Targeting GSNOR for functional recovery in a middle-aged mouse model of stroke.

The nitric oxide (NO) metabolome and the NO metabolite-based neurovascular protective pathways are dysregulated after stroke. The major NO metabolite S-nitrosoglutahione (GSNO) is essential for S-nitrosylation-based signaling events and the inhibition of S-nitrosoglutahione (GSNO)-metabolizing enzyme GSNO reductase (GSNOR) provides protective effects following cardiac ischemia. However, the role of GSNOR and GSNOR inhibition-mediated increased GSNO/S-nitrosylation is not understood in neurovascular diseases such as stroke.

Regulation of IL-10 and IL-17 mediated experimental autoimmune encephalomyelitis by S-nitrosoglutathione.

In this study, we investigated IL-10 and IL-17 specific immunomodulatory potential of S-nitrosoglutathione (GSNO), a physiological nitric oxide carrier molecule, in experimental autoimmune encephalomyelitis (EAE). In active EAE model, GSNO treatment attenuated EAE severity and splenic CD4 T cells isolated from these mice exhibited decreased IL-17 expression without affecting the IFN-γ expression compared to the cells from untreated EAE mice. Similarly, adoptive transfer of these cells to nave mice resulted in reduction in IL-17 expression in the spinal cords of recipient mice with milder EAE severity.

Pathology of nNOS-Expressing GABAergic Neurons in Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common form of dementia that is often accompanied by mood and emotional disturbances and seizures. There is growing body of evidence that neurons expressing γ-aminobutyric acid (GABA) play an important role in regulation of cognition, mood, and emotion as well as seizure susceptibility, but participation of GABAergic neuronal pathology in Alzheimer's disease (AD) is not understood well at present. Here, we report that transgenic mice expressing human amyloid precursor protein Swedish-Dutch-Iowa mutant (APP) exhibit early loss of neurons expressing GAD67, a GABA-synthesizing enzyme, in advance of the loss of pyramidal neurons in hippocampal CA1 region.

Regulation of STAT3 and NF-κB activations by S-nitrosylation in multiple myeloma.

Numerous reports suggest that aberrant activations of STAT3 and NF-κB promote survival and proliferation of multiple myeloma (MM) cells. In the present report, we demonstrate that a synthetic S-nitrosothiol compound, S-nitroso-N-acetylcysteine (SNAC), inhibits proliferation and survival of multiple MM cells via S-nitrosylation-dependent inhibition of STAT3 and NF-κB. In human MM cells (e.

Biochemical, cell biological, pathological, and therapeutic aspects of Krabbe's disease.

Krabbe's disease (KD; also called globoid cell leukodystrophy) is a genetic disorder involving demyelination of the central (CNS) and peripheral (PNS) nervous systems. The disease may be subdivided into three types, an infantile form, which is the most common and severe; a juvenile form; and a rare adult form. KD is an autosomal recessive disorder caused by a deficiency of galactocerebrosidase activity in lysosomes, leading to accumulation of galactoceramide and neurotoxic galactosylsphingosine (psychosine [PSY]) in macrophages (globoid cells) as well as neural cells, especially in oligodendrocytes and Schwann cells.

S-nitrosoglutathione reduces tau hyper-phosphorylation and provides neuroprotection in rat model of chronic cerebral hypoperfusion.

We have previously reported that treatment of rats subjected to permanent bilateral common carotid artery occlusion (pBCCAO), a model of chronic cerebral hypoperfusion (CCH), with S-nitrosoglutathione (GSNO), an endogenous nitric oxide carrier, improved cognitive functions and decreased amyloid-β accumulation in the brains. Since CCH has been implicated in tau hyperphosphorylation induced neurodegeneration, we investigated the role of GSNO in regulation of tau hyperphosphorylation in rat pBCCAO model. The rats subjected to pBCCAO had a significant increase in tau hyperphosphorylation with increased neuronal loss in hippocampal/cortical areas.

STAT3 Regulation By S-Nitrosylation: Implication In Cancer.

In this study, we assessed S-nitrosylation-based regulation of Janus-activated kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway. Our studies show that STAT3 in stimulated microglia underwent two distinct redox-dependent modifications, S-nitrosylation and S-glutathionylation. STAT3 S-nitrosylation was associated with inducible nitric oxide synthase (iNOS)-produced nitric oxide (NO) and S-nitrosoglutathione (GSNO), whereas S-glutathionylation of STAT3 was associated with cellular oxidative stress.

S-Nitrosoglutathione-mediated STAT3 regulation in efficacy of radiotherapy and cisplatin therapy in head and neck squamous cell carcinoma.

S-nitrosoglutathione (GSNO) is an endogenous nitric oxide (NO) carrier that plays a critical role in redox based NO signaling. Recent studies have reported that GSNO regulates the activities of STAT3 and NF-κB via S-nitrosylation dependent mechanisms. Since STAT3 and NF-κB are key transcription factors involved in tumor progression, chemoresistance, and metastasis of head and neck cancer, we investigated the effect of GSNO in cell culture and mouse xenograft models of head and neck squamous cell carcinoma (HNSCC).

Role of S-nitrosoglutathione mediated mechanisms in tau hyper-phosphorylation.

Hyperphosphorylation and polymerization of microtubule-associated protein tau into paired helical filaments (PHFs) is one of the hallmarks of Alzheimer's disease (AD). Here we report that neuronal tau hyperphosphorylation under AD conditions is regulated by S-nitrosoglutathione (GSNO), an endogenous nitric oxide carrier molecule. In cultured rat cortical primary neurons, we observed that GSNO treatment decreased the β-amyloid (Aβ₂₅₋₃₅)-induced pathological tau hyperphosphorylation (Ser396, Ser404, and Ser202/Thr205).

STAT3 regulation by S-nitrosylation: implication for inflammatory disease.

Aims: S-nitrosylation and S-glutathionylation, redox-based modifications of protein thiols, are recently emerging as important signaling mechanisms. In this study, we assessed S-nitrosylation-based regulation of Janus-activated kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway that plays critical roles in immune/inflammatory responses and tumorigenesis.

Results: Our studies show that STAT3 in stimulated microglia underwent two distinct redox-dependent modifications, S-nitrosylation and S-glutathionylation.

Role of endogenous psychosine accumulation in oligodendrocyte differentiation and survival: implication for Krabbe disease.

Krabbe disease is a lethal, demyelinating condition caused by genetic deficiency of galactocerebrosidase (GALC) and resultant accumulation of its cytotoxic substrate, psychosine (galactosylsphingosine), primarily in oligodendrocytes (OLs). Psychosine is generated by galactosylation of sphingosine by UDP-galactose:ceramide galactosyltransferase (CGT), a galactosylceramide synthesizing enzyme which is primarily expressed in OLs. The expression of CGT and the synthesis of galactosyl-sphingolipids are associated with the terminal differentiation of OL, but little is known about the participation of endogenous psychosine accumulation in OL differentiation under GALC deficient conditions.

Protective role of S-nitrosoglutathione (GSNO) against cognitive impairment in rat model of chronic cerebral hypoperfusion.

Chronic cerebral hypoperfusion (CCH), featuring in most of the Alzheimer's disease spectrum, plays a detrimental role in brain amyloid-β (Aβ) homeostasis, cerebrovascular morbidity, and cognitive decline; therefore, early management of cerebrovascular pathology is considered to be important for intervention in the impending cognitive decline. S-nitrosoglutathione (GSNO) is an endogenous nitric oxide carrier modulating endothelial function, inflammation, and neurotransmission. Therefore, the effect of GSNO treatment on CCH-associated neurocognitive pathologies was determined in vivo by using rats with permanent bilateral common carotid artery occlusion (BCCAO), a rat model of chronic cerebral hypoperfusion.

Involvement of AMP-activated-protein-kinase (AMPK) in neuronal amyloidogenesis.

AMP-activated-protein-kinase (AMPK) is a key sensor and regulator of cellular and whole-body energy metabolism and plays a key role in regulation of lipid metabolism. Since lipid metabolism has been implicated in neuronal amyloid-beta (Abeta) homeostasis and onset of Alzheimer's disease, we investigated the involvement of AMPK in neuronal lipid metabolism and Abeta production. We observed in cultured rat cortical neurons that Abeta production was significantly reduced when the neurons were stimulated with AMPK activator, 5-aminoimidazole-4-carboxamide-1-d-ribofuranoside (AICAR), but increased when AMPKalpha2 was knocked out, thus indicating the role of AMPK in amyloidogenesis.

Statin inhibits kainic acid-induced seizure and associated inflammation and hippocampal cell death.

Statins are inhibitors of HMG-CoA reductase that have been recently recognized as anti-inflammatory and neuroprotective drugs. Herein, we investigated anti-excitotoxic and anti-seizure effects of statins by using kainic acid (KA)-rat seizure model, an animal model for temporal lobe epilepsy and excitotoxic neurodegeneration. We observed that pre-treatment with Lipitor (atorvastatin) efficiently reduced KA-induced seizure activities, hippocampal neuron death, monocyte infiltration and proinflammatory gene expression.

Lovastatin inhibits amyloid precursor protein (APP) beta-cleavage through reduction of APP distribution in Lubrol WX extractable low density lipid rafts.

Previous studies have described that statins (inhibitors of cholesterol and isoprenoid biosynthesis) inhibit the output of amyloid-beta (Abeta) in the animal model and thus decrease risk of Alzheimer's disease. However, their action mechanism(s) in Abeta precursor protein (APP) processing and Abeta generation is not fully understood. In this study, we report that lovastatin treatment reduced Abeta output in cultured hippocampal neurons as a result of reduced APP levels and beta-secretase activities in low density Lubrol WX (non-ionic detergent) extractable lipid rafts (LDLR).

Lactosylceramide: a lipid second messenger in neuroinflammatory disease.

Inflammatory disease plays a critical role in the pathogenesis of many neurological disorders. Astrogliosis and induction of pro-inflammatory mediators such as chemokines, cytokines and inducible nitric oxide synthase (iNOS) are the 'hallmarks' of inflammatory disease. Increased activity of lactosylceramide (LacCer) synthase and increased synthesis of LacCer during glial proliferation, and induction of pro-inflammatory cytokines and iNOS suggests a role for LacCer in these cellular signaling pathways.

Sphingolipid signaling and redox regulation.

Sphingolipids including ceramide and its derivatives such as ceramide-1-phosphate, glycosyl-ceramide, and sphinogosine (-1-phosphate) are now recognized as novel intracellular signal mediators for regulation of inflammation, apoptosis, proliferation, and differentiation. One of the important and regulated steps in these events is the generation of these sphingolipids via hydrolysis of sphingomyelin through the action of sphingomyelinases (SMase). Several lines of evidence suggest that reactive oxygen species (ROS; O2-, H2O2, and OH-,) and reactive nitrogen species (RNS; NO, and ONOO-) and cellular redox potential, which is mainly regulated by cellular glutathione (GSH), are tightly linked to the regulation of SMase activation.

Adenosine kinase inhibitor attenuates the expression of inducible nitric oxide synthase in glial cells.

The present study demonstrates the anti-inflammatory effect of adenosine kinase inhibitor (ADKI) in glial cells. Treatment of glial cells with IC51, an ADKI, stimulated the extracellular adenosine release and reduced the LPS/IFNgamma-mediated production of NO, and induction of iNOS and TNF-alpha gene expression. The recovery of IC51-mediated inhibition of iNOS expression by adenosine transport inhibitor, S-(4-nitrobenzyl)-6-thioinosine (NBTI), and the inhibition of LPS/IFNgamma-induced iNOS gene expression by exogenous adenosine indicate a role for adenosine release in IC51-mediated iNOS expression.

Dual role of cAMP in iNOS expression in glial cells and macrophages is mediated by differential regulation of p38-MAPK/ATF-2 activation and iNOS stability.

We reported previously that cAMP analogues or cAMP synthesis activator (forskolin; FSK) inhibit lipopolysaccharide (LPS)-induced inducible nitric-oxide systase (iNOS) gene expression in astrocytes, while they enhance that in macrophages. Here, we report that the FSK-mediated inhibition of iNOS expression in C6 glial cells is due to its reduced transcriptional activity, while the FSK-mediated enhancement of iNOS expression in RAW264.7 macrophages is a result of increased stability of iNOS protein without transcriptional enhancement.

A novel role of lactosylceramide in the regulation of lipopolysaccharide/interferon-gamma-mediated inducible nitric oxide synthase gene expression: implications for neuroinflammatory diseases.

In the present study a possible role of glycosphingolipids (GSLs) in inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) production after spinal cord injury (SCI) in rats has been established. In primary rat astrocytes lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) treatment increased the intracellular levels of lactosylceramide (LacCer) and induced iNOS gene expression. d-Threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol.

The role of neutral sphingomyelinase produced ceramide in lipopolysaccharide-mediated expression of inducible nitric oxide synthase.

Lipopolysaccharide (LPS) and interferon-gamma (IFN) treatment of C6 rat glioma cells increased the intracellular ceramide level and the expression of the inducible nitric oxide synthase (iNOS) gene. To delineate the possible role of ceramide in the induction of iNOS, we examined the source of intracellular ceramide and associated signal transduction pathway(s) with the use of inhibitors of intracellular ceramide generation. The inhibitor of neutral sphingomyelinase (3-O-methylsphingomyelin, MSM) inhibited the induction of iNOS, whereas inhibitor of acidic sphingomyelinase (SR33557) or that of ceramide de novo synthesis (fumonisin B1) had no effect on the induction of iNOS.

The involvement of glucose metabolism in the regulation of inducible nitric oxide synthase gene expression in glial cells: possible role of glucose-6-phosphate dehydrogenase and CCAAT/enhancing binding protein.

In rat glial cells the lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) gene expression was enhanced by extracellular glucose concentration in a dose-dependent manner. On the other hand, 2-deoxy-d-glucose decreased the LPS-induced iNOS gene expression even in the presence of glucose (6 gm/l), suggesting that glucose metabolism is linked to the regulation of iNOS gene expression. The intracellular NADPH/NADP+ directly correlated with the extracellular glucose concentration, and the reduction of NADPH generation via a block of glucose-6-phosphate dehydrogenase (G6PD) by treatment with dehydroepiandrosterone or the antisense DNA oligomer of G6PD mRNA resulted in the inhibition of iNOS gene expression.

The regulation of inducible nitric oxide synthase gene expression induced by lipopolysaccharide and tumor necrosis factor-alpha in C6 cells: involvement of AP-1 and NFkappaB.

The roles of AP-1 and NFkappaB in the regulation of inducible nitric oxide synthase (iNOS) mRNA expression induced by the combination of lipopolysaccharide and tumor necrosis factor-alpha (LT) in C6 cells were examined in the present study. The iNOS mRNA level and NO release were increased by several cytokines alone or combination treatments at 24 hr. LT-induced iNOS mRNA level was maximally increased at 6 hr and maintained at higher level at least up to 24 hr.

Role of proto-oncogenes in the regulation of proenkephalin mRNA expression induced by repeated nicotine injections in rat adrenal medulla.

We have studied the effect of repeated systemic administrations of nicotine (3 mg/kg) at 30 min intervals on proenkephalin (proENK) mRNA level in rat adrenal gland. Northern blot analysis has shown that proENK mRNA expression was enhanced by repeated nicotine administrations. Additionally, repeated administrations of nicotine transiently induced the c-fos and c-jun mRNA levels after the first-third nicotine administration, and the c-fos and c-jun mRNA levels were returned to the basal level after the seventh administration of nicotine.