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)

To become insulin independent, patients with type 1 diabetes mellitus require transplantation of at least two donor pancreata because of massive beta-cell loss in the early post-transplantation period. Many studies describing the introduction of new immunosuppressive protocols have shown that this loss is due to not only immunological events but also nonimmunological factors. To test to what extent hypoxia may contribute to early graft loss, we analyzed the occurrence of apoptotic events and the expression of hypoxia-inducible factor 1 (HIF-1), a heterodimeric transcription factor consisting of an oxygen-dependent alpha subunit and a constitutive beta subunit. Histological analysis of human and rat islets revealed nuclear pyknosis as early as 6 h after hypoxic exposure (1% O2). Moreover, immunoreactivity to activated caspase-3 was observed in the core region of isolated human islets. Of note, both of these markers of apoptosis topographically overlap with HIF-1alpha immunoreactivity. HIF-1alpha mRNA was detected in islets from human and rat as well as in several murine beta-cell lines. When exposed to hypoxia, mouse insulinoma cells (MIN6) had an increased HIF-1alpha protein level, whereas its mRNA level did not alter. In conclusion, our data provide convincing evidence that reduced oxygenation is an important cause of beta-cell loss and suggest that HIF-1alpha protein level is an indicator for hypoxic regions undergoing apoptotic cell death. These observations suggest that gene expression under the control of HIF-1 represents a potential therapeutic tool for improving engraftment of transplanted islets.
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PMID:Apoptosis in hypoxic human pancreatic islets correlates with HIF-1alpha expression. 1192 16

Increased levels of Mcl-1 (myeloid cell factor-1) have been reported in several cancers, suggesting an important role played by Mcl-1 in cancer cell survival. Mcl-1 is an anti-apoptotic protein shown to delay or block apoptosis. In this work, using semiquantitative immunofluorescence, real-time PCR, and RNase protection assay, an increase in Mcl-1 expression was detected in hepatoma HepG2 cells incubated under hypoxia or in the presence of cobalt chloride. Through analysis of the Mcl-1 promoter sequence, a putative HIF-1 (hypoxiainducible factor-1) binding site was identified. A Mcl-1 promoter fragment containing this hypoxia-responsive element was able to bind HIF-1 in vitro. It also induced hypoxia-dependent transcription of a luciferase reporter gene, which was suppressed by anti-HIF-1alpha short interfering RNA. Finally, overexpression of Mcl-1 protected HepG2 cells against apoptosis induced by tert-butyl hydroperoxide as shown by inhibition of caspase-3 activation and DNA fragmentation. All these data suggest a potential anti-apoptotic role of HIF-1 that could protect cells against apoptosis under hypoxia by overexpression of the Mcl-1 protein.
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PMID:Hypoxia-inducible factor-1-dependent overexpression of myeloid cell factor-1 protects hypoxic cells against tert-butyl hydroperoxide-induced apoptosis. 1561 Oct 89

Electrical stimulation of the vagal efferent nerve improves the survival of myocardial infarcted rats. However, the mechanism for this beneficial effect is unclear. We investigated the effect of acetylcholine (ACh) on hypoxia-inducible factor (HIF)-1alpha using rat cardiomyocytes under normoxia and hypoxia. ACh posttranslationally regulated HIF-1alpha and increased its protein level under normoxia. ACh increased Akt phosphorylation, and wortmannin or atropine blocked this effect. Hypoxia-induced caspase-3 activation and mitochondrial membrane potential collapse were prevented by ACh. Dominant-negative HIF-1alpha inhibited the cell protective effect of ACh. In acute myocardial ischemia, vagal nerve stimulation increased HIF-1alpha expression and reduced the infarct size. These results suggest that ACh and vagal stimulation protect cardiomyocytes through the PI3K/Akt/HIF-1alpha pathway.
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PMID:Acetylcholine from vagal stimulation protects cardiomyocytes against ischemia and hypoxia involving additive non-hypoxic induction of HIF-1alpha. 1581 27

The transcriptional factor hypoxia-inducible factor-1 (HIF-1) plays an important role in solid tumor cell growth and survival. Overexpression of HIF-1alpha has been demonstrated in many human tumors and predicts a poor response to chemoradiotherapy. We examined the HIF-1alpha-induced survival pathways in human oral squamous cell carcinoma cell (OSCC) lines. The results showed that forced expression of HIF-1alpha suppressed hypoxia-induced apoptosis of OSCC lines by inhibiting cytochrome c release from mitochondria. Overexpression of HIF-1alpha inhibited the generation of reactive oxygen species (ROS), elevation of intracellular Ca(2+) concentration, reduction of mitochondrial membrane potential, and cytosolic accumulation of cytochrome c, which resulted in the inactivation of caspase-9 and caspase-3. In addition, antiapoptotic Bcl-2 and Bcl-X(L) levels were increased and pro-apoptotic Bax and Bak levels were decreased in the HIF-1alpha-overexpressing OSCC line. Overexpression of HIF-1alpha also increased the levels of phosphorylation of Akt and extracellular signal-regulated kinases (ERK). These findings indicate that HIF-1alpha prevents apoptotic cell death through two mechanisms, including inhibition of cytochrome c release and activation of Akt and ERK.
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PMID:Mechanism of HIF-1alpha-dependent suppression of hypoxia-induced apoptosis in squamous cell carcinoma cells. 1605 10

Under normoxic conditions the alpha-subunit of hypoxia-inducible factor (HIF-1alpha) protein is targeted for degradation by the von Hippel-Lindau (VHL) tumor suppressor protein acting as an E3 ubiquitin ligase. Recently, we developed a hypoxia-targeting protein, TOP3, which consisted of procaspase-3 with the VHL-mediated protein destruction motif of HIF-1alpha. This design enables procaspase-3 to be regulated similarly with HIF-1alpha, being degraded under normoxia while stabilized under hypoxia. Furthermore, stabilized TOP3 was cleaved by the hypoxic stress-induced endogenous caspases and thus the procaspase-3 was converted to active caspase-3 specifically under hypoxic conditions. These data demonstrated that the VHL-mediated protein destruction motif of HIF-1alpha endowed procaspase-3 with hypoxia-specific cytotoxicity.
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PMID:Mechanism of hypoxia-specific cytotoxicity of procaspase-3 fused with a VHL-mediated protein destruction motif of HIF-1alpha containing Pro564. 1701 Mar 41

The overall goal of the current study was to examine the functional activity of the prolyl hydroxylases (PHDs) in maturing chondrocytes. Herein, we show for the first time that the PHDs are expressed in the maturing zone of the growth plate, and by a chondrocytic cell line. We determined if this protein and its substrate, hypoxia inducible factor (HIF)-1alpha, modulated the induction of apoptosis. Using a chondrocyte cell line that matured in culture, we inhibited HIF-1alpha expression using siRNA technology and pharmacologically blocked PHD activity. We noted that PHD suppression sensitized the cells to an apoptotic challenge with H(2)O(2). We next examined the interplay between the PHDs and HIF-1alpha by suppressing HIF-1alpha and blocking PHD activity. We noted reduced killing when the mature HIF-silenced cells were challenged with H(2)O(2). In contrast, there was limited change in the viability of immature cells. Based on these differences in chondrocyte susceptibility, it is concluded that HIF-1alpha sensitizes maturing cells to H(2)O(2)-mediated killing. We next determined if this change in the viability of the PHD-inhibited cells was linked to changes in activation of caspase-3. It was noted that there was a minimal change in enzyme activity of the PHD-inhibited HIF-1alpha suppressed cells. Finally, we found that as the chondrocytes mature, the activities of catalase and SOD were significantly reduced and that there was a decrease in the levels of Bcl-2 and Bcl(XL). This loss of protective activity together with the changes mediated by HIF would be expected to generate conditions that would favor the induction of chondrocyte apoptosis.
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PMID:Expression of HIF prolyl hydroxylase isozymes in growth plate chondrocytes: relationship between maturation and apoptotic sensitivity. 1704 72

Pathologies of senescence, in particular those of neurosensory organs represent an important health problem. The improvement of the life expectation entails the fast increase of the frequency of the age-related hearing loss (ARHL) in the population. There are numerous factors that contribute to this process, which include altered vascular characteristics, hypoxia/ischemia, genetic mutations and production of reactive oxygen species. We were interested in understanding the mechanisms involved in the cochlear degeneration in a mouse model of ARHL, the cd/1 mice. Since in human, hypoxia/ischemia is an important pathogenetic factor for inner ear disease, the regulation of HIF-1 activity in the cochlea, the presence of radical oxygen species in the cochlea and its subsequent disturbances of cellular signaling cascades were investigated. In this study, we explored auditory function of cd/1 mice at the age of 4, 12 and 24 weeks and correlated it with the presence of oxidative damage in the cochlea, and cochlear HIF-1 responsive target genes regulation, involved in pathways promoting inflammation such as tumor necrosis factor (TNF-alpha), or cell death with the p53 protein, Bax protein and surviving factors with insulin-like growth factor-1 (IGF-1). After implantation of electrodes for auditory nerve acoustic thresholds measurements, we analyzed every cochlea. First, we confirmed that the cd/1 mice presented a characteristic profile of ARHL starting at 12 weeks of age. Then, according to our previous report [Riva, C., Longuet, M., Lucciano, M., Magnan, J., Lavieille, J.P., 2005. Implication of mitochondrial apoptosis in neural degeneration in a murin model for presbyacusis. Rev. Laryngol. Otol. Rhinol. 126 (2), 67-74], we noticed many alterations in the cochlea. Histologically, at 4 weeks, intensive HIF-1alpha expression was detected in the cochlea followed by ROS formation at 12 weeks, which may lead to cochlear degeneration and induction the onset of ARHL in the cd/1 mice model. In the cochlea, while the inner and the outer hair cells remained intact at 4 and 12 weeks, the spiral ganglion was more altered. Moreover, the Schwann cells of the spiral ganglion seemed to be more vulnerable to free radical damage than the neurons and degenerated more rapidly. The mechanisms of degeneration in the spiral ganglion involved a caspase-3 and Bax mediated-apoptosis via p53 protein accumulation. Since oxygen radicals are required for the post-translational stabilization of HIF-1alpha during hypoxia, the tandem " HIF-ROS " induced multiple reactions within the cochlea, like a strong inflammatory response with increased expression of TNF-alpha, and inhibition of neuronal protection mechanisms with repression of IGF-1.
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PMID:Age-related hearing loss in CD/1 mice is associated to ROS formation and HIF target proteins up-regulation in the cochlea. 1714 99

2,2,5,7,8-Pentamethyl-6-hydroxychromane (PMC) is the most potent analogue of alpha-tocopherol for anti-oxidation. It is more hydrophilic than other alpha-tocopherol derivatives and has potent free radical-scavenging activity. In the present study, PMC significantly attenuated middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia in rats. Administration of PMC at 20mg/kg, showed marked reductions in infarct size compared with that of control rats. MCAO-induced focal cerebral ischemia was associated with increases in HIF-1alpha, active caspase-3, iNOS, and nitrotyrosine expressions in ischemic regions. These expressions were markedly inhibited by treatment with PMC (20mg/kg). In addition, PMC (4-12 microM) inhibited respiratory bursts in human neutrophils stimulated by fMLP (800 nM) and PMA (320 nM). Furthermore, PMC (6, 12, and 60 microM) also significantly inhibited neutrophil migration stimulated by leukotriene B(4) (160 nM). An electron spin resonance (ESR) method was conducted on the scavenging activity of PMC on the free radicals formed. PMC (12 microM) greatly reduced the ESR signal intensities of superoxide anion, hydroxyl radical, and methyl radical formation. In conclusion, we demonstrate a potent neuroprotective effect of PMC on MCAO-induced focal cerebral ischemia in vivo. This effect may be mediated, at least in part, by inhibition of free radical formation, followed by inhibition of HIF-1alpha activation, apoptosis formation (active caspase-3), neutrophil activation, and inflammatory responses (i.e., iNOS and nitrotyrosine expressions), resulting in a reduction in the infarct volume in ischemia-reperfusion brain injury. Thus, PMC treatment may represent a novel approach to lowering the risk or improving function in ischemia-reperfusion brain injury-related disorders.
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PMID:Neuroprotective effects of PMC, a potent alpha-tocopherol derivative, in brain ischemia-reperfusion: reduced neutrophil activation and anti-oxidant actions. 1715 67

Photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PPIX) is clinically established approach for a number of defined applications. However, in order to optimize the therapeutic benefits of PDT, the specific mode of cell destruction should be better defined. Apoptosis is favored over necrosis for clinical practice as the latter causes more side-effects. In the present study, we analyse PDT-induced cell death and its correlation to various PDT parameters (different doses applied, time after PDT treatment) in vitro using reverse phase protein arrays. Human urothelial cell lines with varying degrees of differentiation (UROtsa, RT4, RT112, J82) were subjected to in vitro-PDT using increasing doses of irradiation. In addition, positive controls for apoptosis, necrosis and un-/specific cellular damage were included. Cells were harvested over a specified time course, lysed and arrayed onto nitrocellulose-covered glass slides. The arrays were analyzed for expression of apoptosis-related proteins by immunohistochemistry. Analysis of caspase-3 and -9 expression, the activation of HIF-1alpha, Bcl2, Cox2 and the phosphorylation of AKT reveals signal activation due to a PDT-stimulus in correlation with the positive controls. Data were analyzed by unsupervised hierarchical clustering and depicted as a heat map revealing cell-specific patterns of pathway stimulation. Higher differentiated phenotypes showed a more distinct signal response in general and a higher apoptotic response in detail. Lower differentiated cell lines lost pathway regulation capabilities according to their state of dedifferentiation. Reverse phase protein arrays are a promising technique for signal pathway profiling: they exceed the range of traditional western blots by sensitivity, high-throughput capability, minimal sample consumption and easy quantification of results obtained.
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PMID:Analyzing effects of photodynamic therapy with 5-aminolevulinic acid (ALA) induced protoporphyrin IX (PPIX) in urothelial cells using reverse phase protein arrays. 1804 85

Hypoxic preconditioning (HP) and stem cell transplantation have been extensively studied as individual therapies for ischemic stroke. The present investigation is an initial effort to combine these methods to achieve increased therapeutic effects after brain ischemia. Sublethal in vitro hypoxia pretreatment significantly enhanced the tolerance of neurally-differentiating embryonic stem (ES) cells and primary bone marrow mesenchymal stem cells (BMSC) to apoptotic cell death (40-50% reduction in cell death and caspase-3 activation). The HP protective effects on cultured cells lasted for at least 6 days. HP increased secretion of erythropoietin (EPO) and upregulated expression of bcl-2, hypoxia-inducible factor (HIF-1alpha), erythropoietin receptor (EPOR), neurofilament (NF), and synaptophysin in ES cell-derived neural progenitor cells (ES-NPCs). The HP cytoprotective effect was diminished by blocking EPOR, while pretreatment of ES-NPCs with recombinant human EPO mimicked the HP effect. HP-primed ES-NPCs survived better 3 days after transplantation into the ischemic brain (30-40% reduction in cell death and caspase-3 activation). Finally, transplanted HP-primed ES-NPCs exhibited extensive neuronal differentiation in the ischemic brain, accelerated and enhanced recovery of sensorimotor function when compared to transplantation of non-HP-treated ES-NPCs. The cell-priming strategy aimed to promote transplanted cell survival and their tissue repair capability provides a simple yet effective way of optimizing cell transplantation therapy.
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PMID:In vitro hypoxic preconditioning of embryonic stem cells as a strategy of promoting cell survival and functional benefits after transplantation into the ischemic rat brain. 1827 54


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