Impairment of mineralocorticoid receptor (MR)-dependent biological response by oxidative stress and aging: correlation with post-translational modification of MR and decreased ADP-ribosylatable level of elongating factor 2 in kidney cells.
Acute and chronic treatments of mice with the glutathione-depleting agent, L-buthionine-(SR)-sulfoximine (BSO), impaired the mineralocorticoid receptor (MR)-dependent biological response by inhibiting aldosterone binding. This steroid-binding inhibition was fully reversed when reducing agents were added to kidney cytosol obtained from mice treated for 5 h, but it was only partially reversed in cytosol obtained from mice treated for 10 days. Although the oligomeric structure of the MR-hsp90 heterocomplex was always unaffected, a decreased amount of MR protein was evidenced after the long term treatment. Such a deleterious effect was correlated with a post-translational modification of MR, as demonstrated by an increased level of receptor carbonylation. In addition, a failure at the elongation/termination step was also observed during the receptor translation process in a reticulocyte lysate system. Thus, a high polyribosomes/monomers ratio and both increased proteolysis and decreased ADP-ribosylatable concentration of elongation factor 2 (EF-2) were shown. Importantly, similar observations were also performed in vivo after depletion of glutathione. Notwithstanding the EF-2 functional disruption, not all renal proteins were equally affected as the MR. Interestingly, both EF-2 and MR expressed in old mice were similarly affected as in L-buthionine-(SR)-sulfoximine-treated young mice. We therefore propose that a dramatic depletion of glutathione in kidney cells mimics the cumulative effect of aging which, at the end, may lead to a renal mineralocorticoid dysfunction.
Piwien-Pilipuk
Graciela
G
Departamento de Quimica Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
Ayala
Antonio
A
Machado
Alberto
A
Galigniana
Mario D
MD
D020727:ADP-Ribosylation Factors / Q000378:metabolism*; D000375:Aging; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D020652:Peptide Elongation Factor 2 / Q000378:metabolism*; D011132:Polyribosomes / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D018161:Receptors, Mineralocorticoid / Q000378:metabolism*; D012156:Reticulocytes / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic
D000963:Antimetabolites; D004791:Enzyme Inhibitors; D018841:HSP90 Heat-Shock Proteins; D020652:Peptide Elongation Factor 2; D018161:Receptors, Mineralocorticoid; D019328:Buthionine Sulfoximine; D020727:ADP-Ribosylation Factors; D005978:Glutathione; D010100:Oxygen