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)

Fas ligand (FasL) is a cell membrane cytokine that can promote apoptosis through activation of Fas receptors. Fas receptor activation induces glomerular cell apoptosis in vivo and participates in tubular cell death during acute renal failure. However, there is little information on the expression of FasL in the kidney. This study reports that FasL mRNA and protein are present in normal mouse and rat kidney. In situ hybridization and immunohistochemistry showed that proximal tubular epithelium is the main site of FasL expression in the normal kidney. In addition, increased total kidney FasL mRNA and de novo FasL protein expression by glomerular cells were observed in two different models of glomerular injury : rat immune-complex proliferative glumerulonephritis and murine lupus nephritis. Both full-length and soluble FasL were increased in the kidneys of the mice with nephritis. Cultured murine proximal tubular epithelial MCT cells and primary cultures of murine tubular epithelial cells expressed FasL mRNA and protein. Tubular epithelium-derived FasL induced apoptosis in Fassensitive lymphoid cell lines but not in Fas-resistant lymphoid cell lines. By contrast, MCT cells grown in the presence of the survival factors of serum were resistant to FasL, and only became partially sensitive to apoptosis induced by high concentrations (100 ng/ml) of FasL upon serum deprivation. However, MCT cells stimulated with inflammatory mediators (tumor necrosis factor-alpha, interferon-gamma, and lipopolysaccharide) increased cell surface Fas expression and were sensitized to apoptosis induced by FasL (FasL 55 +/- 5% versus control 8.3 +/- 4.1% apoptotic cells at 24 h, P < 0.05). Cytokine-primed primary cultures of tubular epithelial cells also acquired sensitivity to FasL-induced apoptosis. These results suggest that FasL expression by intrinsic renal cells may play a role in cell homeostasis in the normal kidney and during renal injury.
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PMID:Proapoptotic Fas ligand is expressed by normal kidney tubular epithelium and injured glomeruli. 1086 83

The purpose of this study was to determine if alcohol consumption and endotoxin injection change the rate of apoptosis in the pancreas. Rats were fed a Lieber-DeCarli diet for 14 weeks. At 14 weeks, the animals were injected with lipopolysaccharide (LPS) or saline and killed. The pancreata were resected and snap frozen. Apoptosis was detected by TUNEL assay. Caspase-3 activity, Bcl-2 (protein), and Fas ligand (mRNA) were assayed in pancreas extracts and alpha-amylase in plasma. Alcohol feeding significantly decreased alpha-amylase and caspase-3 activity, and significantly increased Bcl-2. LPS injection increased caspase-3 activity and decreased Bcl-2. Fas ligand mRNA was increased only in alcohol-fed, LPS-injected rats. TUNEL labeling was significantly increased only in alcohol-fed, LPS-injected rats. These data show that (a) long-term alcohol feeding suppresses apoptosis in the pancreas; (b) LPS increases the rate of apoptosis in the pancreas; (c) caspase-3 activity and Bcl-2 expression change in opposite directions; (d) TUNEL positivity and Fas ligand expression are increased, and Bcl-2 is decreased in ethanol-fed + LPS-injected rats. These results suggest that prolonged alcohol consumption may sensitize acinar cells to endotoxin-induced injury and raise the possibility that a similar mechanism may cause pancreatitis in human alcoholics.
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PMID:Alcohol feeding and lipopolysaccharide injection modulate apoptotic effectors in the rat pancreas in vivo. 1097 12

To determine the possible contribution of apoptosis in the pathogenesis of acute lung injury (ALI), we investigated Fas antigen (Fas), Fas ligand (FasL), perforin, granzyme A, and granzyme B expressions in a murine model of ALI after intratracheal instillation of Escherichia coli lipopolysaccharide (LPS: 0.3-30 microg) into the left lung. Lung injury, examined by water-to-dry weight ratio and albumin leakage, demonstrated maximal epithelial injury 1 d after 30 microg LPS instillation. Expressions of the proapoptosis molecules' mRNA were dose-dependently up-regulated, with maximal expression in the early phase in the instilled lung and most apparent 1 d after LPS instillation. Negligible mRNA expression of proapoptosis molecules was observed in noninstilled lungs. The terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL) demonstrated positive signals in neutrophils and macrophages as well as in alveolar wall cells of the instilled lung 1 d after LPS instillation. Immunohistochemistry demonstrated that Fas was up-regulated in alveolar and inflammatory cells and FasL-positive inflammatory cells migrated into the air spaces in the LPS-instilled lung. Intratracheal administration of P2 antibody, which is an anti-Fas blocking antibody, attenuated the lung injury after 30 microg LPS instillation without attenuating mRNA expressions of proapoptosis molecules and neutrophil accumulation in the lung. In contrast, concanamycin A, which inhibits the function of perforin, did not alter the outcome after LPS instillation. These results indicate that the Fas/FasL system could be important in the pathogenesis of LPS-induced ALI, and proper regulation of the FasL/Fas system might be important for potential treatment of ARDS.
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PMID:Fas/FasL-dependent apoptosis of alveolar cells after lipopolysaccharide-induced lung injury in mice. 1125 36

T(h)1 cells are cytotoxic effector cells that utilize Fas ligand (FasL) and tumor necrosis factor. The physiological roles of cytotoxic T(h)1 cells are considered to be immunoregulation by eliminating autoreactive lymphocytes or hyper-activated foreign antigen-specific lymphocytes. Their pathological roles, however, remain to be clarified. To investigate whether T(h)1 cells can destroy organs, we generated a Propionibacterium acnes-specific T(h)1 clone from C57BL/6 mice and tested whether the clone could serve as an effector in a P. acnes-primed lipopolysaccharide (LPS)-induced hepatic injury system, one of the septic shock models. B6SMN:C3H-FasL(gld) (B6-gld) mice, which were deficient in functional FasL, were resistant to P. acnes/LPS-induced hepatic shock. The T(h)1 clone rendered B6-gld mice sensitive to the hepatic shock after the i.v. transfer. The hepatic injury in the clone-transferred B6-gld mice, which was evaluated by both biochemical and histological examination, was inhibited by an anti-FasL mAb that we developed. These results suggested that bacterial antigen-specific T(h)1 cells like this clone can participate in organ destruction in vivo as one of the cytotoxic effectors and play a critical role in endotoxin-induced hepatic injury.
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PMID:Antigen-specific T(h)1 cells as direct effectors of Propionibacterium acnes-primed lipopolysaccharide-induced hepatic injury. 1131 48

Kupffer cells play an important role in controlling the growth and development of liver metastases. However, the pathway of Kupffer cells against tumor metastases is not clear. In the present study, we set up an experimental model to investigate the mechanisms on how Kupffer cells kill tumor cells which metastasize to the liver. Malignant glioma cells were cocultured with Kupffer cells or treated with culture medium collected from lipopolysaccharide (LPS)-activated Kupffer cells. The results showed that the interaction between Kupffer cells and malignant glioma cells significantly stimulated the generation of tumor necrosis factoralpha (TNFalpha). TNFalpha was mainly produced by Kupffer cells, as its level in culture medium obtained from LPS-treated Kupffer cells was not significantly different from that of malignant glioma cells treated with the same medium. Both Kupffer cells and LPS/Kupffer cell-conditioned supernatants induced expression of Fas and Fas ligand on malignant glioma cells. Subsequently a significant proportion of malignant glioma cells became apoptotic, as evidenced by positive staining of annexin V and propidium iodine and an increase in cellular DNA fragmentation. Therefore, this study supports a novel pathway of Kupffer cells against liver metastases, in which tumor cells were apoptotic via the Fas-Fas ligand system induced by TNFalpha released from Kupffer cells.
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PMID:Induction of Fas and Fas ligand expression on malignant glioma cells by Kupffer cells, a potential pathway of antiliver metastases. 1167 53

Lipopolysaccharide and D-galactosamine induced lethality and apoptotic liver injury is dependent upon endogenously produced TNF-alpha. Unlike the response to high dose lipopolysaccharide alone, death in this model is a direct result of hepatocyte apoptosis. In a series of recent studies, we have demonstrated that mortality and hepatic injury following lipopolysaccharide administration in D-galactosamine-sensitized mice is dependent upon secreted 17 kDa TNF-alpha acting primarily through the p55 TNF receptor. Transgenic mice expressing null forms of TNF-alpha, the p55 receptor, or expressing only a cell-associated form of TNF-alpha exhibited no mortality and only modest liver injury when challenged with 8 mg of D-galactosamine and 100 ng of lipopolysaccharide. Although Fas ligand expression is increased in the liver, it appeared to play no significant role in outcome, since mice expressing a mutant form of Fas ligand are still sensitive to LPS- and D-galactosamine-induced lethality. Finally, we have seen significant variation in LPS- and D-galactosamine-mediated lethality among different strains of mice. The non-obese diabetic or NOD mouse is highly resistant to LPS-and D-galactosamine-induced lethality, and this appears to be secondary to a post-receptor defect in p55 TNF receptor signaling. The studies confirm an essential role for TNF-alpha and p55 TNF receptor signaling in the hepatocyte apoptosis and lethality associated with lipopolysaccharide and D-galactosamine administration.
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PMID:Genetic determinants of lipopolysaccharide and D-galactosamine-mediated hepatocellular apoptosis and lethality. 1175 6

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

HIV-1 infection in the brain induces neuronal apoptosis leading to HIV-associated dementia. To explore the underlying mechanism, we developed a murine model by using human peripheral blood mononuclear cell (PBMC)-transplanted nonobese diabetic (NOD)-severe combined immunodeficiency (SCID) (hu-PBMC-NOD-SCID) mice. Administration of lipopolysaccharide (LPS) to HIV-1-infected hu-PBMC-NOD-SCID mice induced infiltration of HIV-1-infected human cells into the perivascular region of the brain and neuronal apoptosis was found in macrophage (M)-tropic but not T cell (T)-tropic HIV-1-infected brains. The apoptotic neurons were frequently colocalized with the HIV-1-infected macrophages that expressed tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). Administration of a neutralizing antibody against human TRAIL but not human TNF-alpha or Fas ligand (FasL) blocked the neuronal apoptosis in the HIV-1-infected brain. These results strongly suggest a critical contribution of TRAIL expressed on HIV-1-infected macrophages to neuronal apoptosis.
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PMID:Tumor necrosis factor-related apoptosis-inducing ligand induces neuronal death in a murine model of HIV central nervous system infection. 1260 Nov 60

Phylogenetic analysis clusters caspase-12 with the inflammatory caspases 1 and 11. We analyzed the expression of caspase-12 in mouse embryos, adult organs, and different cell types and tested the effect of interferons (IFNs) and other proinflammatory stimuli. Constitutive expression of the caspase-12 protein was restricted to certain cell types, such as epithelial cells, primary fibroblasts, and L929 fibrosarcoma cells. In fibroblasts and B16/B16 melanoma cells, caspase-12 expression is stimulated by IFN-gamma but not by IFN-alpha or -beta. The effect is increased further when IFN-gamma is combined with TNF, lipopolysaccharide (LPS), or dsRNA. These stimuli also induce caspase-1 and -11 but inhibit the expression of caspase-3 and -9. In contrast to caspase-1 and -11, no caspase-12 protein was detected in macrophages in any of these treatments. Transient overexpression of full-length caspase-12 leads to proteolytic processing of the enzyme and apoptosis. Similar processing occurs in TNF-, LPS-, Fas ligand-, and thapsigargin (Tg)-induced apoptosis. However, B16/B16 melanoma cells die when treated with the ER stress-inducing agent Tg whether they express caspase-12 or not.
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PMID:Regulation of the expression and processing of caspase-12. 1288 62

Signaling through the Fas/Fas ligand (FasL) pathway plays a central role in immune-cell response and function; however, under certain pathological conditions such as sepsis, it may contribute to the animal's or patient's morbidity and mortality. To determine the contribution of FasL to mortality, we conducted survival studies by blocking Fas/FasL with Fas receptor fusion protein (FasFP) in vivo. C3H/HeN mice received FasFP or the saline vehicle (veh) immediately (0 h) or delayed (12 h), after sepsis induced by cecal ligation and puncture (CLP). Subsequently, we examined the effect of FasFP treatment (12 h post-CLP) on macrophage apoptosis and functional capacities. Peritoneal and splenic macrophages and Kupffer cells from sham-veh-, CLP-veh-, sham-FasFP-, or CLP-FasFP-treated mice were harvested 24 h after CLP and stimulated with lipopolysaccharide (LPS) for 24 h. The results indicate that only delayed (12 h) but not 0 h administration of FasFP demonstrated a significant increase in survival. The ability of all macrophage populations to release interleukin (IL)-6 was significantly depressed, and IL-10 release was augmented after CLP. FasFP treatment attenuated the increased IL-10 release in Kupffer cells. However, althogh enhanced susceptibility to LPS-induced apoptosis could be suppressed in CLP mouse Kupffer cells by FasFP, FasFP did not change the peritoneal or splenic macrophage response. Furthermore, FasFP attenuated the elevated plasma levels of liver enzymes after sepsis. These data indicate that in vivo inhibition of Fas/FasL signaling has tissue-specific effects on the induction of macrophage apoptosis, functional changes, and liver damage, which may contribute to the host's ability to ward off a septic challenge.
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PMID:Inhibition of Fas/Fas ligand signaling improves septic survival: differential effects on macrophage apoptotic and functional capacity. 1294 37


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