Oxidative stress in the aging murine olfactory bulb: Redox proteomics and cellular localization

Abstract

A recent proteomics analysis from our laboratory demonstrated that several oxidative stress response proteins showed significant changes in steady-state levels in olfactory bulbs (OBs) of 20- vs. 1.5-month-old mice. Oxidative stress may result in protein oxidation. In this study, we investigated two forms of protein oxidative modification in murine OBs: carbonylation and nitration. Redox proteomics with two-dimensional gel electrophoresis, Western blotting, protein digestion, and mass spectrometry was used to quantify total and specific protein carbonylation and to identify differentially carbonylated proteins and determine the carbonylation status of previously identified proteins in OBs of 1.5- and 20-month-old mice. Immunohistochemistry was used to demonstrate the relative intensity and localization of protein nitration in OBs of 1.5-, 6-, and 20-month-old mice. Total protein carbonylation was significantly greater in OBs of 20- vs. 1.5-month-old mice. Aldolase 1 (ALDO1) showed significantly more carbonylation in OBs from 20- vs. 1.5-month-old mice; heat shock protein 9A and dihydropyrimidinase-like 2 showed significantly less. Several previously investigated proteins were also carbonylated, including ferritin heavy chain (FTH). Nitration, identified by 3-nitrotyrosine immunoreactivity, was least abundant at 1.5 months, intermediate at 6 months, and greatest at 20 months and was localized primarily in blood vessels. Proteins that were specific targets of oxidation were also localized: ALDO1 in astrocytes of the granule cell layer and FTH in mitral/tufted cells. These results indicate that specific carbonylated proteins, including those in astrocytes and mitral/tufted neurons, and nitrated proteins in the vasculature are molecular substrates of age-related olfactory dysfunction.

Protein oxidation inhibits NO-mediated signaling pathway for synaptic plasticity

“…In aged brain of rodents, protein oxidation is enhanced (Cini and Moretti, 1995;Forster et al, 1996;Sohal et al, 1994;Vaishnav et al, 2007) and behavioral deficits of aged animals are associated with increases in oxidative stress Cantuti-Castelvetri et al, 2000;Carney et al, 1991;Forster et al, 1996;Fukui et al, 2001). These observations strongly indicate that oxidative stress is a primary factor inducing deficits in synaptic plasticity and memory in aged animals.…”

“…ROS also modifies cysteine residues and exert its action on cellular proteins. It has long been known that protein oxidation is enhanced in the brains of aged rodents (Cini and Moretti, 1995;Forster et al, 1996;Sohal et al, 1994;Vaishnav et al, 2007) . Thus, it is highly possible that impairment of PF-PTP and PF-LTP in the aged cerebellum could be due to the blockade of protein S-nitrosylation by preceding protein oxidization by endogenous ROS.…”

“…Actually, numerous studies have demonstrated various correlations between age and the accumulation of oxidative damage to cellular macromolecules (Floyd and Hensley, 2002;Stadtman, 2001). For example, enhanced lipid peroxidation (Calabrese et al, 2004;Devi and Kiran, 2004;Gupta et al, 1991;Murray and Lynch, 1998;O'Donnell and Lynch, 1998 ) and protein oxidation (Cini and Moretti, 1995;Forster et al, 1996;Sohal et al, 1994;Sultana et al, 2009;Vaishnav et al, 2007) are observed in the brains of aged rodents. Furthermore, several studies have shown that behavioral deficits of aged animals are associated with increases in oxidative stress Cantuti-Castelvetri et al, 2000;Carney et al, 1991;Forster et al, 1996;Fukui et al, 2001).…”

Role of oxidative stress and AT1 receptors in cerebral vascular dysfunction with aging

“…The interaction of NO with superoxide results in the formation of peroxynitrite, and increases in superoxide and peroxynitrite in the vasculature, including in cerebral vessels, have been described in models of aging (3,4,7,34,39). Peroxynitrite may be an important mediator of cellular injury through several effects, including the activation of PARP (24,26,27,33).…”

Cardiovascular Redox and Ox Stress Proteomics

“…For example, OPTMs of manganese SOD in the mitochondria would indicate mitochondrial dysfunction, which has been detected in various diseases (175) and the aging process (290,291,304). Depending on whether a protein is a transmembrane, membrane associated, or cytosolic protein, the subcellular location of the exposed amino acid can affect the protein residues that are targeted for modification by RNOS.…”