Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent studies have demonstrated the activation of caspase-1 and caspase-3 in mice expressing mutant superoxide dismutase 1 (SOD1), models of amyotrophic lateral sclerosis. Caspase-1 converts the prointerleukin-1beta into a potent proinflammatory molecule involved in the innate immune response and in neurodegenerative diseases. We report on the chronic expression of interleukin-1beta mRNA in the spinal cord of SOD1G37R mice, together with robust mRNA expression for the nuclear factor-kappaB (NF-kappaB) inhibitor IkappaBalpha, for other proinflammatory cytokines and chemokines (interleukin-6, tumor necrosis factor-alpha, monocyte chemoattractant protein-1) and for the toll-like receptor TLR2 involved in innate immunity. To further assess the interleukin-1beta contribution to neurodegeneration, we generated mice expressing SOD1G37R in a context of interleukin-1beta gene knockout. Surprisingly, the absence of interleukin-1beta had no effect on the life span of SOD1G37R mice, nor on the extent of motor axon degeneration at age 7 and 10 months. Whereas neither compensatory induction of the interleukin-1alpha mRNA nor increases in mRNA levels for IkappaBalpha, tumor necrosis factor-alpha and macrophage chemoattractant protein-1 occurred as a result of interleukin-1beta gene disruption, enhanced levels of TLR2 mRNA were detected in SOD1G37R mice lacking interleukin-1beta. We conclude that interleukin-1beta does not directly contribute to motor neuron degeneration in SOD1G37R mice, but it may act as a modulator of the innate immune response.
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PMID:Induction of proinflammatory molecules in mice with amyotrophic lateral sclerosis: no requirement for proapoptotic interleukin-1beta in neurodegeneration. 1170 69

Lipoproteins of Mycoplasma salivarium and Mycoplasma fermentans preferentially induced necrotic cell death in lymphocytic cell lines, MOLT-4 and Raji, and in one monocytic cell line, THP-1, whereas they preferentially induced apoptotic cell death in another monocytic cell line, HL-60. These findings were also supported by ultrastructural observations by the use of scanning and transmission electron microscopes and by agarose gel electrophoresis of the genomic DNA. The lipoproteins activated caspase-3 in both MOLT-4 and HL-60 cells, which was assessed by the cleavage of the synthetic substrate DEVD-pNA and the endogenous substrate poly(ADP-ribose) polymerase. The cytotoxicity to MOLT-4 and HL-60 cells was inhibited by various caspase inhibitors, Ac-DMQD-CHO, Ac-IETD-CHO, and Z-VAD-FMK. The cytotoxicity was also partially suppressed by the monoclonal antibody to Toll-like receptor 2. Thus this study demonstrated that mycoplasmal lipoproteins induce caspases-dependent necrotic and apoptotic cell death in lymphocytes and monocytes/macrophages, which is partially induced by TLR2-mediated signaling.
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PMID:Mycoplasmal lipoproteins induce toll-like receptor 2- and caspases-mediated cell death in lymphocytes and monocytes. 1206 29

Although the probiotic Escherichia coli strain Nissle 1917 has been proven to be efficacious for the treatment of inflammatory bowel diseases, the underlying mechanisms of action still remain elusive. The aim of the present study was to analyze the effects of E. coli Nissle 1917 on cell cycling and apoptosis of peripheral blood and lamina propria T cells (PBT and LPT, respectively). Anti-CD3-stimulated PBT and LPT were treated with E. coli Nissle 1917-conditioned medium (E. coli Nissle 1917-CM) or heat-inactivated E. coli Nissle 1917. Cyclin B1, DNA content, and caspase 3 expression were measured by flow cytometry to assess cell cycle kinetics and apoptosis. Protein levels of several cell cycle and apoptosis modulators were determined by immunoblotting, and cytokine profiles were determined by cytometric bead array. E. coli Nissle 1917-CM inhibits cell cycling and expansion of peripheral blood but not mucosal T cells. Bacterial lipoproteins mimicked the effect of E. coli Nissle 1917-CM; in contrast, heat-inactivated E. coli Nissle 1917, lipopolysaccharide, or CpG DNA did not alter PBT cell cycling. E. coli Nissle 1917-CM decreased cyclin D2, B1, and retinoblastoma protein expression, contributing to the reduction of T-cell proliferation. E. coli Nissle 1917 significantly inhibited the expression of interleukin-2 (IL-2), tumor necrosis factor alpha, and gamma interferon but increased IL-10 production in PBT. Using Toll-like receptor 2 (TLR-2) knockout mice, we further demonstrate that the inhibition of PBT proliferation by E. coli Nissle 1917-CM is TLR-2 dependent. The differential reaction of circulating and tissue-bound T cells towards E. coli Nissle 1917 may explain the beneficial effect of E. coli Nissle 1917 in intestinal inflammation. E. coli Nissle 1917 may downregulate the expansion of newly recruited T cells into the mucosa and limit intestinal inflammation, while already activated tissue-bound T cells may eliminate deleterious antigens in order to maintain immunological homeostasis.
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PMID:Escherichia coli Nissle 1917 distinctively modulates T-cell cycling and expansion via toll-like receptor 2 signaling. 1573 Oct 43

Chlamydia pneumoniae is a common respiratory pathogen that is associated with an increased risk of cardiovascular disease. However, the mechanisms by which C. pneumoniae contributes to cardiovascular disease have not been determined yet. C. pneumoniae infection may accelerate the death of cells within atherosclerotic lesions and contribute to the formation of unstable lesions. To test this hypothesis, the impact of C. pneumoniae infection on the death of lipid-loaded mouse macrophages was investigated. It was observed that RAW 264.7 cells are highly susceptible to the toxic effects of oxidized low-density lipoprotein (LDL) and exhibit markers of cell death within 24 h of treatment with as little as 5 microg/ml oxidized LDL. Subsequent infection with either live C. pneumoniae or heat-killed or UV-inactivated C. pneumoniae at a low multiplicity of infection for 24 to 72 h stimulated both additional binding of annexin V and the uptake of propidium iodide. Thus, C. pneumoniae augments the effects of oxidized LDL on cell death independent of a sustained infection. However, unlike oxidized LDL, C. pneumoniae infection does not activate caspase 3 or induce formation of the mitochondrial transition pore or the fragmentation of DNA, all of which are classical markers of apoptosis. Furthermore, primary bone marrow macrophages isolated from mice deficient in Toll-like receptor 2 (TLR-2) but not TLR-4 are resistant to C. pneumoniae-induced death. These data suggest that C. pneumoniae kills cells by a caspase-independent pathway and that the process is potentially mediated by activation of TLR-2.
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PMID:Chlamydia pneumoniae augments the oxidized low-density lipoprotein-induced death of mouse macrophages by a caspase-independent pathway. 1597 25

Toll-like receptor (TLR) 2 functions as a sensor for detecting various microbial components conserved in bacteria or fungi in innate immunity. TLR2 induces several signalling pathways linking to activation of the transcriptional factors NF-kappaB and AP-1 as well as induction of cell death. In human embryonic kidney 293 cells expressed human TLR2, mycoplasmal lipoproteins (MLP) or staphylococcal peptidoglycans (PGN) induced sustained phosphorylation of p38 mitogen-activated protein kinase (MAPK), accompanied by generation of reactive oxygen species. This observation encouraged us to examine roles of apoptosis signal-regulating kinase 1 (ASK1) in TLR2 signalling, because ASK1 is an upstream activator of p38 MAPK during exposure to oxidative stress and other stressful stimuli. A kinase-inactive mutant of ASK1 greatly impaired the sustained phosphorylation of p38 MAPK induced by MLP or PGN. This mutant also attenuated MLP- or PGN-induced transcriptional activities of NF-kappaB and AP-1 via inhibition of p38 MAPK activation. MLP- or PGN-induced cell death reactions, including DNA fragmentation and caspase-3/7 activation, were also down-regulated by the ASK1 mutant via p38 MAPK inhibition. Furthermore, TLR2 signalling had a potential to phosphorylate and dephosphorylate ASK1 at Ser83 residue. Thus, MLP and PGN have capabilities to induce ASK1-dependent signalling pathways which regulate p38 MAPK activation through TLR2, leading to activation of NF-kappaB and AP-1 as well as induction of cell death.
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PMID:Apoptosis signal-regulating kinase 1-mediated sustained p38 mitogen-activated protein kinase activation regulates mycoplasmal lipoprotein- and staphylococcal peptidoglycan-triggered Toll-like receptor 2 signalling pathways. 1609 18

The interaction between epithelial cells and micro-organisms is often a crucial initiating event in infectious diseases. Infection with Porphyromonas gingivalis, a Gram-negative anaerobe, is strongly associated with severe periodontal disease. This bacterium possesses an array of virulence factors, some of which can induce apoptosis. The tumour necrosis factor (TNF) receptor family is involved in the regulation of cellular homeostasis, cell surface molecules involved in phagocytosis, Fas ligand (L) expression and activation of the caspase cascade resulting in DNA fragmentation and cell blebbing. The current study examined the role of nuclear factor-kappaB (NFkappaB) in FasL-mediated apoptotic cell death in primary human gingival epithelial cells (HGEC) induced by heat-killed P. gingivalis, probably through TLR signalling pathways. A marked up-regulation of TLR2 and Fas-FasL was detected in HGEC stimulated with P. gingivalis. Activation of NFkappaB by P. gingivalis in HGEC was demonstrated by an NFkappaB promoter luciferase assay as well as by phosphorylation of p65 as detected by Western blotting. Activation of cleaved caspase-3 and caspase-8 resulted in apoptotic cell death of HGEC. The survival proteins c-IAP-1/c-IAP-2 were decreased in HGEC exposed to P. gingivalis. HGEC apoptosis induced by P. gingivalis was inhibited by an anti-human FasL monoclonal antibody. Blockade of NFkappaB by helenalin resulted in down-regulation of FasL whereas a caspase-8 inhibitor did not decrease FasL. Taken together, these studies show that P. gingivalis can induce epithelial cell apoptosis through Fas-FasL up-regulation and activation of caspase-3 and caspase-8.
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PMID:Porphyromonas gingivalis enhances FasL expression via up-regulation of NFkappaB-mediated gene transcription and induces apoptotic cell death in human gingival epithelial cells. 1651 59

Vibrio cholerae hemolysin (HlyA) can exist as a monomer with hemolytic activity and an oligomer that agglutinates erythrocytes. Biochemical differences accompanying the change in state of aggregation led us to weigh possible differences between the two forms from mucosal immunoregulation perspective. HlyA oligomer-treated murine B-1a cells up-regulated TLR2 and involved the signaling molecules MyD88, TRAF6 and NF-kappaB. The cells subsequently expressed IgM and IgA. HlyA monomer treatment although resulted in TLR2 up-regulation, could not induce these effects. Apoptosis was detected in majority of the monomer-treated cells that involved caspase-9 and caspase-3. This study shows for the first time that two forms of the same protein could drive the host immune cell to two different outcomes, one of death and the other towards activation.
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PMID:Vibrio cholerae hemolysin is apoptogenic to peritoneal B-1a cells but its oligomer shepherd the cells for IgA response. 1757 May 27

We previously reported marked differences in small intestinal morphology, including changes in crypt depth and villous height, after inoculation of germ-free pigs with different bacterial species. In an attempt to identify the mechanisms governing changes in villous morphology associated with bacterial colonization, 2 gnotobiotic experiments were performed. In each experiment, 16 piglets were allocated to 4 treatment groups including germ-free (GF), monoassociation with Lactobacillus fermentum (LF) or Escherichia coli (EC), or conventionalized with sow feces (SF). Piglets were reared under gnotobiotic conditions until 14 d of age, at which time whole intestinal tissue and enterocytes were collected for histological, gene expression, and protein analysis. Proliferating cell nuclear antigen, tumor necrosis factor alpha (TNFalpha), Fas ligand (FasL), CD3epsilon, caspase 3 (casp3), and toll-like receptors (TLR)2, 4, and 9 expression were measured by quantitative PCR. Activated casp3 was measured by Western blot. Increased abundance of activated casp3 and transcripts encoding proliferating cell nuclear antigen, TNFalpha, CD3epsilon, and FasL was observed in SF and EC treatment groups compared with GF and LF. Expression of TLR2 was increased (P < 0.05) in the SF treatment and tended to be greater (P < 0.08) in EC relative to LF and GF. Results indicate that conventional bacteria and E. coli but not L. fermentum increase overall cell turnover by stimulating increased apoptosis through the expression of FasL and TNFalpha and by increasing cell proliferation. The differential regulation of TLR expression indicates that microbially induced changes may be mediated in part by these receptors. Induction of inflammatory responses and activation of apoptosis through death receptors appears to play a significant role in enterocyte turnover mediated by commensal bacteria.
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PMID:Enterocyte proliferation and apoptosis in the caudal small intestine is influenced by the composition of colonizing commensal bacteria in the neonatal gnotobiotic pig. 1778 95

Microglia, the resident innate immune cells of the CNS, detect invading pathogens via various receptors, including the TLR. Microglia are involved in a number of neurodegenerative diseases in which their activation may be detrimental to neurons. It is largely unknown how this potentially deleterious action can be countered on a cellular level. We previously found that the interaction of TLR2 with group B Streptococcus (GBS), the most important pathogen in neonatal bacterial meningitis, activates microglia that in turn generate neurotoxic NO. We report in this study that GBS not only activates microglia, but also induces apoptosis in these cells via TLR2 and the TLR-adaptor molecule MyD88. Soluble toxic mediators, such as NO, are not responsible for this form of cell death. Instead, interaction of GBS with TLR2 results in formation and activation of caspase-8, a process that involves the transcription factor family Ets. Whereas caspase-8 plays an essential role in GBS-induced microglial apoptosis, caspase-3 is dispensable in this context. We suggest that TLR2- and caspase-8-mediated microglial apoptosis constitutes an autoregulatory mechanism that limits GBS-induced overactivation of the innate immune system in the CNS.
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PMID:TLR2 and caspase-8 are essential for group B Streptococcus-induced apoptosis in microglia. 1794 88

Sepsis induces widespread lymphocyte apoptosis, resulting in impaired immune defenses and increased morbidity and mortality. There are multiple potential triggers or signaling molecules involved in mediating death signals. Elucidating the specific signaling pathways that are involved in mediating lymphocyte apoptosis may lead to improved therapies of this lethal disorder. We investigated a number of key cellular receptors and intracellular signaling pathways that may be responsible for apoptotic cell death. Specifically, we investigated the role of pathogen-associated molecular patterns (TLR2, TLR4, and IL-1R), intracellular signaling proteins (MyD88 and TRIF), cytoplasmic transcription factors (STAT1 and STAT4), and the MAPK pathway (JNK1) in sepsis-induced lymphocyte apoptosis. Studies were performed in the cecal ligation and puncture (CLP) model of sepsis using specific gene-targeted deletions. CLP-induced lymphocyte apoptosis was evaluated 20 h post-operation by active caspase-3 and TUNEL staining. Surprisingly, the only genetic construct that ameliorated T and B lymphocyte sepsis-induced apoptosis ( approximately 80% and 85%, respectively) occurred in MyD88(-/-) mice. Despite the marked decrease in sepsis-induced apoptosis, MyD88(-/-) mice had a worsened survival. In conclusion, lymphocyte death in sepsis likely involves multiple pathogen-sensing receptors and redundant signaling pathways. MyD88 was effective in blocking apoptosis, as it is essential in mediating most pathogen recognition pathways; however, MyD88 is also critical for host survival in a model of severe peritonitis.
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PMID:Deletion of MyD88 markedly attenuates sepsis-induced T and B lymphocyte apoptosis but worsens survival. 1821 65


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