2-2--(hydroxynitrosohydrazono)bis-ethanamine and Neurodegenerative-Diseases

Studies have shown that nitric oxide (NO)-induced apoptosis is mediated by a variety of cellular signaling pathways. However, the information is relatively limited to neural progenitor cells (NPCs). In this study, the role of p53 in the NO-induced apoptosis was examined in an in vitro model of NPCs. Comparisons were made between NPCs derived from either wild type or p53 knockout mice brain stimulated by diethylenetriamine/nitric oxide adduct (DETA/NO), an established NO donor that constantly releases NO through its known first order pharmacological kinetics and prolonged half-life. We found that treatment by DETA/NO both time- and dose-dependently induced a significant increase of apoptosis in wild type NPCs, while p53 knockout NPCs were resistant to the DETA/NO challenge. In addition, the DETA/NO-triggered alteration of mitochondrial membrane permeability, cleavage of caspase-9/3, and expression of pro-apoptotic Bcl-2 family members noxa and puma occurred in wild type NPCs but not in p53 knockout NPCs. Our current results suggest a central role of p53 in the NO-induced apoptotic pathway in NPCs, which may hence provide new insights into the regulation of cell death in NPCs that respond to overproduction of NO in injured brain.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Caspase 9; Cells, Cultured; Dose-Response Relationship, Drug; Membrane Potential, Mitochondrial; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurodegenerative Diseases; Neurons; Nitric Oxide; Nitric Oxide Donors; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Stem Cells; Time Factors; Triazenes; Tumor Suppressor Protein p53; Tumor Suppressor Proteins

Topics: Animals; Antidepressive Agents; Brain-Derived Neurotrophic Factor; Cell Proliferation; CREB-Binding Protein; Depression; Diet; Feeding Behavior; Hippocampus; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Nitric Oxide; Nitroso Compounds; Nuclear Proteins; Rats; Trans-Activators

Primary culture rat astrocytes exposed to the long acting nitric oxide donor (Z)-1-[2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NO) for 24 h approximately double their concentration of glutathione (GSH) and show no sign of cell death. In contrast, GSH was depleted by 48%, and significant loss of mitochondrial respiratory chain complex activity and cell death were observed in primary culture rat neurones subjected to DETA-NO for 18 h. Northern blot analysis suggested that mRNA amounts of both subunits of glutamate-cysteine ligase (GCL), the rate-limiting enzyme in GSH synthesis, were elevated in astrocytes following nitric oxide (NO) exposure. This correlated with an increase in astrocytic GCL activity. Neurones on the other hand did not exhibit increased GCL activity when exposed to NO. In addition, the rate of GSH efflux was doubled and gamma-glutamyltranspeptidase (gamma-GT) activity was increased by 42% in astrocytes treated with NO for 24 h. These results suggest that astrocytes, but not neurones, up-regulate GSH synthesis as a defence mechanism against excess NO. It is possible that the increased rate of GSH release and activity of gamma-GT in astrocytes may have important implications for neuroprotection in vivo by optimizing the supply of GSH precursors to neurones in close proximity.

Topics: Animals; Astrocytes; Cells, Cultured; Electron Transport; gamma-Glutamyltransferase; Glutamate-Cysteine Ligase; Glutathione; Mitochondria; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Nitric Oxide; Nitric Oxide Donors; Rats; Rats, Wistar; RNA, Messenger; Triazenes

Increasing experimental, clinical, and epidemiological studies point to the pivotal role of inflammation in the pathogenesis of acute and chronic neurodegenerative diseases and to the protective effects of nonsteroidal antiinflammatory drug (NSAID) therapies. Nonetheless, NSAID long-term therapies are limited by their significant adverse effects on gastrointestinal tract and kidneys. Nitroflurbiprofen (NO-flurbiprofen) belongs to a novel class of antiinflammatory agents obtained by derivatization of conventional NSAIDs with a nitric oxide (NO)-releasing moiety, which strongly reduces their untoward side effects without altering the antiinflammatory effectiveness. The recent evidence of neuroprotective effects of NO-NSAIDs in animal models of chronic brain inflammation prompted us to investigate the activities of NO-flurbiprofen and its parent molecule flurbiprofen on activated rat microglia, the brain resident macrophages. We found that NO-flurbiprofen was as potent as flurbiprofen in preventing prostaglandin E(2) synthesis in lipopolysaccharide-activated microglial cultures. At variance with previous observations on peripheral macrophages is that NO-flurbiprofen did not show any additional capacity to inhibit interleukin-1beta synthesis compared with flurbiprofen. Moreover, NO enhanced the expression of the inducible NO synthase; this effect was most likely attributable to the NO released from the drug, as suggested by experiments performed in the presence of the NO donor Deta-NONOate, which similarly to NO-flurbiprofen is characterised by a slow and long-lasting release. Our findings indicate that NO-NSAIDs may differently affect peripheral and brain macrophages. Given their potential therapeutic role in brain inflammation, further in vivo and in vitro studies are required to understand fully their mechanism of action in the CNS.

Topics: Animals; Animals, Newborn; Anti-Inflammatory Agents, Non-Steroidal; Brain; Cell Survival; Cells, Cultured; Dinoprostone; Dose-Response Relationship, Drug; Down-Regulation; Encephalitis; Flurbiprofen; Interleukin-1; Lipopolysaccharides; Macrophages; Microglia; Neurodegenerative Diseases; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Nitrites; Nitroso Compounds; Prostaglandin-Endoperoxide Synthases; Rats