Nitric oxide subserves diverse physiologic roles in the nervous system. NO is produced from at least three different NO synthase (NOS) isoforms: neuronal NOS (nNOS), endothelial NOS, and immunologic NOS (iNOS). We show that nNOS is the predominant isoform constitutively expressed in glia. NO derived from nNOS in glia inhibits the transcription factor nuclear factor B (NFB) as NOS inhibitors enhance basal NFB activation. Pyrrolidine dithiocarbamate (PDTC) is an inhibitor of NFB in most cells; however, we show that PDTC is also a potent scavenger of NO through formation of mononitrosyl iron complexes with PDTC. In Jurkat cells, a human T-cell lymphoma cell line, tumor necrosis factor-␣ (TNF-␣) induces NFB activation that is inhibited by PDTC. Contrary to the results in Jurkat cells, PDTC did not inhibit tumor necrosis factor-␣-induced NFB activation in astrocytes; instead PDTC itself induces NFB activation in astrocytes, and this may be related to scavenging of endogenously produced NO by the PDTC iron complex. In astrocytes PDTC also dramatically induces the NFBdependent enzyme, iNOS, supporting the physiologic relevance of endogenous NO regulation of NFB. NFB activation in glia from mice lacking nNOS responds more rapidly to PDTC compared with astrocytes from wild-type mice. Our data suggest that nNOS in astrocytes regulates NFB activity and iNOS expression, and indicate a novel regulatory role for nNOS in tonically suppressing central nervous system, NFBregulated genes.Nitric oxide is a potent messenger molecule with diverse physiologic activities, including regulation of vascular tone, neurotransmission, and killing of microorganisms and tumor cells (1-3). NO is produced from L-arginine (L-Arg) by the enzyme NO synthase (NOS). A family of related NOS proteins are the products of different genes and include neuronal NOS (nNOS, type 1), immunologic NOS (iNOS, type 2), and endothelial NOS (eNOS, type 3) (3). nNOS occurs in discreet neuronal populations in the brain and also is localized to the sarcoplasmic reticulum of skeletal muscle (4). eNOS primarily has endothelial cell localizations, but also is localized to a variety of other tissue types, including CA1 pyramidal cells of the hippocampus (5). Both nNOS and eNOS are constitutively expressed and are calcium-calmodulin-dependent enzymes (3, 4). iNOS is expressed in response to cytokines, lipopolysaccharide (LPS), and a host of other agents (6, 7). iNOS has been localized to a variety of cell types upon appropriate immunologic stimulation (6, 7). The key to regulation of NO production by iNOS is through regulation of transcription (8, 9).Characterization of the promoter region of the gene for iNOS reveals a complex pattern of regulation (8-12). Upstream from the transcription start site are distinct regulatory regions, including LPS-related response elements, binding sites for NFB, and ␥-interferon motifs (8-11). Recent studies indicate that NO transcriptionally inhibits iNOS mRNA expression in astrocytes (13). However, the mechanism by which NO transc...

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Recent studies implicating dendritic protein synthesis in synaptic plasticity have focused attention on identifying components of the molecular machinery involved in processing dendritic RNA. Although Translin was originally identified as a protein capable of binding single-stranded DNA, subsequent studies have demonstrated that it also binds RNA in vitro. Because previous studies indicated that Translin-containing RNA/singlestranded DNA binding complexes are highly enriched in brain, we and others have proposed that it may be involved in dendritic RNA processing. To assess this possibility, we have conducted studies aimed at defining the localization of Translin and its partner protein, Trax, in brain. In situ hybridization studies demonstrated that both Translin and Trax are expressed in neurons with prominent staining apparent in cerebellar Purkinje cells and neuronal layers of the hippocampus. Subcellular fractionation studies demonstrated that both Translin and Trax are highly enriched in the cytoplasmic fraction compared with nuclear extracts. Furthermore, immunohistochemical studies with Translin antibodies revealed prominent staining in Purkinje neuron cell bodies that extends into proximal and distal dendrites. A similar pattern of somatodendritic localization was observed in hippocampal and neocortical pyramidal neurons. These findings demonstrate that Translin is expressed in neuronal dendrites and therefore support the hypothesis that the Translin/Trax complex may be involved in dendritic RNA processing. Key Words: Dendritic protein synthesisPurkinje cells-Synaptic plasticity-GS1 complex-Pyramidal neurons.

Amida was isolated by the yeast two-hybrid system as a novel protein which associated with Arc, a non-transcriptional immediate early gene specific to the brain. Amida was confirmed to be associated with Arc in vitro and in vivo. Amida shows no homology to known proteins. Amida is ubiquitously expressed, although it is abundant in the brain. A transfection study revealed that Amida was localized in the nucleus and after 72 h the transfected cells underwent apoptosis. Furthermore, we found two nuclear localization signals and a domain needed for interacting with Arc was encompassed by two nuclear localization signals. Co-transfection experiment with Amida and Arc suggested that Amida transported Arc into the nucleus and negatively regulated Amida-induced cell death. These results indicate that Arc together with Amida may modulate cell death in the brain.

Increased gene expression levels of sodium-glucose cotransporter 1 (SGLT1) are associated with hypertrophic and ischemic cardiomyopathy. However, it remains unclear whether chronic pressure overload increases SGLT1 expression, which in turn induces hypertrophic cardiomyopathy. We hypothesized that pressure overload could increase SGLT1 gene expression, leading to the development of hypertrophic cardiomyopathy.To create pressure overload-induced cardiomyopathy, transverse aortic constriction (TAC) was performed in SGLT1-deficient (SGLT1) and wild-type (WT) mice. Six weeks after surgery, all mice were investigated. We observed a reduction of left ventricular fractional shortening and left ventricular dilatation in TAC-operated WT but not in TAC-operated SGLT1 mice. SGLT1, interleukin 18, connective tissue growth factor, and collagen type 1 gene expression levels were increased in TAC-operated WT mouse hearts compared with that of sham-operated WT mouse hearts. Moreover, heart/body weight ratio and ventricular interstitial fibrosis were increased in TAC-operated WT mice compared with that of sham-operated WT mice. Interestingly, these factors did not increase in TAC-operated SGLT1 mice compared with that of sham-operated WT and SGLT1 mice. Phenylephrine, an adrenergic α receptor agonist, caused cardiomyocyte hypertrophy in neonatal WT mouse hearts to a significantly larger extent than in neonatal SGLT1 mouse hearts.In conclusion, the results indicate that chronic pressure overload increases SGLT1 and IL-18 gene expressions, leading to the development of hypertrophic cardiomyopathy. These results make SGLT1 a potential candidate for the therapeutic target for hypertension-induced cardiomyopathy.