401
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Contributions of the Raf/MEK/ERK, PI3K/PTEN/Akt/mTOR and Jak/STAT pathways to leukemia. Leukemia 2008; 22:686-707. [DOI: 10.1038/leu.2008.26] [Citation(s) in RCA: 293] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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402
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Kuhn P, Sarkar DK. Ethanol induces apoptotic death of beta-endorphin neurons in the rat hypothalamus by a TGF-beta 1-dependent mechanism. Alcohol Clin Exp Res 2008; 32:706-14. [PMID: 18341643 DOI: 10.1111/j.1530-0277.2008.00627.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND We have previously shown that developing beta-endorphin neurons, in the arcuate nucleus of the hypothalamus become increasingly apoptotic when exposed to ethanol. As in the previous study we have observed an involvement in transforming growth factor beta 1 (TGF-beta1) in mediation of the apoptotic process, the present study was conducted to determine the ethanol-induced changes in this apoptotic regulatory peptide signaling in the arcuate nucleus of the hypothalamus of neonatal rats. METHODS Pups were exposed to 11.34% ethanol in a milk-based diet or control diet on postnatal day (PND) 3 to PND7. Two hours after the last daily feeding, brains were collected and frozen in liquid nitrogen for analysis of various apoptosis regulatory proteins in the arcuate tissue by Western blots. Some animals were fixed in 4% paraformaldehyde and analyzed immunohistochemically. RESULTS Ethanol exposure increased apoptotic death of beta-endorphin neurons in the arcuate nucleus of the hypothalamus. The cell death was associated with an increase in the tissue levels of TGF-beta1 in the mediobasal hypothalamus. This was correlated with a reduction in the arcuate level of retinoblastoma protein (Rb) phosphorylation. The reduced level of Rb phosphorylation was associated with an increased protein level of the cyclin dependent kinase inhibitor p27/kip but with a decreased protein level of cyclin dependent kinase 4 and cyclin D3. In addition, the apoptotic cell death was positively correlated with the level of Bclxs but negatively correlated with the level of the Bcl2. CONCLUSIONS These results suggest that ethanol exposure increases TGF-beta1 signaling involving Bcl2 and Rb repression that may lead to apoptotic death of cells including beta-endorphin neurons in the arcuate nucleus of the hypothalamus.
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Affiliation(s)
- Peter Kuhn
- Endocrine Program, Center of Alcohol Studies and Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA
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403
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Duarte AI, Santos P, Oliveira CR, Santos MS, Rego AC. Insulin neuroprotection against oxidative stress is mediated by Akt and GSK-3beta signaling pathways and changes in protein expression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:994-1002. [PMID: 18348871 DOI: 10.1016/j.bbamcr.2008.02.016] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 01/28/2008] [Accepted: 02/11/2008] [Indexed: 01/01/2023]
Abstract
Previously we demonstrated that insulin protects against neuronal oxidative stress by restoring antioxidants and energy metabolism. In this study, we analysed how insulin influences insulin-(IR) and insulin growth factor-1 receptor (IGF-1R) intracellular signaling pathways after oxidative stress caused by ascorbate/Fe2+ in rat cortical neurons. Insulin prevented oxidative stress-induced decrease in tyrosine phosphorylation of IR and IGF-1R and Akt inactivation. Insulin also decreased the active form of glycogen synthase kinase-3beta (GSK-3beta) upon oxidation. Since phosphatidylinositol 3-kinase (PI-3K)/Akt-mediated inhibition of GSK-3beta may stimulate protein synthesis and decrease apoptosis, we analysed mRNA and protein expression of "candidate" proteins involved in antioxidant defense, glucose metabolism and apoptosis. Insulin prevented oxidative stress-induced increase in glutathione peroxidase-1 and decrease in hexokinase-II expression, supporting previous findings of changes in glutathione redox cycle and glycolysis. Moreover, insulin precluded Bcl-2 decrease and caspase-3 increased expression. Concordantly, insulin abolished caspase-3 activity and DNA fragmentation caused by oxidative stress. Thus, insulin-mediated activation of IR/IGF-1R stimulates PI-3K/Akt and inhibits GSK-3beta signaling pathways, modifying neuronal antioxidant defense-, glucose metabolism- and anti-apoptotic-associated protein synthesis. These and previous data implicate insulin as a promising neuroprotective agent against oxidative stress associated with neurodegenerative diseases.
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Affiliation(s)
- Ana I Duarte
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
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404
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Kim MH, Kim MO, Heo JS, Kim JS, Han HJ. Acetylcholine inhibits long-term hypoxia-induced apoptosis by suppressing the oxidative stress-mediated MAPKs activation as well as regulation of Bcl-2, c-IAPs, and caspase-3 in mouse embryonic stem cells. Apoptosis 2008; 13:295-304. [PMID: 18049903 DOI: 10.1007/s10495-007-0160-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This study examined the effect of acetylcholine (ACh) on the hypoxia-induced apoptosis of mouse embryonic stem (ES) cells. Hypoxia (60 h) decreased both the cell viability and level of [3H] thymidine incorporation, which were prevented by a pretreatment with ACh. However, the atropine (ACh receptor [AChR] inhibitor) treatment blocked the protective effect of ACh. Hypoxia (90 min) increased the intracellular level of reactive oxygen species (ROS). On the other hand, ACh inhibited the hypoxia-induced increase in ROS, which was blocked by an atropine treatment. Subsequently, the hypoxia-induced ROS increased the level of p38 mitogen activated protein kinase (MAPK) and Jun-N-terminal kinase (JNK) phosphorylation, which were inhibited by the ACh pretreatment. Moreover, hypoxic exposure (90 min) increased the level of nuclear factor-kappa B (NF-kappa B) phosphorylation, which was blocked by a pretreatment with SB 203580 (p38 MAPK inhibitor) or SP 600125 (JNK inhibitor). However, hypoxia (60 h) decreased the protein levels of Bcl-2 and c-IAPs (cellular inhibitor of apoptosis proteins) but increased the level of caspase-3 activation. All these effects were inhibited by a pretreatment with ACh. In conclusion, ACh prevented the hypoxia-induced apoptosis of mouse ES cells by inhibiting the ROS-mediated p38 MAPK and JNK activation as well as the regulation of Bcl-2, c-IAPs, and caspase-3.
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Affiliation(s)
- Min Hee Kim
- Department of Rehabilitation Science, Graduate school of Daegu University, Daegu 705-714, Korea
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405
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Morissette M, Le Saux M, D'Astous M, Jourdain S, Al Sweidi S, Morin N, Estrada-Camarena E, Mendez P, Garcia-Segura LM, Di Paolo T. Contribution of estrogen receptors alpha and beta to the effects of estradiol in the brain. J Steroid Biochem Mol Biol 2008; 108:327-38. [PMID: 17936613 DOI: 10.1016/j.jsbmb.2007.09.011] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Clinical and experimental studies show a modulatory role of estrogens in the brain and suggest their beneficial action in mental and neurodegenerative diseases. The estrogen receptors ERalpha and ERbeta are present in the brain and their targeting could bring selectivity and reduced risk of cancer. Implication of ERs in the effect of estradiol on dopamine, opiate and glutamate neurotransmission is reviewed. The ERalpha agonist, PPT, is shown as estradiol to modulate hippocampal NMDA receptors and AMPA receptors in cortex and striatum of ovariectomized rats whereas the ERbeta agonist DPN is inactive. Striatal DPN activity suggests implication of ERbeta in estradiol modulation of D2 receptors and transporters in ovariectomized rats and is supported by the lack of effect of estradiol in ERbeta knockout (ERKObeta) mice. Both ERalpha and ERbeta agonists modulate striatal preproenkephalin (PPE) gene expression in ovariectomized rats. In male mice PPT protects against MPTP toxicity to striatal dopamine; this implicates Akt/GSK3beta signaling and the apoptotic regulators Bcl2 and Bad. This suggests a role for ERalpha in striatal dopamine neuroprotection. ERKOalpha mice are more susceptible to MPTP toxicity and not protected by estradiol; differences in ERKObeta mice are subtler. These results suggest therapeutic potential for the brain of ER specific agonists.
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Affiliation(s)
- M Morissette
- Molecular Endocrinology and Oncology Research Center, Medical Center and Faculty of Pharmacy, Laval University, 2705 Laurier Boulevard, Sainte-Foy, Québec, Canada
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406
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Wang Z, Gardiner NJ, Fernyhough P. Blockade of hexokinase activity and binding to mitochondria inhibits neurite outgrowth in cultured adult rat sensory neurons. Neurosci Lett 2008; 434:6-11. [PMID: 18308470 DOI: 10.1016/j.neulet.2008.01.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 12/19/2007] [Accepted: 01/10/2008] [Indexed: 01/03/2023]
Abstract
Hexokinase is known as the first enzyme and rate-limiting step in glycolysis. The role of hexokinase activity and localization in regulating the rate of axonal regeneration was studied in cultured adult sensory neurons of dorsal root ganglia (DRG). Immunofluorescent staining of DRG demonstrated that small-medium neurons and satellite cells exhibited high levels of expression of hexokinase I. Large neurons had negative staining for hexokinase I. Intracellular localization and biochemical studies in cultured adult rat sensory neurons revealed that hexokinase I was almost exclusively found in the mitochondrial compartment. The hypothesis that neurotrophic factor dependent activation of Akt would regulate hexokinase association with the mitochondria was tested and quantitative Western blotting showed no effect of blockade of the phosphoinositide 3-kinase (PI 3-kinase)/Akt pathway using the inhibitor LY294002, indicating this interaction of hexokinase with mitochondria was not neurotrophic factor or Akt-dependent. Finally, pharmacological blockade of hexokinase activity and inhibition of localization to the mitochondrial compartment with hexokinase II VDAC binding domain (Hxk2VBD) peptide caused a significant inhibition of neurotrophic factor-directed axon outgrowth. The results support a key role for hexokinase activity and/or localization to the mitochondria in the regulation of neurite outgrowth in cultured adult sensory neurons.
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Affiliation(s)
- Zuocheng Wang
- Division of Neurodegenerative Disorders, St Boniface Research Centre, Winnipeg, Manitoba, Canada
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407
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CREB Activation and Ischaemic Preconditioning. Cardiovasc Drugs Ther 2008; 22:3-17. [DOI: 10.1007/s10557-007-6078-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 12/14/2007] [Indexed: 01/12/2023]
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408
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Vande Walle L, Lamkanfi M, Vandenabeele P. The mitochondrial serine protease HtrA2/Omi: an overview. Cell Death Differ 2008; 15:453-60. [PMID: 18174901 DOI: 10.1038/sj.cdd.4402291] [Citation(s) in RCA: 233] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The HtrA family refers to a group of related oligomeric serine proteases that combine a trypsin-like protease domain with at least one PDZ interaction domain. Mammals encode four HtrA proteases, named HtrA1-4. The protease activity of the HtrA member HtrA2/Omi is required for mitochondrial homeostasis in mice and humans and inactivating mutations associated with neurodegenerative disorders such as Parkinson's disease. Moreover, HtrA2/Omi is released in the cytosol, where it contributes to apoptosis through both caspase-dependent and -independent pathways. Here, we review the current knowledge of HtrA2/Omi biology and discuss the signaling pathways that underlie its mitochondrial and apoptotic functions from an evolutionary perspective.
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Affiliation(s)
- L Vande Walle
- Department for Molecular Biomedical Research, Unit for Molecular Signalling and Cell Death, VIB, Ghent, Belgium
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409
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Wang JA, Chen TL, Jiang J, Shi H, Gui C, Luo RH, Xie XJ, Xiang MX, Zhang X. Hypoxic preconditioning attenuates hypoxia/reoxygenation-induced apoptosis in mesenchymal stem cells. Acta Pharmacol Sin 2008; 29:74-82. [PMID: 18158868 DOI: 10.1111/j.1745-7254.2008.00716.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM Mesenchymal stem cells (MSC) are a promising candidate for cardiac replacement therapies. However, the majority of transplanted MSC are readily lost after transplantation because of poor blood supply, ischemia-reperfusion, and inflammatory factors. We aimed to study the effects of hypoxia preconditioning (HPC) on hypoxia/reoxygenation-induced apoptosis of MSC. METHODS Three generations of MSC were divided into 6 groups, including the normal group, hypoxia-reoxygenation (H/R) group, cyclosporine A (CsA), and the HPC 10 min, 20 min, and 30 min groups. The apoptotic index, cell viability, mitochondrial membrane potential, translocation of Bcl-2 and bax, extracellular regulated kinase (ERK), Akt, hypoxia-inducible factor 1-alpha, and the vascular endothelial growth factor (VEGF) were tested after H/R treatment. RESULTS HPC decreased the apoptotic index and increased the viability induced by H/R. Moreover, HPC markedly stabilized mitochondrial membrane potential, upregulated Bcl-2 and VEGF expressions, and increased the phosphorylation of ERK and Akt. As a positive control, CsA has the same function as HPC, except for promoting ERK and Akt phosphorylation and upregulating VEGF. CONCLUSION HPC had a protective effect against MSC apoptosis induced by H/R via stabilizing mitochondrial membrane potential, upregulating Bcl-2 and VEGF, and promoting ERK and Akt phosphorylation. HPC has implications for the development of novel stem cell protective strategies.
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Affiliation(s)
- Jian-an Wang
- Department of Cardiology, the Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
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410
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Zhang K, Kaufman RJ. Identification and characterization of endoplasmic reticulum stress-induced apoptosis in vivo. Methods Enzymol 2008; 442:395-419. [PMID: 18662581 DOI: 10.1016/s0076-6879(08)01420-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is recognized primarily as the site of synthesis and folding of secreted and membrane-bound proteins. The ER provides stringent quality control systems to ensure that only correctly folded, functional proteins are released from the ER and that misfolded proteins are degraded. The efficient functioning of the ER is essential for most cellular activities and for survival. Stimuli that interfere with ER function can disrupt ER homeostasis, impose stress to the ER, and subsequently cause accumulation of unfolded or misfolded proteins in the ER lumen. ER transmembrane proteins detect the onset of ER stress and initiate highly specific signaling pathways collectively called the "unfolded protein response" (UPR) to restore normal ER functions. However, if ER homeostasis cannot be reestablished in response to intense or prolonged ER stress, the UPR induces ER stress-associated apoptosis to protect the organism by removing the stressed cells that produce misfolded or malfunctioning proteins. This chapter summarizes current understanding of ER stress-induced apoptosis and reliable methods to examine ER stress and apoptosis in mammalian cells. Since the liver is the major organ dealing with metabolic or pathological stress and is responsible for the detoxification of chemical compounds, the experimental protocols described here focus on identification and characterization of ER stress-induced apoptosis in mouse liver.
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Affiliation(s)
- Kezhong Zhang
- Department of Biological Chemistry, The University of Michigan Medical Center, Ann Arbor, Michigan, USA
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411
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Ischemic tolerance as an active and intrinsic neuroprotective mechanism. HANDBOOK OF CLINICAL NEUROLOGY 2008; 92:171-95. [PMID: 18790275 DOI: 10.1016/s0072-9752(08)01909-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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412
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Tolosa L, Mir M, Asensio VJ, Olmos G, Lladó J. Vascular endothelial growth factor protects spinal cord motoneurons against glutamate-induced excitotoxicity via phosphatidylinositol 3-kinase. J Neurochem 2007; 105:1080-90. [PMID: 18182045 DOI: 10.1111/j.1471-4159.2007.05206.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the selective death of motoneurons. Recently, vascular endothelial growth factor (VEGF) has been identified as a neurotrophic factor and has been implicated in the mechanisms of pathogenesis of ALS and other neurological diseases. The potential neuroprotective effects of VEGF in a rat spinal cord organotypic culture were studied in a model of chronic glutamate excitotoxicity in which glutamate transporters are inhibited by threohydroxyaspartate (THA). Particularly, we focused on the effects of VEGF in the survival and vulnerability to excitotoxicity of spinal cord motoneurons. VEGF receptor-2 was present on spinal cord neurons, including motoneurons. Chronic (3 weeks) treatment with THA induced a significant loss of motoneurons that was inhibited by co-exposure to VEGF (50 ng/mL). VEGF activated the phosphatidylinositol 3-kinase/Akt (PI3-K/Akt) signal transduction pathway in the spinal cord cultures, and the effect on motoneuron survival was fully reversed by the specific PI3-K inhibitor, LY294002. VEGF also prevented the down-regulation of Bcl-2 and survivin, two proteins implicated in anti-apoptotic and/or anti-excitotoxic effects, after THA exposure. Together, these findings indicate that VEGF has neuroprotective effects in rat spinal cord against chronic glutamate excitotoxicity by activating the PI3-K/Akt signal transduction pathway and also reinforce the hypothesis of the potential therapeutic effects of VEGF in the prevention of motoneuron degeneration in human ALS.
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Affiliation(s)
- Laia Tolosa
- Grup de Neurobiologia Cellular, Departament de Biologia, Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Universitat de les Illes Balears, Palma de Mallorca, Spain
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413
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Glucose-dependent insulinotropic polypeptide-mediated up-regulation of beta-cell antiapoptotic Bcl-2 gene expression is coordinated by cyclic AMP (cAMP) response element binding protein (CREB) and cAMP-responsive CREB coactivator 2. Mol Cell Biol 2007; 28:1644-56. [PMID: 18086876 DOI: 10.1128/mcb.00325-07] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The cyclic AMP (cAMP)/protein kinase A (PKA) cascade plays a central role in beta-cell proliferation and apoptosis. Here, we show that the incretin hormone glucose-dependent insulinotropic polypeptide (GIP) stimulates expression of the antiapoptotic Bcl-2 gene in pancreatic beta cells through a pathway involving AMP-activated protein kinase (AMPK), cAMP-responsive CREB coactivator 2 (TORC2), and cAMP response element binding protein (CREB). Stimulation of beta-INS-1 (clone 832/13) cells with GIP resulted in increased Bcl-2 promoter activity. Analysis of the rat Bcl-2 promoter revealed two potential cAMP response elements, one of which (CRE-I [GTGACGTAC]) was shown, using mutagenesis and deletion analysis, to be functional. Subsequent studies established that GIP increased the nuclear localization of TORC2 and phosphorylation of CREB serine 133 through a pathway involving PKA activation and reduced AMPK phosphorylation. At the nuclear level, phospho-CREB and TORC2 were demonstrated to bind to CRE-I of the Bcl-2 promoter, and GIP treatment resulted in increases in their interaction. Furthermore, GIP-mediated cytoprotection was partially reversed by small interfering RNA-mediated reduction in BCL-2 or TORC2/CREB or by pharmacological activation of AMPK. The antiapoptotic effect of GIP in beta cells is therefore partially mediated through a novel mode of transcriptional regulation of Bcl-2 involving cAMP/PKA/AMPK-dependent regulation of CREB/TORC2 activity.
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414
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Yano T, Liu Z, Donovan J, Thomas MK, Habener JF. Stromal cell derived factor-1 (SDF-1)/CXCL12 attenuates diabetes in mice and promotes pancreatic beta-cell survival by activation of the prosurvival kinase Akt. Diabetes 2007; 56:2946-57. [PMID: 17878289 DOI: 10.2337/db07-0291] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Diabetes is caused by a deficiency of pancreatic beta-cells that produce insulin. Approaches to enhance beta-cell mass by increasing proliferation and survival are desirable. We determined whether stromal cell-derived factor (SDF)-1/CXCL12 and its receptor, CX chemokine receptor (CXCR)4, are important for the survival of beta-cells. RESEARCH DESIGN AND METHODS Mouse pancreata and clonal beta-cells were examined for expression of SDF-1 and CXCR4, activation of AKT and downstream signaling pathways by SDF-1, and protection against apoptosis and diabetes induced by streptozotocin (STZ). RESULTS CXCR4 is expressed in beta-cells, and SDF-1 is expressed in microvascular endothelial cells within the islets and in surrounding interstitial stromal tissue. Transgenic mice overexpressing SDF-1 within their beta-cells (RIP-SDF-1 mice) are resistant to STZ-induced beta-cell apoptosis and diabetes. In MIN6 beta-cells, a CXCR4 antagonist (AMD3100) induces apoptosis, increases reactive oxygen species, decreases expression levels of the anti-apoptotic protein Bcl-2, and reduces phosphorylation of the proapoptotic protein Bad. Active phosphorylated prosurvival kinase Akt is increased both in the beta-cells of RIP-SDF-1 mice and in INS-1 cells treated with SDF-1 and sensitive to AMD3100. Inhibition of AKT expression by small interfering RNA attenuates the ameliorative effects of SDF-1 on caspase-dependent apoptosis induced by thapsigargin or glucose deprivation in INS-1 beta-cells. Specific inhibition of Akt activation by a soluble inhibitor (SH-5) reverses the anti-apoptotic effects of SDF-1 in INS-1 cells and mouse islets. CONCLUSIONS SDF-1 promotes pancreatic beta-cell survival via activation of Akt, suggesting that SDF-1 agonists may prove beneficial for treatment of diabetes.
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Affiliation(s)
- Tatsuya Yano
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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415
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Ceder JA, Jansson L, Ehrnström RA, Rönnstrand L, Abrahamsson PA. The characterization of epithelial and stromal subsets of candidate stem/progenitor cells in the human adult prostate. Eur Urol 2007; 53:524-31. [PMID: 18053634 DOI: 10.1016/j.eururo.2007.11.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Accepted: 11/09/2007] [Indexed: 01/16/2023]
Abstract
OBJECTIVES Questions regarding the cell source and mechanisms in the initiation and progression of prostate cancer are today still open for debate. Indeed, our knowledge regarding prostate cell regulation, self-renewal, and cytodifferentiation is presently rather limited. In this study, we investigated these processes in the normal adult human prostate. METHODS Dynamic expression patterns in prostate stem/progenitor cells, intermediate/transit-amplifying cells, and cell lineages were immunohistochemically identified in an in situ explant renewal model of the human normal/benign adult prostate (n=6). RESULTS Cells with a basal phenotype proliferated significantly in explant cultures, whereas luminal cells went into apoptosis. Results further show down-regulation in tissue cultures of the basal and hypothetical stem cell marker Bcl-2 in the majority of cells, except in rare putative epithelial stem cells. Investigation of established (AC133) and novel candidate prostate stem/progenitor markers, including the cell surface receptor tyrosine kinase KIT and its ligand stem cell factor (SCF), showed that these rare epithelial cells are AC133(+)/CD133(low)/Bcl-2(high)/cytokeratin(+)/vimentin(-)/KIT(low)/SCF(low). In addition, we report on a stromal population that expresses the mesenchymal marker vimentin and that is AC133(-)/CD133(high)/Bcl-2(-)/cytokeratin(-)/KIT(high)/SCF(high). CONCLUSIONS We provide evidence for epithelial renewal in response to tissue culture and for basal and epithelial stem/progenitor cell recruitment leading to an expansion of an intermediate luminal precursor phenotype. Data further suggest that SCF regulates prostate epithelial stem/progenitor cells in an autocrine manner and that all or a subset of the identified novel stromal phenotype represents prostate stromal progenitor cells or interstitial pacemaker cells or both.
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Affiliation(s)
- Jens A Ceder
- Lund University, Department of Clinical Sciences, Division of Urological Research, University Hospital MAS, S-205 02 Malmö, Sweden.
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416
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Wang P, Yan H, Li JC. CREB-mediated Bcl-2 expression in trichosanthin-induced Hela cell apoptosis. Biochem Biophys Res Commun 2007; 363:101-5. [PMID: 17825790 DOI: 10.1016/j.bbrc.2007.08.141] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2007] [Accepted: 08/20/2007] [Indexed: 12/22/2022]
Abstract
Bcl-2 plays a pivotal role in the control of cell death and is down-regulated in trichosanthin (TCS)-induced cell apoptosis. Because Bcl-2 expression is regulated by the transcription factor cyclic AMP response element-binding protein (CREB), we investigated the role of CREB activation in TCS-induced Hela cells apoptosis. Our results showed that TCS-caused Hela cell apoptosis was accompanied by the decrease of Bcl-2 and phosphorylated CREB protein levels. Interesting, this inhibitive effect can be abolished by the combined treatment of TCS/cAMP agonists. Furthermore, TCS-mediated Bcl-2 protein was abrogated by the suppression of CREB expression with antisense treatment, and blocking the interaction between CREB-binding protein and the Bcl-2 cyclic AMP-responsive element (CRE) by a CRE decoy oligonucleotide. Therefore, these data support the hypothesis that CREB plays a critical role in the regulation of Bcl-2 expression in TCS-induced Hela cell death.
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Affiliation(s)
- Ping Wang
- Institute of Cell Biology, Zhejiang University, Hangzhou 310058, PR China
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417
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Ruiz-Llorente S, Montero-Conde C, Milne RL, Moya CM, Cebrián A, Letón R, Cascón A, Mercadillo F, Landa I, Borrego S, Pérez de Nanclares G, Alvarez-Escolá C, Díaz-Pérez JA, Carracedo A, Urioste M, González-Neira A, Benítez J, Santisteban P, Dopazo J, Ponder BA, Robledo M. Association study of 69 genes in the ret pathway identifies low-penetrance loci in sporadic medullary thyroid carcinoma. Cancer Res 2007; 67:9561-7. [PMID: 17909067 DOI: 10.1158/0008-5472.can-07-1638] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To date, few association studies have been done to better understand the genetic basis for the development of sporadic medullary thyroid carcinoma (sMTC). To identify additional low-penetrance genes, we have done a two-stage case-control study in two European populations using high-throughput genotyping. We selected 417 single nucleotide polymorphisms (SNP) belonging to 69 genes either related to RET signaling pathway/functions or involved in key processes for cancer development. TagSNPs and functional variants were included where possible. These SNPs were initially studied in the largest known series of sMTC cases (n = 266) and controls (n = 422), all of Spanish origin. In stage II, an independent British series of 155 sMTC patients and 531 controls was included to validate the previous results. Associations were assessed by an exhaustive analysis of individual SNPs but also considering gene- and linkage disequilibrium-based haplotypes. This strategy allowed us to identify seven low-penetrance genes, six of them (STAT1, AURKA, BCL2, CDKN2B, CDK6, and COMT) consistently associated with sMTC risk in the two case-control series and a seventh (HRAS) with individual SNPs and haplotypes associated with sMTC in the Spanish data set. The potential role of CDKN2B was confirmed by a functional assay showing a role of a SNP (rs7044859) in the promoter region in altering the binding of the transcription factor HNF1. These results highlight the utility of association studies using homogeneous series of cases for better understanding complex diseases.
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Affiliation(s)
- Sergio Ruiz-Llorente
- Hereditary Endocrine Cancer Group, Human Genetics Group, Biomedical Research Institute, CSIC, UAM, Madrid, Spain
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418
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Engelbrecht AM, Mattheyse M, Ellis B, Loos B, Thomas M, Smith R, Peters S, Smith C, Myburgh K. Proanthocyanidin from grape seeds inactivates the PI3-kinase/PKB pathway and induces apoptosis in a colon cancer cell line. Cancer Lett 2007; 258:144-53. [PMID: 17923279 DOI: 10.1016/j.canlet.2007.08.020] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 08/22/2007] [Accepted: 08/31/2007] [Indexed: 01/06/2023]
Abstract
The aim of this investigation was to evaluate the chemopreventative/antiproliferative potential of a grape seed proanthocyanidin extract (GSPE) against colon cancer cells (CaCo2 cells) and to investigate its mechanism of action. GSPE (10-100 microg/ml) significantly inhibited cell viability and increased apoptosis in CaCo2 cells, but did not alter viability in the normal colon cell line (NCM460). The increased apoptosis observed in GSPE-treated CaCo2 cells correlated with an attenuation of PI3-kinase (p110 and p85 subunits) and decreased PKB Ser(473) phosphorylation. GSPE might thus exert its beneficial effects by means of increased apoptosis and suppression of the important PI3-kinase survival-related pathway.
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Affiliation(s)
- A-M Engelbrecht
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa.
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419
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Ricci C, Pastukh V, Mozaffari M, Schaffer SW. Insulin withdrawal induces apoptosis via a free radical-mediated mechanism. Can J Physiol Pharmacol 2007; 85:455-64. [PMID: 17612655 DOI: 10.1139/y07-029] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diabetes is characterized by chronic hyperglycemia as well as insulin deficiency or resistance. However, the majority of research has focused on the consequences of hyperglycemia in development of diabetic complications, whereas the effects of insulin deficiency or resistance, independent of hyperglycemia, have received little attention. Since insulin is a well known cytoprotective factor, we hypothesized that its removal could significantly impact cell survival. To examine this possibility, cultured neonatal cardiomyocytes were subjected to insulin withdrawal and examined for apoptosis. Insulin deficient cells succumbed to apoptosis, an effect associated with impaired PI3-kinase/Akt signaling and reduction in the Bcl-2 to Bax ratio. Perhaps more importantly, superoxide generation was altered in cells subjected to insulin withdrawal. Removal of insulin caused a significant increase in reactive oxygen species production and resulted in oxidative mitochondrial DNA damage the latter effect is associated with impaired expression of mitochondrially encoded proteins that make up the electron transport chain. Significantly, the effects of insulin withdrawal could be mitigated by treatment with the antioxidant, Tiron. Collectively, these data demonstrate that insulin deficiency leads to apoptosis and suggest a role for oxidative mitochondrial DNA damage in this cascade.
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Affiliation(s)
- Craig Ricci
- University of South Alabama, College of Medicine, Department of Pharmacology, Mobile, AL 36688, USA
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420
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Wu Y, Shang Y, Sun SG, Liu RG, Yang WQ. Protective effect of erythropoietin against 1-methyl-4-phenylpyridinium-induced neurodegenaration in PC12 cells. Neurosci Bull 2007; 23:156-64. [PMID: 17612594 PMCID: PMC5550630 DOI: 10.1007/s12264-007-0023-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE The neuroprotective effect of erythropoietin (EPO) against 1-methyl-4-phenylpyridinium (MPP(+))-induced oxidative stress in cultured PC12 cells, as well as the underlying mechanism, were investigated. METHODS PC12 cells impaired by MPP(+) were used as the cell model of Parkinson's disease. Methyl thiazolyl tetrazolium (MTT) was used to assay the viability of the PC12 cells exposed to gradient concentrations of EPO, and the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay was used to analyze the apoptosis ratio of PC12 cells. The expression of Bcl-2 and Bax in PC12 cells were examined by Western blot, and the reactive oxygen species (ROS), the mitochondrial transmembrane potential and the activity of caspase-3 in each group were detected by spectrofluorometer. RESULTS Treatment of PC12 cells with MPP(+) caused the loss of cell viability, which may be associated with the elevation in apoptotic rate, the formation of ROS and the disruption of mitochondrial transmembrane potential. It was also shown that MPP(+) significantly induced the upregulation of Bax/Bcl-2 ratio and the activation of caspase-3. In contrast, EPO significantly reversed these responses and had the maximum protective effect at 1 U/mL. CONCLUSION The inhibitive effect of EPO on the MPP(+)-induced cytotoxicity may be ascribed to its anti-oxidative property and anti-apoptotic activity, and EPO may provide a useful therapeutic strategy for treatment of neurodegenerative diseases such as Parkinson's disease.
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Affiliation(s)
- Yan Wu
- Department of Neurology, Huazhong University of Science and Technology, Wuhan, 430022 China
| | - You Shang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022 China
| | - Sheng-Gang Sun
- Department of Neurology, Huazhong University of Science and Technology, Wuhan, 430022 China
| | - Ren-Gang Liu
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Wen-Qiong Yang
- Department of Neurology, Dongfeng Hospital, Yunyang Medical College, Shiyan, 442008 China
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421
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Bredow S, Juri DE, Cardon K, Tesfaigzi Y. Identification of a novel Bcl-2 promoter region that counteracts in a p53-dependent manner the inhibitory P2 region. Gene 2007; 404:110-6. [PMID: 17913397 PMCID: PMC2288782 DOI: 10.1016/j.gene.2007.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 08/27/2007] [Accepted: 09/04/2007] [Indexed: 01/06/2023]
Abstract
Expression of the anti-apoptotic proto-oncogene bcl-2 is negatively affected by the pro-apoptotic p53. To understand the regulation of bcl-2 expression by p53, we studied the bcl-2 promoter regions individually and in the context of the full-length promoter. While the P1 promoter displayed the highest p53-independent activity, the P2 promoter activity was suppressed in p53-sufficient cancer cell lines. In addition, P2 activity was higher in primary airway epithelial cells from p53(-/-) mice compared to those from p53(+/+) mice. Chromatin immunoprecipitation assays confirmed that p53 interacts within a 140 bp sequence of P2 that contained the CCAAT- and TATA-elements. However, when P1 and P2 are linked in one construct, P2 suppressed P1 activity independent of p53. A potential novel promoter with a p53-dependent activity was identified located between P1 and P2, and was designated M. In the context of the full-length bcl-2 promoter, M counteracted in a p53-dependent manner the suppressive activity of P2 on P1. Collectively, these data suggest that P1 promoter is the main driving force for transcribing the bcl-2 gene and P1 activity is modulated by M and P2 in a p53-dependent and -independent manner. These findings may have implications for therapies that are geared towards inhibiting bcl-2 gene expression and inducing cell death.
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Affiliation(s)
- Sebastian Bredow
- Respiratory Immunology and Asthma Program, Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM 87108, USA
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422
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O'Driscoll C, Wallace D, Cotter TG. bFGF promotes photoreceptor cell survival in vitro by PKA-mediated inactivation of glycogen synthase kinase 3beta and CREB-dependent Bcl-2 up-regulation. J Neurochem 2007; 103:860-70. [PMID: 17714451 DOI: 10.1111/j.1471-4159.2007.04827.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Although there is substantial evidence supporting the neuroprotective efficacy of basic fibroblast growth factor (bFGF) in the rodent retina there is no consensus to date as to the protective mechanism involved. We hypothesise that bFGF can assert its neuroprotective effects directly on mouse photoreceptors transduced via the activation of specific intracellular signalling pathways. In mouse photoreceptor-derived 661W cells, bFGF promoted a rapid inactivation of glycogen synthase kinase 3beta (GSK3beta) by phosphorylation at Ser9. The effects of bFGF on GSK3beta were dependent on protein kinase A (PKA) activation, as inhibition of this pathway blocked inactivation. Furthermore, bFGF protection against oxidative stress was dependent on PKA inactivation of GSK3beta as PKA inhibition attenuated bFGF-induced protection. Furthermore, transfection of cells with mutant dominant negative GSK3betaS9A that cannot be phosphorylated on Ser9 also abrogated neuroprotection. Activation of the transcription factor cAMP-response element binding protein (CREB) and subsequent up-regulation of Bcl-2 in response to bFGF was also dependent on PKA as inhibition with H-89 attenuated increased pCREB levels and Bcl-2 expression. These results indicate that the protective efficacy of bFGF in mouse photoreceptors involves PKA-dependent inactivation of GSK3beta and subsequent up-regulation of Bcl-2 via CREB activation.
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Affiliation(s)
- Carolyn O'Driscoll
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
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423
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Sarkar SA, Gunter J, Bouchard R, Reusch JEB, Wiseman A, Gill RG, Hutton JC, Pugazhenthi S. Dominant negative mutant forms of the cAMP response element binding protein induce apoptosis and decrease the anti-apoptotic action of growth factors in human islets. Diabetologia 2007; 50:1649-59. [PMID: 17593347 DOI: 10.1007/s00125-007-0707-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 04/03/2007] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Transplantation of islets is a viable option for the treatment of diabetes. A significant proportion of islets is lost during isolation, storage and after transplantation as a result of apoptosis. cAMP response element binding protein (CREB) is an important cell survival factor. The aim of the present study was to determine whether preservation of CREB function is needed for survival of human islets. MATERIALS AND METHODS To determine the effects of downregulation of CREB activity on beta cell apoptosis in a transplantation setting, adenoviral vectors were used to express two dominant negative mutant forms of CREB in human islets isolated from cadaveric donors. Markers of apoptosis were determined in these transduced islets under basal conditions and following treatment with growth factor. RESULTS Expression of CREB mutants in human islets resulted in significant (p < 0.001) activation of caspase-9, a key regulatory enzyme in the mitochondrial pathway of apoptosis, when compared with islets transduced with adenoviral beta galactosidase. Immunocytochemical analysis showed the activation of caspase-9 to be predominantly in beta cells. Other definitive markers of apoptosis such as parallel activation of caspase-3, accumulation of cleaved poly-(ADP-ribose) polymerase and nuclear condensation were also observed. Furthermore, the anti-apoptotic action of growth factors exendin-4 and betacellulin in human islets exposed to cytokines was partially lost when CREB function was impaired. CONCLUSIONS/INTERPRETATION Our findings suggest that impairment of CREB-mediated transcription could lead to loss of islets by apoptosis with potential implications in islet transplantation as well as in the mechanism of beta cell loss leading to diabetes.
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Affiliation(s)
- S A Sarkar
- Barbara Davis Center for Childhood Diabetes and Rocky Mountain Islet Transplantation Program, Aurora, CO, USA
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424
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Pertusa M, Morenilla-Palao C, Carteron C, Viana F, Cabedo H. Transcriptional control of cholesterol biosynthesis in Schwann cells by axonal neuregulin 1. J Biol Chem 2007; 282:28768-28778. [PMID: 17652086 DOI: 10.1074/jbc.m701878200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A characteristic feature of many vertebrate axons is their wrapping by a lamellar stack of glially derived membranes known as the myelin sheath. Myelin is a cholesterol-rich membrane that allows for rapid saltatory nerve impulse conduction. Axonal neuregulins instruct glial cells on when and how much myelin they should produce. However, how neuregulin regulates myelin sheath development and thickness is unknown. Here we show that neuregulin receptors are activated by drops in plasma membrane cholesterol, suggesting that they can sense sterol levels. In Schwann cells neuregulin-1 increases the transcription of the 3-hydroxy-3-methylglutarylcoenzyme A reductase, the rate-limiting enzyme for cholesterol biosynthesis. Neuregulin activity is mediated by the phosphatidylinositol 3-kinase pathway and a cAMP-response element located on the reductase promoter. We propose that by activating neuregulin receptors, neurons exploit a cholesterol homeostatic mechanism forcing Schwann cells to produce new membranes for the myelin sheath. We also show that a strong phylogenetic correlation exists between myelination and cholesterol biosynthesis, and we propose that the absence of the sterol branch of the mevalonate pathway in invertebrates precluded the myelination of their nervous system.
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Affiliation(s)
- Maria Pertusa
- Instituto de Neurociencias de Alicante, UMH-CSIC, 03550 Sant Joan, Alicante, Spain
| | - Cruz Morenilla-Palao
- Instituto de Neurociencias de Alicante, UMH-CSIC, 03550 Sant Joan, Alicante, Spain
| | - Christelle Carteron
- Instituto de Neurociencias de Alicante, UMH-CSIC, 03550 Sant Joan, Alicante, Spain
| | - Felix Viana
- Instituto de Neurociencias de Alicante, UMH-CSIC, 03550 Sant Joan, Alicante, Spain
| | - Hugo Cabedo
- Instituto de Neurociencias de Alicante, UMH-CSIC, 03550 Sant Joan, Alicante, Spain; Unidad de Investigación del Hospital de Sant Joan d'Alacant, 03550 Sant Joan, Alicante, Spain.
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425
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Parcellier A, Tintignac LA, Zhuravleva E, Hemmings BA. PKB and the mitochondria: AKTing on apoptosis. Cell Signal 2007; 20:21-30. [PMID: 17716864 DOI: 10.1016/j.cellsig.2007.07.010] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 07/18/2007] [Indexed: 10/23/2022]
Abstract
Cellular homeostasis depends upon the strict regulation of responses to external stimuli, such as signalling cascades triggered by nutrients and growth factors, and upon cellular metabolism. One of the major molecules coordinating complex signalling pathways is protein kinase B (PKB), a serine/threonine kinase also known as Akt. The number of substrates known to be phosphorylated by PKB and its interacting partners, as well as our broad understanding of how PKB is implicated in responses to growth factors, metabolic pathways, proliferation, and cell death via apoptosis is constantly increasing. Activated by the insulin/growth factor-phosphatidylinositol 3-kinase (PI3K) cascade, PKB triggers events that promote cell survival and prevent apoptosis. It is also now widely accepted that mitochondria are not just suppliers of ATP, but that they participate in regulatory and signalling events, responding to multiple physiological inputs and genetic stresses, and regulate both cell proliferation and death. Thus, mitochondria are recognized as important players in apoptotic events and it is logical to predict some form of interplay with PKB. In this review, we will summarize mechanisms by which PKB mediates its anti-apoptotic activities in cells and survey recent developments in understanding mitochondrial dynamics and their role during apoptosis.
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Affiliation(s)
- Arnaud Parcellier
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
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426
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Liu D, Si H, Reynolds KA, Zhen W, Jia Z, Dillon JS. Dehydroepiandrosterone protects vascular endothelial cells against apoptosis through a Galphai protein-dependent activation of phosphatidylinositol 3-kinase/Akt and regulation of antiapoptotic Bcl-2 expression. Endocrinology 2007; 148:3068-76. [PMID: 17395704 DOI: 10.1210/en.2006-1378] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The adrenal steroid dehydroepiandrosterone (DHEA) may improve vascular function, but the mechanism is unclear. In the present study, we show that DHEA significantly increased cell viability, reduced caspase-3 activity, and protected both bovine and human vascular endothelial cells against serum deprivation-induced apoptosis. This effect was dose dependent and maximal at physiological concentrations (0.1-10 nM). DHEA stimulation of bovine aortic endothelial cells resulted in rapid and dose-dependent phosphorylation of Akt, which was blocked by LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), the upstream kinase of Akt. Accordingly, inhibition of PI3K or transfection of the cells with dominant-negative Akt ablated the antiapoptotic effect of DHEA. The induced Akt phosphorylation and subsequent cytoprotective effect of DHEA were dependent on activation of Galphai proteins, but were estrogen receptor independent, because these effects were blocked by pertussis toxin but not by the estrogen receptor inhibitor ICI182,780 or the aromatase inhibitor aminoglutethimide. Finally, DHEA enhanced antiapoptotic Bcl-2 protein expression, its promoter activity, and gene transcription attributable to the activation of the PI3K/Akt pathway. Neutralization of Bcl-2 by antibody transfection significantly decreased the antiapoptotic effect of DHEA. These findings provide the first evidence that DHEA acts as a survival factor for endothelial cells by triggering the Galphai-PI3K/Akt-Bcl-2 pathway to protect cells against apoptosis. This may represent an important mechanism underlying the vascular protective effect of DHEA.
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Affiliation(s)
- Dongmin Liu
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, USA.
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427
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Bok J, Wang Q, Huang J, Green SH. CaMKII and CaMKIV mediate distinct prosurvival signaling pathways in response to depolarization in neurons. Mol Cell Neurosci 2007; 36:13-26. [PMID: 17651987 PMCID: PMC2040167 DOI: 10.1016/j.mcn.2007.05.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Revised: 05/10/2007] [Accepted: 05/22/2007] [Indexed: 01/29/2023] Open
Abstract
By fusing the CaMKII-inhibitory peptide AIP to GFP, we constructed a specific and effective CaMKII inhibitor, GFP-AIP. Expression of GFP-AIP and/or dominant-inhibitory CaMKIV in cultured neonatal rat spiral ganglion neurons (SGNs) shows that CaMKII and CaMKIV act additively and in parallel to mediate the prosurvival effect of depolarization. Depolarization or expression of constitutively active CaMKII functionally inactivates Bad, indicating that this is one means by which CaMKII promotes neuronal survival. CaMKIV, but not CaMKII, requires CREB to promote SGN survival, consistent with the exclusively nuclear localization of CaMKIV and indicating that the principal prosurvival function of CaMKIV is activation of CREB. Consistent with this, a constitutively active CREB construct that provides a high level of CREB activity promotes SGN survival, although low levels of CREB activity did not do so. Also, in apoptotic SGNs, activation of CREB by depolarization is disabled, presumably as part of a cellular commitment to apoptosis.
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Affiliation(s)
- Jinwoong Bok
- Department of Biological Sciences, University of Iowa, Iowa City, IA 52242, USA
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428
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Brynczka C, Merrick BA. Nerve growth factor potentiates p53 DNA binding but inhibits nitric oxide-induced apoptosis in neuronal PC12 cells. Neurochem Res 2007; 32:1573-85. [PMID: 17592775 PMCID: PMC2231119 DOI: 10.1007/s11064-007-9362-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 04/25/2007] [Indexed: 12/16/2022]
Abstract
NGF is recognized for its role in neuronal differentiation and maintenance. Differentiation of PC12 cells by NGF involves p53, a transcription factor that controls growth arrest and apoptosis. We investigated NGF influence over p53 activity during NO-induced apoptosis by sodium nitroprusside in differentiated and mitotic PC12 cells. NGF-differentiation produced increased p53 levels, nuclear localization and sequence-specific DNA binding. Apoptosis in mitotic cells also produced these events but the accompanying activation of caspases 1-10 and mitochondrial depolarization were inhibited during NGF differentiation and could be reversed in p53-silenced cells. Transcriptional regulation of PUMA and survivin expression were not inhibited by NGF, although NO-induced mitochondrial depolarization was dependent upon de novo gene transcription and only occurred in mitotic cells. We conclude that NGF mediates prosurvival signaling by increasing factors such as Bcl-2 and p21(Waf1/Cip1) without altering p53 transcriptional activity to inhibit mitochondrial depolarization, caspase activation and apoptosis.
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Affiliation(s)
- Christopher Brynczka
- National Center for Toxicogenomics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
- Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, North Carolina 27606
| | - B. Alex Merrick
- National Center for Toxicogenomics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
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429
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Abstract
Unfolded protein response (UPR) is an important genomic response to endoplasmic reticulum (ER) stress. The ER chaperones, GRP78 and Gadd153, play critical roles in cell survival or cell death as part of the UPR, which is regulated by three signaling pathways: PERK/ATF4, IRE1/XBP1 and ATF6. During the UPR, accumulated unfolded protein is either correctly refolded, or unsuccessfully refolded and degraded by the ubiquitin-proteasome pathway. When the unfolded protein exceeds a threshold, damaged cells are committed to cell death, which is mediated by ATF4 and ATF6, as well as activation of the JNK/AP-1/Gadd153-signaling pathway. Gadd153 suppresses activation of Bcl-2 and NF-kappaB. UPR-mediated cell survival or cell death is regulated by the balance of GRP78 and Gadd153 expression, which is coregulated by NF-kappaB in accordance with the magnitude of ER stress. Less susceptibility to cell death upon activation of the UPR may contribute to tumor progression and drug resistance of solid tumors.
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Affiliation(s)
- R Kim
- International Radiation Information Center, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.
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430
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Aarabi S, Bhatt KA, Shi Y, Paterno J, Chang EI, Loh SA, Holmes JW, Longaker MT, Yee H, Gurtner GC. Mechanical load initiates hypertrophic scar formation through decreased cellular apoptosis. FASEB J 2007; 21:3250-61. [PMID: 17504973 DOI: 10.1096/fj.07-8218com] [Citation(s) in RCA: 358] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hypertrophic scars occur following cutaneous wounding and result in severe functional and esthetic defects. The pathophysiology of this process remains unknown. Here, we demonstrate for the first time that mechanical stress applied to a healing wound is sufficient to produce hypertrophic scars in mice. The resulting scars are histopathologically identical to human hypertrophic scars and persist for more than six months following a brief (one-week) period of augmented mechanical stress during the proliferative phase of wound healing. Resulting scars are structurally identical to human hypertrophic scars and showed dramatic increases in volume (20-fold) and cellular density (20-fold). The increased cellularity is accompanied by a four-fold decrease in cellular apoptosis and increased activation of the prosurvival marker Akt. To clarify the importance of apoptosis in hypertrophic scar formation, we examine the effects of mechanical loading on cutaneous wounds of animals with altered pathways of cellular apoptosis. In p53-null mice, with down-regulated cellular apoptosis, we observe significantly greater scar hypertrophy and cellular density. Conversely, scar hypertrophy and cellular density are significantly reduced in proapoptotic BclII-null mice. We conclude that mechanical loading early in the proliferative phase of wound healing produces hypertrophic scars by inhibiting cellular apoptosis through an Akt-dependent mechanism.
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Affiliation(s)
- Shahram Aarabi
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
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431
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Marzioni M, Ueno Y, Glaser S, Francis H, Benedetti A, Alvaro D, Venter J, Fava G, Alpini G. Cytoprotective effects of taurocholic acid feeding on the biliary tree after adrenergic denervation of the liver. Liver Int 2007; 27:558-68. [PMID: 17403196 DOI: 10.1111/j.1478-3231.2007.01443.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Cholangiopathies impair the balance between proliferation and apoptosis of cholangiocytes leading to the disappearance of bile ducts and liver failure. Taurocholic acid (TC) is essential for cholangiocyte proliferative and functional response to cholestasis. Bile acids and neurotransmitters co-operatively regulate the biological response of the biliary epithelium to cholestasis. Adrenergic denervation of the liver during cholestasis results in the damage of bile ducts. AIM To verify whether TC feeding prevents the damage of the biliary tree induced by adrenergic denervation in the course of cholestasis. METHODS Rats subjected to bile duct ligation (BDL) and to adrenergic denervation were fed a TC-enriched diet, in the absence or presence of daily administration of the phosphatidyl-inositol-3-kinase (PI3K) inhibitor wortmannin for 1 week. RESULTS TC prevented the induction of cholangiocyte apoptosis induced by adrenergic denervation. TC also restored cholangiocyte proliferation and functional activity, reduced after adrenergic denervation. TC prevented AKT dephosphorylation induced by adrenergic denervation. The cytoprotective effects of TC were abolished by the simultaneous administration of wortmannin. SUMMARY/CONCLUSIONS TC administration prevents the damage of the biliary tree induced by the adrenergic denervation of the liver. These novel findings open novel perspectives in the understanding of the potential of bile acids especially in post-transplant liver disease.
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Affiliation(s)
- Marco Marzioni
- Department of Gastroenterology, Università Politecnica delle Marche, Ancona, Italy.
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432
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Kayser KJ, Glenn MP, Sebti SM, Cheng JQ, Hamilton AD. Modifications of the GSK3β substrate sequence to produce substrate-mimetic inhibitors of Akt as potential anti-cancer therapeutics. Bioorg Med Chem Lett 2007; 17:2068-73. [PMID: 17276059 DOI: 10.1016/j.bmcl.2007.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 12/20/2006] [Accepted: 01/05/2007] [Indexed: 10/23/2022]
Abstract
Amplification, overexpression, and elevated activation of Akt have been detected in many human malignancies making it an important target for cancer therapy. The Akt substrate-binding site offers a large number of potential interactions to an appropriately designed small molecule and can form the basis for the development of selective inhibitors. Here, we report the progression of GSK3beta substrate-mimetic inhibitors towards the development of a potent, small molecule substrate-mimetic inhibitor of Akt.
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Affiliation(s)
- Katherine J Kayser
- Department of Chemistry, Yale University, PO Box 208107, New Haven, CT 06520, USA
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433
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Yang L, Sun M, Sun XM, Cheng GZ, Nicosia SV, Cheng JQ. Akt Attenuation of the Serine Protease Activity of HtrA2/Omi through Phosphorylation of Serine 212. J Biol Chem 2007; 282:10981-7. [PMID: 17311912 DOI: 10.1074/jbc.m700445200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serine protease HtrA2/Omi is released from the mitochondria into the cytosol following apoptosis stimuli, leading to the programmed cell death in caspase-dependent and -independent manners. The function of HtrA2/Omi closely relates to its protease activity, which is required for cleavage of its substrate such as the members of the X-linked inhibitor of apoptotic protein family. However, the regulation of HtrA2/Omi by signaling molecule has not been documented. Here we report that serine/threonine kinases Akt1 and Akt2 phosphorylate mitochondria-released HtrA2/Omi on serine 212 in vivo and in vitro, which results in attenuation of its serine protease activity and pro-apoptotic function. Abolishing HtrA2/Omi phosphorylation by Akt through mutation of serine 212 to alanine (HtrA2/Omi-S212A) retains its serine protease activity and induces more apoptosis as compared with wild-type HtrA2/Omi. Conversely, HtrA2/Omi-S212D, a mutant mimicking phosphorylation, lost the protease activity and failed to induce the programmed cell death. Furthermore, the phosphorylated HtrA2/Omi fails to cleave X-linked inhibitor of apoptotic protein without interfering with their complex formation. In addition, Akt inhibits the release of HtrA2/Omi from the mitochondria into the cytoplasm in response to cisplatin treatment. These data reveal for the first time that HtrA2/Omi is directly regulated by Akt and provide a mechanism by which Akt induces cell survival at post-mitochondrial level.
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Affiliation(s)
- Lin Yang
- Department of Pathology and Cell Biology and Molecular Oncology Program, H. Lee Moffitt Cancer Center and College of Medicine, University of South Florida, Tampa, Florida 33612, USA
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434
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Chen MJ, Russo-Neustadt AA. Running exercise- and antidepressant-induced increases in growth and survival-associated signaling molecules are IGF-dependent. Growth Factors 2007; 25:118-31. [PMID: 17852404 DOI: 10.1080/08977190701602329] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
It is known that physical exercise increases hippocampal brain-derived neurotrophic factor (BDNF) mRNA and protein, as well as the expression of several pro-survival signaling proteins and that many of these effects depend on the uptake of peripheral insulin-like growth factor-1 (IGF-1) into the CNS. Because treatment with antidepressants has similar effects upon neurotrophin expression, we investigated whether antidepressant-induced BDNF changes also depend on IGF-1 uptake, as well as whether IGF-1 plays a role in the exercise/antidepressant-induced expression of molecules associated with plasticity/growth (GAP-43, SCG-10) and the intracellular activation of molecules associated with neuronal survival (Akt, ERK1/2). We evaluated the effects of a well known monoamine oxidase inhibitor, tranylcypromine, on BDNF mRNA and protein levels and phospho-Akt and phospho-ERK1/2 immunoreactivity, both with and without systemic blockade of IGF-1 uptake through the use of an antiserum raised against IGF-1. Anti-IGF-1 reversed the increase in BDNF mRNA and protein elicited by exercise as well as tranylcypromine. Exercise also significantly enhanced transcription of axon growth protein, GAP-43, an effect that was also evidenced to be IGF-1-dependent. The combination of exercise-plus-tranylcypromine also increased several cell survival signaling measures, but the BDNF changes associated with the combination treatment appeared to be independent of IGF-1 uptake. Together, these results indicate that the uptake of peripheral IGF-1 in the CNS is essential for antidepressant- as well as exercise-induced enhancement in hippocampal BDNF expression and thus, enhanced hippocampal neuronal survival and plasticity.
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Affiliation(s)
- Michael J Chen
- Department of Biological Sciences, California State University, 5151 State University Drive, Los Angeles, CA 90032, USA.
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435
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McCubrey JA, Steelman LS, Franklin RA, Abrams SL, Chappell WH, Wong EWT, Lehmann BD, Terrian DM, Basecke J, Stivala F, Libra M, Evangelisti C, Martelli AM. Targeting the RAF/MEK/ERK, PI3K/AKT and p53 pathways in hematopoietic drug resistance. ACTA ACUST UNITED AC 2007; 47:64-103. [PMID: 17382374 PMCID: PMC2696319 DOI: 10.1016/j.advenzreg.2006.12.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- James A McCubrey
- Department of Microbiology & Immunology, Brody School of Medicine at East Carolina University Greenville, NC 27858, USA.
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436
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Watson PA, Reusch JEB, McCune SA, Leinwand LA, Luckey SW, Konhilas JP, Brown DA, Chicco AJ, Sparagna GC, Long CS, Moore RL. Restoration of CREB function is linked to completion and stabilization of adaptive cardiac hypertrophy in response to exercise. Am J Physiol Heart Circ Physiol 2007; 293:H246-59. [PMID: 17337597 DOI: 10.1152/ajpheart.00734.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Potential regulation of two factors linked to physiological outcomes with left ventricular (LV) hypertrophy, resistance to apoptosis, and matching of metabolic capacity, by the transcription factor cyclic-nucleotide regulatory element binding protein (CREB), was examined in the two models of physiological LV hypertrophy: involuntary treadmill running of female Sprague-Dawley rats and voluntary exercise wheel running in female C57Bl/6 mice. Comparative studies were performed in the models of pathological LV hypertrophy and failure: the spontaneously hypertension heart failure (SHHF) rat and the hypertrophic cardiomyopathy (HCM) transgenic mouse, a model of familial idiopathic cardiomyopathy. Activating CREB serine-133 phosphorylation was decreased early in remodeling in response to both physiological (decreased 50-80%) and pathological (decreased 60-80%) hypertrophic stimuli. Restoration of LV CREB phosphorylation occurred concurrent with completion of physiological hypertrophy (94% of sedentary control), but remained decreased (by 90%) during pathological hypertrophy. In all models of hypertrophy, CREB phosphorylation/activation demonstrated strong positive correlations with 1) expression of the anti-apoptotic protein bcl-2 (a CREB-dependent gene) and subsequent reductions in the activation of caspase 9 and caspase 3; 2) expression of peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1; a major regulator of mitochondrial content and respiratory capacity), and 3) LV mitochondrial respiratory rates and mitochondrial protein content. Exercise-induced increases in LV mitochondrial respiratory capacity were commensurate with increases observed in LV mass, as previously reported in the literature. Exercise training of SHHF rats and HCM mice in LV failure improved cardiac phenotype, increased CREB activation (31 and 118%, respectively), increased bcl-2 content, improved apoptotic status, and enhanced PGC-1 content and mitochondrial gene expression. Adenovirus-mediated expression of constitutively active CREB in neonatal rat cardiac recapitulated exercise-induced upregulation of PGC-1 content and mitochondrial oxidative gene expression. These data support a model wherein CREB contributes to physiological hypertrophy by enhancing expression of genes important for efficient oxidative capacity and resistance to apoptosis.
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Affiliation(s)
- Peter A Watson
- University of Colorado Health Sciences Center, and Denver VA Medical Center, 1055 Clermont Street, Denver CO 80220, USA.
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437
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Kim WU, Kang SS, Yoo SA, Hong KH, Bae DG, Lee MS, Hong SW, Chae CB, Cho CS. Interaction of vascular endothelial growth factor 165 with neuropilin-1 protects rheumatoid synoviocytes from apoptotic death by regulating Bcl-2 expression and Bax translocation. THE JOURNAL OF IMMUNOLOGY 2007; 177:5727-35. [PMID: 17015762 DOI: 10.4049/jimmunol.177.8.5727] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Rheumatoid arthritis (RA) synoviocytes are resistant to apoptosis and exhibit a transformed phenotype, which might be caused by chronic exposure to genotoxic stimuli including reactive oxygen species and growth factors. In this study, we investigated the role of vascular endothelial growth factor165 (VEGF165), a potent angiogenic factor, and its receptor in the apoptosis of synoviocytes. We demonstrated here that neuropilin-1, rather than fms-like tyrosine kinase-1 and kinase insert domain-containing receptor, is the major VEGF165 receptor in the fibroblast-like synoviocytes. Neuropilin-1 was highly expressed in the lining layer, infiltrating leukocytes, and endothelial cells of rheumatoid synovium. The production of VEGF165, a ligand for neuropilin, was significantly higher in the RA synoviocytes than in the osteoarthritis synoviocytes. The ligation of recombinant VEGF165 to its receptor prevented the apoptosis of synoviocytes induced by serum starvation or sodium nitroprusside (SNP). VEGF165 rapidly triggered phospho-Akt and phospho-ERK activity and then induced Bcl-2 expression in the rheumatoid synoviocytes. The Akt or ERK inhibitor cancelled the protective effect of VEGF165 on SNP-induced synoviocyte apoptosis. Moreover, VEGF165 blocks SNP-induced Bcl-2 down-regulation as well as SNP-induced Bax translocation from the cytosol to the mitochondria. The down-regulation of the neuropilin-1 transcripts by short interfering RNA caused spontaneous synoviocyte apoptosis, which was associated with both the decrease in Bcl-2 expression and the increase in Bax translocation to mitochondria. Collectively, our data suggest that the interaction of VEGF165 with neuropilin-1 is crucial to the survival of rheumatoid synoviocytes and provide important implications for the abnormal growth of synoviocytes and therapeutic intervention in RA.
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Affiliation(s)
- Wan-Uk Kim
- Department of Internal Medicine, Division of Rheumatology, School of Medicine, Catholic University of Korea, Seoul, Korea
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438
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Abstract
Hormonal ligands for the nuclear receptor superfamily have at least two interacting mechanisms of action: 1) classical transcriptional regulation of target genes (genomic mechanisms); and 2) nongenomic actions that are initiated at the cell membrane, which could impact transcription. Although transcriptional mechanisms are increasingly well understood, membrane-initiated actions of these ligands are incompletely understood. Historically, this has led to a considerable divergence of thought in the molecular endocrine field. We have attempted to uncover principles of hormone action that are relevant to membrane-initiated actions of estrogens. There is evidence that the membrane-limited actions of hormones, particularly estrogens, involve the rapid activation of kinases and the release of calcium. Membrane actions of estrogens, which activate these rapid signaling cascades, can also potentiate nuclear transcription. These signaling cascades may occur in parallel or in series but subsequently converge at the level of modification of transcriptionally relevant molecules such as nuclear receptors and/or coactivators. In addition, other hormones or neurotransmitters may also activate cascades to crosstalk with estrogen receptor-mediated transcription. The idea of synergistic coupling between membrane-initiated and genomic actions of hormones fundamentally revises the paradigms of cell signaling in neuroendocrinology.
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Affiliation(s)
- Nandini Vasudevan
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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439
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Huang J, Wu L, Tashiro SI, Onodera S, Ikejima T. Fibroblast growth factor-2 suppresses oridonin-induced L929 apoptosis through extracellular signal-regulated kinase-dependent and phosphatidylinositol 3-kinase-independent pathway. J Pharmacol Sci 2007; 102:305-13. [PMID: 17116975 DOI: 10.1254/jphs.fpj06004x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Oridonin, isolated from Rabdosia rubescences, has been reported to exert cytotoxic effects on L929 cells. In this study, we investigated the mechanisms of FGF-2 protection of L929 cells from oridonin-induced apoptosis. Phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) signal did not mediate this effect because the PI3K inhibitor wortmannin failed to reverse this protection and PKB activation was not observed in this process. In contrast, the extracellular signal-regulated kinase (ERK) was responsible for this rescue because its inhibition abolished the protective effect of fibroblast growth factor (FGF)-2. ERK had dual regulatory functions: mediating cell apoptosis or preventing cells from initiating the apoptotic response by phosphorylation or promoting expression of Bcl-2 in dependence of different stimuli. In L929 cells treated with oridonin alone, the activated ERK decreased the ratio of Bcl-2/Bax by mediating the phosphorylation of Bcl-2, resulting in apoptosis; the Ras inhibitor manumycin A and Raf inhibitor GW5074 failed to inhibit this apoptosis, indicating that there is a signal other than Ras/Raf pathway activated ERK. However, in the presence of FGF-2, Bcl-2 phosphorylation was blocked, and the Ras/Raf/ERK signal pathway was activated and protected against the oridonin-induced apoptosis by the alternative function of promoting of Bcl-2 expression.
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MESH Headings
- Animals
- Antineoplastic Agents, Phytogenic/antagonists & inhibitors
- Antineoplastic Agents, Phytogenic/chemistry
- Antineoplastic Agents, Phytogenic/pharmacology
- Apoptosis/drug effects
- Blotting, Western
- Cell Line, Tumor
- Chromatography, High Pressure Liquid
- Diterpenes/antagonists & inhibitors
- Diterpenes/chemistry
- Diterpenes/pharmacology
- Diterpenes, Kaurane/antagonists & inhibitors
- Diterpenes, Kaurane/chemistry
- Diterpenes, Kaurane/pharmacology
- Enzyme Inhibitors/pharmacology
- Extracellular Signal-Regulated MAP Kinases/physiology
- Fibroblast Growth Factor 2/pharmacology
- Genes, bcl-2/genetics
- Genes, ras/genetics
- In Situ Nick-End Labeling
- Indoles/pharmacology
- Mice
- Phenols/pharmacology
- Phosphatidylinositol 3-Kinases/physiology
- Polyenes/pharmacology
- Polyunsaturated Alkamides/pharmacology
- Signal Transduction/drug effects
- raf Kinases/antagonists & inhibitors
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Affiliation(s)
- Jian Huang
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang, China
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440
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Peltier J, O'Neill A, Schaffer DV. PI3K/Akt and CREB regulate adult neural hippocampal progenitor proliferation and differentiation. Dev Neurobiol 2007; 67:1348-61. [PMID: 17638387 DOI: 10.1002/dneu.20506] [Citation(s) in RCA: 324] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The phosphoinositide 3-OH kinase (PI3K)/Akt pathway has been implicated in regulating several important cellular processes, including apoptosis, survival, proliferation, and metabolism. Using both pharmacological and genetic means, we demonstrate here that PI3K/Akt plays a crucial role in the proliferation of adult hippocampal neural progenitor cells. PI3K/Akt transduces intracellular signals from multiple mitogens, including basic fibroblast growth factor (FGF-2), Sonic hedgehog (Shh), and insulin-like growth factor 1 (IGF-1). In addition, retroviral vector-mediated over-expression of wild type Akt increased cell proliferation, while a dominant negative Akt inhibited proliferation. Furthermore, wild type Akt over-expression reduced glial (GFAP) and neuronal (beta-tubulin III) marker expression during differentiation, indicating that it inhibits cell differentiation. We also show that activation of the cAMP response element binding protein (CREB), which occurs in cells stimulated by FGF-2, is limited when Akt signaling is inhibited, demonstrating a link between Akt and CREB. Over-expression of wild type CREB increases progenitor proliferation, whereas dominant negative CREB only slightly decreases proliferation. These results indicate that PI3K/Akt signaling integrates extracellular signaling information to promote cellular proliferation and inhibit differentiation in adult neural progenitors.
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Affiliation(s)
- Joseph Peltier
- Department of Chemical Engineering, University of California, Berkeley, California 94720, USA
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441
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Mendez P, Wandosell F, Garcia-Segura LM. Cross-talk between estrogen receptors and insulin-like growth factor-I receptor in the brain: cellular and molecular mechanisms. Front Neuroendocrinol 2006; 27:391-403. [PMID: 17049974 DOI: 10.1016/j.yfrne.2006.09.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 08/11/2006] [Accepted: 09/01/2006] [Indexed: 01/02/2023]
Abstract
Accumulating evidence suggests that insulin-like growth factor-I (IGF-I) and estradiol interact to regulate neural function. In this review, we focus on the cellular and molecular mechanisms involved in this interaction. The expression of estrogen receptors (ERs) and IGF-I receptor is cross-regulated in the central nervous system and many neurons and astrocytes coexpress both receptors. Furthermore, estradiol activates IGF-I receptor and its intracellular signaling. This effect may involve classical ERs since recent findings suggest that ERalpha may affect IGF-I actions in the brain by a direct interaction with some of the components of IGF-I signaling. In turn, IGF-I may regulate ER transcriptional activity in neuronal cells. In conclusion, ERs appear to be part of the signaling mechanism of IGF-I, and IGF-I receptor part of the mechanism of estradiol signaling in the nervous system.
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Affiliation(s)
- Pablo Mendez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), E-28002 Madrid, Spain
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442
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Sribnick EA, Matzelle DD, Ray SK, Banik NL. Estrogen treatment of spinal cord injury attenuates calpain activation and apoptosis. J Neurosci Res 2006; 84:1064-75. [PMID: 16902996 DOI: 10.1002/jnr.21016] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spinal cord injury (SCI) is a devastating neurologic injury, and currently, the only recommended pharmacotherapy is high-dose methylprednisolone, which has limited efficacy. Estrogen is a multi-active steroid with anti-oxidant and anti-apoptotic effects. Estrogen may modulate intracellular Ca2+ and prevent inflammation. For this study, male rats were divided into three groups. Sham-group animals received a laminectomy at T12. Injured rats received both laminectomy and 40 gram centimeter force SCI. Estrogen-group rats received 4 mg/kg 17beta-estradiol (estrogen) at 15 min and 24 hr post-injury, and vehicle-group rats received equal volumes of dimethyl sulfoxide. Animals were sacrificed at 48 hr post-injury, and 1-cm segments of the lesion, rostral penumbra, and caudal penumbra were excised. The degradation of 68 kD neurofilament protein (NFP) and estrogen receptors (ER) was examined by Western blot analysis. Protein levels of calpain and the activities of calpain and caspase-3 were also examined. Levels of cytochrome c were determined in both cytosolic and mitochondrial fractions. Cell death with DNA fragmentation was examined using the TUNEL assay. At the lesion, samples from both vehicle and estrogen treated animals showed increased levels of 68 kD NFP degradation, calpain content, calpain activity, cytochrome c release, and degradation of ERalpha and ERbeta, as compared to sham. In the caudal penumbra, estrogen treatment significantly attenuated 68 kD NFP degradation, calpain content, calpain activity, levels of cytosolic cytochrome c, and ERbeta degradation. At the lesion, vehicle-treated animals displayed more TUNEL+ cells, and estrogen treatment significantly attenuated this cell death marker. We conclude that estrogen may inhibit cell death in SCI through calpain inhibition.
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Affiliation(s)
- Eric Anthony Sribnick
- Department of Neurosciences, Division of Neurology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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443
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Lee MS, Yoo SA, Cho CS, Suh PG, Kim WU, Ryu SH. Serum Amyloid A Binding to Formyl Peptide Receptor-Like 1 Induces Synovial Hyperplasia and Angiogenesis. THE JOURNAL OF IMMUNOLOGY 2006; 177:5585-94. [PMID: 17015746 DOI: 10.4049/jimmunol.177.8.5585] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Serum amyloid A (SAA) is a major acute-phase reactant, and has been demonstrated to mediate proinflammatory cellular responses. Although SAA has been used as an indicator for a variety of inflammatory diseases, the role of SAA in synovial hyperplasia and proliferation of endothelial cells, a pathological hallmark of rheumatoid arthritis (RA), has yet to be elucidated. In this study, we have demonstrated that SAA promotes the proliferation of human fibroblast-like synoviocytes (FLS). In addition, SAA protects RA FLS against the apoptotic death induced by serum starvation, anti-Fas IgM, and sodium nitroprusside. The activity of SAA appears to be mediated by the formyl peptide receptor-like 1 (FPRL1) receptor, as it was mimicked by the WKYMVm peptide, a specific ligand for FPRL1, but completely abrogated by down-regulating the FPRL1 transcripts with short interfering RNA. The effect of SAA on FLS hyperplasia was shown to be caused by an increase in the levels of intracellular calcium, as well as the activation of ERK and Akt, which resulted in an elevation in the expression of cyclin D1 and Bcl-2. Moreover, SAA stimulated the proliferation, migration, and tube formation of endothelial cells in vitro, and enhanced the sprouting activity of endothelial cells ex vivo and neovascularization in vivo. These observations indicate that the binding of SAA to FPRL1 may contribute to the destruction of bone and cartilage via the promotion of synoviocyte hyperplasia and angiogenesis, thus providing a potential target for the control of RA.
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Affiliation(s)
- Mi-Sook Lee
- Division of Molecular Life Sciences, Pohang University of Science and Technology, Pohang, Korea
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444
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Xiang H, Wang J, Boxer LM. Role of the cyclic AMP response element in the bcl-2 promoter in the regulation of endogenous Bcl-2 expression and apoptosis in murine B cells. Mol Cell Biol 2006; 26:8599-606. [PMID: 16982684 PMCID: PMC1636799 DOI: 10.1128/mcb.01062-06] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have previously shown for B-cell lines that the cyclic AMP response element (CRE) is a major positive regulatory site in the bcl-2 promoter. However, the role of the CRE in the regulation of endogenous bcl-2 expression in vivo has not been characterized. We used gene targeting to generate knock-in mice in which a mutated CRE was introduced into the bcl-2 promoter region (mutCRE-bcl2 mice). Quantitative chromatin immunoprecipitation assays revealed that mutation of the CRE abolished the binding of CREB/ATF and CBP transcription factors to the bcl-2 promoter and greatly diminished the binding of NF-kappaB factors. The mutant CRE significantly reduced the expression of Bcl-2 in B cells and rendered them susceptible to surface immunoglobulin- and chemotherapeutic agent-induced apoptosis. The low levels of Bcl-2 were not changed with activation of the cells. The numbers of pre-B, immature B, and mature B cells in the bone marrow were decreased, as were the numbers of splenic B cells in mutCRE-bcl2 mice. Our findings indicate that the CRE in the bcl-2 promoter has an important functional role in the regulation of endogenous Bcl-2 expression and plays a critical role in the coordination of signals that regulate B-cell survival.
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Affiliation(s)
- Hong Xiang
- Center for Molecular Biology in Medicine, Veterans Affairs Palo Alto Health Care System, and Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305-5156, USA
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445
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Takeuchi K, Motoda YI, Ito F. Role of transcription factor activator protein 1 (AP1) in epidermal growth factor-mediated protection against apoptosis induced by a DNA-damaging agent. FEBS J 2006; 273:3743-55. [PMID: 16911523 DOI: 10.1111/j.1742-4658.2006.05377.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We investigated the survival signals of epidermal growth factor (EGF) in human gastric adenocarcinoma cell line TMK-1. Treatment of TMK-1 cells with adriamycin (ADR) caused apoptosis and apoptosis-related reactions such as the release of cytochrome c from mitochondria and the activation of caspase 9. However, EGF treatment greatly reduced the ADR-induced apoptosis as well as these reactions. We previously reported that hepatocyte growth factor transmitted protective signals against ADR-induced apoptosis by causing activation of the phosphatidylinositol-3'-OH kinase (PtdIns3-K)/Akt signaling pathway in human epithelial cell line MKN74 [Takeuchi K & Ito F (2004) J Biol Chem279, 892-900]. However, PtdIns3-K/Akt signaling did not mediate the antiapoptotic action of EGF in TMK-1 cells. EGF increased the expression of the Bcl-X(L) protein, an antiapoptotic member of the Bcl-2 family, but not that of other anti (Bcl-2) or proapoptotic (Bad and Bax) protein members. Expression of the c-Fos and c-Jun, components of activator protein 1 (AP1), which are known to regulate bcl-X(L) gene transcription, were increased in response to EGF. Pretreatment of the cells with PD98059, an inhibitor of MAP kinase kinase, inhibited the EGF-induced c-Fos and c-Jun expression, AP1 DNA binding, Bcl-X(L) expression, and the resistance against ADR-induced apoptosis, suggesting that EGF transmitted the antiapoptotic signal in such a way that it activated AP1 via a MAP kinase signaling pathway. TMK-1 cells stably transfected with TAM67, c-Jun dominant-negative mutant, did not display EGF-induced Bcl-X(L) expression or resistance against ADR-induced apoptosis. These results indicate that AP1-mediated upregulation of Bcl-X(L) expression is critical for protection of TMK-1 cells against ADR-induced apoptosis.
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Affiliation(s)
- Kenji Takeuchi
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Setsunan University, Osaka, Japan.
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446
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Schiekofer S, Shiojima I, Sato K, Galasso G, Oshima Y, Walsh K. Microarray analysis of Akt1 activation in transgenic mouse hearts reveals transcript expression profiles associated with compensatory hypertrophy and failure. Physiol Genomics 2006; 27:156-70. [PMID: 16882883 DOI: 10.1152/physiolgenomics.00234.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
To investigate molecular mechanisms involved in the development of cardiac hypertrophy and heart failure, we developed a tetracycline-regulated transgenic system to conditionally switch a constitutively active form of the Akt1 protein kinase on or off in the adult heart. Short-term activation (2 wk) of Akt1 resulted in completely reversible hypertrophy with maintained contractility. In contrast, chronic Akt1 activation (6 wk) induced extensive cardiac hypertrophy, severe contractile dysfunction, and massive interstitial fibrosis. The focus of this study was to create a transcript expression profile of the heart as it undergoes reversible Akt1-mediated hypertrophy and during the transition from compensated hypertrophy to heart failure. Heart tissue was analyzed before transgene induction, 2 wk after transgene induction, 2 wk of transgene induction followed by 2 days of repression, 6 wk after transgene induction, and 6 wk of transgene induction followed by 2 wk of repression. Acute overexpression of Akt1 (2 wk) leads to changes in the expression of 826 transcripts relative to noninduced hearts, whereas chronic induction (6 wk) led to changes in the expression of 1,611, of which 65% represented transcripts that were regulated during the pathological phase of heart growth. Another set of genes identified was uniquely regulated during heart regression but not growth, indicating that nonoverlapping transcription programs participate in the processes of cardiac hypertrophy and atrophy. These data define the gene regulatory programs downstream of Akt that control heart size and contribute to the transition from compensatory hypertrophy to heart failure.
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Affiliation(s)
- Stephan Schiekofer
- Molecular Cardiology/Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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447
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Huang YW, Wang LS, Chang HL, Ye W, Shu S, Sugimoto Y, Lin YC. Effect of keratinocyte growth factor on cell viability in primary cultured human prostate cancer stromal cells. J Steroid Biochem Mol Biol 2006; 100:24-33. [PMID: 16854582 DOI: 10.1016/j.jsbmb.2006.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 03/09/2006] [Indexed: 11/15/2022]
Abstract
In normal prostate, keratinocyte growth factor (KGF), also known as fibroblast growth factor-7 (FGF-7) serves as a paracrine growth factor synthesized in stromal cells that acts on epithelial cells through its receptor, KGFR. KGF and KGFR were found in human cancer epithelial cells as well as stromal cells. Since KGF expressed in epithelial cells of benign prostatic hyperplasia (BPH) and in prostate cancer, it has been suggested that KGF might act as an autocrine factor in BPH and prostate cancer. To investigate the roles of KGF in cancerous stroma, primary cultured human prostate cancer stromal cells (PCSCs) were isolated and evaluated. These PCSCs possessed estrogen receptors and KGFR, but not androgen receptor as determined by RT-PCR and Western blot, respectively. KGF exhibited mitogenic and anti-apoptotic effects that correlated with induction of cyclin-D1, Bcl-2, Bcl-xL and phospho-Akt expression in PCSCs, where treatment with KGF antiserum abolished cell proliferation and anti-apoptotic protein expression. PCSCs exposed to KGF for various time periods resulted in phosphorylation of Akt and subsequent up-regulation of Bcl-2. KGF modulated dynamic protein expression indicated that KGF triggered cell cycle machinery and then activated anti-apoptotic actions in PCSCs. Cell proliferation analysis indicated that tamoxifen or ICI 182,780 reduced cell viability in a dose-dependent manner; however, KGF prevented this inhibition, which further demonstrated KGF triggered anti-apoptotic machinery through activating Bcl-2 and phospho-Akt expression. In summary, KGF has an autocrine effect and serves as a survival factor in primary cultured human prostate cancer stromal cells.
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Affiliation(s)
- Yi-Wen Huang
- Laboratory of Reproductive and Molecular Endocrinology, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210, USA
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448
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Alonso de Leciñana M, Egido JA. Estrogens as neuroprotectants against ischemic stroke. Cerebrovasc Dis 2006; 21 Suppl 2:48-53. [PMID: 16651814 DOI: 10.1159/000091703] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Estrogens have proven vasoprotective properties against atherosclerosis that depend on the direct effect on vascular smooth muscle and endothelium and on systemic actions that imply serum lipids, coagulation and fibrinolytic cascades, vasoactive proteins and antioxidant systems. They also have neuroprotective effects against cerebral ischemia that include antioxidant and anti-inflammatory effects, modulation of protein synthesis, inhibition of apoptosis and trophic effects and preservation of microvascular blood flow in the ischemic area. Estrogenic actions depend on activation of specific estrogen receptors that modulate gene expression and produce long-term effects on vascular endothelial and smooth muscle cells, neurons and glia, on interaction with plasma membrane sites that produce rapid non-genomic actions and also on receptor-independent mechanisms. This paper reviews what it is known about the mechanisms underlying the vaso- and neuroprotective effects of estrogens. Experimental and clinical evidences of such protective effects are also discussed. Therapeutical implications for stroke prevention and treatment derived from the available evidence are considered.
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449
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Szegő ÉM, Barabás K, Balog J, Szilágyi N, Korach KS, Juhász G, Ábrahám IM. Estrogen induces estrogen receptor alpha-dependent cAMP response element-binding protein phosphorylation via mitogen activated protein kinase pathway in basal forebrain cholinergic neurons in vivo. J Neurosci 2006; 26:4104-10. [PMID: 16611827 PMCID: PMC6673875 DOI: 10.1523/jneurosci.0222-06.2006] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In addition to classical genomic mechanisms, estrogen also exerts nonclassical effects via a signal transduction system on neurons. To study whether estrogen has a nonclassical effect on basal forebrain cholinergic system, we measured the intensity of cAMP response element-binding protein (CREB) phosphorylation (pCREB) in cholinergic neurons after administration of 17beta-estradiol to ovariectomized (OVX) mice. A significant time-dependent increase in the number of pCREB-positive cholinergic cells was detected after estrogen administration in the medial septum-diagonal band (MS-DB) and the substantia innominata (SI). The increase was first observed 15 min after estrogen administration. The role of classical estrogen receptors (ERs) was evaluated using ER knock-out mice in vivo. The estrogen-induced CREB phosphorylation in cholinergic neurons was present in ERbeta knock-out mice but completely absent in ERalpha knock-out mice in MS-DB and SI. A series of in vitro studies demonstrated that estrogen acted directly on cholinergic neurons. Selective blockade of the mitogen activated protein kinase (MAPK) pathway in vivo completely prevented estrogen-induced CREB phosphorylation in cholinergic neurons in MS-DB and SI. In contrast, blockade of protein kinase A (PKA) was effective only in SI. Finally, studies in intact female mice revealed levels of CREB phosphorylation within cholinergic neurons that were similar to those of estrogen-treated OVX mice. These observations demonstrate an ERalpha-mediated nonclassical effect of estrogen on the cholinergic neurons and that these actions are present under physiological conditions. They also reveal the role of MAPK and PKA-MAPK pathway activation in nonclassical estrogen signaling in the basal forebrain cholinergic neurons in vivo.
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Dworet JH, Meinkoth JL. Interference with 3′,5′-Cyclic Adenosine Monophosphate Response Element Binding Protein Stimulates Apoptosis through Aberrant Cell Cycle Progression and Checkpoint Activation. Mol Endocrinol 2006; 20:1112-20. [PMID: 16410315 DOI: 10.1210/me.2005-0386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Abstract
We previously reported that protein kinase A activity is an important determinant of thyroid cell survival. Given the important role of cAMP response element binding protein (CREB) in mediating the transcriptional effects of protein kinase A, we explored whether interference with CREB family members impaired thyroid cell survival. Expression of A-CREB, a dominant-negative CREB mutant that inhibits CREB DNA binding activity, induced apoptosis in rat thyroid cells. A-CREB inhibited CRE-regulated gene expression but failed to alter the expression of bcl-2 family members or of well-characterized inhibitors of apoptosis. To elucidate the mechanism through which impaired CREB function triggered apoptosis, its effects on cell proliferation were examined. Expression of A-CREB inhibited cell number increases, in part due to delayed cell cycle transit. Protracted S-phase progression in A-CREB-expressing cells was sufficient to activate a checkpoint response characterized by Chk-1, histone H2A.X, and p53 phosphorylation. To determine whether cell cycle progression was required for apoptosis, the effects of p27 overexpression were investigated. Overexpression of p27 prevented cell cycle progression, checkpoint activation, and apoptosis in A-CREB-expressing cells. These data reveal a novel mechanism through which interference with CREB abrogates cell survival, through checkpoint activation secondary to cell cycle delay. This study may explain how interference with CREB induces apoptosis in cells where alterations in the expression of pro- and anti-survival genes are not detected.
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Affiliation(s)
- Jessica H Dworet
- Department of Pharmacology, University of Pennsylvania School of Medicine, 420 Curie Boulevard, Philadelphia, Pennsylvania 19104-6061, USA
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