Poster Sessions CP11: Neurotoxicity and Neuroprotection CP11-01 Secretory phospholipase A2 signalling partly overlaps glutamate-mediated events M. Kolko, E. B. Rodriguez de Turco, N. H. Diemer and N. G. Bazan Neuroscience Center and Department of Ophthalmology, Louisiana State University, New Orleans, USA Here we explored the mechanisms of secretory phospholipase A2 (sPLA2) and glutamate (glu) in neuronal signalling and cell damage. Rats or primary neuronal cultures were treated with MK-801 and injected with/exposed to sPLA2 or glu. MK-801 partially inhibited sPLA2- and glu-induced neuronal death as well as [3H]arachidonic acid release. The involvement of cytosolic PLA2 (cPLA2) and plateletactivating factor (PAF) in sPLA2 or glu signalling was explored by treating cells with the selective cPLA2 inhibitor, AACOCF3, PAF-acetyl hydrolase (PAF-AH) or the presynaptic PAF- receptor antagonist, BN52021. AACOCF3 blocked sPLA2- and glu-induced neuronal death by 26 and 77%, respectively. PAF-AH ameliorated sPLA2 as well as glu neurotoxicity by 31 and 47%, whereas BN52021 inhibited sPLA2 induced neurotoxicity by 11% but did not significantly protect against glu- induced neurotoxicity. Expression in neurons of early response genes in response to sPLA2 or glu was further examined. An up-regulation of COX-2, c-fos, and c-jun, but not COX-1, was observed at earlier time points after rat striatal injection of glu as compared to sPLA2 injection. Moreover we treated neuronal cells with COX-2 inhibitors and found that neuronal cell death after sPLA2 and glu exposure was inhibited by 35 and 33%, respectively. Thus sPLA2 activates a neuronal signalling cascade that includes activation of cPLA2, AA-release, production of PAF and induction of COX-2. Hence sPLA2 and glu signalling are overlapping, but not identical. Cytosolic PLA2 may primarily drive glutamatergic neurotransmission, whereas PAF plays a more crucial role in sPLA2 neuronal signalling. Acknowledgements: Supported by EPSCoR grant NSF/LEQSF(2001-04)- RII-01 from the National Science Foundation. CP11-02 Aluminum triggers NFjB signalling, inflammatory and apoptotic gene expression in human neural cells W. J. Lukiw and N. G. Bazan Neuroscience Center & Deptartment of Ophthalmology, Louisiana State, University Health Sciences Center, New Orleans, LA, USA Aluminum, the most abundant neurotoxic metal in the biosphere, has been implicated in the etiology of neurodegenerative disorders including Alzheimers disease (AD). To further understand aluminum’s influence on brain gene expression we examined 2360 RNA message levels in normal human neural progenitor (NHNP) cells using DNA microarrays. Of the 53 gene expression levels that were altered by a factor of >3-fold (p < 0.05) over control, 44 were down-regulated. This group included transcripts encoding 17 transcription factors (TFs) or TF kinases, 12 membrane receptors, genes encoding 10 growth factors, neurotransmitters, DNA ligase, DNA repair enzymes and antiapoptotic factors such as bcl-2. The only TFs found to be consistently induced by aluminum on these panels were members of the pro-inflammatory (PI) NFjB gene family. As verified independently by RT–PCR, eight of the nine genes found to be induced by aluminum encoded PI or proapoptotic signalling elements, including NFjB p52/p65, IL-1 precursor, COX-2 and DAXX, a FAS binding protein known to induce apoptosis and repress transcription. These PI gene promoters contain multiple NFjB binding sites; electrophoretic mobility shift assay and [kB] 4 vector transfection analysis indicated that aluminum strongly induced NFjB-DNA binding, suggesting a role for aluminum and NFjB in driving PI gene expression in neural cells. Interestingly, many aluminum-induced PI genes are also elevated in AD. These data show that aluminum triggered NHNP cells emulate many of the gene expression patterns observed in AD including the rampant up-regulation of NFjB-sensitive and PI signalling genes. Acknowledgements: Supported in part by NIH AG18031, NS23002 and the EENT Foundation. CP11-03 Glutamate-mediated CA++ influx and nuclear damage in retinal ganglion cells purified by panning: role of glia Mark A. DeCoster and Nicolas G. Bazan Neuroscience Center and Department of Ophthalmology, LSU Health Sciences Center, New Orleans, LA, USA The visual acuity decline in glaucoma is due to degeneration of retinal ganglion cells. We used cell panning with the antibody Thy 1.1 to isolate retinal ganglion cells (RGCs) from rat retina. Individual RGCs were extremely sensitive to glutamate, demonstrating sustained calcium influx responses to 100 nM glutamate. We tested unoprostone for its ability to elicit neuroprotection. This docosanoid decreases intraocular pressure in glaucoma patients and protects mixed retinal ganglion cell cultures from glutamate excitotoxicity and calcium influx. In the presence of retinal glia, RGCs responded to 100 and 500 nM glutamate with transient calcium influx, demonstrating glial buffering effects. Pure retinal glial cultures required on average at least 1 mM glutamate to trigger calcium influx, which was transient and oscillating. Unoprostone (10 lM) inhibited calcium influx stimulated by 5 mM glutamate in retinal glial cultures, while DMSO did not. Unoprostone at 1 lM also blocked neuronal calcium responses to 100 nM glutamate in mixed cultures, while DMSO did not. In RGCs isolated by panning, unoprostone blocked calcium responses to 100 nM glutamate in some cells, while DMSO blocked none. Unoprostone also protected RGCs from 20 lM glutamate-induced toxicity and nuclear damage. We hypothesize that while unoprostone may affect individual RGCs depending on a putative receptor, the presence of retinal glia also plays a key role in neuroprotection and unoprostone action. The use of the cellular model described here and whole retina preparations will be useful to understand the mechanisms of RGC survival. Acknowledgements: Support: Novartis Ophthalmics, Basel, Switzerland. CP11-04 Role of mycotoxin zearalenon poisoning in abnormalities of thromboplastic activity in rats and ways of their correction K. G. Karageuzyan and M. K. Karagyozyan Institute of Molecular Biology of the Armenian National Academy of Sciences, Yerevan, Armenia Intravenous administration of alcohol solution mycotoxin zearalenon (MZ) in quantity of 5.0–15.0 lg/body weight to 46 white mongrel male rats weighing 180–200 g, significantly shorten the blood coagulation time (BCT) and increase brain and erythrocyte thromboplastic activity (TA). Our previous investigations have shown that neutral phospholipids (NPL) particularly, phosphatidylcholines (PC) and phosphatidylethanolamines (PE) accelerate the blood clotting process (BCP), while acidic phospholipids (APL) mainly phosphatidyserines, play the role of inhibitors of BCP. Brain tissue thromboplastins are the membrane-bound PL-dependent enzymes catalysing the process of blood unactive prothrombin transformation into the active thrombin. It is necessary to draw attention to the relationship between the coefficient NPL/APL quota and TA both in normal and pathological conditions. It was demonstrated that modulation of MZ poisoning in rats accompanied by activation of PC biosynthesis. This fact leads us to the conclusion that elevation of PE quantity under the conditions of MZ poisoning is accompanied also with partial involving of them into methylation processes and provides high concentrations of PC. Intramuscular single administration to poisoned rats of 1 mL of 10% water solution of sodium thiosulfate separately and especially in combination with the Ca ions precipitate of dsRNA in concentration 5.0–25.0 mg/kg leads to normalization of all abnormalities mentioned during the period of 2–4 h MZ intoxication. Ó 2002 International Society for Neurochemistry, Journal of Neurochemistry , 81 (Suppl. 1) 101