Polymorphisms of ECE1 May Contribute to Susceptibility to Ischemic Stroke in Han Chinese of Northern China

Endothelin (ET) converting enzyme 1 (ECE1) is well known for its critical role in the process of ET. Recent studies have demonstrated that two genetic variants of ECE1 gene, rs212528 and rs213045 (C338A), are associated with hypertension and atherosclerosis formation. To investigate the association between the ECE1 gene polymorphisms and ischemic stroke (IS) in Chinese population. With a candidate loci strategy, we conducted a case–control study involving 381 IS cases and 366 non-IS controls in Han population of the Northern China. Two single nucleotide polymorphisms of ECE1 were genotyped and assessed the association with the risk of IS. Furthermore, stratified analyses were also carried out to evaluate the association between the gender or two etiologic subtypes [small-artery occlusion (SAO) and large-artery atherosclerosis (LAA)] and IS. Compared with rs213045 G homozygote, rs213045 TG genotype and rs213045 TT/TG genotypes are in dominant model significantly increased the risk of IS [adjusted odds ratio (OR) = 1.47, 95 % confidence interval (CI) = 1.04–2.07, P = 0.03; adjusted OR = 1.43, 95 % CI = 1.04–1.99, P = 0.029, respectively]. However, we did not find the significant association between the ECE1 gene polymorphisms and SAO or LAA of IS in this study. Our results indicated that ECE1 gene polymorphisms may contribute to the susceptibility of IS in Han population of the Northern China.     

Association of AHSG Gene Polymorphisms with Ischemic Stroke in a Han Chinese Population

Previous studies have shown associations of fetuin-A (alpha₂-Heremans-Schmid glycoprotein, AHSG) with various disorders, including insulin resistance, type 2 diabetes mellitus, metabolic syndrome, and atherosclerosis. In this study, genotype and allele frequencies of the rs4918 SNP in the AHSG gene were examined in 380 patients with ischemic stroke and 350 healthy controls from a Northern Han Chinese population via the PCR-RFLP technique. Frequencies of the GG genotype and the G allele in AHSG (rs4918) were significantly higher in patients with ischemic stroke or atherosclerotic cerebral infarction than those in the control group (P < 0.05). Logistic regression analysis demonstrated the significance of rs4918 in these patients, after adjustment for confounding factors (P < 0.05). These findings suggest that rs4918 SNPs of the AHSG gene are associated with a risk for ischemic stroke in a Northern Han Chinese population.     

Two Novel Susceptibility SNPs for Ischemic Stroke Using Exome Sequencing in Chinese Han Population

Genome-wide association studies (GWAS) of ischemic stroke (IS) have been performed on several cohorts of Caucasian or African population and Japanese, resulting in somewhat inconsistent conclusion. We aimed to identify susceptibility loci for IS by exome sequencing in a Chinese Han population. Exome sequencing was used to screen susceptibility loci among 100 cases and 100 matched controls. Significant SNPs from the first stage were verified in up to 3,554 participants from three hospital-based case–control studies. In the initial exome sequencing analysis, rs10489177 in c1orf156 gene located on chromosome 1q24 (p?<?1?×?10^?8) and rs17118 in XYLB gene located on chromosome 3p21 (p?<?1?×?10^?6) were found to be significantly associated with IS. In the following validation stage, significantly increased odds ratios were observed in individuals with rs10489177 GG (OR?=?2.02, 95 % CI?=?1.35–3.03) or rs17118 AA genotype (OR?=?1.50, 95 % CI?=?1.17–1.91). The rs10489177 GG genotype was associated with significantly increased risk for IS in individuals without hypertension (OR?=?2.78, 95 % CI?=?1.59–4.86) and in individuals without diabetes (OR?=?1.93, 95 % CI?=?1.27–2.94). In contrast, the rs17118 AA genotype may significantly increase the risk for IS, particularly for individuals with hypertension (OR?=?1.73, 95 % CI?=?1.08–2.78) and for individuals without diabetes (OR?=?1.52, 95 % CI?=?1.17–1.98) or non-smoker (OR?=?1.59, 95 % CI?=?1.16–2.19). Collectively, our study identified two novel loci (rs17118 and rs10489177) which were associated with an increased risk for IS in Chinese Han populations. Further studies are needed to confirm these associations in other populations and elucidate the biological mechanisms underlying the observed associations.     

中国人诱导型一氧化氮合酶基因STR多态性研究

一氧化氮（nitric oxide,NO）作为一种可在细胞间自由扩散的信使分子在神经递质传递和血管舒张调节等生理与病理过程中起着重要作用。NO通过一氧化氮合酶（nitric oxide synthase,NOS）催化L-精氨酸的氧化反应而生成。目前在哺乳动物中已发现细胞来源、表达方式和活性调节不同的3种NOS同工酶,分别为神经原型NOS(meuronal NOS,nNOS）、诱导型NOS(inducible NOS,iNOS）和内皮细胞型NOS（endothelial NOS,eNOS）。3种NOS由位于不同染色体上的基因所编码。人iNOS基因位于第17号染色体长臂(17q11.2～17q12）,全长约37kb,含有26个外显子,iNOS可在多种类型的细胞中通过IL-1、IFN-a、INF-γ等细胞因子和其他介质的刺激作用而诱导表达。iNOS基因5‘-端调控区内存在一个CCTTT串联重复的多态性位点,这一多态性基因座已居北爱尔兰的糖尿病患者中证实与微血管病变有关。另有实验表明,CCTTT串联重复序列的变化对iNOS基因的转录将产生不同影响。目前在东方种族中有关iNOS基因CCTTT串联重复多态性尚未见报道。将303名中国汉族人基因组DNA用于iNOS基因CCTTT串联重复多态性分析,鉴定出了12种等位基因和49种基因型,其中重复17次、18次和19次的等位基因是在人类中首次发现的新等位基因。统计学检验和比较表明,中国汉族人iNOS基因CCTTT串联重复序列的6个等位基因频率与来自英格兰的高加索人差异显著,说明这一多态性位点的等位基因频率分布存在种族差异。在中国正常人群中获得的有关iNOS基因STR多态性的统计资料,对于进一步研究这一多态性基因座与心脑血管疾病的相关性将有重要应用价值。     

Decoding the Substrate Supply to Human Neuronal Nitric Oxide Synthase

Nitric oxide, produced by the neuronal nitric oxide synthase (nNOS) from L-arginine is an important second messenger molecule in the central nervous system: It influences the synthesis and release of neurotransmitters and plays an important role in long-term potentiation, long-term depression and neuroendocrine secretion. However, under certain pathological conditions such as Alzheimer’s or Parkinson’s disease, stroke and multiple sclerosis, excessive NO production can lead to tissue damage. It is thus desirable to control NO production in these situations. So far, little is known about the substrate supply to human nNOS as a determinant of its activity. Measuring bioactive NO via cGMP formation in reporter cells, we demonstrate here that nNOS in both, human A673 neuroepithelioma and TGW-nu-I neuroblastoma cells can be fast and efficiently nourished by extracellular arginine that enters the cells via membrane transporters (pool I that is freely exchangeable with the extracellular space). When this pool was depleted, NO synthesis was partially sustained by intracellular arginine sources not freely exchangeable with the extracellular space (pool II). Protein breakdown made up by far the largest part of pool II in both cell types. In contrast, citrulline to arginine conversion maintained NO synthesis only in TGW-nu-I neuroblastoma, but not A673 neuroepithelioma cells. Histidine mimicked the effect of protease inhibitors causing an almost complete nNOS inhibition in cells incubated additionally in lysine that depletes the exchangeable arginine pool. Our results identify new ways to modulate nNOS activity by modifying its substrate supply.     

Genetic Variants in C-Reactive Protein and Ischemic Stroke Susceptibility

Considerable discrepancies in the previously reported associations of the C-reactive protein (CRP) gene variants and ischemic stroke (IS) risk prompted us to perform this meta-analysis. We selected the fixed effects Mantel–Haenszel method to estimate the risk of IS [OR (odds ratio) along with its 95 % CI (confidence interval)] in relation to the CRP variants (?717 A > G, 1444 C > T). Heterogeneity test, influence analysis and publication bias test were appropriately performed using respective methods. We analyzed 1,926 IS patients and 2,678 controls and found the ?717 A > G variant was not significantly associated with overall IS risk. Subsequent analysis of the 1444 C > T variant involving 3,278 samples similarly revealed no significant association with IS. There was no substantial heterogeneity or publication bias in this analysis. Our meta-analysis may provide first evidence showing that genetic variants within the CRP locus are unlikely to modulate risk of IS.     

Genetic Variants in Nitric Oxide Synthase Genes and the Risk of Male Infertility in a Chinese Population: A Case-Control Study

Background

In recent years, oxidative stress has been studied extensively as a main contributing factor to male infertility. Nitric Oxide, a highly reactive free radical gas, is potentially detrimental to sperm function and sperm DNA integrity at high levels. Thus, the aim of this study was to investigate the associations between five polymorphisms in nitric oxide synthase genes (NOSs) and the risk of male infertility and sperm DNA damage as well.

Methods

Genotypes were determined by the OpenArray platform. Sperm DNA fragmentation was detected using the Tdt-mediated dUTP nick-end labeling assay, and the level of 8-hydroxydeoxyguanosine (8-OHdG) in sperm DNA was measured using immunofluorescence. The adjusted odds ratio (OR) and 95% confidence interval (CI) were estimated using unconditional logistic regression.

Results

Our results revealed a statistically significant difference between the cases and controls in both genotypic distribution (P<0.001) and allelic frequency (P = 0.021) only for the NOS3 rs1799983 SNP. Multivariate logistic regression analyses revealed that rs1799983 was associated with a borderline significantly increased risk of male infertility (GT vs. GG: adjusted OR = 1.30, 95% CI: 1.00–1.70; GT+TT vs. GG: adjusted OR = 1.34, 95% CI: 1.03–1.74; P _trend = 0.020). Moreover, NOS3 rs1799983 was positively associated with higher levels of sperm DNA fragmentation (β = 0.223, P = 0.044). However, the other 4 polymorphisms (NOS1 rs2682826, NOS1 rs1047735, NOS2 rs2297518, and NOS2 rs10459953) were not found to have any apparent relationships with male infertility risk.

Conclusions

Of five NOS gene polymorphisms investigated in the present study, we found NOS3 rs1799983 might cause oxidative sperm DNA damage, thereby contributing to male infertility.     

逆转录病毒载体介导诱导型NO合酶在神经细胞中表达

为了深入研究诱导型一氧化氮合酶基因表达产物在阿片耐受和依赖中作用,采用脂质体介导基因转染技术,将ｉＮＯＳ ｃＤＮＡ重组逆转录病毒载体导入ＮＧ１０８－１５神经细胞,获得Ｇ４１８抗性克隆,命名为ＮＧ－ＬＮＣＸｉＮＯＳ细胞。ＤＮＡ印迹杂交,ＰＣＲ扩增及ＲＴ－ＰＣＲ和蛋白质免疫印迹杂交分析,证实ＮＧ－ＬＮＣＸｉＮＯＳ细胞有外源ｉＮＯＳ基因整合,转录和表达;ＮＡＤＰＨ黄递酶（ＮＡＤＰＨ ｄｉａｐｈｏｒａｓｅ     

Down-Regulation of Neuronal Nitric Oxide Synthase by Nitric Oxide After Oxygen-Glucose Deprivation in Rat Forebrain Slices

Abstract : The precise role that nitric oxide (NO) plays in the mechanisms of ischemic brain damage remains to be established. The expression of the inducible isoform (iNOS) of NO synthase (NOS) has been demonstrated not only in blood and glial cells using in vivo models of brain ischemia-reperfusion but also in neurons in rat forebrain slices exposed to oxygen-glucose deprivation (OGD). We have used this experimental model to study the effect of OGD on the neuronal isoform of NOS (nNOS) and iNOS. In OGD-exposed rat forebrain slices, a decrease in the calcium-dependent NOS activity was found 180 min after the OGD period, which was parallel to the increase during this period in calcium-independent NOS activity. Both dexamethasone and cycloheximide, which completely inhibited the induction of the calcium-independent NOS activity, caused a 40-70% recovery in calcium-dependent NOS activity when compared with slices collected immediately after OGD. The NO scavenger oxyhemoglobin produced complete recovery of calcium-dependent NOS activity, suggesting that NO formed after OGD is responsible for this down-regulation. Consistently, exposure to the NO donor ( Z )-1-[(2-aminoethyl)- N -(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NONOate) for 180 min caused a decrease in the calcium-dependent NOS activity present in control rat forebrain slices. Furthermore, OGD and DETA-NONOate caused a decrease in level of both nNOS mRNA and protein. In summary, our results indicate that iNOS expression down-regulates nNOS activity in rat brain slices exposed to OGD. These studies suggest important and complex interactions between NOS isoforms, the elucidation of which may provide further insights into the physiological and pathophysiological events that occur during and after cerebral ischemia.     

CTLA4 Variants and Haplotype Contribute Genetic Susceptibility to Myasthenia Gravis in Northern Chinese Population

Background

Cytotoxic T lymphocyte-associated antigen-4 (CTLA4), a critical negative regulator of the T-cell response, has been considered a candidate for many autoimmune diseases. Evidence from Caucasians supported a genetic predisposition of CTLA4 to myasthenia gravis (MG), but the contribution in East Asians has not been established.

Objectives

To investigate the role of CTLA4 variants in the susceptibility to MG and the contribution to subtypes of MG.

Methods

Six autoimmune disease-related risk alleles of CTLA4 (rs1863800, rs733618, rs4553808, rs5742909, rs231775, and rs3087243) were investigated for MG in northern Chinese. 168 patients with MG (mean age 37.1±20.5 years, 64 men and 104 women) and 233 healthy controls (mean age 53.3±8.7 years, 96 men and 137 women) were screened, and the contribution of CTLA4 to the general risk of MG and each subgroup was explored.

Results

rs1863800*C, rs733618*C, and rs231775*G were significantly associated with the whole cohort of patients with MG after permutation correction for multiple-testing adjustment (P = 0.027, 0.001, and 0.032, respectively). A risk haplotype (CCACG) [odds ratio (OR) = 1.535, range = 1.150–2.059, P = 0.004)] was also identified. The stratified subtype analysis indicated that the positive contribution was possibly derived from early onset MG (EOMG), seropositive MG (SPMG), female patients, and MG without thymoma. No association was observed in juvenile MG/LOMG, and MG coupled with thymoma.

Conclusion

A predisposing effect of rs1863800*C, rs733618*C, and rs231775*G of CTLA4 gene to general risk of MG in Chinese was demonstrated for the first time, which was likely derived from EOMG, SPMG, MG without thymoma and the female patients.     

Plasma Total Nitric Oxide and Endothelial Constitutive Nitric Oxide Synthase (ecNOS) Gene Polymorphism: A Study in a South Indian Population

In an analysis of the possible association of endothelial constitutive nitric oxide synthase (ecNOS) gene polymorphism and plasma nitric oxide levels in patients with acute coronary syndrome, we investigated 106 patients with the syndrome and 100 healthy controls. Genotype was determined using the polymerase chain reaction; plasma nitric oxide levels were found using ELISA. The genotype frequencies for the a/b polymorphism in the control group were 77% for bb, 19% for ab, and 4% for aa. In the patients, genotype frequencies were 55% bb, 34% ab, and 11% aa. The allele frequencies were 28% a and 72% b among the patients and 13% a and 87% b among control subjects. Our findings showed a significant association of the ecNOS gene polymorphism with acute coronary syndrome in the South Indian population.     

Cyclosporin-A Inhibits Constitutive Nitric Oxide Synthase Activity and Neuronal and Endothelial Nitric Oxide Synthase Expressions after Spinal Cord Injury in Rats

Nitric oxide (NO) plays a role in the pathophysiology of spinal cord injury (SCI). NO is produced by three types of nitric oxide synthase (NOS) enzymes: The constitutive Ca²⁺/calmodulin-dependent neuronal NOS (nNOS) and endothelial NOS (eNOS) isoforms, and the inducible calcium-independent isoform (iNOS). During the early stages of SCI, nNOS and eNOS produce significant amounts of NO, therefore, the regulation of their activity and expression may participate in the damage after SCI. In the present study, we used Cyclosporin-A (CsA) to further substantiate the role of Ca-dependent NOS in neural responses associated to SCI. Female Wistar rats were subjected to SCI by contusion, and killed 4 h after lesion. Results showed an increase in the activity of constitutive NOS (cNOS) after lesion, inhibited by CsA (2.5 mg/kg i.p.). Western blot assays showed an increased expression of both nNOS and eNOS after trauma, also antagonized by CsA administration.     

A TagSNP in SIRT1 Gene Confers Susceptibility to Myocardial Infarction in a Chinese Han Population

SIRT1 exerts protective effects against endothelial cells dysfunction, inflammation and atherosclerosis, indicating an important role on myocardial infarction (MI) pathogenesis. Nonetheless, the effects of SIRT1 variants on MI risk remain poorly understood. Here we aimed to investigate the influence of SIRT1 polymorphisms on individual susceptibility to MI. Genotyping of three tagSNPs (rs7069102, rs3818292 and rs4746720) in SIRT1 gene was performed in a Chinese Han population, consisting of 287 MI cases and 654 control subjects. In a logistic regression analysis, we found that G allele of rs7069102 had increased MI risk with odds ratio (OR) of 1.57 [95% confidence interval (CI) = 1.15–2.16, Bonferroni corrected P (P_c) = 0.015] after adjustment for conventional risk factors compared to C allele. Similarly, the combined CG/GG genotypes was associated with the increased MI risk (OR = 1.64, 95% CI = 1.14–2.35, P_c = 0.021) compared to the CC genotype. Further stratified analysis revealed a more significant association with MI risk among younger subjects (≤ 55 years old). Consistent with these results, the haplotype rs7069102G-rs3818292A-rs4746720T containing the rs7069102 G allele was also associated with the increased MI risk (OR = 1.41, 95% CI = 1.09–1.84, P_c = 0.040). However, we did not detect any association of rs3818292 and rs4746720 with MI risk. Our study provides the first evidence that the tagSNP rs7069102 and haplotype rs7069102G-rs3818292A-rs4746720T in SIRT1 gene confer susceptibility to MI in the Chinese Han population.     

Striatal Malonate Lesions Are Attenuated in Neuronal Nitric Oxide Synthase Knockout Mice

Abstract: Intrastriatal administration of the reversible succinate dehydrogenase inhibitor malonate produces both energy depletion and striatal lesions by a secondary excitotoxic mechanism. To investigate the role of nitric oxide (NO^•) in the pathogenesis of the lesions we examined malonate toxicity in mice in which the genes for neuronal nitric oxide synthase (nNOS) or endothelial nitric oxide synthase (eNOS) were disrupted. Malonate striatal lesions were significantly attenuated in the nNOS mutant mice, and they were significantly increased in the eNOS mutant mice. Malonate-induced increases in levels of 2,3- and 2,5-dihydroxybenzoic acid/salicylate, markers of hydroxyl radical generation, were significantly attenuated in the nNOS knockout mice. Malonate-induced increases in 3-nitrotyrosine, a marker for peroxynitrite-mediated damage, were blocked in the nNOS mice, whereas a significant increase occurred in the eNOS mice. These findings show that NO^• produced by nNOS results in generation of peroxynitrite, which plays a role in malonate neurotoxicity.     

Muscular Dystrophy in mdx Mice Despite Lack of Neuronal Nitric Oxide Synthase

Abstract: Neuronal nitric oxide synthase (nNOS) is a component of the dystrophin complex in skeletal muscle. The absence of dystrophin protein in Duchenne muscular dystrophy and in mdx mouse causes a redistribution of nNOS from the plasma membrane to the cytosol in muscle cells. Aberrant nNOS activity in the cytosol can induce free radical oxidation, which is toxic to myofibers. To test the hypothesis that derangements in nNOS disposition mediate muscle damage in Duchenne dystrophy, we bred dystrophin-deficient mdx male mice and female mdx heterozygote mice that lack nNOS. We found that genetic deletion of nNOS does not itself cause detectable pathology and that removal of nNOS does not influence the extent of increased sarcolemmal permeability in dystrophin-deficient mice. Thus, histological analyses of nNOS-dystrophin double mutants show pathological changes similar to the dystrophin mutation alone. Taken together, nNOS defects alone do not produce muscular dystrophy in the mdx model.     

Endothelial NO Synthase Gene Polymorphisms and Risk of Ischemic Stroke in Asian Population: A Meta-Analysis

Background

The association between polymorphism 4b/a, T-786C and G894T in endothelial NO synthase gene (eNOS) and ischemic stroke (IS) remains controversial in Asian. A meta-analysis was performed to better clarify the association between eNOS gene and IS risk.

Methods

Based on the search of PubMed, Web of Science (ISI), CNKI (National Knowledge Infrastructure), Wan Fang Med Online and CBM (Chinese Biology Medical Literature Database) databases, all eligible case-control or cohort studies were identified. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) from fixed and random effect models were calculated. Heterogeneity among studies was evaluated using the I². Meta-regression was used to explore the potential sources of between-study heterogeneity. Begg''s test was used to estimate publication bias.

Results

Our study included 27 articles, contained 28 independent case–control studies, involved a total of 3,742 cases and 3,691 controls about 4b/a, 1,800 cases and 1,751 controls about T-786C and 2,747 cases and 2,872 controls about G894T. A significant association of 4a allele with increased risk of IS was found in dominant (FEM: OR = 1.498, 95% CI = 1.329–1.689), recessive (FEM: OR = 2.132, 95% CI = 1.383–3.286) and codominant (REM: OR = 1.456, 95% CI = 1.235–1.716) models. For T-786C and G894T, there were significant associations with dominant and codominant genetic models, but not with recessive genetic model.

Conclusions

The meta-analysis indicated that eNOS gene 4b/a, T-786C, G894T polymorphism might be associated with IS.     

Association Between Single-Nucleotide Polymorphism in CISH Gene and Susceptibility to Tuberculosis in Chinese Han Population

The cytokine-inducible SRC homology 2 domain (CISH) gene is up-regulated by IL-2 in response to infection, and inhibits microbial infection. The objective of the present study was to examine whether genetic variants of CISH (SNPs) are associated with increased susceptibility to tuberculosis (TB) in individuals of Chinese Han ethnicity. We sequenced five previously identified SNPs of CISH in patients with TB or healthy controls. Three of the SNPs, rs148685070 [position ?639; C/C], rs414171 [position ?292; A/T], and rs6768300 [position ?163; C/G]) are located in the promoter region, while the fourth (rs2239751 [position +1320; A/C]) near the translation start site, and the fifth (rs622502 [position +3415; C/G]) in the third intron. The AA genotypes of the SNPs rs2239751 and rs414171 were significantly associated with TB. Multivariate logistic regression analysis demonstrated that subjects with the rs414171 AA genotype were more likely to have TB than those with the AT genotype. By contrast, we did not observe genetic variants of the rs148685070 SNP. In conclusion, two genetic variants in CISH gene appear to increase susceptibility to TB in Chinese Han population.     

Anomalous Increase in Nitric Oxide Synthase Activity by Certain Nitric Oxide-Generating Compounds in Intact Neuronal Cells

Abstract: It has been shown that nitric oxide (NO) regulates NO synthase (NOS) activity through negative feedback in cytosolic enzyme preparations in various cell types. We compared the effects of the NO-generating compounds S-nitroso-N-acetylpenicillamine (SNAP), 3-morpholinosydnonimine (SIN-1), and sodium nitroprusside (SNP) on NOS activity in intact neuroblastoma N1E-115 cells and in the cytosol obtained from the same cells. Enzyme activity was measured by the conversion of l -[³H]arginine into l -[³H]citrulline. At concentrations that elicit almost complete inhibition of NOS activity in cytosolic enzyme preparations of these cells, SIN-1 and SNP did not cause significant attenuation of enzyme activity measured at 45 min in intact cells. It is surprising that SIN-1 and SNP markedly stimulated l -[³H]citrulline formation in a time- and concentration-dependent manner when cells were incubated with the compounds for >1.5 h. Neither inhibitory nor stimulatory effects of SNAP on NOS were observed in intact N1E-115 cells. This is in contrast to the inhibitory effects of SNAP in cytosolic preparations of the enzyme. The increased NOS activity by SIN-1 or SNP in intact cells was dependent on the presence of extracellular Ca²⁺, suggesting that it might be due to increased Ca²⁺ influx. On the other hand, measurements of the activity of lactate dehydrogenase showed that there was no generalized increase in cell permeability in response to SIN-1 or SNP. There was no agreement in the rank order of potencies of these compounds in activating guanylate cyclase and in affecting NOS activity, both in broken-cell preparations and in intact cells. Thus, modulation of NOS activity by NO-releasing compounds is not dependent on cyclic GMP formation and might not be related in a simple fashion to NO generation. Alternatively, activation of guanylate cyclase and stimulation of NOS activity might require different redox species of NO. Our present findings might be of clinical relevance in relation to long-term use of NO-generating compounds as therapeutic agents.     

Regulation of the Manganese Superoxide Dismutase and Inducible Nitric Oxide Synthase Gene in Rat Neuronal and Glial Cells

Abstract: Bidirectional communication occurs between neuroendocrine and immune systems through the action of various cytokines. Responses to various inflammatory mediators include increases in intracellular reactive oxygen species (ROS), notably, superoxide anion (O₂⁻) and nitric oxide (NO^•). Neurotoxicity mediated by NO^• may result from the reaction of NO^• with O₂, leading to formation of peroxynitrite (ONOO⁻). ROS are highly toxic, potentially contributing to extensive neuronal damage. We, therefore, evaluated the effects of a variety of inflammatory mediators on the regulation of mRNA levels for manganese superoxide dismutase (MnSOD) and inducible nitric oxide synthase (iNOS) in primary cultures of rat neuronal and glial cells. To determine age-dependent variation of mRNA expression, we used glial cells derived from newborn, 3-, 21-, and 95-day-old rat brains. Interleukin-1β, interferon-γ (IFN-γ), bacterial lipopolysaccharide (LPS), and tumor necrosis factor-α showed significant induction of MnSOD in both glial and neuronal cells. However, only LPS and IFN-γ increased iNOS mRNA. These data demonstrate that these two genes are similarly regulated in two cells of the nervous system, further suggesting that the oxidative state of a cell may dictate a neurotoxic or neuroprotective outcome.