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Characterization of seven murine caspase family members.

Seven members of the murine caspase (mCASP) family were cloned and functionally characterized by transient overexpression: mCASP-1 (mICE), mCASP-2 (Ich1), mCASP-3 (CPP32), mCASP-6 (Mch2), mCASP-7 (Mch3), mCASP-11 (TX) and mCASP-12. mCASP-11 is presumably the murine homolog of human CASP-4. Although mCASP-12 is related to human CASP-5 (ICErel-III), it is most probably a new CASP-1 family member. On the basis of sequence homology, the caspases can be divided into three subfamilies: first, mCASP-1, mCASP-11 and mCASP-12; second, mCASP-2; third, mCASP-3, mCASP-6 and mCASP-7. The tissue distribution of the CASP-1 subfamily transcripts is more restricted than that of the CASP-3 subfamily transcripts, suggesting that the transcriptional regulation of the CASP members within one subfamily is related, but is quite different between the CASP-1 and the CASP-3 subfamilies. Transient overexpression of each of the seven CASPs induced apoptosis in mammalian cells. Only two, mCASP-1 as well as mCASP-3, were able to process precursor interleukin (IL)-1beta to biologically active IL-1beta. In addition, mCASP-3 is the predominant PARP-cleaving enzyme in vivo.

Amino Acid Sequence↗

Caspase-mediated degradation of human 5-lipoxygenase in B lymphocytic cells.

5-Lipoxygenase (5-LO) is a tightly regulated enzyme in the synthesis of bioactive lipids from arachidonic acid. Here, we demonstrate that 5-LO is regulated by caspases, which are signaling molecules that control critical biological processes by means of specific limited proteolysis. Cell splitting of the Epstein-Barr virus-transformed B lymphocytic cell line BL41-E95-A caused a pronounced, but transient, reduction of functional 5-LO protein, accompanied by the appearance of a 62-kDa 5-LO cleavage product. In parallel, splitting of BL41-E95-A cells induced activation of caspase-6 (casp-6) and casp-8. Caspase activation and 5-LO degradation were blocked by the protein-synthesis inhibitor cycloheximide, and cell-permeable peptide inhibitors of casp-6 and casp-8 prevented 5-LO cleavage. Activation of casp-6 and casp-8 was connected to subsequent enhancement of cell proliferation, whereas selective caspase inhibition blocked cell growth. Last, isolated human 5-LO was cleaved by recombinant casp-6 in vitro to a 58-kDa fragment. Based on site-directed mutagenesis studies, 5-LO is cleaved by casp-6 after Asp-170, which in a homology-based 3D model of 5-LO is located on the enzyme periphery. We suggest that splitting of BL41-E95-A cells induces de novo synthesis of a protein involved in the activation of casp-6, which cleaves 5-LO.

Arachidonate 5-Lipoxygenase↗

Salmonella exploits caspase-1 to colonize Peyer's patches in a murine typhoid model.

Salmonella typhimurium invades host macrophages and induces apoptosis and the release of mature proinflammatory cytokines. SipB, a protein translocated by Salmonella into the cytoplasm of macrophages, is required for activation of Caspase-1 (Casp-1, an interleukin [IL]-1beta-converting enzyme), which is a member of a family of cysteine proteases that induce apoptosis in mammalian cells. Casp-1 is unique among caspases because it also directly cleaves the proinflammatory cytokines IL-1beta and IL-18 to produce bioactive cytokines. We show here that mice lacking Casp-1 (casp-1(-/)- mice) had an oral S. typhimurium 50% lethal dose (LD(50)) that was 1,000-fold higher than that of wild-type mice. Salmonella breached the M cell barrier of casp-1(-/)- mice efficiently; however, there was a decrease in the number of apoptotic cells, intracellular bacteria, and the recruitment of polymorphonuclear lymphocytes in the Peyer's patches (PP) as compared with wild-type mice. Furthermore, Salmonella did not disseminate systemically in the majority of casp-1(-/)- mice, as demonstrated by significantly less colonization in the PP, mesenteric lymph nodes, and spleens of casp-1(-/)- mice after an oral dose of S. typhimurium that was 100-fold higher than the LD(50). The increased resistance in casp-1(-/)- animals appears specific for Salmonella infection since these mice were susceptible to colonization by another enteric pathogen, Yersinia pseudotuberculosis, which normally invades the PP. These results show that Casp-1, which is both proapoptotic and proinflammatory, is essential for S. typhimurium to efficiently colonize the cecum and PP and subsequently cause systemic typhoid-like disease in mice.

Animals↗

Outcome of carotid endarterectomy and stent insertion based on grading of carotid endarterectomy risk: a 7-year prospective study.

OBJECT: The authors of this study prospectively compared periprocedural neurological morbidity and the appearance of lesions on diffusion-weighted (DW) magnetic resonance (MR) imaging in patients who had undergone carotid endarterectomy (CEA) or carotid artery stent placement (CASP) with distal balloon protection, based on a CEA risk grading scale. METHODS: Patients undergoing CEA (139 patients) and CASP (92 patients) were classified into Grades I to IV, based on the presence of angiographic (Grade II), medical (Grade III), and neurological (Grade IV) risks. Although not randomized, the CEA and CASP groups were well matched in terms of the graded risk factors except for a greater proportion of neurologically unstable patients in the CEA group (11 compared with 3%, p = 0.037). There were greater proportions of asymptomatic (64 compared with 34%, p = 0.006) and North American Symptomatic Carotid Endarterectomy Trial-ineligible patients (29 compared with 14%, p < 0.0001) in the CASP group. The overall rates of neurological morbidity with ischemic origin and the appearance of lesions on DW MR imaging after CEA were 2.2 and 9.3%, and those after CASP were 7.6 and 35.9% (nondisabling stroke only), respectively. The only disabling stroke was caused by an intracerebral hemorrhage attributable to hyperperfusion in one case (0.7%) of CEA. There were no deaths. There was no significant association between neurological morbidity and the risk grade in patients who had undergone CEA, although the incidence of lesions on DW imaging was significantly greater in the Grade IV risk group compared with that in the other risk groups combined (42.1 compared with 4.2%, p < 0.0001). After CASP, a higher incidence of neurological morbidity and lesions on DW imaging was noted for the Grade II and III risk groups combined as compared with that in the Grade I risk group, regardless of a symptomatic or an asymptomatic presentation (neurological morbidity: 10.5 compared with 3.1%, respectively, p = 0.41; and DW imaging lesions: 47.4 compared with 19.4%, p = 0.01). The incidence of lesions on DW imaging after CEA was significantly lower than that after CASP except for the Grade IV risk groups. CONCLUSIONS: Despite a higher incidence of DW imaging-demonstrated lesions in the Grade IV risk group, there was no significant association between the risk group and neurological morbidity rates after CEA. The presence of vascular and medical risk profiles conferred higher rates of neurological morbidity and an increased incidence of lesions on DW imaging after CASP. Considering that no serious nonneurological complications were noted, CEA and CASP appear to be complementary methods of revascularization for carotid artery stenosis with various risk profiles.

Aged↗

CAFASP2: the second critical assessment of fully automated structure prediction methods.

The results of the second Critical Assessment of Fully Automated Structure Prediction (CAFASP2) are presented. The goals of CAFASP are to (i) assess the performance of fully automatic web servers for structure prediction, by using the same blind prediction targets as those used at CASP4, (ii) inform the community of users about the capabilities of the servers, (iii) allow human groups participating in CASP to use and analyze the results of the servers while preparing their nonautomated predictions for CASP, and (iv) compare the performance of the automated servers to that of the human-expert groups of CASP. More than 30 servers from around the world participated in CAFASP2, covering all categories of structure prediction. The category with the largest participation was fold recognition, where 24 CAFASP servers filed predictions along with 103 other CASP human groups. The CAFASP evaluation indicated that it is difficult to establish an exact ranking of the servers because the number of prediction targets was relatively small and the differences among many servers were also small. However, roughly a group of five "best" fold recognition servers could be identified. The CASP evaluation identified the same group of top servers albeit with a slightly different relative order. Both evaluations ranked a semiautomated method named CAFASP-CONSENSUS, that filed predictions using the CAFASP results of the servers, above any of the individual servers. Although the predictions of the CAFASP servers were available to human CASP predictors before the CASP submission deadline, the CASP assessment identified only 11 human groups that performed better than the best server. Furthermore, about one fourth of the top 30 performing groups corresponded to automated servers. At least half of the top 11 groups corresponded to human groups that also had a server in CAFASP or to human groups that used the CAFASP results to prepare their predictions. In particular, the CAFASP-CONSENSUS group was ranked 7. This shows that the automated predictions of the servers can be very helpful to human predictors. We conclude that as servers continue to improve, they will become increasingly important in any prediction process, especially when dealing with genome-scale prediction tasks. We expect that in the near future, the performance difference between humans and machines will continue to narrow and that fully automated structure prediction will become an effective companion and complement to experimental structural genomics.

Automation↗

Induction of apoptosis in human tumor cells after exposure to Auger electrons: comparison with gamma-ray exposure.

To clarify the contribution of apoptosis to cell death in four human solid tumor cell lines, clonogenic cell survival (indicator of radiosensitivity) and induction of caspase-3 (CASP-3)/caspase-3-like proteases (CASP-3LP) and the production of DNA fragmentation (markers for apoptosis) were studied in RKO, LS174T, MCF7 and TE671 cells exposed to DNA-incorporated Auger-electron-emitting (125)I (5-[(125)I]iodo-2'-deoxyuridine) or gamma-radiation. Clonogenic survival was assessed by colony-forming assay, CASP-3/CASP-3LP induction with a fluorogenic substrate and DNA fragmentation by ligation-mediated polymerase chain reaction. For (125)I, log dose-survival curves had no shoulder [high-linear-energy-transfer (LET)-like] and decreased exponentially at different rates in various cell lines. Induction of CASP-3/CASP-3LP in radiosensitive RKO and LS174T cells was threefold greater than that in radioresistant TE671 and MCF7 cells. Nucleosomal laddering in (125)I-radiosensitive cell lines was dose-dependent, and no laddering was detected in radioresistant lines. For gamma-radiation, the survival curve for LS174T cells was monoexponential and that for the other lines exhibited a distinct shoulder (low-LET-like). The most radiosensitive cell line, LS174T, showed the highest induction of CASP-3/CASP-3LP, and the most radioresistant line, TE671, showed the lowest induction. Although DNA laddering was not detectable in TE671 cells, it was observed in other lines, being most prominent in LS174T cells. We conclude that apoptosis initiated by DNA-incorporated (125)I is dose-dependent, correlates with cell radiosensitivity and takes place through a CASP-3-mediated pathway, whereas that after gamma-irradiation probably occurs via a CASP-3-independent pathway and/or a CASP-3-mediated pathway and does not correlate with cell radiosensitivity.

Apoptosis↗

Characterization of a novel isoform of caspase-9 that inhibits apoptosis.

We have identified a novel isoform of rat caspase-9 in which the C terminus of full-length caspase-9 is replaced with an alternative peptide sequence. Casp-9-CTD (where CTD is carboxyl-terminal divergent) is expressed in multiple tissues, with the relative highest expression observed in ovary and heart. Casp-9-CTD was found primarily in the cytoplasm and was not detected in the nucleus. Structural predictions suggest that in contrast to full-length caspase-9, casp-9-CTD will not be processed. Our model is supported by reduced protease activity of casp-9-CTD preparations in vitro and by the lack of detectable processing of casp-9-CTD proenzyme or the induction of cell death following transfection into cells. Both neuronal and non-neuronal cell types transfected with casp-9-CTD were resistant to death evoked by trophic factor deprivation or DNA damage. In addition, cytosolic lysates prepared from cells permanently expressing exogenous casp-9-CTD were resistant to caspase induction by cytochrome c in reconstitution assays. Taken together, our observations indicate that casp-9-CTD acts as a dominant-negative variant. Its expression in various tissues indicates a physiological role in regulating cell death.

Amino Acid Sequence↗

Essential role of gamma interferon in survival of colon ascendens stent peritonitis, a novel murine model of abdominal sepsis.

Despite considerable progress, peritonitis and sepsis remain life-threatening conditions. To improve the understanding of the pathophysiology encountered in sepsis, a new standardized and highly reproducible murine model of abdominal sepsis termed colon ascendens stent peritonitis (CASP) was developed. In CASP, a stent is inserted into the ascending colon, which generates a septic focus. CASP employing a stent of 14-gauge diameter (14G stent) results in a mortality of 100% within 18 to 48 h after surgery. By inserting stents of small diameters, mortality can be exactly controlled. Thus, CASP surgery with insertion of a 22G or 18G stent (22G or 18G CASP surgery) results in 38 or 68% mortality, respectively. 14G CASP surgery leads to a rapid invasion of bacteria into the peritoneum and the blood. As a consequence, endotoxemia occurs, inflammatory cells are recruited, and a systemic inflammatory response syndrome develops. Interestingly, the most pronounced upregulation of inflammatory cytokines (gamma interferon [IFN-gamma], tumor necrosis factor alpha [TNF-alpha] and interleukin-12) is observed in spleen and lungs. CASP surgery followed by stent removal at specific time intervals revealed that all animals survived if intervention was performed after 3 h, whereas removal of the septic focus after 9 h did not prevent death, suggesting induction of autonomous mechanisms of a lethal inflammatory response syndrome. 18G CASP surgery in IFN-gamma receptor-deficient (IFNgammaR-/-) mice revealed an essential role of IFN-gamma in survival of sepsis, whereas TNF receptor p55-deficient (TNFRp55-/-) mice did not show altered survival rates. In summary, this study describes a novel animal model that closely mimics human sepsis and appears to be highly suitable for the study of the pathophysiology of abdominal sepsis. Importantly, this model demonstrates a protective role of IFN-gamma in survival of bacterial sepsis.

Abdomen↗

Acid and particulate-induced aspiration lung injury in mice: importance of MCP-1.

A model of aspiration lung injury was developed in WT C57BL/6 mice to exploit genetically modified animals on this background, i.e., MCP-1(-/-) mice. Mice were given intratracheal hydrochloric acid (ACID, pH 1.25), small nonacidified gastric particles (SNAP), or combined acid plus small gastric particles (CASP). As reported previously in rats, lung injury in WT mice was most severe for "two-hit" aspiration from CASP (40 mg/ml particulates) based on the levels of albumin, leukocytes, TNF-alpha, IL-1beta, IL-6, MCP-1, KC, and MIP-2 in bronchoalveolar lavage (BAL) at 5, 24, and 48 h. MCP-1(-/-) mice given 40 mg/ml CASP had significantly decreased survival compared with WT mice (32% vs. 80% survival at 24 h and 0% vs. 72% survival at 48 h). MCP-1(-/-) mice also had decreased survival compared with WT mice for CASP aspirates containing reduced particulate doses of 10-20 mg/ml. MCP-1(-/-) mice given 5 mg/ml CASP had survival similar to WT mice given 40 mg/ml CASP. MCP-1(-/-) mice also had differing responses from WT mice for several inflammatory mediators in BAL (KC or IL-6 depending on the particle dose of CASP and time of injury). Histopathology of WT mice with CASP (40 mg particles/ml) showed microscopic areas of compartmentalization with prominent granuloma formation by 24 h, whereas lung tissue from MCP-1(-/-) mice had severe diffuse pneumonia without granulomas. These results indicate that MCP-1 is important for survival in murine aspiration pneumonitis and appears to act partly to protect uninjured lung regions by promoting isolation and compartmentalization of tissue with active inflammation.

Animals↗

CAFASP-1: critical assessment of fully automated structure prediction methods.

The results of the first Critical Assessment of Fully Automated Structure Prediction (CAFASP-1) are presented. The objective was to evaluate the success rates of fully automatic web servers for fold recognition which are available to the community. This study was based on the targets used in the third meeting on the Critical Assessment of Techniques for Protein Structure Prediction (CASP-3). However, unlike CASP-3, the study was not a blind trial, as it was held after the structures of the targets were known. The aim was to assess the performance of methods without the user intervention that several groups used in their CASP-3 submissions. Although it is clear that "human plus machine" predictions are superior to automated ones, this CAFASP-1 experiment is extremely valuable for users of our methods; it provides an indication of the performance of the methods alone, and not of the "human plus machine" performance assessed in CASP. This information may aid users in choosing which programs they wish to use and in evaluating the reliability of the programs when applied to their specific prediction targets. In addition, evaluation of fully automated methods is particularly important to assess their applicability at genomic scales. For each target, groups submitted the top-ranking folds generated from their servers. In CAFASP-1 we concentrated on fold-recognition web servers only and evaluated only recognition of the correct fold, and not, as in CASP-3, alignment accuracy. Although some performance differences appeared within each of the four target categories used here, overall, no single server has proved markedly superior to the others. The results showed that current fully automated fold recognition servers can often identify remote similarities when pairwise sequence search methods fail. Nevertheless, in only a few cases outside the family-level targets has the score of the top-ranking fold been significant enough to allow for a confident fully automated prediction. Because the goals, rules, and procedures of CAFASP-1 were different from those used at CASP-3, the results reported here are not comparable with those reported in CASP-3. Nevertheless, it is clear that current automated fold recognition methods can not yet compete with "human-expert plus machine" predictions. Finally, CAFASP-1 has been useful in identifying the requirements for a future blind trial of automated served-based protein structure prediction.

Algorithms↗

[Molecular aspects of alterations in normal normal conjunctival epithelium. Role of apoptosis-associated genes].

BACKGROUND: The aim of the present study was to evaluate the age-dependent physiological expression pattern of apoptosis-related genes in the normal conjunctiva. PATIENTS AND METHODS: Healthy probands (group A: 24 probands and group B: 24 probands) were subjected to modified impression cytology using a PTFE membrane for evaluation of age-dependent expression of apoptosis-related genes in the normal conjunctiva. RNA was isolated from the cytologic impression specimens and used for cDNA synthesis employing SuperScriptTM II reverse transcriptase. RESULTS: RT-PCR revealed the detection of apoptosis-related mRNAs as follows (group A compared to group B): Apaf-1: 4.2/4.2%, Bcl-2: 41.7/41.7%, Bim: 0/0%, Bag-1: 70.8/100%, p53: 0/8.3%, Casp-3: 4.2/66.7%, Casp-5: 70.8/37.5%, Casp-8: 62.5/20.8%, Casp-9: 25/12.5%, c-myc: 83.3/95.8%, BAX: 91.7/70.8%, and BAD: 95.8/87.5%. CONCLUSION: The results revealed an age-dependent expression of apoptosis-associated genes (proapoptotic: Casp-3, Casp-5, Casp-8, antiapoptotic Bag-1) in normal human conjunctiva. Taken together these investigations provide basic information to understand the expression of apoptosis-associated genes in various diseases of the conjunctiva.

Adult↗

Polymorphisms in the caspase-8 gene and the risk of lung cancer.

Caspase-8 (CASP-8) is an initiator CASP in the cell death receptor-mediated apoptotic pathway, and plays an important role in the development of cancer. Polymorphisms and their haplotypes in the CASP-8 gene can result in alterations in CASP-8 expression and/or activity, thereby modulating the susceptibility to lung cancer. To test this hypothesis, we examined the association of -678_-673delAGTAAG (-678del) and IVS12-19G-->A polymorphisms and their haplotypes with the risk of lung cancer in a Korean population. The CASP-8 genotypes were determined in 432 lung cancer patients and 432 healthy age- and gender-matched control subjects. The distributions of the CASP-8 -678del and IVS12-19G-->A genotypes were not significantly different between the overall lung cancer cases and the controls. When the cases were categorized by tumor histology, however, the IVS12-19 AA genotype and the combined IVS12-19 GA + AA genotype were associated with a significantly decreased risk of small cell carcinoma (SmCC) compared with the IVS12-19 GG genotype [adjusted odds ratio (OR) = 0.14, 95% confidence interval (CI) = 0.03-0.64, P = 0.01; and adjusted OR = 0.56, 95% CI = 0.33-0.96, P = 0.03, respectively]. Consistent with the genotyping analyses, the -678del-/IVS12-19A haplotype containing 94% of the IVS12-19A allele in the study population was associated with a significantly decreased risk of SmCC compared with the -678del-/IVS12-19G (adjusted OR = 0.58, 95% CI = 0.36-0.93, P = 0.023, and Pc = 0.046). These findings suggest that the CASP-8 gene may contribute to an inherited predisposition to SmCC of the lung.

Aged↗

Characterization of a novel proapoptotic caspase-2- and caspase-9-binding protein.

Caspases play important roles in regulating apoptotic signaling pathways. Here we report the cloning, by the yeast two hybrid system with dominant negative caspase-2 as "bait," of a proapoptotic molecule named proapoptotic caspase adaptor protein (PACAP), encoded by a 372-base pair open reading frame. Binding of this novel protein to caspase-2 (casp-2) was confirmed in yeast two hybrid, in vitro, and in vivo assays. The deduced amino acid sequence revealed homology to functional motifs, including ATP and cytochrome c binding sites. PACAP mRNA was widely expressed in most human tissues; in transfected cells, PACAP was diffusely expressed in the cytoplasm. Bindings studies with the PACAP recombinant protein demonstrated specific binding to casp-2 and casp-9 but not to casp-3, -4, -7, or -8 in cell extracts. Cotransfection experiments showed that PACAP binds to casp-2 and -9 in 293T cells. In addition, studies with truncated PACAP demonstrated a requirement for residues 39-72 of PACAP for specific binding to casp-2 and -9. Transient transfection of PACAP into 293T human kidney cells and rat-1 fibroblasts triggered apoptosis at 24 h, which was at least in part prevented by an inhibitor of casp-3-like enzymes. Transfection of PACAP into human B cell lines using a retroviral system also triggered apoptotic cell death. In addition, transcription of PACAP in primary human B cells was dramatically down-regulated early after cellular activation by CD40L and Staphylococcus aureus and markedly up-regulated as the cells apoptose. These findings identify a novel proapoptotic caspase adaptor protein.

Adaptor Proteins, Signal Transducing↗

Caspase 9 promoter polymorphisms and risk of primary lung cancer.

Caspase-9 (CASP-9) is an initiator CASP in the apoptosome-driven apoptosis pathway and plays an important role in the development and progression of cancer. Polymorphisms in the promoter region of the CASP-9 gene may influence the promoter activity of this gene, thereby modulating susceptibility to lung cancer. To test this hypothesis, we examined the association of four polymorphisms [-1263A>G, -905T>G, -712C>T and -293_-275delCGTGAGGTCAGTGCGGGGA (-293del)] in the CASP-9 promoter with the risk of lung cancer in a Korean population. The CASP-9 genotypes were determined in 432 lung cancer patients and 432 healthy controls that were frequency-matched for age and gender. The -1263 GG genotype was associated with a significantly decreased risk of lung cancer compared with the -1263 AA genotype or combined -1263 AA+AG genotype [adjusted odds ratio (OR)=0.64, 95% confidence interval (95% CI)=0.42-0.98, P=0.04 and adjusted OR=0.67, 95% CI=0.46-0.97, P=0.01, respectively]. For the -712C>T polymorphism, individuals with at least one -712T allele were at a significantly increased risk of lung cancer compared with those harboring the -712 CC genotype (adjusted OR=1.42, 95% CI=1.06-1.89, P=0.02). Consistent with the results of genotype analyses, the -1263G/-712C (G-C) haplotype was associated with a significantly decreased risk of lung cancer [adjusted OR=0.59, 95% CI=0.47-0.75, P and Bonferroni corrected P (Pc)<0.001]. Moreover, the risk of lung cancer decreased in a dose-dependent manner as the number of the G-C haplotypes increased (adjusted OR=0.60, 95% CI=0.45-0.81, P=0.0007 and Pc=0.0014 for the G-C heterozygotes and adjusted OR=0.34, 95% CI=0.17-0.68, P=0.0023 and Pc=0.0046 for the G-C homozygotes; P(trend)<0.001). The promoter assay revealed the G-C haplotype to have a significantly higher promoter activity than the -1263G/-712T and -1263A/-712C haplotypes. These results suggest that CASP-9 promoter polymorphisms affect CASP-9 expression and contribute to genetic susceptibility to lung cancer.

Aged↗

Molecular cloning of a pepper gene that is homologous to SELF-PRUNING.

"Determinate" and "indeterminate" inflorescences in plants are controlled by a single recessive gene, for example, SELF-PRUNING (SP) in Solanum lycopersicum, TERMINAL FLOWER1 in Arabidopsis, CENTRORADI-ALIS in Antirrhinum, and CENTRORADIALIS-like gene in tobacco. Pepper (Capsicum annuum L.) is an indeterminate species in which shoots grow indefinitely. In this study, we cloned and characterized the pepper SP-like gene (CaSP). RT-PCR revealed that the CaSP transcript accumulates to higher levels in floral buds than in other organs. Comparison of genomic DNA and cDNA sequences from indeterminate and determinate pepper plants revealed the insertion of a single base in the first exon of CaSP in the determinate pepper plants. CaSP is annotated in linkage group 8 (chromosome 6) of the SNU2 pepper genetic map and showed similar synteny to SP in tomato. Transgenic tobacco plants overexpressing CaSP displayed late-flowering phenotypes similar to the phenotypes caused by overexpression of CaSP orthologs in other plants. Collectively, these results suggest that pepper CaSP is an ortholog of SP in tomato.

Amino Acid Sequence↗

Activation of caspase-8 in the Alzheimer's disease brain.

Recent studies support the activation of apoptotic pathways in the Alzheimer's disease (AD) brain. Neurons committed to apoptosis may do so by either activation of a receptor-mediated pathway employing caspase-8 or through an alternative mitochondrial pathway involving oxidative stress. In the present study, the role of caspase-8 in the AD brain was examined by designing a caspase-cleavage site-directed antibody to one of the active fragments of caspase-8. In vitro analysis with this antibody, termed CASP-8p18, demonstrated that it recognized the active 18-kDa fragment of caspase-8 but not the precursor protein. In vivo immunohistochemical analysis using hippocampal tissue sections from AD or aged-matched control brains demonstrated CASP-8p18 immunolabeling of neurons in all AD cases, whereas little staining was observed in controls. These results were confirmed using a commercially available antibody that, like the CASP-8p18 antibody reacts only with the 18-kDa fragment of caspase-8 and not full-length caspase-8. As with CASP-8p18 antibody, the commercial antibody-labeled neurons in all AD cases, while showing a relative paucity of staining in representative control cases. Labeling of CASP-8p18 within tangle-bearing neurons was observed in double-labeling studies with AT8 or PHF-1, both markers for neurofibrillary tangles (NFTs). In addition, using a caspase-cleavage site-directed antibody that recognizes cleavage products of caspase-3 showed colocalization of this antibody with the CASP-8p18 antibody within NFTs. These results suggest a role for caspase-8 and the receptor-mediated apoptotic pathway as a mechanism leading to the activation of caspase-3 within neurons of the AD brain.

Aged↗

Identification and characterization of AtCASP, a plant transmembrane Golgi matrix protein.

Golgins are a family of coiled-coil proteins that are associated with the Golgi apparatus. They are necessary for tethering events in membrane fusion and may act as structural support for Golgi cisternae. Here we report on the identification of an Arabidopsis golgin which is a homologue of CASP, a known transmembrane mammalian and yeast golgin. Similar to its homologues, the plant CASP contains a long N-terminal coiled-coil region protruding into the cytosol and a C-terminal transmembrane domain with amino acid residues which are highly conserved across species. Through fluorescent protein tagging experiments, we show that plant CASP localizes at the plant Golgi apparatus and that the C-terminus of this protein is sufficient for its localization, as has been shown for its mammalian counterpart. In addition, we demonstrate that the plant CASP is able to localize at the mammalian Golgi apparatus. However, mutagenesis of a conserved tyrosine in the transmembrane domain revealed that it is necessary for ER export and Golgi localization of the Arabidopsis CASP in mammalian cells, but is not required for its correct localization in plant cells. These data suggest that mammalian and plant cells have different mechanisms for concentrating CASP in the Golgi apparatus.

Amino Acid Motifs↗

Progressive, severe lung injury secondary to the interaction of insults in gastric aspiration.

This study examines lung injury and inflammation over 24 hours following intratracheal instillation of hydrochloric acid (acid), small nonacidic gastric particles (SNAP), or combined acid and small particles (CASP) in adult rats. The severity and duration of injury was significantly greater for CASP compared to acid or SNAP based on PaO2/FiO2, bronchoalveolar lavage (BAL) albumin, and BAL cell numbers. The inflammatory response associated with aspiration injury from CASP was distinct in several respects. Tumor necrosis factor (TNF)-alpha was greatly reduced in CASP compared to SNAP or acid, whereas interleukin (IL)-1beta was increased. Levels of cytokine-induced neutrophil chemoattractant (CINC)-1, monocyte chemoattractant protein (MCP)-1, and IL-10 in lavage were also significantly increased in animals injured with CASP compared to other forms of aspiration. Statistical analysis showed that BAL levels of IL-10 correlated most strongly with albumin leakage in aspiration-injured animals at 6 and 24 hours, followed by BAL levels of MCP-1. Additional cytokine cluster analyses indicated that levels of MCP-1 and CINC-1 in BAL from all injured animals were strongly correlated with inflammatory neutrophil numbers at 6 and 24 hours post aspiration, and that IL-10 levels in BAL were strongly correlated with inflammatory cell numbers at 24 hours. Preliminary blocking experiments showed that administration of anti-IL-10 antibody increased the albumin permeability index at 6 hours in SNAP and CASP animals, but anti-MCP-1 antibody did not affect the severity of injury. The results of this study support the possibility that different forms of aspiration are associated with identifiable cytokine profiles, and that specific cytokines, including IL-10 and MCP-1, may have utility as diagnostic or prognostic markers in clinical applications.

Animals↗