salicylates and 4-hydroxy-2-nonenal

Reduced mechanical loading during bedrest, spaceflight, and casting, causes rapid morphological changes in skeletal muscle: fiber atrophy and reduction of slow-twitch fibers. An emerging signaling event in response to unloading is the translocation of neuronal nitric oxide synthase (nNOSμ) from the sarcolemma to the cytosol. We used EUK-134, a cell-permeable mimetic of superoxide dismutase and catalase, to test the role of redox signaling in nNOSμ translocation and muscle fiber atrophy as a result of short-term (54 h) hindlimb unloading. Fischer-344 rats were divided into ambulatory control, hindlimb-unloaded (HU), and hindlimb-unloaded + EUK-134 (HU-EUK) groups. EUK-134 mitigated the unloading-induced phenotype, including muscle fiber atrophy and muscle fiber-type shift from slow to fast. nNOSμ immunolocalization at the sarcolemma of the soleus was reduced with HU, while nNOSμ protein content in the cytosol increased with unloading. Translocation of nNOS from the sarcolemma to cytosol was virtually abolished by EUK-134. EUK-134 also mitigated dephosphorylation at Thr-32 of FoxO3a during HU. Hindlimb unloading elevated oxidative stress (4-hydroxynonenal) and increased sarcolemmal localization of Nox2 subunits gp91phox (Nox2) and p47phox, effects normalized by EUK-134. Thus, our findings are consistent with the hypothesis that oxidative stress triggers nNOSμ translocation from the sarcolemma and FoxO3a dephosphorylation as an early event during mechanical unloading. Thus, redox signaling may serve as a biological switch for nNOS to initiate morphological changes in skeletal muscle fibers.

Topics: Aldehydes; Animals; Antioxidants; Cytosol; Disease Models, Animal; Forkhead Box Protein O3; Forkhead Transcription Factors; Hindlimb Suspension; Membrane Glycoproteins; Muscle Fibers, Fast-Twitch; Muscle Fibers, Skeletal; Muscle Fibers, Slow-Twitch; Muscular Atrophy; NADPH Oxidase 2; NADPH Oxidases; Nitric Oxide Synthase Type I; Organometallic Compounds; Oxidation-Reduction; Oxidative Stress; Phenotype; Phosphorylation; Protein Transport; Rats; Rats, Inbred F344; Salicylates; Sarcolemma; Signal Transduction; Time Factors

In the present study, the anti-inflammatory effect of salicylideneamino-2-thiophenol (SAL-2), a derivative of salicylate, on a potent oxidant 4-hydroxynonenal (HNE)-induced oxidative stress was investigated using rat prostate endothelial (YPEN-1) cells. We focused on anti-inflammatory activity of SAL-2 which was determined by its ability to suppress COX-2 and iNOS gene expression through suppression of NF-κB and redox regulation. We found that SAL-2 effectively inhibited HNE-induced reactive species generation, while upregulated GSH/GSSG ratio. Prostagrandin (PG) E2 production stimulated by arachidonic acid was suppressed by SAL-2. SAL-2 also downregulated COX-2 and iNOS expression induced by HNE, but salicylate did not. We found that SAL-2 inhibited HNE-mediated IKK phosphorylation, IκBα degradation and nuclear translocation of p65 which are linked to NF-κB activation. Furthermore, SAL-2 inhibited HNE-induced activation of mitogen-activated protein kinases. Collectively, SAL-2 inhibited COX-2 and iNOS gene expression through suppression of NF-κB leading to the inhibition of PGE2 synthesis. Based on these data, we propose that with its combined effect on strong anti-oxidant and anti-inflammatory action, SAL-2 can be a potent anti-inflammatory agent for treatment of inflammatory-related diseases.

Topics: Aldehydes; Animals; Cell Line; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Endothelial Cells; NF-kappa B; Rats; Reactive Oxygen Species; Salicylates; Signal Transduction; Sulfhydryl Compounds

Cell death in outer hair cells of the mammalian inner ear induced by aminoglycoside antibiotics is mediated by reactive oxygen species (ROS) and can be prevented by antioxidants. The current study investigates the role of the nuclear factor (NF)-kappaB pathway in cell death or survival in adult CBA mice. Kanamycin (700 mg/kg subcutaneously, twice per day) progressively destroys hair cells but after 7 days of treatment auditory function and morphology are not yet affected significantly, permitting investigations of early events in drug-induced cell death. Immunostaining for 4-hydroxynonenal, indicative of lipid peroxidation, was elevated in the cochlea, but there was no effect on nitrotyrosine, a marker for peroxynitrite. NF-kappaB was increased at 3 hr, 3 days, and 7 days of treatment, with p50 and p65 proteins as its most abundant subunits. Immunoreactivity for p50 was present in nuclei of inner hair cells and supporting cells that survive the drug treatment. In contrast, nuclei of outer hair cells were devoid of label. Concomitant injections of antioxidants, however, such as 2,3-dihydroxybenzoic acid or salicylate (which prevent cell death induced by kanamycin), promoted the translocation of NF-kappaB into the nuclei of outer hair cells. In addition, kanamycin treatment decreased tyrosine phosphorylation of the inhibitory IkappaBalpha protein, leading to increased IkappaBalpha levels in the cochlea; the effect was reversed by cotreatment with antioxidants. These results suggest that changes in the redox state of the cochlea stimulate the activation of NF-kappaB and that this activation is cell protective.

Topics: Aldehydes; Animals; Anti-Bacterial Agents; Auditory Threshold; Benzimidazoles; Blotting, Western; Calcium-Binding Proteins; Cell Cycle Proteins; Cell Death; Cell Fractionation; Cochlea; Cyclooxygenase Inhibitors; DNA Replication Timing; Drosophila Proteins; Drug Administration Schedule; Drug Interactions; Electrophoretic Mobility Shift Assay; Enzyme Activation; Hair Cells, Auditory; Hydroxybenzoates; Immunohistochemistry; Immunoprecipitation; Iron Chelating Agents; Kanamycin; Male; Membrane Glycoproteins; Mice; Mice, Inbred CBA; Molecular Chaperones; Nerve Tissue Proteins; NF-kappa B; Phosphorylation; Protective Agents; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Salicylates; Signal Transduction; Synaptotagmin I; Synaptotagmins; Time Factors; Tyrosine