Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.36 (caspase-1)
 6,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the clinical setting of solid organ transplantation the event of graft-versus-host disease (GvHD) is rare and not easily predictable. Even intestinal and multivisceral transplants harbour a huge amount of immunocompetent cells and they do not exert a significantly higher risk to trigger serious GvH reactions. A series of our own experimental studies has been conducted to delineate the role of the host's innate immune system in the context of GvHD following parental to F1 hybrid semiallogeneic small bowel transplantation (SBTx). These results clearly demonstrated the immunological significance of the recipient's status of natural killer (NK) cell activity to counteract donor-derived lymphocytes and related cytotoxicity. NK cells and macrophages are both endowed with Ca2+-dependent receptors of the C-type lectin family which interact with a diversity of high-affinity oligosaccharide ligands expressed on potential target cells. One of these proteins of the C-type lectin family, termed NKR-P1, has been cloned and sequenced. Activation of NKR-P1 stimulates activation-induced cell death (AICD) of bound target cells. As intracellular mediators of apoptotic cell death a new family of cysteine proteases, the caspases, have been defined. These proteases appear to be involved in the initiation of apoptosis in response to a number of stimuli. This study was conducted to investigate the impact on the activity level of host NK cells and on target cell lysis of donor-derived lymphocytes after heterotopic semiallogeneic (parental [DA;RT1.aaav1] to F1 [DA x LEW;RT1.(1)]) small bowel transplantation using a rat model. The host's NK activity was either specifically activated (by use of polyinosinic:polycytodilic acid [poly-I:C]) or suppressed (by depletion of host NK cells after intraperitoneal administration of the NKR-P1 monoclonal antibody 3.2.3). The impact of NK-activity on the incidence of GvHD and the recipients' survival was correlated with the frequency of apoptotic cell death and related expression of caspases 1 (ICE) and 3 (CPP-32) from donor and recipient small bowel tissues. Our results confirm that depletion of NK cells in F1 host rats prior to parental small bowel transplantation significantly decreased the mean survival to 11.4 days versus 16.2 days of nondepleted F1 rats (p < 0.01). Conversely, activation of host NK activity with poly-I:C abrogated GvHD in all 12 recipient rats and led to long-term survival in seven of 12 animals. Long-term survival was associated with a substantially higher frequency of apoptotic cell death in donor and recipient small bowel and mesenteric lymph nodes. On day 10 after transplantation, Northern blot analysis of these tissues revealed profound upregulation of mRNA-specific gene expression for caspase 1 and 3 as potential mediators of programmed cell death of activated lymphocytes. Our findings emphasize the importance of NK cell associated innate immunity in the context of GvHD after semiallogeneic small bowel transplantation. Killing of alloreactive donor-derived lymphocytes was mediated by the NKR-P1 protein on NK cells and could be suppressed after pretreatment of F1 hosts with anti-NKR-P1 mAb 3.2.3. Moreover, NK cell-mediated apoptosis induced upregulation of caspases 1 and 3, thus elucidating the involvement of this protein in the context of caspase-mediated target cell killing.
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PMID:The role of natural killer cell mediated caspases activation in a graft-versus-host disease model of semiallogeneic small bowel transplantation. 1037 71

Caspases are a family of cysteine proteases which have important roles in activation of cytokines and in apoptosis. Caspase-1, or interleukin-1 beta converting enzyme (ICE), promotes maturation of interleukin-1 beta (IL-1 beta) and interleukin-18 (IL-18) by proteolytic cleavage of precursor forms to generate biologically active peptides. We report the cloning and sequencing of equine caspase-1 cDNA. Equine caspase-1 is 405 amino acids in length and has 72% and 63% identity to human and mouse caspase-1, respectively, at the amino acid level. Sites of proteolytic cleavage and catalytic activity as identified in human caspase-1, are conserved.
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PMID:Nucleotide sequence of equine caspase-1 cDNA. 1037 17

Interleukin-1 beta (IL-1 beta)-converting enzyme (ICE, caspase-1) processes the IL-1 beta precursor to mature inflammatory cytokine IL-1 beta. ICE has been identified as a unique cysteine protease, which cleaves Asp-X bonds, shows resistance to E-64 (an inhibitor of most cysteine proteases) and has a primary structure that is homologous to CED-3, a protein required for apoptosis (programmed cell death) in the nematode Caenorhabditis elegans, and to mammalian cysteine proteases that initiate and execute apoptosis, e.g., apopain/CPP32/caspase-3. The inhibitors of the ICE/CED-3 family or caspases, as they are called recently, may constitute therapeutic agents for amelioration of inflammatory and apoptosis-associated diseases. The most efficient ICE inhibitors are peptide aldehydes and peptidyl chloro or (acyloxy)methanes. A recent study revealed that both D- and L-Asp are accepted by ICE at the P1 of such inhibitors, and the peptidyl (acyloxy)methane analogues having the beta-homo-aspartyl residue [-NH-CH(CH2COOH)-CH2CO-] are inactive. These findings we reexamined in terms of two issues. (a) ICE's resistance to E-64. Since it was thought to be caused by the enzyme's unique substrate specificity, we prepared substrate-based analogues, which were not inhibitory suggesting significant structural difference between the active centers of ICE and papain-like enzymes. (b) Tolerance for D-stereochemistry at the P1 of these inhibitors. In view of the mechanism of cysteine protease inhibition by peptidyl X-methanes, we thought that this phenomenon should be a general characteristic of cysteine proteases and the hAsp-containing analogues should behave as reversible inhibitors. Here, we analyzed the inhibition of ICE and apopain in comparison with that of papain, thrombin, and trypsin by peptide L/D-alpha-aldehydes and their L-beta-homo-aldehyde [-NH-CH(R)-CH2-CHO] analogues. The following results were found. (1) The peptidyl L-beta-homo-aspartals are potent inhibitors for caspases. (2) The L-beta-homo analogues of peptide aldehyde inhibitors designed for other proteases are not inhibitory. (3) Unlike trypsin and thrombin (serine proteases), papain (cysteine protease) shows tolerance for D-stereochemistry at the P1 site of peptide aldehydes in proportion to the lability of the alpha-hydrogen of the P1-D-residue. The complete tolerance of ICE for P1-D-Asp may arise from this residue's high tendency to epimerization. (4) Reaction of cysteine proteases with peptide aldehyde or peptidyl X-methane inhibitors containing P1-D-residues may include alpha-proton abstraction followed by asymmetric induction leading to P1-L-residue-containing products.
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PMID:Peptidyl beta-homo-aspartals (3-amino-4-carboxybutyraldehydes): new specific inhibitors of caspases. 1038 Mar 58

Manganese ions block apoptosis of phagocytes induced by various agents. The prevention of apoptosis was attributed to the activation of manganous superoxide dismutase (Mn-SOD) and to the antioxidant function of free Mn2+ cations. However, the effect of Mn2+ on B cell apoptosis is not documented. In this study, we investigated the effects of Mn2+ on the apoptotic process in human B cells. We observed that Mn2+ but not Mg2+ or Ca2+, inhibited cell growth and induced apoptosis of activated tonsilar B cells, Epstein Barr virus (EBV)-negative Burkitt's lymphoma cell lines (BL-CL) and EBV-transformed B cell lines (EBV-BCL). In the same conditions, no apoptosis was observed in U937, a monoblastic cell line. Induction of B cell apoptosis by Mn2+ was time- and dose-dependent. The cell permeable tripeptide inhibitor of ICE family cysteine proteases, zVAD-fmk, suppressed Mn2+-induced apoptosis. Furthermore, Mn2+ triggered the activation of interleukin-1beta converting enzyme (ICE/caspase 1), followed by the activation of CPP32/Yama/Apopain/caspase-3. In addition, poly-(ADP-ribose) polymerase (PARP), a cellular substrate for CPP32 protease was degraded to generate apoptotic fragments in Mn2+-treated B cell lines. The inhibitor, zVAD-fmk suppressed Mn2+-triggered CPP32 activation and PARP cleavage and apoptosis. These results indicate that the activation of caspase family proteases is required for the apoptotic process induced by Mn2+ treatment of B cells. While the caspase-1 inhibitor YVAD was unable to block apoptosis, the caspase-3 specific inhibitor DEVD-cmk, partially inhibited Mn2+-induced CPP32 activation, PARP cleavage and apoptosis of cells. Moreover, Bcl-2 overexpression in BL-CL effectively protected cells from apoptosis and cell death induced by manganese. This is the first report showing the involvement of Mn2+ in the regulation of B lymphocyte death presumably via a caspase-dependent process with a death-protective effect of Bcl-2.
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PMID:Manganese induces apoptosis of human B cells: caspase-dependent cell death blocked by bcl-2. 1038 35

Apoptosis eliminates inappropriate or autoreactive T lymphocytes during thymic development. Intracellular mediators involved in T-cell receptor (TCR)-mediated apoptosis in developing thymocytes during negative selection are therefore of great interest. Caspases, cysteine proteases that mediate mature T-cell apoptosis, have been implicated in thymocyte cell death, but their regulation is not understood. We examined caspase activities in distinct thymocyte subpopulations that represent different stages of T-cell development. We found caspase activity in CD4+CD8+ double positive (DP) thymocytes, where selection involving apoptosis occurs. Earlier and later thymocyte stages exhibited no caspase activity. Only certain caspases, such as caspase-3 and caspase-8-like proteases, but not caspase-1, are active in DP thymocytes in vivo and can be activated when DP thymocytes are induced to undergo apoptosis in vitro by TCR-crosslinking. Thus, specific caspases appear to be developmentally regulated in thymocytes.
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PMID:Caspases in T-cell receptor-induced thymocyte apoptosis. 1038 40

Apoptosis is an important mechanism for regulating the numbers of monocytes and macrophages. Caspases (cysteine-aspartate-specific proteases) are key molecules in apoptosis and require proteolytic removal of prodomains for activity. Caspase-1 and caspase-3 have both been connected to apoptosis in other model systems. The present study attempted to delineate what role these caspases play in spontaneous monocyte apoptosis. In serum-free conditions, monocytes showed a commitment to apoptosis as early as 4 h in culture, as evidenced by caspase-3-like activity. Apoptosis, as defined by oligonucleosomal DNA fragmentation, was prevented by a generalized caspase inhibitor, z-VAD-FMK, and the more specific caspase inhibitor, z-DEVD-FMK. The caspase activity was specifically attributable to caspase-3 by the identification of cleavage of procaspase-3 to active forms by immunoblots and by cleavage of the fluorogenic substrate DEVD-AFC. In contrast, a caspase-1 family inhibitor, YVAD-CMK, did not protect monocytes from apoptosis, and the fluorogenic substrate YVAD-AFC failed to show an increase in activity in apoptotic monocytes. When cultured with LPS (1 microgram/ml), monocyte apoptosis was prevented, as was the activation of caspase-3. Unexpectedly, LPS did not change baseline caspase-1 activity. These findings link spontaneous monocyte apoptosis to the proteolytic activation of caspase-3.
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PMID:Spontaneous human monocyte apoptosis utilizes a caspase-3-dependent pathway that is blocked by endotoxin and is independent of caspase-1. 1043 6

Stress response is a universal phenomenon. However, a rat histiocytic cell line, BC-8, showed no heat shock response and failed to synthesize heat shock protein 70 (hsp70) upon heat shock at 42 degrees C for 30 min. BC-8 is a clone of AK-5, a rat macrophage tumor line that is adapted to grow in culture and has the same chromosome number and tumorigenic potential as AK-5. An increase in either the incubation temperature or time or both to BC-8 cells leads to loss of cell viability. In addition, heat shock conditions activated apoptotic cell death in these cells as observed by cell fragmentation, formation of nuclear comets, apoptotic bodies, DNA fragmentation and activation of ICE-like cysteine proteases. Results presented here demonstrate that BC-8 cells cannot mount a typical heat shock response unlike all other eukaryotic cells and that in the absence of induction of hsps upon stress, these cells undergo apoptosis at 42 degrees C.
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PMID:Lack of heat shock response triggers programmed cell death in a rat histiocytic cell line. 1045 35

In view of a large and growing literature, this overview emphasizes recent advances in neuronal caspases and their role in cell death. To provide historical perspective, morphology and methods are surveyed with emphasis on early studies on interleukin converting enzyme (ICE) as a prototype for identifying zymogen subunits. The unexpected homology of ICE (caspase-1) to Caenorhabditis elegans death gene CED-3 provided early clues linking caspases to programmed cell death, and led later to discovery of bcl-2 proteins (CED-9 homologs) and 'apoptosis associated factors' (Apafs). Availability of substrates, inhibitors, and cDNAs led to identification of up to 16 caspases as a new superfamily of unique cysteine proteinases targeting Asp groups. Those acting as putative death effectors dismantle neurons by catabolism of proteins essential for survival. Caspases degrade amyloid precursor protein (APP), presenilins (PS1, PS2), tau, and huntingtin, raising questions on their role in neurodegeneration. Brain contains 'inhibitors of apoptosis proteins' (IAPs) survivin and NAIP associated also with some neuronal disorders. Apoptotic stress in neurons initiates a chain of events leading to activation of distal caspases by pathways that remain to be fully mapped. Neuronal caspases play multiple roles for initiation and execution of cell death, for morphogenesis, and in non-mitotic neurons for homeostasis. Recent studies focus on cytochrome c as pivotal in mediating conversion of procaspase-9 as a major initiator for apoptosis. Identifying signaling pathways and related events paves the way to design useful therapeutic remedies to prevent neuronal loss in disease or aging.
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PMID:Recent advances on neuronal caspases in development and neurodegeneration. 1045 52

The regulation of caspases, cysteine proteinases that cleave their substrates after aspartic residues, is poorly understood, even though they are involved in tightly regulated cellular processes. The recently discovered serpin analogue proteinase inhibitor 9 (PI9) is unique among human serpin analogues in that it has an acidic residue in the putative specificity-determining position of the reactive-site loop. We measured the ability of PI9 to inhibit the amidolytic activity of several caspases. The hydrolysis of peptide substrates by caspase-1 (interleukin-1beta-converting enzyme), caspase-4 and caspase-8 is inhibited by PI9 in a time-dependent manner. The rate of reaction of caspase-1 with PI9, as well as the rate of substrate hydrolysis of the initial caspase-PI9 complex, shows a hyperbolic dependence on the concentration of PI9, indicative of a two-step kinetic mechanism for inhibition with an apparent second-order rate constant of 7x10(2) M(-1).s(-1). The hydrolysis of a tetrapeptide substrate by caspase-3 is not inhibited by PI9. The complexes of caspase-1 and caspase-4 with PI9 can be immunoprecipitated but no complex with caspase-3 can be detected. No complex can be immunoprecipitated if the active site of the caspase is blocked with a covalent inhibitor. These results show that PI9 is an inhibitor of caspase-1 and to a smaller extent caspase-4 and caspase-8, but not of the more distantly related caspase-3. PI9 is the first example of a human serpin analogue that inhibits members of this class of cysteine proteinases.
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PMID:Caspase-1 (interleukin-1beta-converting enzyme) is inhibited by the human serpin analogue proteinase inhibitor 9. 1047 77

Gingipains are cysteine proteinases acting as key virulence factors of the bacterium Porphyromonas gingivalis, the major pathogen in periodontal disease. The 1.5 and 2.0 A crystal structures of free and D-Phe-Phe-Arg-chloromethylketone-inhibited gingipain R reveal a 435-residue, single-polypeptide chain organized into a catalytic and an immunoglobulin-like domain. The catalytic domain is subdivided into two subdomains comprising four- and six-stranded beta-sheets sandwiched by alpha-helices. Each subdomain bears topological similarities to the p20-p10 heterodimer of caspase-1. The second subdomain harbours the Cys-His catalytic diad and a nearby Glu arranged around the S1 specificity pocket, which carries an Asp residue to enforce preference for Arg-P1 residues. This gingipain R structure is an excellent template for the rational design of drugs with a potential to cure and prevent periodontitis. Here we show the binding mode of an arginine-containing inhibitor in the active-site, thus identifying major interaction sites defining a suitable pharmacophor.
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PMID:Crystal structure of gingipain R: an Arg-specific bacterial cysteine proteinase with a caspase-like fold. 1052 90


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