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)

The purposes of this experiment were (1) to determine if apoptosis was accelerated during formation of selenite cataract, and (2) to determine the role of calpains and caspases in lens apoptosis. Evidence for apoptosis in selenite-injected rats included: approximately 7-8% of epithelial cells in germinative zone were positive, disappearance of the nuclear membrane, condensation of the chromatin, and breakdown of PARP. Activation of calpains was indicated by characteristic limited proteolysis of crystallins, breakdown of alpha-spectrin to 150/145 kDa fragments, hydrolysis of vimentin, and autolytic breakdown of m-calpain. Selenite cataract did not have an appreciable effect on the mRNA levels for caspase-3, calpains, and calpastatin. This indicated the increased enzyme activity of m-calpain and caspase-3 in selenite cataract occurred at the enzyme level rather than by upregulation of mRNAs. Increased calpain and caspase activity may be linked to the selenite-induced apoptosis. Such data are important because they indicate that apoptosis may be a fairly early event in selenite cataract.
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PMID:Evidence for apoptosis in the selenite rat model of cataract. 1096 62

It is well established that the proto-oncogene, bcl-2, can prevent apoptosis induced by a variety of factors. Regarding the mechanism by which BCL-2 prevents cell death, one theory suggests that it acts by protecting cells from oxidative stress. In the lens system, oxidative stress-induced apoptosis is implicated in cataractogenesis. To explore the possibility of anti-apoptotic gene therapy development for cataract prevention and also to further test the anti-oxidative stress theory of BCL-2 action, we have introduced the human bcl-2 gene into an immortalized rabbit lens epithelial cell line, N/N1003A. The stable expression clones of both vector- and bcl-2-transfected cells have been established. Treatment of the two cell lines with H(2)O(2) revealed that bcl-2-transfected cells were less capable of detoxifying H(2)O(2) than the control cells. Moreover, bcl-2-transfected cells are more susceptible to H(2)O(2)-induced apoptosis. To explore why bcl-2-transfected cells have reduced resistance to H(2)O(2)-induced apoptosis, we examined the expression patterns of several relevant genes and found that expression of the alphaB-crystallin gene was distinctly down-regulated in bcl-2-transfected cells compared with that in vector-transfected cells. This down-regulation was specific because a substantial inhibition of BCL-2 expression through antisense bcl-2 RNA significantly restored the level of alphaB-crystallin and, moreover, enhanced the ability of the bcl-2-transfected cells against H(2)O(2)-induced apoptosis. Introduction of a mouse alphaB-crystallin gene into bcl-2-transfected cells also counteracted the BCL-2 effects. Down-regulation of alphaB-crystallin gene was largely derived from changed lens epithelial cell-derived growth factor activity. Besides, alphaB-crystallin prevents apoptosis through interaction with procaspase-3 and partially processed procaspase-3 to prevent caspase-3 activation. Together, our results reveal that BCL-2 can regulate gene expression in rabbit lens epithelial cells. Through down-regulation of the alphaB-crystallin gene, BCL-2 attenuates the ability of rabbit lens epithelial cells against H(2)O(2)-induced apoptosis.
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PMID:Human bcl-2 gene attenuates the ability of rabbit lens epithelial cells against H2O2-induced apoptosis through down-regulation of the alpha B-crystallin gene. 1154 95

Apoptosis has been implied in normal lens development in the embryo as well as in lens fibre differentiation. It has also been suggested to play a role in non-congenital cataract and in the formation of posterior subcapsular opacification, but data on the presence of apoptosis in human lens epithelium from cataractous lenses are scarce and conflicting. The present study aimed to investigate apoptosis in lens epithelium from patients undergoing cataract surgery. The amount of apoptosis detected was correlated to age, gender, type of cataract, medications and disease. Moreover, the ability of human lens epithelial cells in culture to respond to the apoptosis-inducing agent staurosporin by activation of caspase-3 was investigated. Human lens capsulotomy specimens were collected immediately after surgery, frozen and later analysed with respect to caspase-3 activity, using the fluorogenic substrate Ac-DEVD-AMC. Generally, the activity of caspase-3 detected in this manner was very low and in 23% of the specimens it was non-detectable. However, there were differences in caspase activity between lens epithelial cells from different types of cataract, where samples from lenses with posterior subcapsular cataract exhibited significantly lower caspase-3 activity than lenses with a clear subcapsular zone. Age, gender or medications did not show any correlation with caspase activity but human capsulotomy specimens from diabetic patients exhibited significantly lower caspase-3 activity. Staurosporin caused a concentration-dependent increase in caspase activity in cultured human lens epithelial cells and the amount of apoptotic nuclei was also increased as viewed by staining with Hoechst 33342, showing chromatin condensation and nuclear fragmentation. Similar results were obtained when fresh human lens capsulotomy specimens were exposed to 1000 nM staurosporin for 24 hr. To conclude, the present data indicate that human lens epithelial cells have the ability to respond to apoptosis-inducing agents with caspase-3 dependent apoptosis, and that even though the general level of apoptosis in human lens epithelium in vivo is low, there are differences in caspase-3 activity levels in lenses with or without posterior subcapsular cataract. The latter finding supports previous studies indicating that this type of cataract may result from defective differentiation, in which apoptosis may play an important role.
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PMID:Decreased caspase-3 activity in human lens epithelium from posterior subcapsular cataracts. 1256 5

Exposure to ultraviolet radiation (UVR) and reactive oxygen species (ROS) can damage the human lens and contribute to cataract formation. Recent evidence suggests that apoptosis in lens epithelial cells (LEC) is an initiating event in noncongenital cataract formation in humans and animals. The present study examines the cellular and molecular mechanisms by which environmental (ultraviolet B [UVB]) and chemical (hydrogen peroxide [H(2)O(2)], t-butyl hydroperoxide [TBHP]) stress induces cell death in an SV-40 immortalized human lens epithelial (HLE) cell line. Treatment of HLE cells with UVB, H(2)O(2), and TBHP significantly decreased cell density with LD50 values of 350 J/m(2), 500 muM, and 200 muM, respectively. Cellular morphology, DNA fragmentation, and annexin/propidium iodide staining consistent with apoptosis was observed only in UVB-treated cells, whereas lactate dehydrogenase (LDH) release was significantly higher in H(2)0(2)- and TBHP-treated cells. In addition, activation of apoptotic stress-signaling proteins, including c-Jun NH2-terminal kinase (JNK), caspase-3, and DNA fragmentation factor 45 (DFF45) was observed only in UVB-treated cells. Inhibition of JNK activity increased UVB-induced cell death, suggesting that this pathway may serve a prosurvival role in HLE cells. These findings suggest UVB predominantly induces apoptosis in HLE cells, whereas H(2)O(2) and TBHP induce necrosis.
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PMID:Apoptotic and necrotic mechanisms of stress-induced human lens epithelial cell death. 1552 44

Heat shock protein 27 (Hsp27) is a stress-inducible protein in cells that functions as a molecular chaperone and also as an anti-apoptotic protein. Methylglyoxal (MGO) is a reactive dicarbonyl compound produced from cellular glycolytic intermediates that reacts non-enzymatically with proteins to form products such as argpyrimidine. We found considerable amount of Hsp27 in phosphorylated form (pHsp27) in human cataractous lenses. pHsp27 was the major argpyrimidine-modified protein in brunescent cataractous lenses. Modification by MGO enhanced the chaperone function of both pHsp27 and native Hsp27, but the effect on Hsp27 was at least three-times greater than on pHsp27. Phosphorylation of Hsp27 abolished its chaperone function. Transfer of Hsp27 using a cationic lipid inhibited staurosporine (SP)-induced apoptotic cell death by 53% in a human lens epithelial cell line (HLE B-3). MGO-modified Hsp27 had an even greater effect (62% inhibition). SP-induced reactive oxygen species in HLE-B3 cells was significantly lower in cells transferred with MGO-modified Hsp27 when compared to native Hsp27. In vitro incubation experiments showed that MGO-modified Hsp27 reduced the activity of caspase-9, and MGO-modified pHsp27 reduced activities of both caspase-9 and caspase-3. Based on these results, we propose that Hsp27 becomes a better anti-apoptotic protein after modification by MGO, which may be due to multiple mechanisms that include enhancement of chaperone function, reduction in oxidative stress, and inhibition of activity of caspases. Our results suggest that MGO modification and phosphorylation of Hsp27 may have important consequences for lens transparency and cataract development.
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PMID:Effect of methylglyoxal modification and phosphorylation on the chaperone and anti-apoptotic properties of heat shock protein 27. 1661 38

Posterior capsule opacification is the main complication of cataract surgery. Using adenovirus-mediated gene transfer, we recently reported that it was feasible to prevent PCO by overexpressing pro-apoptotic molecules such as pro-caspase 3 or Bax in the residual lens epithelial cells post-cataract surgery. However, this approach is feasible only if gene transfer can be restricted to the residual cells responsible for PCO. Initially, we tested an adenovirus (human serotype 5, HAd5), a lentivirus (HIV) and an oncoretrovirus (MLV) vector for the their in vivo transduction efficiency of rabbit lens cells. We found that HAd5 vectors were the most efficient (>90% of the cells could be transduced). Six potential lens-specific promoters were then cloned into HAd5 vectors and assayed for their ability to target expression to a specific population of cells, using in vitro, ex vivo and in vivo rabbit tissues and human lens capsular bags. We found that the LEP503, MIP and Filensin promoters induced strong lens-specific expression of a reporter gene, in human lens cells. Following this ex vivo assay, we showed in a rabbit PCO model that gene transfer could be spatially restricted to the capsular bag by confining the vector with Matrigel. Our combined approach using a lens-specific promoter and a biocompatible gel should render feasible a novel therapeutic strategy for PCO that targets the remaining lens cells.
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PMID:Lens cell targetting for gene therapy of prevention of posterior capsule opacification. 1672 94

The apoptosis of lens epithelial cells has been proposed as the common basis of cataract formation, with oxidative stress as the major cause. This study was performed to investigate the protective effect of the herbal constituent parthenolide against oxidative stress-induced apoptosis of human lens epithelial (HLE) cells and the possible molecular mechanisms involved. HLE cells (SRA01-04) were incubated with 50 microM H(2)O(2) in the absence or presence of different doses of parthenolide (10, 20 and 50 microM). To study apoptosis, the cells were assessed by morphologic examination and Annexin V-propidium iodide double staining flow cytometry; to investigate the underlying molecular mechanisms, the expression of caspase-3 and caspase-9 were assayed by Western blot and quantitative RT-PCR, and the activities of caspase-3 and caspase-9 were measured by a Chemicon caspase colorimetric activity assay kit. Stimulated with H(2)O(2) for 18 h, a high fraction of HLE cells underwent apoptosis, while in the presence of parthenolide of different concentrations, dose-dependent blocking of HLE cell apoptosis was observed. The expression of caspase-3 and caspase-9 induced by H(2)O(2) in HLE cells was significantly reduced by parthenolide both at the protein and mRNA levels, and the activation of caspase-3 and caspase-9 was also suppressed by parthenolide in a dose-dependent manner. In conclusion, parthenolide prevents HLE cells from oxidative stress-induced apoptosis through inhibition of the activation of caspase-3 and caspase-9, suggesting a potential protective effect against cataract formation.
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PMID:Parthenolide protects human lens epithelial cells from oxidative stress-induced apoptosis via inhibition of activation of caspase-3 and caspase-9. 1733 84

Ultraviolet radiation (UVR) is a risk factor for the development of ocular disease in humans, including acute photokeratitis, chronic corneal spheroidal degeneration, and cataract formation. This report describes the ocular lesions seen in 21 mice chronically exposed to UVR as part of a skin carcinogenicity study. All globes were affected to varying degrees. The primary lesion, not previously reported in UVR-exposed mice, was marked loss of keratocytes relative to age-matched controls. Secondary lesions included corneal stromal thinning, keratoconus, corneal vascularization and fibrosis, keratitis, globe rupture, and phthisis bulbi. In addition, more than 90% of UVR-exposed and unexposed lenses had evidence of cataract formation; this is the first report of the occurrence of spontaneous cataracts in 129 mice. In a subsequent study, apoptotic cells were identified histologically and by cleaved caspase 3 immunoreactivity in the corneal epithelium and, less commonly, in the corneal stroma after acute UVR exposure. Based on this finding, we propose that the loss of keratocytes observed in the chronic study was due to UVR-induced apoptosis.
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PMID:Ultraviolet radiation-induced corneal degeneration in 129 mice. 1794 56

Indoleamine 2,3-dioxygenase (IDO) is the first enzyme in the kynurenine pathway. The kynurenines formed in this pathway chemically modify proteins and cause apoptosis in cells. Evidence suggests that kynurenines and their protein modifications are involved in cataract formation, but this has yet to be directly demonstrated. We generated transgenic (Tg) mouse lines that overexpress human IDO in the lens. Homozygous Tg (homTg) lenses had higher IDO immunoreactivity, approximately 4.5 times greater IDO mRNA, and approximately 8 times higher IDO activity compared to lenses from hemizygous Tg (hemTg) animals. The kynurenine content was threefold higher in homTg than in hemTg but was not detected in wild-type (Wt) lenses. Kynurenine modifications were approximately 2.6 times greater in homTg than in hemTg or Wt. HomTg lenses had vacuoles in the epithelium and cortical fiber cells. Kynurenine modifications coincided with apoptosis in the secondary fiber cells of homTg lenses. Caspase-3 and caspase-9 activities were markedly higher in homTg than in hemTg and Wt. The glutathione content was approximately 36% lower in homTg compared to hemTg and Wt lenses. HomTg animals also developed bilateral cataracts within 3 months of birth. Together these data demonstrate that IDO-mediated production of kynurenines results in defects in fiber cell differentiation and their apoptosis and suggest that IDO activity is kept low in the lens to prevent deleterious effects by kynurenines.
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PMID:Indoleamine 2,3-dioxygenase overexpression causes kynurenine-modification of proteins, fiber cell apoptosis and cataract formation in the mouse lens. 1930 46

Oxidative stress plays a significant role in the progression of cataract. We aimed to investigate the protective effect of magnolol, a compound extracted from the Chinese herb Magnolia officinalis, against oxidative stress in human lens epithelial (HLE) cells as well as the possible molecular mechanism involved. In this study, magnolol was observed to protect against H2O2-induced cytotoxicity in HLE B-3 cells. Magnolol inhibited the generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential (Delta psi m) and release of cytochrome c from mitochondria caused by H2O2 into cytosol in HLE B-3 cells. Magnolol also inhibited H2O2-induced expressions of caspase-9 and caspase-3 and reduction of Bcl-2/Bax ratio. Moreover, magnolol attenuated the deactivation of ERK/MAPK (extracellular signal-regulated kinase/mitogen activated protein kinase) and the enhanced activation of p38, JNK (c-Jun N-terminal kinase) induced by H2O2. Magnolol could be useful in protecting against oxidative stress in HLE cells, suggesting a potential protective effect against cataractogenesis effect against cataractogenesis.
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PMID:Protective effect of magnolol against hydrogen peroxide-induced oxidative stress in human lens epithelial cells. 1965 15


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