Expression Inducible Nitric Oxide Synthase Research Articles

Paeonol regulates NLRP3 inflammasomes and pyroptosis to alleviate spinal cord injury of rat

BackgroundSpinal cord injury (SCI) is a life-threatening traumatic disorder. Paeonol has been confirmed to be involved in a variety of diseases. The purpose of this study is to investigate the role of paeonol on SCI progression.MethodsSprague Dawley (SD) rat was used for the establishment of SCI model to explore the anti-inflammation, anti-oxidation, and neuroprotective effects of paeonol (60 mg/kg) on SCI in vivo. For in vitro study, mouse primary microglial cells (BV-2) were induced by lipopolysaccharide (LPS)/adenosine triphosphate (ATP) treatment. The effect of paeonol on the polarization of LPS/ATP-induced BV-2 cells was determined by detection the expression inducible nitric oxide synthase (iNOS), tumour necrosis factor alpha (TNF-α), arginase-1 (Arg-1), and interleukin (IL)-10 using qRT-PCR. ELISA was used to assess the levels of IL-1β, IL-18, TNF-α, malondialdehyde (MDA), and glutathione (GSH). Western blotting was conducted to determine the levels of NLRP3 inflammasomes and TLR4/MyD88/NF-κB (p65) pathway proteins.ResultsPaeonol promoted the recovery of locomotion function and spinal cord structure, and decreased spinal cord water content in rats following SCI. Meanwhile, paeonol reduced the levels of apoptosis-associated speck-like protein (ASC), NLRP3, active caspase 1 and N-gasdermin D (N-GSDMD), repressed the contents of IL-1β, IL-18, TNF-α and MDA, and elevated GSH level. In vitro, paeonol exerted similarly inhibiting effects on pyroptosis and inflammation. Meanwhile, paeonol promoted BV-2 cells M2 polarization. In addition, paeonol also inactivated the expression of TLR4/MyD88/NF-κB (p65) pathway.ConclusionPaeonol may regulate NLRP3 inflammasomes and pyroptosis to alleviate SCI, pointing out the potential for treating SCI in clinic.

Inhibitory Effects of the Lactobacillus rhamnosus GG Effector Protein HM0539 on Inflammatory Response Through the TLR4/MyD88/NF-кB Axis.

Inflammatory bowel disease (IBD) is a chronic and relapsing intestinal inflammatory condition with no effective treatment. Probiotics have gained wide attention because of their outstanding advantages in intestinal health issues. In previous studies, a novel soluble protein, HM0539, which is derived from Lactobacillus rhamnosus GG (LGG), showed significant protective effects against murine colitis, but no clear precise mechanism for this effect was provided. In this study, we hypothesized that the protective function of HM0539 might be derived from its modulation of the TLR4/Myd88/NF-κB axis signaling pathway, which is a critical pathway widely involved in the modulation of inflammatory responses. To test this hypothesis, the underlying anti-inflammatory effects and associated mechanisms of HM0539 were determined both in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and in dextran sulfate sodium (DSS)-induced murine colitis. Our results showed that HM0539 inhibited the expression of cyclooxygenase-2 (COX-2) and the expression inducible nitric oxide synthase (iNOS) by down-regulating the activation of their respective promoter, and as a result this inhibited the production of prostaglandin E2 (PGE2) and nitric oxide (NO). Meanwhile, we demonstrated that HM0539 could ultimately modulate the activation of distal NF-κB by reducing the activation of TLR4 and suppressing the transduction of MyD88. However, even though the overexpression of TLR4 or MyD88 obviously reversed the effect of HM0539 on LPS-induced inflammation, HM0539 still retained some anti-inflammatory activity. Consistent with the in vitro findings, we found that HM0539 inhibited to a great extent the production of inflammatory mediators associated with the suppression of the TLR4/Myd88/NF-κB axis activation in colon tissue. In conclusion, HM0539 was shown to be a promising anti-inflammatory agent, at least in part through its down-regulation of the TLR4-MyD88 axis as well as of the downstream MyD88-dependent activated NF-κB signaling, and hence might be considered as a potential therapeutic option for IBD.

Monocytes from IgE- and IgE+ Adults with Allergies and Asthma Continue to Express Inducible Nitric Oxide Synthase (iNOS) after Frozen Storage

Monocytes from IgE- and IgE+ Adults with Allergies and Asthma Continue to Express Inducible Nitric Oxide Synthase (iNOS) after Frozen Storage

Bioactive triterpene glycosides from the fruit of Stauntonia hexaphylla and insights into the molecular mechanism of its inflammatory effects.

Chromatography of the ethanol extract of the medicinal fruit Stauntonia hexaphylla resulted in the purification of 26 compounds (1-26), including two undescribed triterpene saponins 1 and 2 (hexaphylosides A and B). Their structures were confirmed by spectroscopic data, including IR, HR QTOF MS, 1H, 13C NMR, COSY, HMQC, HMBC, and TOCSY, and HPLC sugar analysis after acid hydrolysis. The anti-inflammatory effects of the high-purity constituents (1-26) on lipopolysaccharide (LPS)-induced RAW264.7 macrophage cells were investigated by screening nitric oxide production. The NO inhibitory activity of compounds 6 and 10 with the IC50 values of 1.33 and 1.10 µM, respectively. The structure-activity relationships (SAR) of the isolated compounds were also analyzed. Furthermore, compounds 6 and 10 inhibited the protein expression inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 via Western blotting analysis. This showed that compounds 6 and 10 contributed to the anti-inflammatory effects of S. hexaphylla fruit, which could be developed as a natural nutraceutical and functional food ingredient.

Mycobacterium tuberculosis-Infected Hematopoietic Stem and Progenitor Cells Unable to Express Inducible Nitric Oxide Synthase Propagate Tuberculosis in Mice.

Persistence of Mycobacterium tuberculosis within human bone marrow stem cells has been identified as a potential bacterial niche during latent tuberculosis. Using a murine model of tuberculosis, we show here that bone marrow stem and progenitor cells containing M. tuberculosis propagated tuberculosis when transferred to naive mice, given that both transferred cells and recipient mice were unable to express inducible nitric oxide synthase, which mediates killing of intracellular bacteria via nitric oxide. Our findings suggest that bone marrow stem and progenitor cells containing M. tuberculosis propagate hallmarks of disease if nitric oxide-mediated killing of bacteria is defective.

Prim-O-glucosylcimifugin Attenuates Lipopolysaccharideinduced Inflammatory Response in RAW 264.7 Macrophages.

Background:Radix Saposhnikoviae (RS) exerts anti-inflammatory, analgesic, antipyretic, antioxidation effects and has been used in traditional Chinese medicine to treat common colds, headache, and rheumatoid arthritis. Prim-O-glucosylcimifugin (POG) is the highest content chromone and one of the major active constituents in RS.Objective:The study was aimed to explore the anti-inflammation effects of POG in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.Materials and Methods:Cell viability was detected by Cell Counting Kit-8 assay. Production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 was assessed by enzyme-linked immunosorbent assay. Real-time polymerase chain reaction and Western blot were performed to analyze mRNA and protein levels, respectively.Results:During the whole experiment, 15, 50, and 100 μg/mL of POG had no cytotoxicity on RAW 264.7 cells. POG dose-dependently inhibited the production of NO, TNF-α, IL-1β, and IL-6 that were induced by LPS. POG treatment downregulated the mRNA and protein expression inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2) in LPS-activated RAW 264.7 macrophages in a concentration-dependent manner. Furthermore, LPS-induced JAK2/STAT3 activation was prevented in RAW 264.7 macrophages by POG treatment. STAT3 overexpression significantly reversed the effects of POG on LPS-activated RAW 264.7 macrophages.Conclusion:These results demonstrate that POG exerts anti-inflammatory effects through the inhibition of iNOS and COX-2 expression by inhibiting the phosphorylation of JAK2/STAT3.SUMMARY POG exerts anti-inflammatory effects in RAW 264.7 macrophages through the inhibition of iNOS and COX-2 expression by inhibiting JAK2/STAT3 signaling. Abbreviations used: LPS: Lipopolyssacharide; NO: Nitric oxide; TNF-α: Tumor necrosis factor-α; IL: Interleukin; RS: Radix Saposhnikoviae; POG: Prim-O-glucosylcimifugin; iNOS: Inducible NO synthase; COX2: Cyclooxygenase; FBS: Fetal bovine serum; DMSO: Dimethylsulfoxide; CCK-8: Cell Counting Kit; RIPA: Radio immunoprecipitation assay buffer; ECL: Enhanced chemiluminescence; SD: Standard deviation; ELISA: Enzyme-Linked immunosorbent assay.

Mo1201 Pancreatic Stellate Cells Express Inducible Nitric Oxide Synthase

BACKGROUND: IPMN is a precursor lesion to pancreatic ductal adenocarcinoma consisting of 4 epithelial subtypes with varying grades of dysplasia. Intestinal type (IPMN-I) often involves the main duct and has a higher risk of developing invasive carcinoma in comparison to gastric type (IPMN-G). Differentiation of high-risk/malignant IPMN from low-risk IPMN and other benign/low-grade cystic pancreatic lesions remains a challenge, especially in the preoperative setting. mAb Das-1 reacts specifically to a colonic epithelial phenotype. It is both sensitive and specific in identifying various pre-malignant and malignant lesions of the upper GI tract including Barrett's esophagus and incomplete gastrointestinal metaplasia associated with gastric cancer. We have previously demonstrated that it specifically detects high risk IPMN tissue histologically. AIM: To assess the ability of mAb Das-1 to identify cyst fluid of IPMN with a high risk of malignant transformation. METHODS: Cyst fluid was aspirated during surgical resection of IPMN (n=10), serous cystadenoma (n=1), and cystic low-grade neuroendocrine tumor (n=1). Cyst fluid was also aspirated during EUS-FNA of pancreatic pseudocysts (n=4). Sandwich ELISA was performed on each sample (utilizing mAb Das-1 IgM & IgG isotypes) and results were confirmed by Western Blot analysis. Statistical significance was calculated by T-test. RESULTS: Pancreatic cyst fluid from all benign/low-grade lesions (n=8) demonstrated very little reactivity with mAb Das-1 (OD 0.137±0.181). Specifically, reactivity was low among cyst fluid collected from low-grade IPMN-G (OD 0.088±0.003, n=2), pseudocyst (n=4) (OD 0.088±0.041), and non-pseudocyst, benign/low-grade lesions (n=4) (OD 0.187±0.251). In comparison, high-risk and malignant IPMN lesions (intermediate-grade IPMN-I & all high-grade/invasive IPMNs n=8) expressed a significantly higher amount of reactivity (OD 0.866±0.151) when compared to low-grade IPMN-G (p<0.001), pseudocyst (p<0.001), and all benign/low-grade lesions (p<0.002). When stratified by subtype, low-grade IPMN-G (n=2, OD 0.088±0.003), IPMN-G with highgrade dysplasia or invasive carcinoma (n=2, OD 0.402±0.313), intermediate-grade IPMN-I (n=2, OD 0.6339±0.100), IPMN-I with high-grade dysplasia or invasive carcinoma (n=3, OD 1.232±0.265) and high-grade Oncocytic IPMN (OD 1.161), demonstrated a progressive increase in reactivity to mAb Das-1 among each subtype. All results obtained by ELISA were confirmed by western blot analysis. CONCLUSION: mAb Das-1 demonstrates significantly higher reactivity in cyst fluid from high-risk and malignant IPMN compared to fluid from low-grade IPMN-G, pancreatic pseudocyts, and other low-grade pancreatic cystic lesions. The expression of this marker in preoperative cyst fluid may be a useful tool to identify high-risk IPMN lesions and stratify surgical management.

Trypanosoma carassii hsp70 increases expression of inflammatory cytokines and chemokines in macrophages of the goldfish ( Carassius auratus L.)

We report on the cloning and characterization of Trypanosoma carassii 70 KDa heat shock protein (hsp70). T. carassii hsp70 was secreted/excreted into culture medium in vitro and was recognized by sera from infected fish. Recombinant hsp70 (rhsp70) activated goldfish macrophages and stimulated the production of pro-inflammatory cytokines including interferon gamma (IFNγ), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, (IL)-12 and chemokines CCL-1 and CXCL-8 (IL-8). T. carassii hsp70-induced cytokine expression was abrogated by pronase treatment of macrophages confirming the existence of receptor(s) on goldfish macrophage surface that recognize parasite molecule. Parasite hsp70 also up-regulated the expression inducible nitric oxide synthase (iNOS) isoforms A and B and induced a strong nitric oxide response of goldfish macrophages.

Thymic Dendritic Cells Express Inducible Nitric Oxide Synthase and Generate Nitric Oxide in Response to Self- and Alloantigens

Thymocytes maturing in the thymus undergo clonal deletion/apoptosis when they encounter self- or allo-Ags presented by dendritic cells (DCs). How this occurs is a matter of debate, but NO may play a role given its ability of inducing apoptosis of these cells. APC (a mixed population of macrophages (Mphi) and DCs) from rat thymus expressed high levels of inducible NO synthase (iNOS) and produced large amounts of NO in basal conditions whereas iNOS expression and NO production were very low in thymocytes. Analysis by FACS and by double labeling of cytocentrifuged preparations showed that DCs and MPhi both express iNOS within APC. Analysis of a purified preparation of DCs confirmed that these cells express high levels of iNOS and produce large amounts of NO in basal conditions. The capacity of DCs to generate NO was enhanced by exposure to rat albumin, a self-protein, and required a fully expressed process of Ag internalization, processing, and presentation. Peptides derived from portions of class II MHC molecules up-regulate iNOS expression and NO production by DCs as well, both in self and allogeneic combinations, suggesting a role of NO in both self and acquired tolerance. We also found that NO induced apoptosis of rat double-positive thymocytes, the effect being more evident in anti-CD3-stimulated cells. Altogether, the present findings might suggest that DC-derived NO is at least one of the soluble factors regulating events, in the thymus, that follow recognition of self- and allo-Ags.

Children with Celiac Disease Express Inducible Nitric Oxide Synthase in the Small Intestine during Gluten Challenge

Background: Childhood celiac disease in Sweden is presently seen at an incidence of around 1/250 and is thus one of the commonest chronic diseases in children. It has recently been shown that children with untreated celiac disease have increased levels of nitrate/nitrite in the urine, most likely reflecting an increased production of nitric oxide in the inflamed mucosa. Nitric oxide is produced from L-arginine by an inducible or a constitutive nitric oxide synthase. The inducible nitric oxide synthase (iNOS) can be stimulated in various cells by, for instance, inflammatory mediators. The present study has been done to find a possible source of nitric oxide in the small intestine that could result in the increased levels of nitrate/nitrite in the urine in children with active celiac disease. Methods: Small-intestinal biopsy specimens from children with active celiac disease were labeled with rabbit-anti-human antibodies to iNOS and visualized with fluorescent pig anti-rabbit antibodies. The specimens were then analyzed with confocal microscopy to assess the labeling pattern. Results: In all of seven specimens from children with increased levels of nitrate/nitrite in the urine, we detected antibodies to iNOS, whereas in five of six control specimens-that is, from children with normal nitrate/nitrite levels-we could not detect any iNOS. Conclusions: Children with active celiac disease have a gluten-induced nitric oxide production in the small intestine reflected by increased urine levels of nitrate/nitrite and iNOS expression in the intestine. We conclude that the increased production of nitric oxide could presumably, directly or indirectly, result in injury of the small-intestinal tissue.

Dedifferentiated human ventricular cardiac myocytes express inducible nitric oxide synthase mRNA but not protein in response to IL-1, TNF, IFNgamma, and LPS.

There is evidence that nitric oxide (NO) may mediate some of the functional myocardial changes caused by bacterial LPS and inflammatory cytokines. The expression of the inflammatory or inducible NO synthase (iNOS) in human cardiac myocytes, however, has not been well characterized. Therefore, we treated cultured, dedifferentiated human ventricular cardiac myocytes with the combination of TNF-alpha (500 U/ml), IL-1beta (30U/ml), IFNgamma (100 U/ml), and LPS (E.coli 0111:B4, 10 microg/ml). Northern blot analysis revealed a approximately 4.5 kb transcript for inducible NOS (iNOS) in the stimulated human heart cells but not in untreated cells. RT-PCR confirmed that iNOS mRNA was only present in stimulated cells. However, treatment of the myocytes for up to 96 h with cytokines and LPS did not result in NO synthesis as measured by nitrite + nitrate accumulation in the culture medium, and no iNOS enzymatic activity could be detected in the cell lysates. Western blot analysis failed to detect iNOS protein. Thus, despite high and persistent levels of iNOS mRNA in cytokine-treated cells, iNOS protein was absent in this experimental model. GTP-cyclohydrolase I was induced both at the mRNA and protein levels and resulted in increased biopterin levels, indicating sufficient amounts of the cofactor tetrahydrobiopterin (BH4) were present, and that the failure to express an inducible protein was specific to iNOS. To determine if the absence of iNOS protein was due to a novel cardiac iNOS gene or modified iNOS transcript in human myocytes, we cloned an iNOS cDNA from cytokine-treated myocytes. Sequencing and expression of the clone revealed a functional iNOS cDNA with >99% identity to other human iNOS cDNA clones. When human cardiac cells were transduced with a retroviral vector carrying only the coding region of the human hepatocyte iNOS cDNA, both iNOS mRNA and protein could be detected. In conclusion, these cells derived from cultured human cardiac myocytes lacked the capacity to express an endogenous iNOS protein, the basis of which appears to be a cell-specific suppression or failure of iNOS translation.