Nitric oxide protects the mitochondria of anterior pituitary cells and prevents cadmium-induced cell death by reducing oxidative stress.
Cadmium (Cd2+) is a highly toxic metal that affects the endocrine system. We have previously shown that Cd2+ induces caspase-3 activation and apoptosis of anterior pituitary cells and that endogenous nitric oxide (NO) protects these cells from Cd2+. Here we investigate the mechanisms by which NO exerts this protective role. Cd2+ (25 microM) reduced the mitochondrial membrane potential (MMP) as measured by flow cytometry. Cd2+-induced apoptosis was mitochondrial dependent since cyclosporin A protected the cells from this metal. Inhibition of NO synthesis with 0.5 mM L-NAME increased the effect of Cd2+ on MMP, whereas the NO donor DETANONOate (0.1 mM) reduced it. Cd2+ increased the production of reactive oxygen species (ROS) as measured by flow cytometry. This effect was electron-transfer-chain-dependent since it was inhibited by rotenone. In fact, rotenone reduced the cytotoxic effect of the metal. The action of Cd2+ on mitochondrial integrity was ROS dependent. Trolox, an antioxidant, inhibited the effect of the metal on the MMP. Cd2+-induced increase in ROS generation was reduced by DETANONOate. There are discrepancies concerning the role of NO in Cd2+ toxicity. Here we show that NO reduces Cd2+ toxicity by protecting the mitochondria from oxidative stress in a system where NO plays a regulatory role.
Poliandri
Ariel H B
AH
Department of Biological Chemistry, IQUIFIB, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina.
Machiavelli
Leticia I
LI
Quinteros
Alnilan F
AF
Cabilla
Jimena P
JP
Duvilanski
Beatriz H
BH
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002104:Cadmium / Q000633:toxicity*; D002478:Cells, Cultured; D016572:Cyclosporine / Q000494:pharmacology; D005434:Flow Cytometry; D007166:Immunosuppressive Agents / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects*; D009569:Nitric Oxide / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism
D007166:Immunosuppressive Agents; D017382:Reactive Oxygen Species; D002104:Cadmium; D009569:Nitric Oxide; D016572:Cyclosporine