Requirement for endogenous heat shock factor 1 in inducible nitric oxide synthase induction in murine microglia

Aim Inducible nitric oxide synthase （iNOS） makes a great contribution to host defense and inflamma-tion. In many settings, lipopolysaccharide （LPS） induces iNOS expression through activation of the inhibitor of KB- α （IKB-α） -nuclear factor-KB （NF-KB） cascade, whereas interferon-γ （IFN-γ） acts through Janus kinase （ JAK）- signal transducer and activator of transcription 1 （ STAT1 ） signals. Heat shock factor 1 （ HSF1 ）, a major regulator of heat shock protein transcription, has been shown to regulate the production of pro-inflammatory cytokines such as tumor necrosis factor-α（TNF-α） and interleukin-6 （IL-6）. But it remains obscure whether and how HSF1 affects iNOS induction. Methods Western blot was used to measure the protein expression. The mRNA level was meas- ured by real time-PCR. Silence of HSF1 was achieved by small interfering RNA. Nitric oxide （NO） content and NF-KB binding activity were assayed by commercial kits. Chromatin immunoprecipitation （CHIP） was used to measure the binding activity of NF-KB and STAT1 to iNOS promoters. Results HSF1 inhibition or knockdown pre- vented the LPS- and/or IFN-γ-stimulated iNOS protein expression in cultured microglia. HSF1 inhibition blocked iNOS mRNA transcription. These inhibitory effects of HSF1 inhibition on iNOS expression were confirmed in brain tissues from endotoxemic mice. Further analysis showed that HSF1 inhibition had no effect on IKB-α degradation and NF-KB or STAT1 phosphorylation in LPS/IFN-γ-stimulated cells. The nuclear transport of active NF-KB or STAT1 was also not affected by HSF1 inhibition. But HSF1 inhibition reduced the binding of NF-KB and STAT1 to their DNA elements. In addition, HSF1 inhibition reduced NF-KB and STAT1 bindings to iNOS promoter inside the LPS/IFN-γ-stimulated cells. Conclusions This preventing effect of HSF1 inhibition on iNOS mRNA transcription presents the necessary role of HSF1 in iNOS induction.

Biliverdin Reductase-A correlates with inducible nitric oxide synthasein in atorvastatin treated aged canine brain

Alzheimer’s disease is a neurodegenerative disorder characterized by progressive cognitive impairment and neuropathology. Recent preclinical and epidemiological studies proposed statins as a possible therapeutic drug for Alzheimer’s disease, but the exact mechanisms of action are still unknown. Biliverdin reductase-A is a pleiotropic enzyme involved in cellular stress responses. It not only transforms biliverdin-IX alpha into the antioxidant bilirubin-IX alpha but its serine/threonine/ tyrosine kinase activity is able to modulate cell signaling networks. We previously reported the beneficial effects of atorvastatin treatment on biliverdin reductase-A and heme oxygenase-1 in the brains of a well characterized pre-clinical model of Alzheimer’s disease, aged beagles, together with observed improvement in cognition. Here we extend our knowledge of the effects of atorvastatin on inducible nitric oxide synthase in parietal cortex, cerebellum and liver of the same animals. We demonstrated that atorvastatin treatment （80 mg/day for 14.5 months） to aged beagles selectively increased inducible nitric oxide synthase in the parietal cortex but not in the cerebellum. In contrast, inducible nitric oxide synthase protein levels were significantly decreased in the liver. Significant positive correlations were found between biliverdin reductase-A and inducible nitric oxide synthase as well as heme oxygenase-1 protein levels in the parietal cortex. The opposite was observed in the liver. Inducible nitric oxide synthase up-regulation in the parietal cortex was positively associated with improved biliverdin reductase-A functions, whereas the oxidative-induced impairment of biliverdin reductase-A in the liver negatively affected inducible nitric oxide synthase expression, thus suggesting a role for biliverdin reductase-A in atorvastatin-dependent inducible nitric oxide synthase changes. Interestingly, increased inducible nitric oxide synthase levels in the parietal cortex were not associated with higher oxidative/nitrosative stress levels. We hypothesize that biliverdin reductase-A-dependent inducible nitric oxide synthase regulation strongly contributes to the cognitive improvement observed following atorvastatin treatment.

Prednisolone inhibits SaOS2 osteosarcoma cell proliferation by activating inducible nitric oxide synthase

AIM:To investigate the effect of prednisolone,a synthetic glucocorticoid used in inflammatory diseases,on the growth of cultured osteosarcoma cells.METHODS:Two osteosarcoma cell lines with different degree of differentiation were used.SaOS2 show a rather mature phenotype,while U2 OS are negative for almost all osteoblastic markers.The cells were exposed to different concentrations of prednisolone(1-9 μmol/L) with or without antioxidants or the inhibitor of inducible nitric oxide synthase(i NOS) l-N6-(iminoethyl)-lysine-HCl(L-NIL).Cell growth was assessed by counting viable cells.The production of nitric oxide(NO) was measured in the conditioned media by the Griess method.The production of reactive oxygen species was quantified using 2'-7'-dichlorofluorescein diacetate.Western blot with specific antibodies against NOSs was performed on cell extracts.RESULTS:Prednisolone inhibited SaOS2 cell growth in a dose dependent manner.No significant effects were observed in U2OS.The inhibition of SaOS2 growth is not due to oxidative stress,because antioxidants do not rescue cell proliferation.Since high concentrations of NO inhibit bone formation,we also measured NO and found it induced in SaOS2,but not in U2 OS,exposed to prednisolone,because of the upregulation of i NOS as detected by western blot.Therefore,we treated SaOS2 with prednisolone in the presence or in the absence of L-NIL.L-NIL prevented NO release induced by prednisolone at all the concentrations apart from 9 μmol/L.At the same concentrations,we found that L-NIL rescued SaOS2 growth after exposure to prednisolone.In U2 OS cells,prednisolone did not induce NO production nor affected cell growth.All together,these data indicate that a link exists between increased amounts of NO and growth inhibition in response to prednisolone in SaOS2.CONCLUSION:Prednisolone inhibited SaOS2 proliferation by increasing the release of NO through the upregulation of i NOS,while no effect was exerted on U2OS.

Nerve growth factor and inducible nitric oxide synthase expression in the mesencephalon and diencephalon, as well as visual-and auditory-related nervous tissues, in a macaque model of type 2 diabetes

The present study detected distribution and expression of nerve growth factor and inducible nitric oxide synthase in the mesencephalon and diencephalon, as well as visual- and auditory-related nervous tissues, in a macaque model of type 2 diabetes using immunohistochemistry. Results showed that nerve growth factor expression decreased, but inducible nitric oxide synthase expression increased, in the mesencephalon and diencephalon, as well as visual- and auditory- related nervous tissues. These results suggested that nerve growth factor and inducible nitric oxide synthase play an important role in regulating the development of diabetic visual- and auditory-related diseases.

Inflammatory cytokines promote inducible nitric oxide synthase-mediated DNA damage in hamster gallbladder epithelial cells

AIM: To investigate the link between chronic biliary inflammation and carcinogenesis using hamster gallbladder epithelial cells. METHODS: Gallbladder epithelial cells were isolated from hamsters and cultured with a mixture of inflammatory cytokines including interleukin-1β,interferon-γ,and tumor necrosis factor-α. Inducible nitric oxide synthase (iNOS) expression,nitric oxide (NO) generation,and DNA damage were evaluated. RESULTS: NO generation was increased significantly following cytokine stimulation,and suppressed by an iNOS inhibitor. iNOS mRNA expression was demonstrated in the gallbladder epithelial cells during exposure to inflammatory cytokines. Furthermore,NO-dependent DNA damage,estimated by the comet assay,was significantly increased by cytokines,and decreased to control levels by an iNOS inhibitor. CONCLUSION: Cytokine stimulation induced iNOS expression and NO generation in normal hamster gallbladder epithelial cells,which was sufficient to cause DNA damage. These results indicate that NO-mediated genotoxicity induced by inflammatory cytokines through activation of iNOS may be involved in the process of biliary carcinogenesis in response to chronic inflammation of the biliary tree.

Ginkgo biloba leaf extract effects on inducible nitric oxide synthase, Bcl-2, and Bax expression in rat models of spinal cord injury

BACKGROUND：Ginkgo biloba leaf extract exhibits neuroprotective effects in spinal cord injury. However, the mechanisms of action remain unclear. OBJECTIVE： To investigate inducible nitric oxide synthase （iNOS） and Bcl-2/Bax expression in the injured spinal cord, and to explore the neuroprotective mechanisms of ginkgo biloba leaf extract in rats with spinal cord injury. DESIGN, TIME AND SETTING： The randomized, controlled, cell molecular biology experiment was performed at Soochow University, China from March 2007 to March 2008. MATERIALS： A total of 120 healthy, adult Sprague Dawley rats were selected for this study. Rat models of moderate acute thoracic （T9） spinal cord injury were established using the modified Allen method. Shuxuening injection was obtained from Zhenbaodao Pharmaceutical Co., Ltd., China. Methylprednisolone was purchased from North China Pharmaceutical Co., Ltd. METHODS： All rats were equally and randomly divided into four groups. Only the spinal cord was exposed in the sham operation group rats. In the trauma group, rats were not treated with drugs following spinal cord injury. Rats in the hormone group were intraperitoneally injected with 30 mg/kg methylprednisolone following spinal cord injury. Rats in the ginkgo biloba leaf extract group were intraperitoneally infused with a 1.0 mL/kg Shuxuening injection per day. MAIN OUTCOME MEASURES： At 1 hour, as well as 1, 3, 5, 7, and 14 days after spinal cord injury, iNOS- and Bcl-2/Bax-positive cells were quantified with immunohistochemistry. Pathological changes were detected using hematoxylineosin staining under an optical microscope. RESULTS： Spinal cord injury in the ginkgo biloba leaf extract and hormone groups was milder compared with the trauma group. Demyelination was significantly ameliorated and the necrotic cavity was obviously reduced in the injured spinal cord of rats in the ginkgo biloba leaf extract and hormone groups at each time point. iNOS expression was increased in the injured spinal cord, and reached a peak at 5 days. The number of iNOS-positive cells was lower in the ginkgo biloba leaf extract and hormone groups compared with the trauma group （P 〈 0.05-0.01）. The number of iNOS-positive cells was lower in the ginkgo biloba leaf extract group compared with the hormone group at 7 and 14 days after spinal cord injury （P 〈 0.05）. Bcl-2 expression reached a peak at 3 days, and Bax expression reached a peak at 5 days following rat spinal cord injury. Bcl-2 expression was increased, but Bax expression was decreased in the ginkgo biloba leaf extract and hormone groups compared with the trauma group （P 〈 0.05-0.01）. Bcl-2 expression was greater, but Bax expression was reduced in the ginkgo biloba leaf extract group compared with the hormone group at 7 and 14 days after spinal cord injury （P 〈 0.05）. CONCLUSION： Ginkgo biloba leaf extract exhibits neuroprotective effects by upregulating Bcl-2 expression, downregulating Bax expression, and significantly inhibiting high expressions of iNOS in the injured spinal cord. The neuroprotective effects of ginkgo biloba leaf extract are greater compared with methylprednisolone at 1 week after spinal cord injury.

Production of reactive oxygen species and expression of inducible nitric oxide synthase in rat isolated Kupffer cells stimulated by Leptospira interrogans and Borrelia burgdorfen

AIM： To evaluate the production of reactive oxygen species （ROS） and the expression of inducible nitric oxide synthase （iNOS） in rat isolated Kupffer cells （KCs） stimulated by Leptospira interrogans and Borrelia burgdorferi. METHODS： Rat Kupffer cells were separated by perfusion of the liver with 0.05% collagenase, and purified by Percoll gradients. Pudfied Kupffer cells were tested in vitro with alive L.interogans and B. burgdorferi preparations. The production of ROS was determined by chemiluminescence, whereas iNOS protein expression was evaluated by Western blot assay using anti-iNOS antibodies. RESULTS： B. burgdorferi and to a less extent L. interrogans induced ROS production with a peak 35 min after infection. The chemiluminescence signal progressively diminished and was undetectable by 180 min of incubation. Leptospirae and borreliae induced an increased iNOS expression in Kupffer cells that peaked at 6 hours and was still evident 22 h after infection. CONCLUSION： Both genera of spirochetes induced ROS and iNOS production in rat Kupffer cells. Since the cause of liver damage both in leptospiral as well as in borrelial infections are still unknown, we suggest that leptospira and borrelia damage of the liver can be initially mediated by oxygen radicals, and is then maintained at least in part by nitric oxide.

Spatio-temporal expression of inducible nitric oxide synthase in and surrounding a region of rat frontal lobe damaged with a sharp instrument

BACKGROUND： Inducible nitric oxide synthase （iNOS） cannot be detected in the neurons and glial cells of normal rats, but iNOS can be found in some neurons and glial cells of rats following ischemic, traumatic, neurotoxic or inflammatory damage. OBJECTIVE： To investigate iNOS expression and iNOS-positive cell types at various time points following damage to the rat frontal lobe using a sharp instrument. DESIGN： A nerve molecular biology, randomized, controlled study. TIME AND SETTING： This experiment was performed at the Department of Human Anatomy, Institute of Neurobiology, Medical School of Nantong University, between April 2006 and December 2007. MATERIALS： Rabbit anti-iNOS antibody （Santa Cruz, USA）, biotin labeled goat anti-rabbit antibody （Sigma, USA）, reverse transcription kit （Biouniquer, Hong Kong, China） and horseradish peroxidase labeled goat anti-rabbit antibody （Pierce, USA） were used for this study. METHODS： A total of 112 healthy rats aged 3 months were randomly assigned into a sham operation group （n = 28） and a damage group （n = 84）. Rat models of frontal lobe damage were induced in the damage group using a sharp instrument to make an incision in the frontal lobe cortex. In the sham operation group, the rat bone window was opened but brain tissues were left intact. MAIN OUTCOME MEASURES： Parameters were measured at 3, 6, 12, 24, 72, 120 and 168 hours following damage in both groups. Pathological changes were observed using Nissl staining and hematoxylin-eosin staining. Expression of iNOS mRNA, iNOS protein and iNOS-positive cells were examined by RT-PCR, Western blot analysis and immunohistochemistry, respectively. RESULTS： A large number of inflammatory cells infiltrated the damaged region 12 and 24 hours following damage, iNOS mRNA and iNOS protein expression increased in and around the damaged region 3 hours following damage, reached a peak at 24 hours, and then gradually decreased. The changes in iNOS-positive cell number reflected the changes in iNOS mRNA and iNOS protein expression after damage, iNOS was mainly found in neural cells at 3 and 6 hours, in macrophages at 12 and 24 hours, and in glial cells at 72 and 120 hours after damage. iNOS-positive cells were few in and surrounding the damaged region at 168 hours. There were a few iNOS-positive neural cells in the rat frontal lobe cortex in the sham operation group. CONCLUSION： Neurons, macrophages and glial cells can express iNOS following rat frontal lobe damage caused by a sharp instrument. The levels of iNOS expression, and the cell types expressing iNOS, change with time.

Spatiotemporal expression of inducible nitric oxide synthase and cyclooxygenase 2 in the spinal cord during early stage sciatic nerve crush injury

BACKGROUND： Previous studies have shown that inducible nitric oxide synthase （iNOS） and cyclooxygenase 2 （COX-2） participate in inflammatory immune responses and neuropathic pain following peripheral nerve injury. However, few reports have addressed time-dependent expression of iNOS and COX-2 following peripheral nerve injury. OBJECTIVE： To investigate spatiotemporal expression of iNOS and COX-2 during early stage sciatic nerve crush injury.DESIGN, TIME AND SETTING： The randomized, controlled, animal experiment was performed at the Laboratory of Applied Anatomy, Department of Human Anatomy and Neurobiology, Central South University, China from September 2006 to September 2007.MATERIALS： Mouse anti-rat iNOS monoclonal antibody and goat anti-rat COX-2 monoclonal antibody （Transduction Laboratory, USA）, as well as biotinylated rabbit anti-mouse lgG and biotinylated rabbit anti-goat IgG （Santa Cruz Biotechnology, USA） were used in the present study.METHODS： A total of 48 healthy, adult, Sprague Dawley rats were randomly assigned to three groups. In the model group （n = 32）, crush injury to the right sciatic nerve was established using an artery clamp. The model group was further assigned to four subgroups according to survival time （6,12, 24, and 72 hours）, respectively （n = 8）. Sham surgery （n = 8） and normal control （n = 8） groups were also established.MAIN OUTCOME MEASURES： iNOS and COX-2 expression was detected in the L4-6 spinal cord with immunohistochemistry. Gray values of iNOS- and COX-2-postive cells in the anterior horn and posterior horn of spinal cord, as well as quantification of iNOS- and COX-2-positive cells in the anterior horn of spinal cord, were measured.RESULTS： iNOS and COX-2 expression gradually increased in the anterior horn and posterior horn of the spinal cord on the damaged side over time from 6 hours following sciatic nerve injury （P〈0.05） and peaked at 72 hours. Simultaneously, the number of iNOS- and COX-2-positive cells similarly increased in the anterior horn of spinal cord on the damaged side （P〈 0.05）.CONCLUSION： iNOS and COX-2 expression increased in the spinal cord during early stage sciatic nerve crush, which suggested that iNOS and COX-2 participate in occurrence and development of inflammatory immune responses following peripheral nerve injury.

Role of neuronal nitric oxide synthase and inducible nitric oxide synthase in intestinal injury in neonatal rats

AIM： TO investigate the dynamic change and role of neuronal nitric oxide synthase （nNOS） and inducible nitric oxide synthase （iNOS） in neonatal rat with intestinal injury and to define whether necrotizing enterocolitis （NEC） is associated with the levels of nitric oxide synthase （NOS） in the mucosa of the affected intestine tissue. METHODS： Wistar rats less than 24 h in age received an intraperitoneal injection with 5 mg/kg lipopolysaccharide （LPS）. Ileum tissues were collected at 1, 3, 6, 12 and 24 h following LPS challenge for histological evaluation of NEC and for measurements of nNOS and iNOS. The correlation between the degree of intestinal injury and levels of NOS was determined. RESULTS： The LPS-injected increase in injury scores pups showed a significant versus the control. The expression of nNOS protein and mRNA was diminished after LPS injection. There was a negative significant correlation between the nNOS protein and the grade of median intestinal injury within 24 h. The expression of iNOS protein and mRNA was significantly increased in the peak of intestinal injury. CONCLUSION： nNOS and iNOS play different roles in LPS-induced intestinal injury. Caution should be exerted concerning potential therapeutic uses of NOS inhibitors in NEC.

Lanthanum Chloride Inhibiting Expression of Inducible Nitric Oxide Synthase in RAW264.7 Macrophages Induced by Lipopolysaccharide

Nitric oxide（NO）and its reaction products were key players in the pathophysiology of sepsis and shock.The present study was designed to explore the effects of lanthanum chloride（LaCl3）on inducible nitric oxide synthase（iNOS）expression,at both gene and protein levels,in RAW264.7 macrophages induced by Lipopolysaccharide（LPS）.Reverse transcription polymerase chain reaction（RT-PCR）,immunofluorescence,and western blot were employed to measure iNOS gene expression,localization,and protein expression respectively.NO production in culture supernatants was detected by the nitrate reductase method.The results showed that LaCl3 significantly attenuated the iNOS gene and protein expression,as well as NO production in RAW264.7cells induced by LPS.

Nitric oxide production and inducible nitric oxide synthase protein expression in human abdominal aortic aneurysms and cultured aneurismal smooth muscle cells

Objective：To investigate the production of nitric oxide（NO） and the expression of inducible nitric oxide synthase （iNOS）, and their possible role in abdominal aortic aneurysm （AAA）. Methods： A total of 28 patients with AAA, 10 healthy controls, and 8 patients with arterial occlusive disease were enrolled into this study. Standard colorimetric assay was used to examine NO concentration in plasma from patients with AAA and normal controls, and in cultured smooth muscle cells （SMCs）. Expression of iNOS in aortas and cultured SMCs were detected by immunochemistry. The correlation of iNOS expression with age of the patient, size of aneurysm, and degree of inflammation was also investigated by Cochran-Mantel-Haenszel χ^2 test and Kendall correlation. Results ： Expression of iNOS increased significantly in the wall of aneurism in the patients with AAA compared to the healthy controls （P〈0.05） and the patients with occlusive arteries （P〈0.05）. iNOS protein and media NOx （nitrite＋nitrate） also increased in cultured SMCs from human AAA （n=4, P〈0.05）, while plasma NOx decreased in patients with AAA （n= 25） compared to the healthy controls （n=20）. There was a positive correlation between iNOS protein and the degree of inflammation in aneurismal wall （Kendall coefficient = 0. 5032, P= 0. 0029）. Conclusion： SMCs and inflammatory cells are main cellular sources of increased iNOS in AAA, and NO may play a part in pathogenesis in AAA through inflammation, SMCs and oxidative stress.

Expressions of inducible nitric oxide synthase and matrix metalloproteinase-9 and their effects on angiogenesis and progression of hepatocellular carcinoma

AIM： To determine the expressions of inducible nitric oxide synthase （iNOS） and matrix metalloproteinase-9 （MMP-9） in hepatocellular carcinoma （HCC） and to investigate the relationship between iNOS and MMP-9 expression and their effects on angiogenesis and progression of HCC.METHODS： In this study, we examined iNOS, MMP-9, and CD34 expression in specimens surgically removed from 32 HCC patients and 7 normal liver tissues by immunohistochemical staining. Meanwhile, microvessel density （MVD） was determined as a marker of angiogenesis by counting CD34-positive cells. RESULTS： The positive rates of iNOS and MMP-9 expression were 71.88% （23/32） and 78.13% （25/32） in HCC. MMP-9 expression was significantly correlated with tumor size, capsule status, TNM stage, and risk of HCC recurrence （P = 0.032, P= 0.033, P= 0.007, and P= 0.001, respectively）. There was also a significant relationship between iNOS expression and capsule status and risk of HCC recurrence （P = 0.049 and P = 0.004, respectively）, but no correlation between iNOS expression and tumor size and TNM stage. There was a positive association between MVD and TNM stage and risk of HCC recurrence （P = 0.037 and P = 0.000, respectively）. The count of MVD was significantly different in different iNOS and MMP-9 immunoreactivity groups （F= 17.713 and 17.097, P= 0.000 and P = 0.000, respectively）. The examination of Spearman＇s rank correlation coefficient showed that there was a significant positive correlation between MVD and iNOS, MMP-9 immunoreactivity （r = 0.754 and 0.751, P= 0.000 and P=-0.000, respectively）. There was also a significant association between MMP-9 and iNOS expression in HCC （P = 0.010）. CONCLUSION： Nitric oxide （NO） produced by iNOS could modulate MMP-9 production and therefore contribute totumor cell angiogenesis and invasion and metastasis in HCC. The strong expression of iNOS and MMP-9 in HCC may be helpful in evaluating the recurrence of HCC, predicting poor prognosis. For patients with strong expression of MMP-9 and iNOS, the optimal treatment scheme needs to be selected.

Expression and activity of inducible nitric oxide synthase and endothelial nitric oxide synthase correlate with ethanolinduced liver injury

AIM： To study the expression and activity of inducible nitric oxide synthase （iNOS） and endothelial nitric oxide synthase （eNOS） in rats with ethanol-induced liver injury and their relation with liver damage, activation of nuclear factor-KB （NF-κB） and tumor necrosis factor-α （TNF-α） expression in the liver. METHODS： Female Sprague-Dawley rats were given fish oil （0.5 mL） along with ethanol or isocaloric dextrose daily via gastrogavage for 4 or 6 wk. Liver injury was assessed using serum alanine aminotransferase （ALT） activity and pathological analysis. Liver malondialdehyde （MDA）, nitric oxide contents, iNOS and eNOS activity were determined. NF-κB p65, iNOS, eNOS and TNF-α protein or mRNA expression in the liver were detected by immunohistochemistry or reverse transcriptase-polymerase chain reaction （RT-PCR）. RESULTS： Chronic ethanol gavage for 4 wk caused steatosis, inflammation and necrosis in the liver, and elevated serum ALT activity. Prolonged ethanol administration （6 wk） enhanced the liver damage. These responses were accompanied with increased lipid peroxidation, NO contents, iNOS activity and reduced eNOS activity. NF-κB p65, iNOS and TNF-α protein or mRNA expression were markedly induced after chronic ethanol gavage, whereas eNOS mRNA expression remained unchanged. The enhanced iNOS activity and expression were positively correlated with the liver damage, especially the necro-inflammation, activation of NF-KB, and TNF-α mRNA expression. CONCLUSION： iNOS expression and activity are induced in the liver after chronic ethanol exposure in rats, which are correlated with the liver damage, especially the necro-inflammation, activation of NF-KB and TNF-α expression, eNOS activity is reduced, but its mRNA expression is not affected.

Inducible nitric oxide synthase polymorphism is associated with the increased risk of differentiated gastric cancer in a Japanese population

AIM： To examine the association of inducible nitric oxide synthase （iNOS） C150T polymorphism with gastric cancer, as well as with gastric atrophy and H pylori seropositivity.METHODS： A single nucleotide polymorphism of iNOS CtSOT was examined for 454 Japanese health checkup examinees （126 males and 328 females） aged 35 to 85 years without a history of cancer and 202 gastric cancer patients （134 males and 68 females） aged 33 to 94 years with pathologically confirmed diagnosis of gastric adenocarcinoma.RESULTS： The iNOS C150T polymorphism was not associated with gastric atrophy or with H pylori seropositivity. The odds ratio （OR） of the C/T ＋T/T for gastric cancer was increased without statistical significance （OR=1.19, 95% confidence interval （CI）： 0.68-2.08）. In the differentiated subgroup （n = 113）, however, the OR of the C/T genotvpe for gastric cancer was significant （OR = 2.02, 95% CI： 1.04-3.92） relative to the C/C genotype. In addition, considering the location of gastric cancer （n = 105）, there were significant differences between the controls and non-cardia group with the ORof 2.13 （95% CI： 1.08-4.18） for C/T and 1.94 （95% CI： 1.00-3.78） for C/T ＋ T/T.CONCLUSION： The iNOS C150T polymorphism is associated with the risk of H pylori-related gastric cancer in a Japanese population. This polymorphism may play an important role in increasing the risk of gastric cancer in Asian countires with the highest rates of gastric cancer.

Temporal expression of hepatic inducible nitric oxide synthase in liver cirrhosis

AIM: Nitric oxide (NO) has been implicated in the pathogenesis of liver cirrhosis. We have found inducible nitric oxide synthase (iNOS) can be induced in hepatocytes of cirrhotic liver. This study further investigated the temporal expression and activity of hepatic iNOS in cirrhosis development. METHODS: Cirrhosis was induced in rats by chronic bile duet ligatjon (BDL). At different time points after the operation, samples were collected to examine NO concentration, liver function, and morphological changes. Hepatocytes were isolated for determination of iNOS mRNA, protein and enzymatic activity. RESULTS: Histological examination showed early cirrhosis 1-2 wk after BDL, with advanced cirrhosis at 3-4 wk. Bilirubin increased dramatically 3 d after BDL, but decreased by 47% on d 14. Three weeks after BDL, it elevated again. Systemic NO concentration did not increase significantly until 4 wk after BDL, when ascites developed. Hepatocyte iNOS mRNA expression was identified 3 d after BDL, and enhanced with time to 3 wk, but reduced thereafter. iNOS protein showed a similar pattern to mRNA expression. iNOS activity decreased from d 3 to d 7, but increased again thereafter till d 21. CONCLUSION: Hepatic iNOS can be induced in the early stage, which increases with time as cirrhosis develops. lts enzymatic activity is significantly correlated with protein expression and histological alterations of the liver, but not with systemic NO levels, nor with absolute values of liver function markers.

EFFECT OF TNF-a AND IFN-g ON THE EXPRESSION OF INDUCIBLE NITRIC OXIDE SYNTHASE GENE AND PROLIFERATION INHIBITION OF HUMAN COLON CANCER CELL LINE

Objective: To study the expression of the inducible nitric oxide synthase (iNOS) gene and the effects of tumor necrosis factor-α(TNF-a) and interferon-γ(IFN-g)on proliferation of the continuous cultured human colon cancer cell line CCL229. Methods: Using the molecular and biochemical techniques and electron microscopy to analyze the expression of iNOS, production of NO and growth characteristics of human colon cancer cells. Results: cytokine treatment can induce expression of the iNOS gene and production of nitric oxide was significantly higher after treatment of CCL229 cells with TNF-αor IFN-γ. Treatment with either cytokine or a combination of both significantly increased levels of Malondialdehyde (MDA) over control. Furthermore, cytokine treatment increased the proliferation inhibition rate as assessed in vitro and decreased the cell proliferation index on flow cytometry. Electron microscopy showed that cells treated with cytokines had fewer pseudopodia or cell processes than control cells and that cytokine treated cells had dilatation of the mitochondria and endoplasmic reticulum and dilated vesicular or tubular cisternae. Conclusion: Our findings indicate that TNF-α and IFN-γ induce the expression of iNOS gene in CCL229 cells, which increases the production of nitric oxide, inhibits proliferation, causes lipid peroxidation, and results in ultrastructural changes.

Clinical Significance of a Myeloperoxidase Gene Polymorphism and Inducible Nitric Oxide Synthase Expression in Cirrhotic Patients with Hepatopulmonary Syndrome

The clinical significance of a myeloperoxidase (MPO) gene polymorphism and inducible nitric oxide synthase (iNOS) expression in cirrhotic patients with hepatopulmonary syndrome (HPS) was explored. Enrolled subjects were divided into three groups according to their disease/health conditions: the HPS group (cirrhotic patients with HPS; n=63), the non-HPS group (cirrhotic patients without HPS; n=182), and the control group (healthy subjects without liver disease; n=35). The distribution of the MPO–463 G/A genotype and its relationship with iNOS expression in a typical cell block from ascitic fluid were detected by immunohistochemistry and polymerase chain reaction-restricted fragment length polymorphism analysis (PCR-RFLP). In the HPS group, the partial pressure of oxygen in blood and ascitic fluid was significantly decreased (8.95±1.58 kPa and 6.81±0.95 kPa, respectively; both P<0.01), while the partial pressure of carbon dioxide significantly increased (4.62±0.20 kPa and 5.92±0.45 kPa, respectively; P<0.01). MPO and iNOS levels were significantly increased in the HPS group as compared with the non-HPS group. These increases were even more remarkable in ascitic fluid (41.36±11.62 and 13.23±4.81 μg/L; 10.27± 3.20 and 4.95±1.12 μg/L) than in blood (16.66±5.24 and 4.87±1.73 μg/L; 5.79±2.31 and 2.35±0.84 μg/L). The distribution of the MPO genotypes GG, GA, and AA were 76.2%, 22.2% and 1.6% in the HPS group, and 57.7%, 37.9% and 4.4% in the non-HPS group (P<0.05). The expression of iNOS was significantly higher in patients with the G alleles (G/G and G/A) (61.54%, 48/78) than in patients with A alleles (G/A and A/A) (38.46%, 30/78) (P<0.01). It was suggested that the expression levels of iNOS and MPO were correlated with HPS-induced hypoxemia. The MPO-463 G/A mutation might be a protective factor that prevents the development of HPS. The MPO might be involved in the regulation of iNOS expression. In humans, MPO pathways, the iNOS/NO system, and their interaction might have an impact on the occurrence and development of HPS.

氟骨症患者血清一氧化氮含量和外周血白细胞诱导型一氧化氮合酶mRNA表达的意义

目的 探讨氟骨症患者患者外周血白细胞诱导型一氧化氮合酶(induciblenitricoxidesynthaseiNOS)mRNA表达的意义。方法 选择3 5例氟骨症患者患者及3 0例正常人的外周血白细胞。iNOS -mRNA表达采用原位杂交方法。血浆一氧化氮(nitricoxideNO)水平采用硝酸还原酶比色法测定。结果 正常人外周血白细胞未见iNOS -mRNA表达,而氟骨症患者外周血白细胞iNOS -mRNA表达高度增强,其阳性率达40 .82 %。AR组血清NO水平显著高于对照组(t =2 7.89,P <0 .0 1)。结论 氟骨症患者病人血清NO水平与外周血白细胞iNOS -mRNA表达高度增强有关。提示iNOS-NO通路在氟骨症的发病过程中可能起重要作用。本研究为检测体内某些信号提供了简便易行的原位杂交试验方法。

Association of inducible nitric oxide synthetase genotype and Helicobacter pylori infection gastric cancer risk may be due to faulty primer design

Rafiei et al recently described an association between the presence of the C150T polymorphism of the induc-ible nitric oxide synthase(iNOS)gene and Helicobacter pylori(H.pylori)induced gastric cancer.When we used primer-BLAST to find the polymerase chain reaction (PCR)product that would be generated by the primers used by these authors no products against any of the sequences present in the GenBank database were found.Further analysis of the iNOS sequences present in the GenBank suggest that the result from their study might come from a faulty primer design and may thus represent an artifact.Alternatively they may be correct and have identified a truly interesting explanation for the mechanism whereby H.pylori induces gastric cancer but some additional experiments would be in order to exclude the possibility of a PCR artifact.