These are listed in Table 2. Of note, Th1 and MM cytokines upegu lated nitric oxide synthase 2 by 15 fold, while Th2 cytokines markedly downregulated genes for angiotensin receptor type 1b, beta tubulin 2b, and chapsyn 110, all p 0. 05, but upregulated arginase and low density lipoprotein receptor 1 by 5 fold. QRT PCR We validated expression changes in three genes by QRT PCR iNOS, the till enzyme that synthesizes NO from arginine. arginase, the enzyme that breaks down arginine, thus limiting production of NO. and P glycoprotein, an ABC transporter involved in regulation of glutathione levels. As noted in Table 3, we were able to confirm striking upregulation of the gene for iNOS by Th1 and MM at 6 hours employing QRT PCR.

Although no effect on the gene for Inhibitors,Modulators,Libraries iNOS expression was observed at 6 hours in response to Th2 cytokines on microarray, we detected modest downregulation employ ing QRT PCR. For arginase, we confirmed upregulation by Th2, with no change induced by Th1. however, in contrast to the array results, PCR indicated some upregulation of arginase by MM at 6 hours, rather than no change. For P glycoprotein, PCR showed upregulation by Th1 and MM, as on the gene array, but also indicated a modest increase with Th2 rather than no change. The results for these three genes show relatively good agreement, and indicate that the arrays are not giv ing false positive results, but in some instances may give false negative results, suggesting that PCR may be more sensitive than the gene array.

Inhibitors,Modulators,Libraries Discussion In our two preceding papers, we showed marked differen Inhibitors,Modulators,Libraries tial early effects of Th1 cytokines, MM cytokines and Th2 cytokines on glial expression of a variety of genes, includ ing those for immune related molecules and for neu rotrophins, growth factors and structural proteins. In addition, following the 6 hours of cytokine exposure used in these studies, we saw changes in expression of a large number of genes involved in signaling, regulation and metabolism. Some of these changes might be predicted from known effects of cytokines in vitro and in EAE or MS tissue, while other changes were unexpected. In contrast to the in vivo studies, our examination of an early 6 hour time point provides information about what might be some of the initial responses of glia per se to these cytokines.

Inhibitors,Modulators,Libraries Neurotransmitters and receptors Glial Inhibitors,Modulators,Libraries cells have been reported to express different neuro transmitters and receptors as well as transporters for these transmitters. With increasing evidence that both oligodendrocyte and neuronalaxonal damage may be caused by glutamate induced Z-VAD-FMK side effects toxicity, and that other glutamate receptors may be protective, the effects of cytokine mixtures on different GluR may influ ence and modify the effects of glutamate. AMPA, kainate and NMDA receptors may be important in oligodendro cyte toxicity in MS and EAE whereas upregulation of metabotropic GluRs may provide protection.