Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P43026 (lipopolysaccharide)
62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

D-Galactosamine (GalN) depletes UTP primarily in liver, resulting in decreased RNA synthesis in hepatocytes. When given together with a sublethal dose of lipopolysaccharide (LPS), GalN highly sensitizes animals to produce apoptotic liver injury with severe hepatic congestion, resulting in rapid death. Melatonin is a cytokine modulator, antioxidant and anti-apoptotic agent. In the present study, we investigated the effect of melatonin on LPS-induced apoptotic liver damage in GalN-sensitized mice. Female CD-1 mice were intraperitoneally (i.p.) injected with melatonin (5.0mg/kg) 30min before GalN/LPS (700mg10microg/kg, i.p.), another two doses of melatonin (2.5mg/kg, i.p.) being administered 1 and 2h after GalN/LPS. Results showed that serum alanine aminotransferase (ALT) activities were markedly increased 8h after GalN/LPS treatment, massive hemorrhage being observed in histological sections of liver from GalN/LPS-treated mice. Melatonin significantly attenuated GalN/LPS-induced elevation of serum ALT. In parallel, melatonin distinctly improved GalN/LPS-induced congestion. Additional experiment showed that melatonin significantly attenuated GalN/LPS-induced hepatic apoptosis, measured by inhibition of caspase-3 activities and attenuation of DNA laddering. Furthermore, melatonin markedly increased hepatic Se-dependent glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rd) activities and attenuated hepatic glutathione (GSH) depletion in GalN/LPS-treated mice. Increases in serum tumor necrosis factor alpha (TNF-alpha), which were observed in GalN/LPS-treated mice, were significantly reduced by melatonin. However, melatonin had no effect on LPS-evoked nitric oxide production in GalN-sensitized mice. Taken together, these results indicate that melatonin protected against LPS-induced liver damage in GalN-sensitized mice through its strong ROS-scavenging, antiinflammatory and antiapoptotic effects.
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PMID:Melatonin attenuates lipopolysaccharide (LPS)-induced apoptotic liver damage in D-galactosamine-sensitized mice. 1760 19

Hibiscus cannabinus L. (Malvaceae) (known as Kenaf) has long been used as a folk medicine in India and Africa for the treatment of blood and throat disorders, bilious conditions, fever and puerperium. In this study, therefore, we aimed either to demonstrate its ethnopharmacological activity by examining its macrophage function-regulating effects or to expand its therapeutic efficacy into other macrophage-mediated diseases. The total crude extract (EtOH extract) of Hibiscus cannabinus fresh leaves, prepared with 80% ethanol, significantly suppressed TNF-alpha production and the mRNA expression of interleukin (IL)-3 and IL-12 in the RAW264.7 cells, stimulated by lipopolysaccharide (LPS, 2.5 microg/ml). The secretion of inflammatory mediators (i.e., nitric oxide [NO], reactive oxygen species [ROS] and prostaglandin E(2) [PGE(2)]) was diminished by the EtOH extract. The extract induced the expression of heme oxygenase-1 (HO-1) mRNA, a potent cytoprotective molecule. The Kenaf extract suppressed both the phagocytic uptake and the expression of costimulatory molecules (CD80 and CD86) of LPS-activated RAW264.7 cells. It is interesting that Kenaf also down-regulated both the functional activation of beta1-integrin (CD29) and the LPS-induced up-regulation of the surface CD29 level. Taken together, these data suggest that Kenaf may be able to modulate macrophage-mediated responses and that some of the activities may contribute to expand its therapeutic usage.
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PMID:Immunomodulatory effect of Hibiscus cannabinus extract on macrophage functions. 1760 25

Sepsis is characterized by an inappropriate host immune-inflammatory response and sustained oxidative damage. Nrf2, a bZIP oxidant-responsive transcription factor, regulates a battery of cytoprotective genes including antioxidants and maintains cellular redox homeostasis. Mouse studies have demonstrated a critical role of Nrf2 in improving survival during sepsis. This preclinical ex vivo study using neutrophils and peripheral blood mononuclear cells (PBMCs) as a surrogate cells evaluates the efficacy of CDDO-Im and CDDO-Me [imidazole and methyl ester derivative of 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO)] to activate the Nrf2 pathway and protect from lipopolysaccharide (LPS)-induced inflammatory response in humans. CDDO-Im treatment significantly induced Nrf2-dependent antioxidative genes (HO-1, GCLC, GCLM, and NQO1) in PBMCs isolated from six normal subjects. CDDO-Im increased nuclear accumulation of Nrf2 protein. Pretreatment of PBMC by CDDO-Im significantly attenuated LPS-induced cytokine expression. Similar increases in levels of antioxidant genes and suppression of LPS-induced cytokine expression was observed after CDDO-Me pretreatment. CDDO-Im also greatly inhibited LPS, fMLP, TNF-alpha, and TPA-induced ROS generation in neutrophils. In conclusion, these results demonstrate that activation of the Nrf2-dependent antioxidative pathway by CDDO-Im or CDDO-Me protects against the LPS-induced inflammatory response and suggest that they can be potential therapeutic candidates for intervening sepsis syndrome.
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PMID:Preclinical evaluation of targeting the Nrf2 pathway by triterpenoids (CDDO-Im and CDDO-Me) for protection from LPS-induced inflammatory response and reactive oxygen species in human peripheral blood mononuclear cells and neutrophils. 1782 64

The mushroom Phellinus linteus has been known to exhibit potent biological activity. In contrast to the immuno-potentiating properties of Phellinus linteus, the anti-inflammatory properties of Phellinus linteus have rarely been investigated. Recently, ethanol extract and n-BuOH fractions from Phellinus linteus were deemed most effective in anti-inflammatory activity in RAW 264.7 macrophages. The regulatory mechanisms of Phellinus linteus butanol fractions (PLBF) on the pharmacological and biochemical actions of macrophages involved in inflammation have not been clearly defined yet. In the present study, we tested the role of PLBF on anti-inflammation patterns in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. To investigate the mechanism by which PLBF inhibits NO and PGE2 production as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, we examined the activation of IkappaB and MAPKs in LPS-activated macrophages. PLBF clearly inhibited nuclear translocation of NF-kappaB p65 subunits, which correlated with PLBF's inhibitory effects on IkappaBalpha phosphorylation and degradation. PLBF also suppressed the activation of mitogen-activated protein (MAP) kinases including p38 and stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK). Furthermore, macrophages stimulated with LPS generated ROS via activation of membrane-bound NADPH oxidase, and ROS played an important role in the activation of nuclear factor-kappaB (NF-kappaB) and MAPKs. We demonstrated that PLBF directly blocked intracellular accumulation of reactive oxygen species in RAW 264.7 cells stimulated with LPS much as the NADPH oxidase inhibitors, diphenylene iodonium, and antioxidant pyrrolidine dithiocarbamate did. The suppression of NADPH oxidase also inhibited NO production and iNOS protein expression. Cumulatively, these results suggest that PLBF inhibits the production of NO and PGE2 through the down-regulation of iNOS and COX-2 gene expression via ROS-based NF-kappaB and MAPKs activation. Thus, PLBF may provide a potential therapeutic approach for inflammation-associated disorders.
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PMID:Phellinus linteus inhibits inflammatory mediators by suppressing redox-based NF-kappaB and MAPKs activation in lipopolysaccharide-induced RAW 264.7 macrophage. 1793 30

Many herbal medicines and dietary supplements sold as aids to improve memory or treat neurodegenerative diseases or have other favorable effects on the CNS contain a catechol or similar 1,2-dihydroxy aromatic moiety in their structure. As an approach to isolate and examine the neuroprotective properties of catechols, a simple catechol 4-t-Butylcatechol (TBC) has been used as a model. In this study, we investigated the effects of TBC on lipopolysaccharide (LPS)-activated microglial-induced neurotoxicity by using the in vitro model of coculture murine microglial-like cell line HAPI with the neuronal-like human neuroblastoma cell line SH-SY5Y. We also examined the effects of TBC on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in human dopaminergic neuroblastoma SH-SY5Y cells. TBC at concentrations from 0.1-10 microM had no toxic effect on HAPI cells and SH-SY5Y cells, and it inhibited LPS (100 ng/ml)-induced increases of superoxide, intracellular ROS, gp91(Phox), iNOS and a decrease of HO-1 in HAPI cells. Under coculture condition, TBC significantly reduced LPS-activated microglia-induced dopaminergic SH-SY5Y cells death. Moreover, TBC (0.1-10 microM) inhibited 6-OHDA-induced increases of intracellular ROS, iNOS, nNOS, and a decrease of mitochondria membrane potential, and cell death in SH-SY5Y cells. However, the neurotoxic effects of TBC (100 microM) on SH-SY5Y cells were also observed including the decrease in mitochondria membrane potential and the increase in COX-2 expression and cell death. TBC-induced SH-SY5Y cell death was attenuated by pretreatment with NS-398, a selective COX-2 inhibitor. In conclusion, this study suggests that TBC might possess protective effects on inflammation- and oxidative stress-related neurodegenerative disorders. However, the high concentration of TBC might be toxic, at least in part, for increasing COX-2 expression.
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PMID:Neuronal effects of 4-t-Butylcatechol: a model for catechol-containing antioxidants. 1819 Sep 40

A prominent feature of various inflamed and diseased tissue is the presence of low oxygen tension (hypoxia). Effector cells of the innate immune system must maintain their viability and physiologic functions in a hypoxic microenvironment. Monocytes circulating in the bloodstream differentiate into macrophages. During this process, cells acquire the ability to exert effects at hypoxic sites of inflammation. The transcription factor hypoxia-inducible factor 1 (HIF-1) mediates adaptive responses to reduced oxygen availability. In this study, we demonstrated that lipopolysaccharide (LPS) induces HIF-1 activation by enhancing both HIF-1alpha protein expression through a translation-dependent pathway and HIF-1alpha transcriptional activity in THP-1 human myeloid cells that have undergone macrophage differentiation but not in undifferentiated monocytic THP-1 cells. LPS-induced HIF-1 activation was blocked by treatment with antioxidant (N-acetylcysteine or thioredoxin-1), NADPH oxidase inhibitor (diphenyleneiodonium), indicating that reactive oxygen species generated in response to LPS are essential in this process. LPS-mediated activation of HIF-1 was independent of NF-kappaB activity. LPS-induced ROS generation and HIF-1 activation required the expression of Toll-like receptor 4 or myeloid differentiation factor (MyD) 88, thus providing a molecular basis for the selective activation of HIF-1 in differentiated THP-1 cells.
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PMID:LPS induces hypoxia-inducible factor 1 activation in macrophage-differentiated cells in a reactive oxygen species-dependent manner. 1819 3

Hypoxia Inducible Factor-1 (HIF-1) is activated by a variety of stimuli, including inflammatory mediators. In this report we investigated the role that bacterial lipopolysaccharide (LPS) and hypoxia play in the regulation of HIF-1-dependent gene expression in macrophages. We report that murine macrophages stimulated with low concentrations of LPS (1-10 ng/ml) expressed significantly higher levels of inducible nitric oxide synthase (iNOS) mRNA when cultured under hypoxic compared to normoxic conditions. Functional studies of the iNOS promoter demonstrated that the synergistic interaction between LPS and hypoxia was mediated, at least in part, by the NFkappaB and the HIF-1 binding sites. In addition, transient transfection experiments using a Hypoxia Response Element (HRE)-containing plasmid showed that LPS and hypoxia synergistically induced HIF-1-dependent transcriptional activity. Interestingly, LPS did not significantly affect HIF-1alpha protein levels or HIF-1 DNA binding activity relative to hypoxic induction. HIF-1alpha, but not HIF-2alpha, was critical for the synergistic induction of HRE-dependent transcriptional activity in macrophages, as indicated by experiments using siRNA targeting HIF-1alpha or HIF-2alpha. Addition of ROS-scavengers completely abrogated the synergistic induction of HIF-1 transcriptional activity by LPS and hypoxia, but neither inhibited HIF-1 transcriptional activity induced by hypoxia alone nor affected HIF-1alpha protein levels or HIF-1 DNA binding induced by hypoxia alone or hypoxia plus LPS. Taken together, our results demonstrate that LPS and hypoxia act synergistically to induce HIF-1alpha-transcriptional activity and they emphasize the existence of a cross talk between hypoxic and non-hypoxic signaling pathways in the regulation of macrophages gene expression.
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PMID:Synergystic induction of HIF-1alpha transcriptional activity by hypoxia and lipopolysaccharide in macrophages. 1821 34

MTAP (5'-methylthioadenosine phosphorylase) catalyses the reversible phosphorolytic cleavage of methylthioadenosine leading to the production of methylthioribose-1-phosphate and adenine. Deficient MTAP activity has been correlated with human diseases including cirrhosis and hepatocellular carcinoma. In the present study we have investigated the regulation of MTAP by ROS (reactive oxygen species). The results of the present study support the inactivation of MTAP in the liver of bacterial LPS (lipopolysaccharide)-challenged mice as well as in HepG2 cells after exposure to t-butyl hydroperoxide. Reversible inactivation of purified MTAP by hydrogen peroxide results from a reduction of V(max) and involves the specific oxidation of Cys(136) and Cys(223) thiols to sulfenic acid that may be further stabilized to sulfenyl amide intermediates. Additionally, we found that Cys(145) and Cys(211) were disulfide bonded upon hydrogen peroxide exposure. However, this modification is not relevant to the mediation of the loss of MTAP activity as assessed by site-directed mutagenesis. Regulation of MTAP by ROS might participate in the redox regulation of the methionine catabolic pathway in the liver. Reduced MTA (5'-deoxy-5'-methylthioadenosine)-degrading activity may compensate for the deficient production of the precursor S-adenosylmethionine, allowing maintenance of intracellular MTA levels that may be critical to ensure cellular adaptation to physiopathological conditions such as inflammation.
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PMID:Redox regulation of methylthioadenosine phosphorylase in liver cells: molecular mechanism and functional implications. 1823 76

The purpose of this study was to analyze the combined effects of regular exercise and ginseng supplementation on peritoneal exudate ROS (reactive oxygen species), lymphocyte proliferation by splenocytes, and DNA damage following exhaustive exercise stress. Thirty-six female BALB/c mice were randomly divided into control (UT, n = 12), trained (TR, n = 12), and ginseng supplemented and trained (GT, n = 12) groups. Each group was divided into two equal subgroups where mice were studied at rest (UTre, TRre, and GTre) or immediately after exhaustive exercise stress (UTex, TRex, and GTex). Animals were bred in the animal facility, where they were housed at 22-24 degrees C and relative humidity (RH) 50-60% in a controlled environment with a 12-hour photoperiod, and provided food and water ad libitum. The trained mice underwent 10 weeks of endurance swim training (5 times/week) in water at 27-30 degrees C for 60 minutes. The analytical items examined were weight, proliferative activity, the production of ROS from peritoneal exudate cells, and DNA damage following exhaustive exercise stress (2 h exercise stress). Significant level was set at p < 0.05. The results obtained showed that the trained group had a significantly lower mean body weight than the untrained group (p < 0.05). However, there was no significant difference between UT and GT. Swim training increased swim survival time in TRex and GTex, and TRex showed the highest swim survival time. With regard to mitogenic activities of splenocytes in response to exhaustive exercise stress, all groups showed much lower lymphocyte proliferative activity when stimulated with media (Med), concanavalin A (ConA), or lipopolysaccharide (LPS) after exhaustive exercise stress. However, GTex had a higher proliferative activity than the other groups. Trained and ginseng-supplemented groups showed lower peritoneal ROS responses and lymphocyte DNA damage levels after exhaustive exercise. These findings suggest that the combined effect of swim training and ginseng supplementation sustain lymphocyte function in the presence of reduced ROS production and DNA damage following acute exercise stress.
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PMID:Combined effects of swim training and ginseng supplementation on exercise performance time, ROS, lymphocyte proliferation, and DNA damage following exhaustive exercise stress. 1827 Dec 84

Septic shock is a complex syndrome that claims over 200,000 lives per year in the United States. While majority of the late mortality of sepsis appears to be due to multi-system organ failure, early death has been attributed either to distributive shock or to a cardiogenic form of septic shock. Overproduction of nitric oxide (NO), presumably by NO synthase 2 (NOS 2), has been implicated in the pathogenesis of cardiovascular dysfunction of sepsis. However, in clinical trials, NOS inhibitors that are not isoform-specific increased mortality in septic patients due to cardiac dysfunction, suggesting salutary effects of NOS 1 and/or NOS 3. Recently, we found that cardiomyocyte-specific overexpression of NOS 3 prevents lipopolysaccharide (LPS)-induced myocardial dysfunction and mortality in mice. Myocardial mechanical efficiency was markedly impaired in wild-type and NOS 3-deficient mice but not in mice with the NOS 3 transgene after LPS challenge. Improved myocardial function by excess NO during endotoxemia was associated with decreased myocardial oxidative stress, increased myofilament sensitivity to calcium, and increased phospholamban (PLB) phosphorylation. These results suggest that increased myocardial NO levels attenuate endotoxin-induced ROS production and increase total sarcoplasmic reticulum Ca2+ load and myofilament sensitivity to Ca2+ thereby reducing myocardial dysfunction and mortality in murine models of septic shock.
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PMID:[Impact of nitric oxide synthase 3 on myocardial dysfunction in sepsis]. 1834 Sep 97


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