UNIPROT:P43026 - FACTA Search

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

Kupffer cells (KC) become activated in response to lipopolysaccharide (LPS) and produce a variety of mediators. Among them, TNF alpha is known to injure the liver. Here we report that TNF alpha mediates apoptosis in KC and sinusoidal endothelial cells. After stimulation for 24 h with LPS (0-10 micrograms/mL), apoptosis in KC detected by TUNEL TdT-mediated dUTP-biotin nick end labelling (TUNEL) increased in a concentration-dependent manner (0 micrograms/mL, 12 +/- 4%; 0.1 microgram/mL, 36 +/- 11%; 1.0 micrograms/mL, 65 +/- 9%; 10 micrograms/mL, 78 +/- 15%). In contrast, co-incubation of endothelial cells with LPS-stimulated KC resulted in a marked increase in TUNEL-positive endothelial cells. TNF alpha antibody blocked apoptosis in both KC and endothelial cells. Apoptosis was observed in cells adjacent to or in contact with KC. Reducing transmembrane TNF alpha expressed on KC also led to a decrease in endothelial cell apoptosis, suggesting that transmembrane TNF alpha is implicated in the cell-to-cell contact mechanism of induction of apoptosis. Thus, TNF alpha mediates apoptosis in KC and endothelial cells.
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PMID:Apoptosis: a new mechanism of endothelial and Kupffer cell killing. 858 47

Premature labor, fetal demise, and fetal growth restriction are accompanied by indices of inflammation or infection of the uteroplacental unit. To understand whether these events are causally related, we established an animal model of fetal demise and growth restriction and evaluated the potential utility of the anti-inflammatory cytokine interleukin-10 (IL-10). We administered low-dose endotoxin (lipopolysaccharide, or LPS, 100 microg/kg, i.p.) to third trimester rats (gestational days 14-20). Control rats received normal saline. A third group received IL-10 (100 microg/kg; s.c.) concomitantly with LPS for 7 prenatal days. Cytokine gene expression (IL-10 and TNF-alpha) was evaluated by RT-PCR and tissue levels (TNF-alpha) were determined by ELISA. Apoptosis was evaluated by TdT-mediated dUTP nick end labeling immunohistochemistry, and nitric oxide (NO) levels were quantified by microelectrode electrochemical detection in explants in culture media. LPS exposure resulted in 43% fetal demise and reduced the size of the surviving fetuses. Placental weight was not altered by LPS. IL-10 attenuated the LPS-induced fetal death rate (to 22%) and growth restriction (P<0.05). In normal rats, IL-10 did not affect fetus size or the incidence of resorptions, although placental size was marginally smaller. Increased uterine TNF-alpha content and NO release and apoptosis of uterine epithelia and muscularis were hallmarks of the LPS model. All were normalized by IL-10. IL-10 may represent a new therapeutic option for the treatment of a variety of perinatal complications. Benefit may result from the suppression of TNF-alpha- and NO-mediated cell death.
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PMID:Interleukin-10 attenuates experimental fetal growth restriction and demise. 947 84

The effects of polystyrene (PS) material surface preadsorption with fibrinogen (3 mg/ml) and a low concentration of lipopolysaccharide (LPS; 10 ng/ml) and polystyrene particles (PS; 10(5)/ml) on human monocyte adhesion, viability and cytokine release were studied during 24h culture in vitro. LPS caused an upregulation of CD14 in adherent cells. In comparison with unstimulated cells on uncoated polystyrene surfaces, LPS did not alter the number of adherent cells but caused a markedly increased release of the proinflammatory cytokines (IL-1alpha and TNF-alpha) and the down-regulating IL-10. The expression of indicators of various stages of cell death, TdT, annexin-V, propidium iodide (PI) and lactate dehydrogenase (LDH), were unaltered, decreased, decreased and increased, respectively, after LPS stimulation. PS particles (3 microm psi) caused an increased DNA fragmentation but had a reduced proportion of annexin-V and PI positive cells in comparison with unstimulated cells on uncoated PS. In contrast, 1microm psi particles had a similar proportion of TdT, annexin-V and PI expressing cells as unstimulated controls. Cultures stimulated with particles (irrespective of size), had a similar concentration of proinflammatory cytokines as unstimulated controls, whereas a higher level of IL-10 was detected. Precoating of PS with fibrinogen revealed an enhanced cell adhesion and a concomitant reduction of CD14 expression. irrespective of stimulation with various agonists. The proportions of TdT, annexin-V and PI positive cells were unaltered or reduced on fibrinogen-coated PS in both unstimulated and agonist-challenged cultures. However, depending on the presence and type of agonist, fibrinogen mediated either a markedly increased (LPS) or equivalent (particles and unstimulated) IL-1alpha and TNFalpha release. Further, in comparison with uncoated substrates, fibrinogen was associated with a reduction of IL-10 release, irrespective of the type of stimuli. These observations, using low concentrations of bacterial and material products, indicate that fibrinogen modulates cell material interactions and up- and down-regulates specific events depending on the nature/ type of immediate stimuli.
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PMID:Apoptosis and cytokine release in human monocytes cultured on polystyrene and fibrinogen-coated polystyrene surfaces. 1192 67

Potential of sanguiin H-6, a component of Sanguisorbae Radix, to protect against oxidative damage in renal mitochondria and apoptosis mediated by peroxynitrite (ONOO(-)) was examined using a model in which rats were injected with lipopolysaccharide (LPS) and then subjected to renal ischemia followed reperfusion (LPS plus ischemia-reperfusion). Ischemia-reperfusion was achieved by occluding bilateral renal artery for 60 min and then releasing for 350 min. At 50 min after ischemia started, LPS was injected intravenously. LPS plus ischemia-reperfusion induced a large amount of 3-nitrotyrosine, an oxidative product of protein that is produced via ONOO(-) nitration, which was not detectable in normal group. Oxidative damage of mitochondria was indicated by an accumulated thiobarbituric acid (TBA)-reactive substance, glutathione (GSH) depletion and glutathione peroxidase (GSH-Px) inactivation in the mitochondria. Treatment of rats with sanguiin H-6 (10 mg/kg body weight/day) for 30 days prior to LPS plus ischemia-reperfusion attenuated the oxidative damage in the mitochondria. The amount of TBA-reactive substance was decreased and the GSH levels significantly increased as compared with that in control group. However, its effect on GSH-Px activity was much weaker. Apoptosis induced by LPS plus ischemia-reperfusion was detected by fluorescence staining, TdT-mediated dUTP-biotin nick end labeling and electrophoretic analysis. Sanguiin H-6 appeared to inhibit apoptosis, and this was associated with the suppression of caspase-3 activity. These beneficial effects of sanguiin H-6 against oxidative damage in mitochondria and apoptosis contributed to the improvement in renal function by reversing the elevated levels of blood urea nitrogen and creatinine caused by ONOO(-).
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PMID:Potential of sanguiin H-6 against oxidative damage in renal mitochondria and apoptosis mediated by peroxynitrite in vivo. 1218 96

Nuclear factor kappa B (NF-kappaB), a pleiotropic transcriptional factor that promotes cell survival and protects cells from apoptosis, requires reduced thiols at critical steps in its activation pathway. Mercuric ion (Hg(2+)), one of the strongest thiol-binding agents known, impairs NF-kappaB activation and transcriptional activity in normal rat kidney epithelial (NRK52E) cells at concentrations as low as 0.5 microM by binding to specific reduced thiol moieties in the NF-kappaB activation pathway. We hypothesized that prevention of NF-kappaB activation by Hg(2+) will increase the sensitivity of kidney cells to the apoptosis-inducing effects of other toxicants to which these cells are otherwise resistant by virtue of their NF-kappaB-activating capacity. Fewer than 5% of untreated kidney cells in culture (70-90% confluent) were found to be apoptotic when evaluated by DNA fragmentation (terminal deoxynucleotide transferase-mediated dUTP nick-end labeling) or flow cytometric DNA profile analyses. Hg(2+) (5 microM) treatment for 24 hr increased this proportion by 1.5- to 2-fold. Neither lipopolysaccharide (LPS) (1 microg/mL) nor tumor necrosis factor-alpha (TNF-alpha; 300 U/mL), both potent activators of NF-kappaB in kidney cells, significantly altered the proportion of apoptotic cells, compared with untreated controls, when applied without Hg(2+) pretreatment. However, when LPS or TNF-alpha was administered after Hg(2+) pretreatment (5 microM for 30 min), the proportion of cells undergoing apoptosis 22 hr later increased by 4- to 6-fold compared with untreated controls. In contrast, Hg(2+) pretreatment did not increase the amount of apoptosis caused by apoptosis-inducing agents that do not activate NF-kappaB (staurosporine, Fas ligand). These findings suggest that Hg(2+) enhances the sensitivity of kidney cells to apoptotic stimuli as a consequence of inhibition of NF-kappaB activity. Because apoptosis is known to play a key role in the pathogenesis of renal failure resulting from toxicant injury to proximal tubular cells, promotion of apoptosis via inhibition of NF-kappaB activity may define a novel molecular mechanism by which Hg(2+) toxicity is initiated in kidney cells.
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PMID:Attenuation of nuclear factor kappa B (NF-kappaB) promotes apoptosis of kidney epithelial cells: a potential mechanism of mercury-induced nephrotoxicity. 1242 38

2-Oxo-3,23-isopropylidene-asiatate (AS2006A), a wound-healing asiatate derivative, exerts anti-inflammatory effect. Macrophages produce cytokines that recruit other inflammatory cells and are responsible for the diverse effects of inflammation. In the present study, we comparatively evaluated the cytotoxicity of AS2006A to Raw264.7, H4IIE and L-929 cells as part of the studies on its anti-inflammatory effect. Among the cells examined, AS2006A was selectively cytotoxic to Raw264.7 cells, a macrophage cell line. AS2006A increased the number of cells positively stained with TdT-mediated dUTP nick end labeling (TUNEL), and upregulated the expression of the genes implicated with apoptosis, which included caspase-8, c-myc, iNOS, mdm2, NF-kappaB1, I-kappaBalpha and NF-kappaB p105 genes, as assessed by the membrane DNA array technique. The expression of the genes related with cell cycle control was not changed. Thus, the primary targets of AS2006A in macrophages might include the genes implicated with apoptosis. Immunoblot analysis revealed that AS2006A caused the release of cytochrome c from the mitochondria to the cytoplasm in macrophages. Caspase-3 activity and poly(ADP-ribose) polymerase cleavage were both increased by AS2006A in macrophages, indicating that AS2006A induced apoptosis. Viability of macrophages activated by lipopolysaccharide and their NO production were also decreased by AS2006A in a concentration-dependent manner. These results demonstrated that AS2006A selectively induces apoptosis of macrophages with cytochrome c release, caspase 3 activation and poly(ADP-ribose) polymerase cleavage, and that cytotoxicity of AS2006A to macrophages may contribute to anti-inflammatory and wound-healing effects.
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PMID:2-Oxo-3,23-isopropylidene-asiatate (AS2006A), a wound-healing asiatate derivative, exerts anti-inflammatory effect by apoptosis of macrophages. 1294 39

The wide diversity of the T and B Ag receptor repertoires becomes even more extensive postneonatally due to the activity of TdT, which adds nontemplated N nucleotides to Ig and TCR coding ends during V(D)J recombination. In addition, complementarity-determining region 3 sequences formed in the absence of TdT are more uniform due to the use of short sequence homologies between the V, D, and J genes. Thus, the action of TdT produces an adult repertoire that is both different from, and much larger than, the repertoire of the neonate. We have generated TdT-deficient nonobese diabetic (NOD) and MRL-Fas(lpr) mice, and observed a decrease in the incidence of autoimmune disease, including absence of diabetes and decreased pancreatic infiltration in NOD TdT(-/-) mice, and reduced glomerulonephritis and increased life span in MRL-Fas(lpr) TdT(-/-) mice. Using tetramer staining, TdT(-/-) and TdT(+/+) NOD mice showed similar frequencies of the diabetogenic BDC 2.5 CD4(+) T cells. We found no increase in CD4(+)CD25(+) regulatory T cells in NOD TdT(-/-) mice. Thus, TdT deficiency ameliorates the severity of disease in both lupus and diabetes, two very disparate autoimmune diseases that affect different organs, with damage conducted by different effector cell types. The neonatal repertoire appears to be deficient in autoreactive T and/or B cells with high enough affinities to induce end-stage disease. We suggest that the paucity of autoreactive specificities created in the N region-lacking repertoire, and the resultant protection afforded to the newborn, may be the reason that TdT expression is delayed in ontogeny.
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PMID:Terminal deoxynucleotidyltransferase deficiency decreases autoimmune disease in diabetes-prone nonobese diabetic mice and lupus-prone MRL-Fas(lpr) mice. 1503 81

Endonuclease-induced DNA fragmentation is a hallmark of apoptosis. DNase gamma (DNase gamma) was recently identified as one of the endonucleases responsible for apoptotic DNA fragmentation. In this study, immunohistochemistry for DNase gamma was performed on paraffin sections of rodent liver in well-defined models of hepatocyte apoptosis induced by Fas antibody (Fas) or cycloheximide (CHX), and necrosis induced by lipopolysaccharide (LPS) or carbon tetrachloride (CCl4). DNase gamma immunoreactivity was compared with TdT-mediated dUTP nick-end labeling (TUNEL) reactivity. Our results showed TUNEL reactivity in both apoptotic and necrotic hepatocytes. DNase gamma immunoreactivity was not detected during LPS-induced or CCl4-induced hepatocyte necrosis. In contrast, it was evident during CHX-induced, but not Fas-induced, apoptotic DNA fragmentation. These findings suggest that DNase gamma plays an important role in Fas-independent apoptotic DNA fragmentation in hepatocytes.
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PMID:Expression of DNase gamma during Fas-independent apoptotic DNA fragmentation in rodent hepatocytes. 1511 3

Chronic alcohol consumption is known to increase the susceptibility to acute and chronic pancreatitis, and it is likely that a cofactor is required to initiate the progression to alcoholic pancreatitis. The severity and complications of alcoholic and nonalcoholic acute pancreatitis may be influenced by a number of cofactors, including endotoxemia. To explore the effect of a possible cofactor, we used endotoxin [lipopolysaccharide (LPS)] as a tool to induce cellular injury in the alcoholic pancreas. Single, increasing doses of endotoxin were injected in rats fed an alcohol or control diet and killed 24 h after the injection. We examined the mechanism by which LPS exacerbates pancreatic injury in alcohol-fed rats and whether the injury is associated with apoptosis or necrosis. We showed that chronic alcohol exposure alone inhibits apoptosis through the intrinsic pathway and the downstream apoptosis executor caspase-3 compared with the controls. Pancreatic necrosis and inflammation increased after LPS injection in control and alcohol-fed rats in a dose-dependent fashion but with a significantly greater response in the alcohol-fed animals. Caspase activities and TdT-mediated dUTP nick-end labeling positivity were lower in the alcoholic pancreas injected with LPS, whereas the histopathology and inflammation were more severe compared with the control-fed animals. Assessment of a putative indicator of necrosis, the ratio of ADP to ATP, indicated that alcohol exposure accelerates pancreatic necrosis in response to endotoxin. These findings suggest that the pancreas exposed to alcohol is more sensitive to LPS-induced damage because of increased sensitivity to necrotic cell death rather than apoptotic cell death. Similar to the liver, the pancreas is capable of responding to LPS with a more severe response in alcohol-fed animals, favoring pancreatic necrosis rather than apoptosis. We speculate that this mechanism may occur in acute alcoholic pancreatitis patients.
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PMID:Pancreatic response to endotoxin after chronic alcohol exposure: switch from apoptosis to necrosis? 1597 89

Apoptosis of lymphoid tissues during sepsis is well documented and linked to the pathobiology of organ failure and death. In this study, we evaluated the effect of a single dose of recombinant erythropoietin (EPO) on thymic and splenic apoptosis in an endotoxic sepsis model. Young male Wistar rats were divided into 3 groups and administered intraperitoneally (IP) either normal saline; lipopolysaccharide (LPS) 10 mg/kg; or EPO (5000 U/kg) 30 min before lipopolysaccharide. Six hours following LPS administration animals were sacrificed. Apoptosis was assessed by hematoxylin-eosin staining, terminal deoxynucleotide transferase-mediated fluorescein-dUTP nick end labeling (TUNEL), and caspase-3 immunostaining. When compared with animals given LPS, animals pretreated with EPO displayed reduced splenic and thymic TUNEL positivity of 44+/-3 (p<0.05) and 143+/-4 (p<0.05) nuclei per high power field (hpf), respectively. Caspase-3 positivity was also significantly reduced in the spleen and thymus, with 31+/-4 (p<0.05) and 93+/-3 (p<0.05) positive stained nuclei per hpf, respectively. Serum nitrite levels were elevated in animals given lipopolysaccharide. Pretreatment with EPO attenuated the increase in nitrite levels; however, this did not reach statistical significance. We conclude that a single dose of recombinant erythropoietin can reduce thymic and splenic apoptosis associated with lipopolysaccharide administration.
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PMID:Erythropoietin attenuates lipopolysaccharide-induced splenic and thymic apoptosis in rats. 1608 14

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