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Wang M, Yao SQ, Huang Y, Liang JJ, Xu Y, Chen S, Wang Y, Ng TK, Chu WK, Cui Q, Cen LP. Casein kinase-2 inhibition promotes retinal ganglion cell survival after acute intraocular pressure elevation. Neural Regen Res 2024; 19:1112-1118. [PMID: 37862216 PMCID: PMC10749609 DOI: 10.4103/1673-5374.385310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 05/18/2023] [Accepted: 07/03/2023] [Indexed: 10/22/2023] Open
Abstract
Intraocular pressure elevation can induce retinal ganglion cell death and is a clinically reversible risk factor for glaucoma, the leading cause of irreversible blindness. We previously demonstrated that casein kinase-2 inhibition can promote retinal ganglion cell survival and axonal regeneration in rats after optic nerve injury. To investigate the underlying mechanism, in the current study we increased the intraocular pressure of adult rats to 75 mmHg for 2 hours and then administered a casein kinase-2 inhibitor (4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole) by intravitreal injection. We found that intravitreal injection of 4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole promoted retinal ganglion cell survival and reduced the number of infiltrating macrophages. Transcriptomic analysis showed that the mitogen activated protein kinase signaling pathway was involved in the response to intraocular pressure elevation but was not modulated by the casein kinase-2 inhibitors. Furthermore, casein kinase-2 inhibition downregulated the expression of genes (Cck, Htrsa, Nef1, Htrlb, Prph, Chat, Slc18a3, Slc5a7, Scn1b, Crybb2, Tsga10ip, and Vstm21) involved in intraocular pressure elevation. Our data indicate that inhibition of casein kinase-2 can enhance retinal ganglion cell survival in rats after acute intraocular pressure elevation via macrophage inactivation.
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Affiliation(s)
- Meng Wang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
- Shantou University Medical College, Shantou, Guangdong Province, China
| | - Shi-Qi Yao
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
- Shantou University Medical College, Shantou, Guangdong Province, China
| | - Yao Huang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Jia-Jian Liang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
| | - Yanxuan Xu
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
| | - Shaowan Chen
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
| | - Yuhang Wang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
| | - Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
- Shantou University Medical College, Shantou, Guangdong Province, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Qi Cui
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Ling-Ping Cen
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province, China
- Shantou University Medical College, Shantou, Guangdong Province, China
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Chao HWH, Chen YK, Liu JH, Pan HT, Lin HM, Chao HM. Emodin protected against retinal ischemia insulted neurons through the downregulation of protein overexpression of β-catenin and vascular endothelium factor. BMC Complement Med Ther 2020; 20:338. [PMID: 33167932 PMCID: PMC7654144 DOI: 10.1186/s12906-020-03136-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 10/28/2020] [Indexed: 11/12/2022] Open
Abstract
Background Emodin has been proved to have an anti-ischemic effect on the brain, however little research has been done on its effect on vision-threatening retinal ischemia. Thus, an investigation was carried out into the hypothetical efficacy of emodin against retinal ischemia and the role of β-catenin/VEGF in its therapeutic mechanism. Methods Retinal ischemia, followed by reperfusion (IR), was inducted by raising the intraocular pressure of a Wistar rat’s eye to 120 mmHg for 60 min. Additionally, pre-ischemic/post-ischemic intravitreous injections of emodin (4, 10 and 20 μM) or vehicle were carried out on the eye with retinal ischemia. MTT assay, electroretinograms, cresyl violet staining retinal thickness measurements, and fluorogold retrograde labelling of retinal ganglion cells (RGCs) as well as Western blotting were carried out. Results Cultured RGC-5 cells subjected to oxygen glucose deprivation (OGD) were used to confirm the effective concentrations of emodin (administered 1 h pre-OGD, pre-OGD emodin). The most effective and significant (P = 0.04) dose of pre-OGD emodin was observed at 0.5 μM (cell viability: 47.52 ± 3.99%) as compared to pre-OGD vehicle treatment group (38.30 ± 2.51%). Furthermore, pre-ischemic intravitreous injection of 20 μM emodin (Emo20 + IR = 0.99 ± 0.18, P < 0.001) significantly attenuated the ischemia induced reduction in ERG b-wave amplitude, as compared to pre-ischemic intravitreous vehicle (Vehicle+IR = 0.04 ± 0.02). Post-ischemic intravitreous 20 μM emodin also significantly (P < 0.001) attenuated the ischemia associated b-wave reduction (IR + Em20 = 0.24 ± 0.09). Compared with pre-ischemic intravitreous vehicle (Vehicle+IR; whole retina thickness = 71.80 ± 1.08 μm; inner retina thickness = 20.97 ± 0.85 μm; RGC =2069.12 ± 212.82/0.17mm2), the significant (P < 0.001) protective effect was also present with pre-ischemic administration of emodin. This was shown by observing cresyl violet stained retinal thickness (Emo20 + IR: whole retina = 170.10 ± 0.10 μm; inner retina = 70.65 ± 2.06 μm) and retrograde fluorogold immunolabeled RGC density (4623.53 ± 179.48/0.17mm2). As compared to the normal control (the ratio of β-catenin/VEGF to β-actin was set as 1 in the Sham group), the β-catenin/VEGF protein level significantly (P < 0.001) increased after retinal ischemia and when pre-ischemic intravitreous vehicle (Vehicle+IR = 1.64 ± 0.14/7.67 ± 2.57) was carried out. However, these elevations were significantly (P = 0.02) attenuated by treatment with emodin 20 μM (Emo20 + IR = 1.00 ± 0.19/1.23 ± 0.44). Conclusions The present results suggest that emodin might protect against retinal ischemia insulted neurons such as RGCs by significantly downregulating the upregulation of β-catenin/VEGF protein that occurs during ischemia. Supplementary Information Supplementary information accompanies this paper at 10.1186/s12906-020-03136-7.
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Affiliation(s)
| | - Yu-Kuang Chen
- Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan
| | - Jorn-Hon Liu
- Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan
| | - Hwai-Tzong Pan
- Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Hsin-May Lin
- Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan
| | - Hsiao-Ming Chao
- Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan. .,Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan. .,Department of Chinese Medicine, School of Chinese Medicine, China Medical University, Taichung, Taiwan.
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3
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Cen LP, Liu YF, Ng TK, Luo JM, van Rooijen N, Zhang M, Pang CP, Cui Q. Casein kinase-II inhibition promotes retinal ganglion cell survival and axonal regeneration. Exp Eye Res 2018; 177:153-159. [PMID: 30118655 DOI: 10.1016/j.exer.2018.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/09/2018] [Accepted: 08/13/2018] [Indexed: 02/05/2023]
Abstract
Neuron survival is critical for the maintenance of central nervous system physiology upon diseases or injury. We previously demonstrated that the blockage of phosphatidylinositol 3-kinase/Akt and Janus kinase/STAT3 pathways promotes retinal ganglion cell (RGC) survival and axonal regeneration via macrophage activation; yet, the complexity of the inflammatory regulation for neural repair indicates the involvement of additional unresolved signaling pathways. Here we report the effects and underlying mechanism of casein kinase-II (CK2) inhibition on RGC survival and axonal regeneration in rats after optic nerve (ON) injury. Adult rats received intravitreal injection of CK2 inhibitors, TBB (4,5,6,7-Tetrabromo-2-azabenzimidazole) and DMAT (2-Dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole), after ON transection and peripheral nerve (PN) grafting. Intravitreal application of TBB and DAMT effectively suppressed the CK2 phosphorylation activity in the retina, and enhanced RGC survival and axonal regeneration in vivo. Meanwhile, the numbers of infiltrating macrophages were increased. Removal of macrophages by clodronate liposomes significantly abolished the CK2 inhibition-induced RGC survival and axonal regeneration. Clodronate liposomes also weakened the RGC protective effects by TBB and DMAT in vitro. In summary, this study revealed that inhibition of CK2 enhances RGC survival and axonal regeneration via macrophage activation in rats. CK2 could be a therapeutic target for RGC protection after ON injury.
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Affiliation(s)
- Ling-Ping Cen
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
| | - Yu-Fen Liu
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China
| | - Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong; Shantou University Medical College, Shantou, Guangdong, China
| | - Jian-Min Luo
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China
| | - Nico van Rooijen
- Department of Cell Biology and Immunology, Faculty of Medicine, Vrije Universiteit, 1081 BT Amsterdam, Netherlands
| | - Mingzhi Zhang
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Chi Pui Pang
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Qi Cui
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
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Canedo-Antelo M, Serrano MP, Manterola A, Ruiz A, Llavero F, Mato S, Zugaza JL, Pérez-Cerdá F, Matute C, Sánchez-Gómez MV. Inhibition of Casein Kinase 2 Protects Oligodendrocytes From Excitotoxicity by Attenuating JNK/p53 Signaling Cascade. Front Mol Neurosci 2018; 11:333. [PMID: 30271323 PMCID: PMC6146035 DOI: 10.3389/fnmol.2018.00333] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 08/27/2018] [Indexed: 12/12/2022] Open
Abstract
Oligodendrocytes are highly vulnerable to glutamate excitotoxicity, a central mechanism involved in tissue damage in Multiple Sclerosis (MS). Sustained activation of AMPA receptors in rat oligodendrocytes induces cytosolic calcium overload, mitochondrial depolarization, increase of reactive oxygen species, and activation of intracelular pathways resulting in apoptotic cell death. Although many signals driven by excitotoxicity have been identified, some of the key players are still under investigation. Casein kinase 2 (CK2) is a serine/threonine kinase, constitutively expressed in all eukaryotic tissues, involved in cell proliferation, malignant transformation and apoptosis. In this study, we identify CK2 as a critical regulator of oligodendrocytic death pathways and elucidate its role as a signal inductor following excitotoxic insults. We provide evidence that CK2 activity is up-regulated in AMPA-treated oligodendrocytes and CK2 inhibition significantly diminished AMPA receptor-induced oligodendroglial death. In addition, we analyzed mitogen-activated protein kinase (MAPK) signaling after excitotoxic insult. We observed that AMPA receptor activation induced a rapid increase in c-Jun N-terminal kinase (JNK) and p38 phosphorylation that was reduced after CK2 inhibition. Moreover, blocking their phosphorylation, we enhanced oligodendrocyte survival after excitotoxic insult. Finally, we observed that the tumor suppressor p53 is activated during AMPA receptor-induced cell death and, interestingly, down-regulated by JNK or CK2 inhibition. Together, these data indicate that the increase in CK2 activity induced by excitotoxic insults regulates MAPKs, triggers p53 activation and mediates subsequent oligodendroglial loss. Therefore, targeting CK2 may be a useful strategy to prevent oligodendrocyte death in MS and other diseases involving central nervous system (CNS) white matter.
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Affiliation(s)
- Manuel Canedo-Antelo
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
| | - Mari Paz Serrano
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
| | - Andrea Manterola
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
| | - Asier Ruiz
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
| | - Francisco Llavero
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Genética, Antropología Física y Fisiología Animal, Universidad del País Vasco (UPV/EHU), Leioa, Spain
| | - Susana Mato
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
| | - José Luis Zugaza
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Genética, Antropología Física y Fisiología Animal, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Fernando Pérez-Cerdá
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
| | - Carlos Matute
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
| | - María Victoria Sánchez-Gómez
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Leioa, Spain
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5
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Kwak YD, Wang B, Pan W, Xu H, Jiang X, Liao FF. Functional interaction of phosphatase and tensin homologue (PTEN) with the E3 ligase NEDD4-1 during neuronal response to zinc. J Biol Chem 2010; 285:9847-9857. [PMID: 20100827 DOI: 10.1074/jbc.m109.091637] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The contribution of zinc-mediated neuronal death in the process of both acute and chronic neurodegeneration has been increasingly appreciated. Phosphatase and tensin homologue, deleted on chromosome 10 (PTEN), the major tumor suppressor and key regulator of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, plays a critical role in neuronal death in response to various insults. NEDD4-1-mediated PTEN ubiquitination and subsequent degradation via the ubiquitin proteosomal system have recently been demonstrated to be the important regulatory mechanism for PTEN in several cancer types. We now demonstrate that PTEN is also the key mediator of the PI3K/Akt pathway in the neuronal response to zinc insult. We used primary cortical neurons and neuroblastoma N2a cells to show that zinc treatment results in a reduction of the PTEN protein level in parallel with increased NEDD4-1 gene/protein expression. The reduced PTEN level is associated with an activated PI3K pathway as determined by elevated phosphorylation of both Akt and GSK-3 as well as by the attenuating effect of a specific PI3K inhibitor (wortmannin). The reduction of PTEN can be attributed to increased protein degradation via the ubiquitin proteosomal system, as we show NEDD4-1 to be the major E3 ligase responsible for PTEN ubiquitination in neurons. Moreover, PTEN and NEDD4-1 appear to be able to counter-regulate each other to mediate the neuronal response to zinc. This reciprocal regulation requires the PI3K signaling pathway, suggesting a feedback loop mechanism. This study demonstrates that NEDD4-1-mediated PTEN ubiquitination is crucial in the regulation of PI3K/Akt signaling by PTEN during the neuronal response to zinc, which may represent a common mechanism in neurodegeneration.
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Affiliation(s)
- Young-Don Kwak
- Neurodegenerative Disease Program, Burnham Institute for Medical Research, La Jolla, California 92037
| | - Bin Wang
- Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Wei Pan
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Huaxi Xu
- Neurodegenerative Disease Program, Burnham Institute for Medical Research, La Jolla, California 92037
| | - Xuejun Jiang
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Francesca-Fang Liao
- Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163.
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6
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Blanquet PR, Mariani J, Fournier B. Temporal assessment of histone H3 phospho-acetylation and casein kinase 2 activation in dentate gyrus from ischemic rats. Brain Res 2009; 1302:10-20. [PMID: 19765564 DOI: 10.1016/j.brainres.2009.09.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 08/31/2009] [Accepted: 09/08/2009] [Indexed: 11/30/2022]
Abstract
Hippocampal dentate gyrus possesses an exceptional capacity of adaptation to ischemic insults. Recently, using a transient global ischemic model in the adult rat, we identified a neuroprotective signalling cascade in the dentate gyrus involving calcium/calmodulin-dependent protein kinase IV (CaMKIV), cyclic AMP response element (CRE)-binding protein (CREB) and brain-derived neurotrophic factor (BDNF), a major regulator of survival. We have shown that intracerebroventricular injections of anti-BDNF and anti-CREB are sufficient to cause substantial tissular damages and apoptotic deaths in late periods (48-72 h) after ischemia. Herein, we provide immunohistochemical and biochemical evidence that antibody-induced impairment of the protective CaMKIV/CREB/BDNF pathway induces an apparent duality of response in the dentate gyrus. The experimental protocol is performed as follows: (a) rats are anesthetized and vertebral arteries are occluded by electrocauterization; (b) on the following day, transient global ischemia is produced by occlusion of carotid arteries for 25 min; (c) finally, rats are infused with the pharmacologic agents into the left cerebral ventricle and then perfusion-fixed at different time points after ischemia for immunohistochemical and immunoblotting analyses. After infusion with anti-CaMKIV, phosphorylation of mitogen-activated protein kinases (MAPK) MKK3, MKK6 and p38 and phospho-acetylation of histone H3 occur at 6 h after ischemia without presence of any caspase-9 activation and cellular injuries. In contrast, infusion of anti-BDNF or anti-CREB surprisingly results in a remarkable stimulation of casein kinase 2 (CK2) and caspase-9 activities at 48-72 h post-insult. This is accompanied by the disappearance of phosphorylation of MKK(3/6) and p38 and phospho-acetylation of histone H3. These results suggest that: (1) activation of a MKK(3/6)/p38/H3 cascade at early periods post-ischemia may be capable of causing a short transient protective effect in the dentate gyrus; (2) CK2 might be implicated in inhibition of activity of molecules such as MKK(3/6), p38 and deacetylases at late periods post-insult, thereby promoting injuries and cell deaths in the dentate cell layer.
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Affiliation(s)
- P R Blanquet
- Laboratoire Développement et Vieillissement du Système Nerveux, UMR 7102 CNRS-UPMC (Neurobiologie des Processus Adaptatifs), Université P & M Curie, 9 Quai Saint-Bernard, Bâtiment B, 4(e)Etage, Boîte 14, 75005, Paris, France.
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Involvement of activating transcription factors JNK, NF-κB, and AP-1 in apoptosis induced by pyrrolidine dithiocarbamate/Cu complex. Eur J Pharmacol 2008; 594:9-17. [DOI: 10.1016/j.ejphar.2008.07.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 07/03/2008] [Accepted: 07/10/2008] [Indexed: 11/23/2022]
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8
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Tapia E, Sánchez-González DJ, Medina-Campos ON, Soto V, Avila-Casado C, Martínez-Martínez CM, Johnson RJ, Rodríguez-Iturbe B, Pedraza-Chaverrí J, Franco M, Sánchez-Lozada LG. Treatment with pyrrolidine dithiocarbamate improves proteinuria, oxidative stress, and glomerular hypertension in overload proteinuria. Am J Physiol Renal Physiol 2008; 295:F1431-9. [PMID: 18753301 DOI: 10.1152/ajprenal.90201.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We evaluated whether the blockade of the proinflammatory transcription factor NF-kappaB would modify the oxidative stress, inflammation, and structural and hemodynamic alterations found in the kidney as a result of massive proteinuria. Twenty male Sprague-Dawley rats were injected with 2 g of BSA intraperitoneally daily for 2 wk. Ten of them received in addition the inhibitor of NF-kappaB activation pyrrolidine dithiocarbamate (PDTC; 200 mg.kg(-1).day(-1) sc) and the rest received vehicle. Seven rats that received intraperitoneal saline were used as controls. Glomerular hemodynamics were studied after 14 days. Markers of oxidative stress (NF-kappaB subunit p65+ cells, 3-nitrotyrosine, and 4-hydroxynonenal), inflammation (cortical CD68+ cells and NOS-II), and afferent arteriole damage were assessed by immunohistochemistry and morphometry. Activity of antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase was evaluated in renal cortex and medulla. Albumin overload induced massive proteinuria, oxidative stress with reduced activity of antioxidant enzymes, NF-kappaB activation, inflammatory cell infiltration, a significant presence of proteinaceous casts, systemic and glomerular hypertension, as well as arteriolar remodeling. Treatment with PDTC prevented or improved all of these findings. In this model of nephrotic syndrome, we demonstrate a key role for oxidative stress and inflammation in causing systemic and glomerular hypertension and proteinuria. Oxidative stress and inflammation may have a key role in accelerating renal injury associated with intense proteinuria.
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Affiliation(s)
- Edilia Tapia
- Department of Nephrology, Instituto Nacional de Cardiología Ignacio Chavez, Juan Badiano 1, 14080 Mexico City, Mexico
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9
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Transcriptional regulation of the hepatocyte growth factor gene by pyrrolidine dithiocarbamate. FEBS Lett 2008; 582:1859-64. [PMID: 18474243 DOI: 10.1016/j.febslet.2008.04.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 04/29/2008] [Accepted: 04/30/2008] [Indexed: 11/19/2022]
Abstract
Hepatocyte growth factor (HGF) mediates cancer cell invasion and metastasis. This study characterised the down-regulation of HGF expression by pyrrolidine dithiocarbamate (PDTC), which markedly reduced HGF mRNA expression and protein production in MRC-5 cells. Reporter gene studies revealed that PDTC inhibited HGF gene transcription and that the response element is located in the region -75 to +42 bp flanking the transcription initiation site. Electrophoretic mobility shift assay identified three specific protein complexes binding in this region, which were abrogated by exposure of cells to PDTC. PDTC deserves further investigation as a novel therapeutic agent for HGF-driven cancers.
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10
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Lee EJ, Seo SR, Um JW, Park J, Oh Y, Chung KC. NF-kappaB-inducing kinase phosphorylates and blocks the degradation of Down syndrome candidate region 1. J Biol Chem 2008; 283:3392-3400. [PMID: 18056702 DOI: 10.1074/jbc.m706707200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Down syndrome, the most frequent genetic disorder, is characterized by an extra copy of all or part of chromosome 21. Down syndrome candidate region 1 (DSCR1) gene, which is located on chromosome 21, is highly expressed in the brain of Down syndrome patients. Although its cellular function remains unknown, DSCR1 expression is linked to inflammation, angiogenesis, and cardiac development. To explore the functional role of DSCR1 and the regulation of its expression, we searched for novel DSCR1-interacting proteins using a yeast two-hybrid assay. Using a human fetal brain library, we found that DSCR1 interacts with NF-kappaB-inducing kinase (NIK). Furthermore, we demonstrate that NIK specifically interacts with and phosphorylates the C-terminal region of DSCR1 in immortalized hippocampal cells as well as in primary cortical neurons. This NIK-mediated phosphorylation of DSCR1 increases its protein stability and blocks its proteasomal degradation, the effects of which lead to an increase in soluble and insoluble DSCR1 levels. We show that an increase in insoluble DSCR1 levels results in the formation of cytosolic aggregates. Interestingly, we found that whereas the formation of these inclusions does not significantly alter the viability of neuronal cells, the overexpression of DSCR1 without the formation of aggregates is cytotoxic.
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Affiliation(s)
- Eun Jung Lee
- Department of Biology, College of Science, Yonsei University, Seoul 120-749
| | - Su Ryeon Seo
- Department of Molecular Bioscience, School of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do 200-701, Korea
| | - Ji Won Um
- Department of Biology, College of Science, Yonsei University, Seoul 120-749
| | - Joongkyu Park
- Department of Biology, College of Science, Yonsei University, Seoul 120-749
| | - Yohan Oh
- Department of Biology, College of Science, Yonsei University, Seoul 120-749
| | - Kwang Chul Chung
- Department of Biology, College of Science, Yonsei University, Seoul 120-749.
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C-Jun N-terminal kinase regulates adenosine A1 receptor-mediated synaptic depression in the rat hippocampus. Neuropharmacology 2007; 53:906-17. [PMID: 17967469 DOI: 10.1016/j.neuropharm.2007.09.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2006] [Revised: 08/31/2007] [Accepted: 09/03/2007] [Indexed: 12/19/2022]
Abstract
Adenosine A1 receptors are ubiquitous mediators of presynaptic inhibition of neurotransmission in the central nervous system, yet the signalling pathway linking A1 receptor activation and decreased neurotransmitter release remains poorly resolved. We tested the contribution of c-Jun N-terminal kinase (JNK) to adenosine A1 receptor-mediated depression of field excitatory postsynaptic potentials (fEPSPs) in area CA1 of the rat hippocampus. We found that inhibition of JNK with SP600125 or JNK inhibitor V, but not an inactive analogue, attenuated the depression of fEPSPs induced by adenosine, hypoxia, and the A1 receptor agonist N(6)-cyclopentyladenosine (CPA). In contrast, the JNK inhibitor SP600125 did not inhibit GABA(B)-mediated synaptic depression. In support of our electrophysiological findings, Western blot analysis showed that A1 receptor stimulation resulted in a transient increase in JNK phosphorylation in the membrane fraction of hippocampal lysates. The total amount of JNK in the membrane fraction was unchanged by CPA treatment. The increase in phosphorylated JNK induced by A1 receptor stimulation was blocked by the A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), indicating that A1 receptors specifically activate JNK in the hippocampus. Together with functional data indicating that JNK inhibition decreased CPA-induced paired pulse facilitation, these results suggest that JNK activation is necessary for adenosine A1 receptor-mediated synaptic depression occurring at a presynaptic locus The adenosine A1 receptor-JNK signalling pathway may represent a novel mechanism underlying inhibition of neurotransmitter release in the CNS.
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12
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Lee EJ, Lee JY, Seo SR, Chung KC. Overexpression of DSCR1 blocks zinc-induced neuronal cell death through the formation of nuclear aggregates. Mol Cell Neurosci 2007; 35:585-95. [PMID: 17596961 DOI: 10.1016/j.mcn.2007.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 05/09/2007] [Accepted: 05/09/2007] [Indexed: 11/22/2022] Open
Abstract
The Down syndrome (DS) candidate region gene 1 (DSCR1) is localized near DS critical region on chromosome 21 and is overexpressed in the brains of DS patients. Although DSCR1 was known for a modulator of calcineurin, the overexpression of DSCR1 is thought to play a role in neuronal cell death. Zinc, one of the most abundant transition metals in the brain, may also contribute to selective neuronal cell death when present in excessive amounts. In the present study, we investigated the effect of DSCR1 overexpression on zinc-induced cell death in hippocampal neuroprogenitor cells. The overexpression of DSCR1 caused apoptotic cell death without an apparent formation of intracellular protein inclusions. Upon exposure to zinc, soluble DSCR1 levels were significantly decreased and insoluble levels were enhanced to a similar extent, which were partially caused by the zinc-induced inhibition of proteasomal activity and a consequently diminished degradation of DSCR1. Furthermore, zinc treatment induced the formation of nuclear DSCR1 aggregates, which blocked zinc-induced cell death. These findings indicate that, although the up-regulation of DSCR1 levels exerts a cytotoxic effect, the addition of zinc leads to the formation of cytoprotective nuclear aggregates in neuronal cells.
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Affiliation(s)
- Eun Jung Lee
- Department of Biology, College of Science, Yonsei University, Shinchon-dong 134, Seodaemun-gu, Seoul 120-749, Republic of Korea
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13
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Franklin RB, Costello LC. Zinc as an anti-tumor agent in prostate cancer and in other cancers. Arch Biochem Biophys 2007; 463:211-7. [PMID: 17400177 PMCID: PMC1991338 DOI: 10.1016/j.abb.2007.02.033] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 02/27/2007] [Accepted: 02/28/2007] [Indexed: 12/14/2022]
Abstract
Human prostate glandular epithelial cells have the unique capability of accumulating high levels of zinc. This is essential to inhibit m-aconitase activity so that citrate can accumulate for secretion into prostatic fluid, which is a major function of the prostate gland. As a result, the Krebs cycle is truncated with the consequence of the lost ATP production that would result from citrate oxidation. The cellular accumulation of zinc also inhibits mitochondrial terminal oxidation and respiration. In addition to these metabolic effects, zinc accumulation exhibits anti-proliferative effects via its induction of mitochondrial apoptogenesis. Zinc accumulation also inhibits the invasive/migration activities in malignant prostate cells. The anti-proliferative effects and the effects on invasion and migration occur through zinc activation of specific intracellular signaling pathways. Consequently, these effects impose anti-tumor actions by zinc. The ability of prostate cells to accumulate zinc is due to the expression and activity of the zinc uptake transporter, ZIP1. To avoid the anti-tumor effects of zinc, in prostate cancer the malignant prostate cells exhibit a silencing of ZIP1 gene expression accompanied by a depletion of cellular zinc. Therefore we regard ZIP1 as a tumor suppressor gene in prostate cancer. In addition to prostate cells, similar tumor suppressor effects of zinc have been identified in several other types of tumors.
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Affiliation(s)
- Renty B Franklin
- Department of Biomedical Sciences, University of Maryland Baltimore, Dental School, 650 West Baltimore Street, Baltimore, MD 21201, USA.
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14
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Min YK, Lee JE, Chung KC. Zinc induces cell death in immortalized embryonic hippocampal cells via activation of Akt-GSK-3β signaling. Exp Cell Res 2007; 313:312-21. [PMID: 17098228 DOI: 10.1016/j.yexcr.2006.10.013] [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] [Received: 08/21/2006] [Revised: 10/04/2006] [Accepted: 10/16/2006] [Indexed: 11/21/2022]
Abstract
Zinc is an essential catalytic and structural element of many proteins and a signaling messenger that is released by neuronal activity at many central excitatory synapses. Excessive synaptic release of zinc followed by entry into vulnerable neurons contributes severe neuronal cell death. We have previously observed that zinc-induced neuronal cell death is accompanied by Akt activation in embryonic hippocampal progenitor (H19-7) cells. In the present study, we examined the role of Akt activation and its downstream signaling events during extracellular zinc-induced neuronal cell death. Treatment of H19-7 cells with 10 microM of zinc plus zinc ionophore, pyrithione, led to increased phosphorylation of Akt at Ser-473/Thr-308 and increased Akt kinase activity. Zinc-induced Akt activation was accompanied by increased Tyr-phosphorylated GSK-3beta as well as increased GSK-3beta kinase activity. Transient overexpression of a kinase-deficient Akt mutant remarkably suppressed GSK-3beta activation and cell death. Furthermore, tau phosphorylation, but not the degradation of beta-catenin, was dependent upon zinc-induced GSK-3beta activation and contributed to cell death. The current data suggest that, following exposure to zinc, the sequential activation of Akt and GSK-3beta plays an important role directing hippocampal neural precursor cell death.
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Affiliation(s)
- Young Kyu Min
- Department of Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
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15
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Yoshikawa Y, Adachi Y, Sakurai H. A new type of orally active anti-diabetic Zn(II)-dithiocarbamate complex. Life Sci 2006; 80:759-66. [PMID: 17137606 DOI: 10.1016/j.lfs.2006.11.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 10/08/2006] [Accepted: 11/02/2006] [Indexed: 12/20/2022]
Abstract
In order to find orally active Zn(II) complexes that can treat diabetes mellitus (DM) at low doses, four new Zn(II)-dithiocarbamate complexes with Zn(II)-sulfur coordination bonds were prepared and their in vitro insulinomimetic activity and in vivo anti-diabetic ability were evaluated. Among the Zn(II)-dithiocarbamate complexes, the bis(pyrrolidine-N-dithiocarbamate)zinc(II) (Zn(pdc)(2)) complex was found to be the most effective in terms of inhibiting free fatty acid-release and enhancing glucose-uptake in adipocytes. After oral administration of the Zn(pdc)(2) complex to KK-A(y) mice with obesity and type 2 DM, we observed that the high blood glucose levels in the mice were lowered from approximately 500 mg/dL to 350 mg/dL within 6 days, and the effect was maintained during the administration period. Also, indicators of insulin resistance such as serum insulin, leptin, and triglyceride levels were also reduced compared with those in untreated mice. Moreover, the Zn(pdc)(2) complex improved not only the hypertension in the mice, but also the adiponectin level in the serum. On the basis of the results, the Zn(pdc)(2) complex is proposed to improve hyperglycemia and insulin resistance in type 2 DM animals on daily oral administrations.
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Affiliation(s)
- Yutaka Yoshikawa
- Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
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16
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Choi SA, Kim SJ, Chung KC. Huntingtin-interacting protein 1-mediated neuronal cell death occurs through intrinsic apoptotic pathways and mitochondrial alterations. FEBS Lett 2006; 580:5275-82. [PMID: 16979168 DOI: 10.1016/j.febslet.2006.08.076] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 08/30/2006] [Accepted: 08/31/2006] [Indexed: 10/24/2022]
Abstract
Huntingtin interacting protein-1 (Hip1) is known to be associated with the N-terminal domain of huntingtin. Although Hip1 can induce apoptosis, the exact upstream signal transduction pathways have not been clarified yet. In the present study, we examined whether activation of intrinsic and/or extrinsic apoptotic pathways occurs during Hip1-mediated neuronal cell death. Overexpression of Hip1 induced cell death through caspase-3 activation in immortalized hippocampal neuroprogenitor cells. Interestingly, proteolytic processing of Hip1 into partial fragments was observed in response to Hip1 transfection and apoptosis-inducing drugs. Moreover, Hip1 was found to directly bind to and activate caspase-9. This promoted cytosolic release of cytochrome c and apoptosis-inducing factor via mitochondrial membrane perturbation. Furthermore, Hip1 could directly bind to Apaf-1, suggesting that the neurotoxic signals of Hip1 transmit through the intrinsic mitochondrial apoptotic pathways and the formation of apoptosome complex.
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Affiliation(s)
- Shin Ae Choi
- Department of Biology, College of Science, Yonsei University, Shinchon-dong 134, Seodaemun-gu, Seoul 120-749, Republic of Korea
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17
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Sheu ML, Ho FM, Yang RS, Chao KF, Lin WW, Lin-Shiau SY, Liu SH. High Glucose Induces Human Endothelial Cell Apoptosis Through a Phosphoinositide 3-Kinase–Regulated Cyclooxygenase-2 Pathway. Arterioscler Thromb Vasc Biol 2005; 25:539-45. [PMID: 15653566 DOI: 10.1161/01.atv.0000155462.24263.e4] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Diabetes mellitus causes endothelial dysfunction. The precise molecular mechanisms by which hyperglycemia causes apoptosis in endothelial cells are not yet well understood. The aim of this study was to explore the role of cyclooxygenase-2 (COX-2) and the possible involvement of phosphoinositide 3-kinase (PI3K) signaling in high glucose (HG)-induced apoptosis in human umbilical vein endothelial cells (HUVECs). METHODS AND RESULTS For detection of apoptosis, the morphological Hoechst staining and Annexin V/propidium iodide staining were used. Glucose upregulated COX-2 protein expression, which was associated with the induction of prostaglandin (PG) E2 (PGE2), caspase-3 activity, and apoptosis. Unexpectedly, we found that PI3K inhibitors could suppress COX-2 expression, PGE2 production, caspase-3 activity, and the subsequent apoptosis under HG condition. Glucose-induced activation of PI3K resulted in the downstream effector Akt phosphorylation. PI3K inhibitors effectively attenuated the intracellular reactive oxygen species (ROS) generation and nuclear factor kappaB (NF-kappaB) activation. Blocking the PI3K and Akt activities with the dominant-negative vectors greatly diminished the HG-triggered NF-kappaB activation and COX-2 expression and apoptosis. CONCLUSIONS These results suggest that HG, via PI3K/Akt signaling, induces NF-kappaB-related upregulation of COX-2, which in turn triggers the caspase-3 activity that facilitates HUVEC apoptosis. Also, HG may cause ROS generation in HUVECs through a PI3K/Akt-dependent pathway.
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Affiliation(s)
- Meei Ling Sheu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
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18
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Sohn WJ, Lee KW, Lee Y, Han JH, Choe YK, Kim DS, Kwon HJ. Pyrrolidine dithiocarbamate-induced macrophage inflammatory protein-2 gene expression is NF-kappaB-independent but c-Jun-dependent in macrophage cell line RAW 264.7. Mol Immunol 2005; 42:1165-75. [PMID: 15829306 DOI: 10.1016/j.molimm.2004.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Indexed: 10/26/2022]
Abstract
Pyrrolidine dithiocarbamate (PDTC) is a stable compound that acts as antioxidant or prooxidant, and is widely used to inhibit the activation of NF-kappaB. PDTC was also reported to activate NF-kappaB depending on its dose and metal ions in PC12 cells. In this work, we demonstrated a working mechanism of PDTC and its effects on the proinflammatory cytokine gene expression in a mouse macrophage cell line, RAW 264.7. PDTC alone induced NF-kappaB-independent MIP-2 promoter activation that can be assessed by transient transfection and confocal image analysis. The involvement of AP-1 transcription factor was noticed by promoter deletion/site-specific mutation analysis and electrophoretic mobility shift assay (EMSA). Among three different mitogen-activated protein kinase (MAPK) pathways tested, only the stress-activated protein kinase (SAPK)/Jun N-terminal kinase (JNK) pathway was significantly activated in RAW 264.7 cells after the stimulation with PDTC. Using pathway-specific inhibitors, we found that the SAPK/JNK pathway is clearly associated with PDTC-induced MIP-2 gene expression. Our experimental results indicate that PDTC-induced proinflammatory cytokine expressions are mediated by SAPK/JNK pathway, which activates AP-1.
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Affiliation(s)
- Wern-Joo Sohn
- Institute of Life Science and Biotechnology, College of Science, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul 120-749, Republic of Korea
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Hilgard P, Czaja MJ, Gerken G, Stockert RJ. Proapoptotic function of protein kinase CK2alpha" is mediated by a JNK signaling cascade. Am J Physiol Gastrointest Liver Physiol 2004; 287:G192-201. [PMID: 14962846 DOI: 10.1152/ajpgi.00507.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Protein kinase CK2 (formerly casein kinase II) is a tetrameric enzyme constitutively expressed in all eurakyotic tissues that plays a significant role in the regulation of cell proliferation, malignant transformation, and apoptosis. The catalytic alpha-subunit of the enzyme is known to exist in three isoforms CK2alpha, CK2alpha' and CK2alpha". CK2alpha" is highly expressed in liver compared with other tissues and is required for the normal trafficking of several hepatocellular membrane proteins. Initial studies of dengue virus infection indicated that the CK2alpha"-deficient membrane trafficking mutant cell line (Trf1) was resistant to virus-induced cell death compared with the parental human hepatoma (HuH)-7 hepatoma line. Expression of recombinant CK2alpha" in Trf1 was capable of reverting this resistant phenotype. This study was extended to TNF-alpha in addition to other stimuli of cell death in an attempt to uncover common death pathways that might be modulated by CK2alpha". Evaluation of different pathways involved in death signaling suggest that the regulation of a critical proapoptotic step in HuH-7 cells by CK2alpha" is mediated by a JNK signaling cascade.
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Affiliation(s)
- Philip Hilgard
- Department for Gastroenterology and Hepatology, University-Hospital Essen, 45133 Essen, Germany
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20
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Lyons TJ, Villa NY, Regalla LM, Kupchak BR, Vagstad A, Eide DJ. Metalloregulation of yeast membrane steroid receptor homologs. Proc Natl Acad Sci U S A 2004; 101:5506-11. [PMID: 15060275 PMCID: PMC397413 DOI: 10.1073/pnas.0306324101] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Zinc is an essential micronutrient that can also be toxic. An intricate mechanism exists in yeast that maintains cellular zinc within an optimal range. The centerpiece of this mechanism is the Zap1p protein, a transcription factor that senses zinc deficiency and responds by up-regulating genes involved in zinc metabolism. A microarray screen for novel Zap1p target genes suggested a role in zinc homeostasis for four homologous yeast genes. The expression of two of these genes, YDR492w and YOL002c, suggested direct regulation by Zap1p, whereas the expression of YOL002c and a third homologous gene, YOL101c, was induced by high zinc. YDR492w and YOL002c are confirmed to be direct Zap1p target genes. The induction of YOL002c and YOL101c by toxic metal ion exposure is shown to be mediated by the Mga2p hypoxia sensor. Furthermore, YOL101c is induced by deletion of the Aft1p iron-responsive transcription factor. These three genes, along with a fourth yeast homolog, YLR023c, have phenotypic effects on zinc tolerance and Zap1p activity. Because of their metalloregulation, zinc-related phenotypes, and highly conserved motifs containing potential metal-binding residues, this family has been renamed the IZH gene family (Implicated in Zinc Homeostasis). Furthermore, these genes are regulated by exogenous fatty acids, suggesting a dual role in lipid metabolism. The IZH genes encode membrane proteins that belong to a ubiquitous protein family that includes hemolysin III and vertebrate membrane steroid receptors. We propose that the IZH genes affect zinc homeostasis either directly or indirectly by altering sterol metabolism.
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Affiliation(s)
- Thomas J Lyons
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32611, USA.
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Kohlstedt K, Brandes RP, Müller-Esterl W, Busse R, Fleming I. Angiotensin-converting enzyme is involved in outside-in signaling in endothelial cells. Circ Res 2003; 94:60-7. [PMID: 14615289 DOI: 10.1161/01.res.0000107195.13573.e4] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Not all of the cardiovascular effects of angiotensin-converting enzyme (ACE) inhibitors can be attributed to changes in angiotensin II and bradykinin levels. Because the cytoplasmic tail of ACE is phosphorylated, we determined whether ACE inhibitors affect the phosphorylation of ACE and whether ACE possesses the characteristics of a signal transduction molecule. The ACE inhibitors ramiprilat and perindoprilat, and the substrate bradykinin (but not angiotensin I), enhanced the activity of ACE-associated CK2 and the phosphorylation of ACE Ser1270 in cultured endothelial cells. Mitogen-activated protein kinase kinase 7 and c-Jun N-terminal kinase (JNK) coprecipitated with ACE, and stimulation of endothelial cells with ACE inhibitors increased the activity of ACE-associated JNK and elicited the accumulation of phosphorylated c-Jun in the nucleus. Ramiprilat was however unable to activate JNK or to stimulate the nuclear accumulation of c-Jun in endothelial cells expressing a S1270A ACE mutant or in ACE-deficient cells. Because the ACE inhibitor-induced increase in ACE expression has been linked to the formation of c-Jun homodimers, we investigated whether ACE signaling via JNK contributes to this response in vitro and in vivo. Prolonged ramiprilat treatment increased ACE expression in primary cultures of human endothelial cells and in vivo (mouse lung), a response that was prevented by pretreatment with the JNK inhibitor SP600125. Thus, ACE is involved in outside-in signaling in endothelial cells and "ACE signaling" may be an important cellular mechanism contributing to the beneficial effects of ACE inhibitors.
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Affiliation(s)
- Karin Kohlstedt
- Institut für Kardiovaskuläre Physiologie, Klinikum der J.W. Goethe-Universität, Frankfurt am Main, Germany
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