UNIPROT:P42574 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Target Concepts:

Query: UNIPROT:P42574 (caspase-3)
45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stress of the endoplasmic reticulum (ER), which is associated with many neurodegenerative conditions, can lead to the elimination of affected cells by apoptosis through only partially understood mechanisms. Thapsigargin, which causes ER stress by inhibiting the ER Ca(2+)-ATPase, was found to not only activate the apoptosis effector caspase-3 but also to cause a large and prolonged increase in the activity of glycogen synthase kinase-3beta (GSK3beta). Activation of GSK3beta was obligatory for thapsigargin-induced activation of caspase-3, because inhibition of GSK3beta by expression of dominant-negative GSK3beta or by the GSK3beta inhibitor lithium blocked caspase-3 activation. Thapsigargin treatment activated GSK3beta by inducing dephosphorylation of phospho-Ser-9 of GSK3beta, a phosphorylation that normally maintains GSK3beta inactivated. Caspase-3 activation induced by thapsigargin was blocked by increasing the phosphorylation of Ser-9-GSK3beta with insulin-like growth factor-1 or with the phosphatase inhibitors okadaic acid and calyculin A, but the calcineurin inhibitors FK506 and cyclosporin A were ineffective. Insulin-like growth factor-1, okadaic acid, calyculin A, and lithium also protected cells from two other inducers of ER stress, tunicamycin and brefeldin A. Thus, ER stress activates GSK3beta through dephosphorylation of phospho-Ser-9, a prerequisite for caspase-3 activation, and this process is amenable to pharmacological intervention.
...
PMID:Central role of glycogen synthase kinase-3beta in endoplasmic reticulum stress-induced caspase-3 activation. 1222 24

We investigated the effect of a chronic exposure to high levels of free fatty acid (FFA; 2 mmol/L oleate/palmitate 2:1) or glucose (16.7 mmol/L) on islet cell apoptosis. Apoptosis was detected using 4 different methods: (1) cell staining with annexin-V fluorescien isothiocyanate (FITC) conjugate and propidium iodide (PI); (2) quantification of cytoplasmatic DNA fragments by an enzyme-linked immunosorbent assay (ELISA); (3) assay of caspase 3 activity; and (4) TdT-mediated dUTP nick-end labeling (TUNEL). Islet cells were also costained with an anti-insulin antibody to identify apoptotic beta cells. We also evaluated by reverse-transcriptase polymerase chain reaction (RT-PCR) the expression of bax, bcl-2, and caspas 3, genes involved in apoptosis. In islets cultured for 7 days in the presence of high FFA or for 3 days in the presence of high glucose levels, we observed: (1) a 2- to 3-fold increase of apoptotic cells conjugated with annexin-V FITC and PI; (2) a 4- to 6-fold increase of cytoplasmatic DNA fragments; (3) a 3- to 4-fold increase of caspase 3 activity; and (4) a significant increase of insulin positive apoptotic cells as detected with the TUNEL method. RT-PCR analysis indicated in islets exposed to high FFA or glucose levels an increase of bax (proapoptotic gene), a reduction of bcl-2 (antiapoptotic gene), and a slight (although not significant) increase in caspase 3 expression. Western blot analysis also showed an increase of Bax protein levels in islets exposed to high FFA or glucose. The simultaneous presence of both metabolic abnormalities did not further increase the amount of apoptotic cells, although the time-course of the cellular damage induced by FFA was accelerated by the contemporary presence of high glucose. To elucidate the mechanism by which FFA and glucose may induce pancreatic beta-cell damage, we examined whether nicotinamide prevents apoptosis in pancreatic islets cultured for 7 days with high FFA or for 3 days with high glucose. Nicotinamide was able to prevent beta-cell damage by significantly reducing apoptosis in both experimental conditions. Also, the increase of Bax protein level was prevented by nicotinamide. These data indicate that chronic exposure to elevated FFA or glucose levels increases apoptosis in rat pancreatic islets and these cytotoxic effects could be mediated by oxidative stress. This may contribute to the beta-cell failure that occurs in most in type 2 diabetic patients few years after clinical diabetes onset.
...
PMID:Chronic exposure to free fatty acids or high glucose induces apoptosis in rat pancreatic islets: possible role of oxidative stress. 1237 Aug 56

A constant remodeling of islet cell mass mediated by proliferative and apoptotic stimuli ensures a dynamic response to a changing demand for insulin. In this study, we investigated the effect of glucagon-like peptide-1 (GLP-1) in Zucker diabetic rats, an animal model in which the onset of diabetes occurs when the proliferative potential and the rate of beta-cell apoptosis no longer compensate for the increased demand for insulin. We subjected diabetic rats to a 2-d infusion of GLP-1 and tested their response to an ip glucose tolerance test. GLP-1 produced a significant increase of insulin secretion, which was paralleled by a decrease in plasma glucose levels (P < 0.001 and P < 0.01, respectively). Four days after the removal of the infusion pumps, rats were killed and the pancreas harvested to study the mechanism by which GLP-1 ameliorated glucose tolerance. Ex vivo immunostaining with the marker of cell proliferation, Ki-67, showed that the metabolic changes observed in rats treated with GLP-1 were associated with an increase in cell proliferation of the endocrine and exocrine component of the pancreas. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling staining, a marker of cellular apoptosis, indicated a reduction of apoptotic cells within the islet as well in the exocrine pancreas in GLP-1-treated rats. Double immunostaining for the apoptotic marker caspase-3 and for insulin showed a significant reduction of caspase-3 expression and an increase in insulin content in GLP-1-treated animals. Finally, staining of pancreatic sections with the nuclear dye 4,6-Diaminidino-2-phenyl-dihydrochloride demonstrated a marked reduction of fragmented nuclei in the islet cells of rats treated with GLP-1. Our findings provide evidence that the beneficial effects of GLP-1 in Zucker diabetic rats is mediated by an increase in islet cell proliferation and a decrease of cellular apoptosis.
...
PMID:Glucagon-like peptide-1 promotes islet cell growth and inhibits apoptosis in Zucker diabetic rats. 1239 37

Withdrawal of NGF (NGF-W) in PC12 cells leads to caspase and GSK3beta activation which results in cell death. Our recent findings suggest that inhibition of GSK3beta promotes PC12 cell survival after NGF-W. To determine whether these pathways interact from a signalling perspective, we compared the effects of BAF (a general caspase inhibitor), Li+ (a GSK3beta inhibitor) and insulin on NGF-W induced PC12 cell death. Maximal increase in DNA fragmentation was observed 3 h after NGF-W and was inhibited by BAF (7.5 microM), Li+ (IC(50) = 2 mM) and insulin (IC(50) = 100 nM). BAF inhibited caspase-3 activity and delayed cell death up to 6 h after NGF-W indicating that caspase inhibition is sufficient to prevent apoptosis. BAF had no major effect on GSK3betaactive site phosphorylation or activity suggesting the caspase pathway does not regulate GSK3beta activity. Conversely, Li+ inhibited caspase activity by only 20% but promoted cell survival for 24 h after NGF-W. Overexpression of dominant negative mutants of GSK3beta also inhibited apoptosis, but had only a minor effect on caspase activity after NGF-W. Taken together, these results suggest that GSK3beta is upstream of caspase signalling, and exerts a small effect on the caspase pathway.
...
PMID:Interactions between GSK3beta and caspase signalling pathways during NGF deprivation induced cell death. 1244 31

It has been reported that inositol hexakisphosphate (InsP(6), phytic acid), a natural product, has an anticancer role. However, there is inadequate information regarding the mechanism by which InsP(6) exerts anticancer actions, and the effect requires relatively high concentration of the agent, both of which hinders the usage of InsP(6) as an anticancer drug. In the present study, we investigated the mechanism by which InsP(6) acts as an anticancer agent, and tried to reduce the concentration of effective InsP(6). Treatment of HeLa cells with InsP(6) at 1 mM induced apoptosis, as assessed by counting the cell number, and by Hoechst and TUNEL staining. This is probably mediated by intracellular InsP(6) itself and/or the dephosphorylated forms of metabolized InsP(6), because incubation of HeLa cells with [(3)H]InsP(6) produces dephosphorylated forms such as InsP(4) and InsP(5). Induction of apoptosis by InsP(6) was examined in two ways: inhibition of cell survival signaling and direct induction of apoptosis. Treatment of HeLa cells with tumor necrosis factor (TNF) or insulin stimulated the Akt-nuclear factor kappaB (NFkappaB) pathway, a cell survival signal, which involves the phosphorylation of Akt and IkappaB, nuclear translocation of NFkappaB and NFkappaB-luciferase transcription activity. InsP(6) blocked all these cellular events, but phosphatidylinositol 3-kinase activity was not affected. As well as inhibiting the Akt-NFkappaB pathway, InsP(6) itself caused mitochondrial permeabilization, followed by cytochrome c release, which later caused activation of the apoptotic machinery, caspase 9, caspase 3 and poly (ADP-ribose) polymerase. When InsP(6) was applied together with histone, the effective concentration to induce apoptosis was approximately 10-fold lower. These results revealed that extracellularly applied InsP(6) directly activates the apoptotic machinery as well as inhibits the cell survival signaling, probably by the intracellular delivery followed by a dephosphorylation.
...
PMID:Inositol hexakisphosphate blocks tumor cell growth by activating apoptotic machinery as well as by inhibiting the Akt/NFkappaB-mediated cell survival pathway. 1250 26

Diabetes is associated with significant changes in plasma concentrations of lipoproteins. We tested the hypothesis that lipoproteins modulate the function and survival of insulin-secreting cells. We first detected the presence of several receptors that participate in the binding and processing of plasma lipoproteins and confirmed the internalization of fluorescent low density lipoprotein (LDL) and high density lipoprotein (HDL) particles in insulin-secreting beta-cells. Purified human very low density lipoprotein (VLDL) and LDL particles reduced insulin mRNA levels and beta-cell proliferation and induced a dose-dependent increase in the rate of apoptosis. In mice lacking the LDL receptor, islets showed a dramatic decrease in LDL uptake and were partially resistant to apoptosis caused by LDL. VLDL-induced apoptosis of beta-cells involved caspase-3 cleavage and reduction in the levels of the c-Jun N-terminal kinase-interacting protein-1. In contrast, the proapoptotic signaling of lipoproteins was antagonized by HDL particles or by a small peptide inhibitor of c-Jun N-terminal kinase. The protective effects of HDL were mediated, in part, by inhibition of caspase-3 cleavage and activation of Akt/protein kinase B. In conclusion, human lipoproteins are critical regulators of beta-cell survival and may therefore contribute to the beta-cell dysfunction observed during the development of type 2 diabetes.
...
PMID:Insulin-secreting beta-cell dysfunction induced by human lipoproteins. 1259 27

In insulin-secreting cells, cytokines activate the c-Jun N-terminal kinase (JNK), which contributes to a cell signaling towards apoptosis. The JNK activation requires the presence of the murine scaffold protein JNK-interacting protein 1 (JIP-1) or human Islet-brain 1(IB1), which organizes MLK3, MKK7 and JNK for proper signaling specificity. Here, we used adenovirus-mediated gene transfer to modulate IB1/JIP-1 cellular content in order to investigate the contribution of IB1/JIP-1 to beta-cell survival. Exposure of the insulin-producing cell line INS-1 or isolated rat pancreatic islets to cytokines (interferon-gamma, tumor necrosis factor-alpha and interleukin-1beta) induced a marked reduction of IB1/JIP-1 content and a concomitant increase in JNK activity and apoptosis rate. This JNK-induced pro-apoptotic program was prevented in INS-1 cells by overproducing IB1/JIP-1 and this effect was associated with inhibition of caspase-3 cleavage. Conversely, reducing IB1/JIP-1 content in INS-1 cells and isolated pancreatic islets induced a robust increase in basal and cytokine-stimulated apoptosis. In heterozygous mice carrying a selective disruption of the IB1/JIP-1 gene, the reduction in IB1/JIP-1 content in happloinsufficient isolated pancreatic islets was associated with an increased JNK activity and basal apoptosis. These data demonstrate that modulation of the IB1-JIP-1 content in beta cells is a crucial regulator of JNK signaling pathway and of cytokine-induced apoptosis.
...
PMID:The scaffold protein IB1/JIP-1 is a critical mediator of cytokine-induced apoptosis in pancreatic beta cells. 1264 31

We have recently shown that conditions known to activate AMP-activated protein kinase (AMPK) in primary beta-cells can trigger their apoptosis. The present study demonstrates that this is also the case in the MIN6 beta-cell line, which was used to investigate the underlying mechanism. Sustained activation of AMPK was induced by culture with the adenosine analogue AICA-riboside or at low glucose concentrations. Both conditions induced a sequential activation of AMPK, c-Jun-N-terminal kinase (JNK) and caspase-3. The effects of AMPK on JNK activation and apoptosis were demonstrated by adenoviral expression of constitutively active AMPK, a condition which reproduced the earlier-described AMPK-dependent effects on pyruvate kinase and acetyl-coA-carboxylase. The effects of JNK activation on apoptosis were demonstrated by the observations that (i). its inhibition by dicumarol prevented caspase-3 activation and apoptosis, (ii). adenoviral expression of the JNK-interacting scaffold protein JIP-1/IB-1 increased AICA-riboside-induced JNK activation and apoptosis. In primary beta-cells, AMPK activation was also found to activate JNK, involving primarily the JNK 2 (p54) isoform. It is concluded that prolonged stimulation of AMPK can induce apoptosis of insulin-producing cells through an activation pathway that involves JNK, and subsequently, caspase-3.
...
PMID:AMP-activated protein kinase can induce apoptosis of insulin-producing MIN6 cells through stimulation of c-Jun-N-terminal kinase. 1268 39

Mice with 50% Pdx1, a homeobox gene critical for pancreatic development, had worsening glucose tolerance with age and reduced insulin release in response to glucose, KCl, and arginine from the perfused pancreas. Surprisingly, insulin secretion in perifusion or static incubation experiments in response to glucose and other secretagogues was similar in islets isolated from Pdx1(+/-) mice compared with Pdx1(+/+) littermate controls. Glucose sensing and islet Ca(2+) responses were also normal. Depolarization-evoked exocytosis and Ca(2+) currents in single Pdx1(+/-) cells were not different from controls, arguing against a ubiquitous beta cell stimulus-secretion coupling defect. However, isolated Pdx1(+/-) islets and dispersed beta cells were significantly more susceptible to apoptosis at basal glucose concentrations than Pdx1(+/+) islets. Bcl(XL) and Bcl-2 expression were reduced in Pdx1(+/-) islets. In vivo, increased apoptosis was associated with abnormal islet architecture, positive TUNEL, active caspase-3, and lymphocyte infiltration. Although similar in young mice, both beta cell mass and islet number failed to increase with age and were approximately 50% less than controls by one year. These results suggest that an increase in apoptosis, with abnormal regulation of islet number and beta cell mass, represents a key mechanism whereby partial PDX1 deficiency leads to an organ-level defect in insulin secretion and diabetes.
...
PMID:Increased islet apoptosis in Pdx1+/- mice. 1269 34

Blockade of mitochondrial permeability transition protects against hypoglycemic brain damage. To study the mechanisms downstream from mitochondria that may cause neuronal death, we investigated the effects of cyclosporin A on subcellular localization of apoptosis-inducing factor and cytochrome c, activation of the cysteine proteases calpain and caspase-3, as well as its effect on brain extracellular calcium concentrations. Redistribution of cytochrome c occurred at 30 min of iso-electricity, whereas translocation of apoptosis-inducing factor to nuclei occurred at 30 min of recovery following 30 min of iso-electricity. Active caspase-3 and calpain-induced fodrin breakdown products were barely detectable in the dentate gyrus and CA1 region of the hippocampus of rat brain exposed to 30 or 60 min of insulin-induced hypoglycemia. However, 30 min or 3 h after recovery of blood glucose levels, fodrin breakdown products and active caspase-3 markedly increased, concomitant with a twofold increase in caspase-3-like enzymatic activity. When rats were treated with neuroprotective doses of cyclosporin A, but not with FK 506, the redistribution of apoptosis-inducing factor and cytochrome c was reduced and fodrin breakdown products and active caspase-3 immuno-reactivity was diminished whereas the extracellular calcium concentration was unaffected. We conclude that hypoglycemia leads to mitochondrial permeability transition which, upon recovery of energy metabolism, mediates the activation of caspase-3 and calpains, promoting cell death.
...
PMID:Cyclosporin A prevents calpain activation despite increased intracellular calcium concentrations, as well as translocation of apoptosis-inducing factor, cytochrome c and caspase-3 activation in neurons exposed to transient hypoglycemia. 1278 63

<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>