Heinrich Heine University, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
Berendji-Grün
Denise
D
Suschek
Christoph V
CV
Kolb-Bachofen
Victoria
V
Kröncke
Klaus-D
KD
D021581:Active Transport, Cell Nucleus; D000818:Animals; D001483:Base Sequence; D016207:Cytokines / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006706:Homeostasis; D066298:In Vitro Techniques; D018836:Inflammation Mediators / Q000494:pharmacology; D008668:Metallothionein / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D015032:Zinc / Q000378:metabolism*
D016207:Cytokines; D018076:DNA, Complementary; D018836:Inflammation Mediators; D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D008668:Metallothionein; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D015032:Zinc