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Catanzaro R, Zerbinati N, Solimene U, Celep G, Marotta F, Kushugulova A, Milazzo M, Tomella C, Bertuccelli G, Zhumadilov Z. Effect of Celergen, a marine derivative, on in vitro hepatocarcinogenesis. Drug Discov Ther 2013; 7:196-200. [PMID: 24270384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The aim of this study was to test for a potential anticarcinogenic effect of Celergen, a marine derivative devoid of traceable amounts of inorganic arsenic, on cell proliferation, cell cycle progression and apoptosis in the HepG2 human liver cancer cell line. Celergen significantly inhibited the proliferation of cancer cells in a dose-dependent manner while limiting the cell cycle progression at the G1 phase and significantly inducing apoptosis. Further examination showed that Celergen enhanced expression of the p21(CIPl1WAF1), GADD153 genes and downregulated the c-myc gene. These results suggest that Celergen exerts promising chemopreventive properties to be further investigated.
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Affiliation(s)
- R Catanzaro
- ReGenera Research Group for Aging-Intervention, Milano, Italy
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202
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Niu Y, Zhang X, Zheng Y, Zhang R. XRCC1 deficiency increased the DNA damage induced by γ-ray in HepG2 cell: Involvement of DSB repair and cell cycle arrest. Environ Toxicol Pharmacol 2013; 36:311-319. [PMID: 23708312 DOI: 10.1016/j.etap.2013.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 06/02/2023]
Abstract
γ-ray irradiation can induce DNA damages which include base damages, single-strand breaks and double-strand breaks in various type cells. The DNA repair protein XRCC1, as a part of the BER pathway, forms complexes with DNA polymerase beta, DNA ligase III and poly-ADP-ribose polymerase (PARP) in the repair of DNA single strand breaks and also affects the repair of double strand breaks. However, it is still not known well whether XRCC1 contributes to affect the irradiation sensitivity and DNA damage in HepG2 cell and the potential mechanism. Hence, the purpose of this study was to explore whether abrogation of XRCC1 gene expression by shRNA could reduce DNA repair and thus sensitize HepG2 cells to γ-ray. Cell viability was measured by Trypan blue staining and cloning efficiency assay. The DNA damage was detected by Comet assay. Apoptosis and cell cycle were detected by flow cytometry. The DNA-PKcs and gadd153 mRNA expression were determined by Real-time PCR. Our results showed that abrogation of XRCC 1 could sensitize HepG2 cells to γ-ray. This enhanced sensitivity could be attributed to the increased DNA damage and increased cell cycle arrest, which might be related with the increasing of DNA-PKcs and gadd153 mRNA expression. Therefore, our results suggested that the γ-ray irradiation sensitivity could be increased by targeting inhibition of XRCC1 in HepG2 cell.
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Affiliation(s)
- Yujie Niu
- Department of Toxicology, School of Public Health, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, Hebei, People's Republic of China; Department of Occupational and Environmental Health, School of Public Health, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, Hebei, People's Republic of China
| | - Xing Zhang
- National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, 29 Nanwei Road, Xuanwu District, Beijing 100050, People's Republic of China
| | - Yuxin Zheng
- National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, 29 Nanwei Road, Xuanwu District, Beijing 100050, People's Republic of China
| | - Rong Zhang
- Department of Toxicology, School of Public Health, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, Hebei, People's Republic of China.
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203
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Marwarha G, Raza S, Prasanthi JRP, Ghribi O. Gadd153 and NF-κB crosstalk regulates 27-hydroxycholesterol-induced increase in BACE1 and β-amyloid production in human neuroblastoma SH-SY5Y cells. PLoS One 2013; 8:e70773. [PMID: 23951005 PMCID: PMC3739769 DOI: 10.1371/journal.pone.0070773] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/21/2013] [Indexed: 11/19/2022] Open
Abstract
β-amyloid (Aβ) peptide, accumulation of which is a culprit for Alzheimer's disease (AD), is derived from the initial cleavage of amyloid precursor protein by the aspartyl protease BACE1. Identification of cellular mechanisms that regulate BACE1 production is of high relevance to the search for potential disease-modifying therapies that inhibit BACE1 to reduce Aβ accumulation and AD progression. In the present study, we show that the cholesterol oxidation product 27-hydroxycholesterol (27-OHC) increases BACE1 and Aβ levels in human neuroblastoma SH-SY5Y cells. This increase in BACE1 involves a crosstalk between the two transcription factors NF-κB and the endoplasmic reticulum stress marker, the growth arrest and DNA damage induced gene-153 (gadd153, also called CHOP). We specifically show that 27-OHC induces a substantial increase in NF-κB binding to the BACE1 promoter and subsequent increase in BACE1 transcription and Aβ production. The NF-κB inhibitor, sc514, significantly attenuated the 27-OHC-induced increase in NF-κB-mediated BACE1 expression and Aβ genesis. We further show that the 27-OHC-induced NF-κB activation and increased NF-κB-mediated BACE1 expression is contingent on the increased activation of gadd153. Silencing gadd153 expression with siRNA alleviated the 27-OHC-induced increase in NF-κB activation, NF-κB binding to the BACE1 promoter, and subsequent increase in BACE1 transcription and Aβ production. We also show that increased levels of BACE1 in the triple transgenic mouse model for AD is preceded by gadd153 and NF-κB activation. In summary, our study demonstrates that gadd153 and NF-κB work in concert to regulate BACE1 expression. Agents that inhibit gadd153 activation and subsequent interaction with NF-κB might be promising targets to reduce BACE1 and Aβ overproduction and may ultimately serve as disease-modifying treatments for AD.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Shaneabbas Raza
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Jaya R. P. Prasanthi
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Othman Ghribi
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
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204
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Schram AW, Baas R, Jansen PWTC, Riss A, Tora L, Vermeulen M, Timmers HTM. A dual role for SAGA-associated factor 29 (SGF29) in ER stress survival by coordination of both histone H3 acetylation and histone H3 lysine-4 trimethylation. PLoS One 2013; 8:e70035. [PMID: 23894581 PMCID: PMC3720948 DOI: 10.1371/journal.pone.0070035] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 06/14/2013] [Indexed: 02/02/2023] Open
Abstract
The SGF29 protein binds to tri-methylated lysine-4 of histone H3 (H3K4me3), which is a histone modification associated with active promoters. Human SGF29 is a subunit of the histone acetyltransferase module of the SAGA (Spt-Ada-Gcn5 acetyltransferase) and ATAC (Ada-Two-A-containing 2A) co-activator complexes. Previous work revealed that the SAGA complex is recruited to endoplasmic reticulum (ER) stress target genes and required for their induction. Here, we report the involvement of SGF29 in the survival of human cells from ER stress. SGF29 knockdown results in impaired transcription of the ER stress genes GRP78 and CHOP. Besides histone H3K14 acetylation, we find that SGF29 is also required for the maintenance of H3K4me3 at these genes, which is already present prior to ER stress. Reduced levels of H3K4me3 in the absence of SGF29 correlate with a decreased association of ASH2L, which is a core component of the SET1/MLL complexes, to GFP78 and CHOP. In conclusion, our results suggest that the H3K4me3-binding protein SGF29 plays a central and dual role in the ER stress response. Prior to ER stress, the protein coordinates H3K4me3 levels, thereby maintaining a ‘poised’ chromatin state on ER stress target gene promoters. Following ER stress induction, SGF29 is required for increased H3K14 acetylation on these genes, which then results in full transcriptional activation, thereby promoting cell survival.
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Affiliation(s)
- Andrea W. Schram
- Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Roy Baas
- Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Pascal W. T. C. Jansen
- Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anne Riss
- Cellular Signaling and Nuclear Dynamics Program, Institut de Génétique et de Biologie, Université de Strasbourg, Illkirch, France
| | - Laszlo Tora
- Cellular Signaling and Nuclear Dynamics Program, Institut de Génétique et de Biologie, Université de Strasbourg, Illkirch, France
| | - Michiel Vermeulen
- Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail: (MV); (HTMT)
| | - H. Th. Marc Timmers
- Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail: (MV); (HTMT)
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205
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Fan L, Song B, Sun G, Ma T, Zhong F, Wei W. Endoplasmic reticulum stress-induced resistance to doxorubicin is reversed by paeonol treatment in human hepatocellular carcinoma cells. PLoS One 2013; 8:e62627. [PMID: 23658755 PMCID: PMC3643935 DOI: 10.1371/journal.pone.0062627] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/22/2013] [Indexed: 01/28/2023] Open
Abstract
Background Endoplasmic reticulum stress (ER stress) is generally activated in solid tumors and results in tumor cell anti-apoptosis and drug resistance. Paeonol (Pae, 2-hydroxy-4-methoxyacetophenone), is a natural product extracted from the root of Paeonia Suffruticosa Andrew. Although Pae displays anti-neoplastic activity and increases the efficacy of chemotherapeutic drugs in various cell lines and in animal models, studies related to the effect of Pae on ER stress–induced resistance to chemotherapeutic agents in hepatocellular carcinoma (HCC) are poorly understood. Methodology/Principal Findings In this study, we investigated the effect of the endoplasmic reticulum (ER) stress response during resistance of human hepatocellular carcinoma cells to doxorubicin. Treatment with the ER stress-inducer tunicamycin (TM) before the addition of doxorubicin reduced the rate of apoptosis induced by doxorubicin. Interestingly, co-pretreatment with tunicamycin and Pae significantly increased apoptosis induced by doxorubicin. Furthermore, induction of ER stress resulted in increasing expression of COX-2 concomitant with inactivation of Akt and up-regulation of the pro-apoptotic transcription factor CHOP (GADD153) in HepG2 cells. These cellular changes in gene expression and Akt activation may be an important resistance mechanism against doxorubicin in hepatocellular carcinoma cells undergoing ER stress. However, co-pretreatment with tunicamycin and Pae decreased the expression of COX-2 and levels of activation of Akt as well as increasing the levels of CHOP in HCC cells. Conclusions/Significance Our results demonstrate that Pae reverses ER stress–induced resistance to doxorubicin in human hepatocellular carcinoma cells by targeting COX-2 mediated inactivation of PI3K/AKT/CHOP.
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Affiliation(s)
- Lulu Fan
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Bing Song
- Department of Cardiovasology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Guoping Sun
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
- * E-mail:
| | - Tai Ma
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Fei Zhong
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Hefei, Anhui, China
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206
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Nashine S, Bhootada Y, Lewin AS, Gorbatyuk M. Ablation of C/EBP homologous protein does not protect T17M RHO mice from retinal degeneration. PLoS One 2013; 8:e63205. [PMID: 23646198 PMCID: PMC3640035 DOI: 10.1371/journal.pone.0063205] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 04/03/2013] [Indexed: 11/18/2022] Open
Abstract
Despite the proposed link between ablation of the CHOP protein and delay of the onset of ER stress-mediated disorders including diabetes, Alzheimer Disease, and cardiac hypertrophy, the role of CHOP protein in photoreceptor cell death associated with Autosomal Dominant Retinitis Pigmentosa (ADRP) has not been investigated. T17M RHO transgenic mice carry a mutated human rhodopsin transgene, the expression of which in retina leads to protein misfolding, activation of UPR and progressive retinal degeneration. The purpose of this study is to investigate the role of CHOP protein in T17M RHO retina. Wild-type, CHOP-/-, T17M RHO and T17M RHO CHOP-/-mice were used in the study. Evaluation of the impact of CHOP ablation was performed using electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), quantitative Real-Time PCR (qRT-PCR) and western blot analysis. Dark-adapted ERG analysis demonstrated that by 1 month, the T17M RHO CHOP-/- mice had a 70% reduction of the a-wave amplitude compared to the T17M RHO mice. The loss of function in T17M RHO CHOP-/- photoreceptors was associated with a 22-24% decline in the thickness of the outer nuclear layer. These mice had significant reduction in the expression of transcription factors, Crx and Nrl, and also in mouse Rho, and human RHO. The reduction was associated with an 8-fold elevation of the UPR marker, p-eIf2α protein and 30% down-regulation of sXbp1 protein. In addition, the histone deacetylase 1 (Hdac1) protein was 2-fold elevated in the T17M RHO CHOP-/- retina. The ablation of CHOP led to a reduction in the expression of photoreceptor-specific transcriptional factors, and both endogenous and exogenous RHO mRNA. Thus, despite its role in promoting apoptosis, CHOP protects rod photoreceptors carrying an ADRP mutation.
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Affiliation(s)
- Sonali Nashine
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Yogesh Bhootada
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Alfred S. Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
| | - Marina Gorbatyuk
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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207
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Zhu H, Qian J, Wang W, Yan Q, Xu Y, Jiang Y, Zhang L, Lu F, Hu W, Zhang X, Wang F, Sun X. RNA interference of GADD153 protects photoreceptors from endoplasmic reticulum stress-mediated apoptosis after retinal detachment. PLoS One 2013; 8:e59339. [PMID: 23555658 PMCID: PMC3612068 DOI: 10.1371/journal.pone.0059339] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 02/13/2013] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Apoptosis of photoreceptors plays a critical role in the vision loss caused by retinal detachment (RD). Pharmacologic inhibition of photoreceptor cell death may prevent RD. This study investigated the role of GADD153 that participates in endoplasmic reticulum (ER) stress-mediated apoptosis of photoreceptor cells after RD. METHODS Retinal detachment was created in Wistar rats by subretinal injection of hyaluronic acid. The rats were then randomly divided into four groups: normal control group, RD group, GADD153 RNAi group and vehicle group. RNA interference of GADD153 was performed using short hairpin RNA (shRNA). Expressions of GADD153 mRNA and protein were examined by RT-PCR and Western blotting analysis, respectively. GADD153 protein distribution in the retinal cells was observed using immunofluorescence confocal laser scanning microscopy. Apoptosis of retinal cells was determined by TdT-mediated fluorescein-16-dUTP nick-end labeling (TUNEL) assay. RESULTS Lentivirus GADD153 shRNA with the most effective silencing effect was chosen for in vivo animal study and was successfully delivered into the retinal tissues. GADD153 mRNA and protein expressions in GADD153 RNAi group were significantly lower than those in the RD group. Silencing of GADD153 by RNAi protected photoreceptors from ER stress-induced apoptosis. CONCLUSION ER stress-mediated pathway is involved in photoreceptor cell apoptosis after RD. GADD153 is a key regulatory molecule regulating ER-stress pathways and plays a crucial role in the apoptosis of photoreceptor cells after RD.
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Affiliation(s)
- Hong Zhu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Department of Ophthalmology, No.3 People’s Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Jin Qian
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Wenqiu Wang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Quan Yan
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Ying Xu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Yuan Jiang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Lei Zhang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Fengqing Lu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Weiting Hu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Xi Zhang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Fenghua Wang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Fundus Disease, Shanghai, China
- * E-mail: (XS); (FW)
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- * E-mail: (XS); (FW)
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208
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Nakamura S, Takizawa H, Shimazawa M, Hashimoto Y, Sugitani S, Tsuruma K, Hara H. Mild endoplasmic reticulum stress promotes retinal neovascularization via induction of BiP/GRP78. PLoS One 2013; 8:e60517. [PMID: 23544152 PMCID: PMC3609792 DOI: 10.1371/journal.pone.0060517] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 02/27/2013] [Indexed: 12/17/2022] Open
Abstract
Endoplasmic reticulum (ER) stress occurs as a result of accumulation of unfolded or misfolded proteins in the ER and is involved in the mechanisms of various diseases, such as cancer and neurodegeneration. The goal of the present study was to clarify the relationship between ER stress and pathological neovascularization in the retina. Proliferation and migration of human retinal microvascular endothelial cells (HRMEC) were assessed in the presence of ER stress inducers, such as tunicamycin and thapsigargin. The expression of ER chaperone immunoglobulin heavy-chain binding protein (BiP), known as Grp78, was evaluated by real time RT-PCR, immunostaining, and Western blotting. Tunicamycin or thapsigargin was injected into the intravitreal body of oxygen-induced retinopathy (OIR) model mice at postnatal day 14 (P14) and retinal neovascularization was quantified at P17. The expression and localization of BiP in the retina was also evaluated in the OIR model. Exposure to tunicamycin and thapsigargin increased the proliferation and migration of HRMEC. Tunicamycin enhanced the expression of BiP in HRMEC at both the mRNA level and at the protein level on the cell surface, and increased the formation of a BiP/T-cadherin immunocomplex. In OIR model mice, retinal neovascularization was accelerated by treatments with ER stress inducers. BiP was particularly observed in the pathological vasculature and retinal microvascular endothelial cells, and the increase of BiP expression was correlated with retinal neovascularization. In conclusion, ER stress may contribute to the formation of abnormal vasculature in the retina via BiP complexation with T-cadherin, which then promotes endothelial cell proliferation and migration.
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Affiliation(s)
- Shinsuke Nakamura
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Haruka Takizawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Yuhei Hashimoto
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Sou Sugitani
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Kazuhiro Tsuruma
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
- * E-mail:
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209
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Shi K, Wang D, Cao X, Ge Y. Endoplasmic reticulum stress signaling is involved in mitomycin C (MMC)-induced apoptosis in human fibroblasts via PERK pathway. PLoS One 2013; 8:e59330. [PMID: 23533616 PMCID: PMC3606443 DOI: 10.1371/journal.pone.0059330] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Accepted: 02/13/2013] [Indexed: 11/18/2022] Open
Abstract
Endoplasmic reticulum (ER) stress-mediated cell apoptosis has been implicated in various cell types, including fibroblasts. Previous studies have shown that mitomycin C (MMC)-induced apoptosis occurs in fibroblasts, but the effects of MMC on ER stress-mediated apoptosis in fibroblasts have not been examined. Here, MMC-induced apoptosis in human primary fibroblasts was investigated by exposing cells to a single dose of MMC for 5 minutes. Significant inhibition of cell proliferation and increased apoptosis were observed using a cell viability assay, Annexin V/propidium iodide double staining, cell cycle analysis, and TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) staining. Upregulation of proapoptotic factors, including cleaved caspase-3 and poly ADP-ribose polymerase (PARP), was detected by Western blotting. MMC-induced apoptosis was correlated with elevation of 78-kDa glucose-regulated protein (GRP78) and C/EBP homologous protein (CHOP), which are hallmarks of ER stress. Three unfolded protein response (UPR) sensors (inositol-requiring enzyme 1, IRE1; activating transcription factor 6, ATF6; and PKR-like ER kinase, PERK) and their downstream signaling pathways were also activated. Knockdown of CHOP attenuated MMC-induced apoptosis by increasing the ratio of BCL-2/BAX and decreasing BIM expression, suggesting that ER stress is involved in MMC-induced fibroblast apoptosis. Interestingly, knockdown of PERK significantly decreased ER stress-mediated apoptosis by reducing the expression of CHOP, BIM and cleaved caspase-3. Reactive oxygen species (ROS) scavenging also decreased the expression of GRP78, phospho-PERK, CHOP, and BIM. These results demonstrate that MMC-induced apoptosis is triggered by ROS generation and PERK activation.
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Affiliation(s)
- Kun Shi
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
| | - Daode Wang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
| | - Xiaojian Cao
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
- * E-mail: (XJC); (YBG)
| | - Yingbin Ge
- Department of Physiology, Nanjing Medical University, Nanjing, People’s Republic of China
- * E-mail: (XJC); (YBG)
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210
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Zha BS, Wan X, Zhang X, Zha W, Zhou J, Wabitsch M, Wang G, Lyall V, Hylemon PB, Zhou H. HIV protease inhibitors disrupt lipid metabolism by activating endoplasmic reticulum stress and inhibiting autophagy activity in adipocytes. PLoS One 2013; 8:e59514. [PMID: 23533630 PMCID: PMC3606318 DOI: 10.1371/journal.pone.0059514] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 02/15/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND HIV protease inhibitors (PI) are core components of Highly Active Antiretroviral Therapy (HAART), the most effective treatment for HIV infection currently available. However, HIV PIs have now been linked to lipodystrophy and dyslipidemia, which are major risk factors for cardiovascular disease and metabolic syndrome. Our previous studies have shown that HIV PIs activate endoplasmic reticulum (ER) stress and disrupt lipid metabolism in hepatocytes and macrophages. Yet, little is known on how HIV PIs disrupt lipid metabolism in adipocytes, a major cell type involved in the pathogenesis of metabolic syndrome. METHODOLOGY AND PRINCIPAL FINDINGS Cultured and primary mouse adipocytes and human adipocytes were used to examine the effect of frequently used HIV PIs in the clinic, lopinavir/ritonavir, on adipocyte differentiation and further identify the underlying molecular mechanism of HIV PI-induced dysregulation of lipid metabolism in adipocytes. The results indicated that lopinavir alone or in combination with ritonavir, significantly activated the ER stress response, inhibited cell differentiation, and induced cell apoptosis in adipocytes. In addition, HIV PI-induced ER stress was closely linked to inhibition of autophagy activity. We also identified through the use of primary adipocytes of CHOP(-/-) mice that CHOP, the major transcriptional factor of the ER stress signaling pathway, is involved in lopinavir/ritonavir-induced inhibition of cell differentiation in adipocytes. In addition, lopinavir/ritonavir-induced ER stress appears to be associated with inhibition of autophagy activity in adipocytes. CONCLUSION AND SIGNIFICANCE Activation of ER stress and impairment of autophagy activity are involved in HIV PI-induced dysregulation of lipid metabolism in adipocytes. The key components of ER stress and autophagy signaling pathways are potential therapeutic targets for HIV PI-induced metabolic side effects in HIV patients.
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Affiliation(s)
- Beth S. Zha
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Xiaoshan Wan
- School of Pharmacy, Wenzhou Medical College, Wenzhou, Zhejiang, P.R. China
| | - Xiaoxuan Zhang
- Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, P.R. China
| | - Weibin Zha
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, P.R. China
| | - Jun Zhou
- School of Pharmacy, Wenzhou Medical College, Wenzhou, Zhejiang, P.R. China
| | - Martin Wabitsch
- Division of Pediatric Endocrinology and Diabetes, University of Ulm, Ulm, Germany
| | - Guangji Wang
- Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, P.R. China
| | - Vijay Lyall
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Phillip B. Hylemon
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
- McGuire Veterans Affairs Medical Center, Richmond, Virginia, United States of America
| | - Huiping Zhou
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
- School of Pharmacy, Wenzhou Medical College, Wenzhou, Zhejiang, P.R. China
- McGuire Veterans Affairs Medical Center, Richmond, Virginia, United States of America
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211
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Dong M, Hu N, Hua Y, Xu X, Kandadi MR, Guo R, Jiang S, Nair S, Hu D, Ren J. Chronic Akt activation attenuated lipopolysaccharide-induced cardiac dysfunction via Akt/GSK3β-dependent inhibition of apoptosis and ER stress. Biochim Biophys Acta Mol Basis Dis 2013; 1832:848-63. [PMID: 23474308 DOI: 10.1016/j.bbadis.2013.02.023] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 02/03/2023]
Abstract
Sepsis is characterized by systematic inflammation and contributes to cardiac dysfunction. This study was designed to examine the effect of protein kinase B (Akt) activation on lipopolysaccharide-induced cardiac anomalies and underlying mechanism(s) involved. Mechanical and intracellular Ca²⁺ properties were examined in myocardium from wild-type and transgenic mice with cardiac-specific chronic Akt overexpression following LPS (4 mg/kg, i.p.) challenge. Akt signaling cascade (Akt, phosphatase and tensin homologue deleted on chromosome ten, glycogen synthase kinase 3 beta), stress signal (extracellular-signal-regulated kinases, c-Jun N-terminal kinases, p38), apoptotic markers (Bcl-2 associated X protein, caspase-3/-9), endoplasmic reticulum (ER) stress markers (glucose-regulated protein 78, growth arrest and DNA damage induced gene-153, eukaryotic initiation factor 2α), inflammatory markers (tumor necrosis factor α, interleukin-1β, interleukin-6) and autophagic markers (Beclin-1, light chain 3B, autophagy-related gene 7 and sequestosome 1) were evaluated. Our results revealed that LPS induced marked decrease in ejection fraction, fractional shortening, cardiomyocyte contractile capacity with dampened intracellular Ca²⁺ release and clearance, elevated reactive oxygen species (ROS) generation and decreased glutathione and glutathione disulfide (GSH/GSSG) ratio, increased ERK, JNK, p38, GRP78, Gadd153, eIF2α, BAX, caspase-3 and -9, downregulated B cell lymphoma 2 (Bcl-2), the effects of which were significantly attenuated or obliterated by Akt activation. Akt activation itself did not affect cardiac contractile and intracellular Ca²⁺ properties, ROS production, oxidative stress, apoptosis and ER stress. In addition, LPS upregulated levels of Beclin-1, LC3B and Atg7, while suppressing p62 accumulation. Akt activation did not affect Beclin-1, LC3B, Atg7 and p62 in the presence or absence of LPS. Akt overexpression promoted phosphorylation of Akt and GSK3β. In vitro study using the GSK3β inhibitor SB216763 mimicked the response elicited by chronic Akt activation. Taken together, these data showed that Akt activation ameliorated LPS-induced cardiac contractile and intracellular Ca²⁺ anomalies through inhibition of apoptosis and ER stress, possibly involving an Akt/GSK3β-dependent mechanism.
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Affiliation(s)
- Maolong Dong
- Department of Burn and Cutaneous Surgery, Xijing Hospital, the Fourth Military Medical University, Xi'an 710032, PR China
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212
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Her GM, Pai WY, Lai CY, Hsieh YW, Pang HW. Ubiquitous transcription factor YY1 promotes zebrafish liver steatosis and lipotoxicity by inhibiting CHOP-10 expression. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1037-51. [PMID: 23416188 DOI: 10.1016/j.bbalip.2013.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 02/06/2023]
Abstract
The ubiquitous transcription factor Yin Yang 1 (YY1) is known to have diverse and complex cellular functions. Although relevant literature has reported that YY1 expression can induce the down-regulation of C/EBP homologous protein 10 (CHOP-10) and then allow the transactivation of certain transcription factors required for lipogenesis, similar properties of YY1 are poorly understood in animal model systems. In this study, we demonstrate hepatic lipid accumulation in YY1 transgenic zebrafish (GY). Oil-red staining cells were predominantly increased in the livers of both GY larvae and adults, indicating that YY1 functionally promoted lipid accumulation in GY livers. Molecular analysis revealed that YY1 over-expression contributed to the accumulation of hepatic triglycerides (TGs) by inhibiting CHOP-10 expression in the juvenile GY and 3 other fish cell lines; the decreased CHOP-10 expression then induced the transactivation of C/EBP-α and PPAR-γ expression. CHOP-10 morpholino (MO)-injected and rosiglitazone-treated G-liver larvae showed liver steatosis by transactivating PPAR-γ. PPAR-γ MO-injected, and GW9662- and astaxanthin-treated GY larvae showed no liver steatosis by inhibiting PPAR-γ. Moreover, a fatty acid (FA) accumulation and a TG decrease were found in the liver of aged GY, leading to the induction of FA-oxidizing systems that increased hepatic oxidative stress and liver damage. This study is the first to examine YY1 as a potential stimulator for GY liver steatosis and lipotoxicity.
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Affiliation(s)
- Guor Mour Her
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan.
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213
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Takayanagi S, Fukuda R, Takeuchi Y, Tsukada S, Yoshida K. Gene regulatory network of unfolded protein response genes in endoplasmic reticulum stress. Cell Stress Chaperones 2013; 18:11-23. [PMID: 22802018 PMCID: PMC3508129 DOI: 10.1007/s12192-012-0351-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 06/29/2012] [Accepted: 07/02/2012] [Indexed: 02/08/2023] Open
Abstract
In the endoplasmic reticulum (ER), secretory and membrane proteins are properly folded and modified, and the failure of these processes leads to ER stress. At the same time, unfolded protein response (UPR) genes are activated to maintain homeostasis. Despite the thorough characterization of the individual gene regulation of UPR genes to date, further investigation of the mutual regulation among UPR genes is required to understand the complex mechanism underlying the ER stress response. In this study, we aimed to reveal a gene regulatory network formed by UPR genes, including immunoglobulin heavy chain-binding protein (BiP), X-box binding protein 1 (XBP1), C/EBP [CCAAT/enhancer-binding protein]-homologous protein (CHOP), PKR-like endoplasmic reticulum kinase (PERK), inositol-requiring 1 (IRE1), activating transcription factor 6 (ATF6), and ATF4. For this purpose, we focused on promoter-luciferase reporters for BiP, XBP1, and CHOP genes, which bear an ER stress response element (ERSE), and p5 × ATF6-GL3, which bears an unfolded protein response element (UPRE). We demonstrated that the luciferase activities of the BiP and CHOP promoters were upregulated by all the UPR genes, whereas those of the XBP1 promoter and p5 × ATF6-GL3 were upregulated by all the UPR genes except for BiP, CHOP, and ATF4 in HeLa cells. Therefore, an ERSE- and UPRE-centered gene regulatory network of UPR genes could be responsible for the robustness of the ER stress response. Finally, we revealed that BiP protein was degraded when cells were treated with DNA-damaging reagents, such as etoposide and doxorubicin; this finding suggests that the expression level of BiP is tightly regulated at the post-translational level, rather than at the transcriptional level, in the presence of DNA damage.
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Affiliation(s)
- Sayuri Takayanagi
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Riga Fukuda
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Yuuki Takeuchi
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Sakiko Tsukada
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Kenichi Yoshida
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
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214
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Woo JS, Kim SM, Jeong CH, Ryu CH, Jeun SS. Lipoxygenase inhibitor MK886 potentiates TRAIL-induced apoptosis through CHOP- and p38 MAPK-mediated up-regulation of death receptor 5 in malignant glioma. Biochem Biophys Res Commun 2012; 431:354-9. [PMID: 23261452 DOI: 10.1016/j.bbrc.2012.11.134] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 11/28/2012] [Indexed: 01/14/2023]
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers specific apoptosis in tumor cells and is one of the most promising candidates for cancer gene therapy. However, resistance to TRAIL is one of the main impediments to use of TRAIL in cancer treatment. We showed previously that the lipoxygenase inhibitor MK886 in combination with TRAIL exhibits enhanced antitumor activities compared with each agent alone in human glioma cells. In this study, we elucidated the molecular mechanisms responsible for MK886-mediated sensitization to TRAIL-induced apoptosis. We found that MK886 sensitized glioma cells to TRAIL-induced apoptosis by upregulating the death receptor 5 (DR5) and that specific knockdown of DR5 attenuated cell death. The mechanisms underlying this sensitization involved activation of the MK886-induced p38 mitogen-activated protein kinase (MAPK) pathway and subsequent DR5 overexpression. However, treatment with a specific inhibitor or gene silencing of p38 MAPK abolished both the DR5 induction and the increase in apoptosis caused by TRAIL. Taken together, our findings indicate that the increased expression of DR5 in a p38 MAPK-dependent manner plays an important role in the sensitization of MK886 to TRAIL-induced apoptosis.
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Affiliation(s)
- Ji Sun Woo
- Department of Biomedical Science, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Republic of Korea
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215
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Shibuya T, Tsujimoto Y. Deleterious effects of mitochondrial ROS generated by KillerRed photodynamic action in human cell lines and C. elegans. J Photochem Photobiol B 2012; 117:1-12. [PMID: 23000754 DOI: 10.1016/j.jphotobiol.2012.08.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Revised: 07/25/2012] [Accepted: 08/07/2012] [Indexed: 11/27/2022]
Abstract
KillerRed, a red fluorescent protein, is a photosensitizer that efficiently generates reactive oxygen species (ROS) when irradiated with green light. Because KillerRed is genetically encoded, it can be expressed in a spatially and temporally regulated manner under control of a chosen promoter and thus is a powerful tool for studying the downstream cellular effects of ROS. However, information is still limited about the effects of KillerRed-mediated production of ROS inside the mitochondria (mtROS). Therefore, we investigated whether mtROS generated by KillerRed could trigger mitochondrial damage and cell death by generating human cell lines (HEK293T and HeLa cells) that stably expressed mitochondria-targeting KillerRed (mtKillerRed). We found that mtROS generated by mtKillerRed caused depolarization of the mitochondrial membrane and morphological changes, which were partly due to the mitochondrial permeability transition (MPT), as well as inducing both caspase-dependent cell death (apoptosis) and caspase-independent cell death. In order to study the pathological processes initiated by mtROS in animals, transgenic Caenorhabditis elegans expressing mtKillerRed in muscle tissue were generated. Transgenic larvae showed developmental delay following light irradiation, suggesting that mtROS influenced the development of C. elegans larvae. In conclusion, our studies demonstrated that the photosensitizer KillerRed is effective at inducing oxidative damage in the mitochondria, and indicated that our experimental systems may be useful for studying the downstream cellular effects of mtROS.
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Affiliation(s)
- Toshiharu Shibuya
- Laboratory of Molecular Genetics, Department of Medical Genetics, Osaka University Medical School, Japan
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216
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Sung B, Prasad S, Ravindran J, Yadav VR, Aggarwal BB. Capsazepine, a TRPV1 antagonist, sensitizes colorectal cancer cells to apoptosis by TRAIL through ROS-JNK-CHOP-mediated upregulation of death receptors. Free Radic Biol Med 2012; 53:1977-87. [PMID: 22922338 PMCID: PMC3731040 DOI: 10.1016/j.freeradbiomed.2012.08.012] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 07/20/2012] [Accepted: 08/07/2012] [Indexed: 11/18/2022]
Abstract
A major problem in clinical trials of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as cancer therapy is the development of resistance to TRAIL. Therefore, agents that can overcome TRAIL resistance have great therapeutic potential. In this study, we evaluated capsazepine, a TRPV1 antagonist, for its ability to sensitize human colon cancer cells to TRAIL-induced apoptosis. Capsazepine potentiated the effect of TRAIL, as shown by its effect on intracellular esterase activity; activation of caspase-8,-9, and -3; and colony-formation assay. Capsazepine induced death receptors (DRs) DR5 and DR4, but not decoy receptors, at the transcriptional level and in a non-cell-type-specific manner. DR induction was dependent on CCAAT/enhancer-binding protein homologous protein (CHOP), as shown by (a) the induction of CHOP by capsazepine and (b) the abolition of DR- and potentiation of TRAIL-induced apoptosis by CHOP gene silencing. CHOP induction was also reactive oxygen species (ROS)-dependent, as shown by capsazepine's ability to induce ROS and by the quenching of ROS by N-acetylcysteine or glutathione, which prevented induction of CHOP and DR5 and consequent sensitization to TRAIL. Capsazepine's effects appeared to be mediated via JNK, as shown by capsazepine's ability to induce JNK and by the suppression of both CHOP and DR5 activation by inhibition of JNK. Furthermore, ROS sequestration abrogated the activation of JNK. Finally, capsazepine downregulated the expression of various antiapoptotic proteins (e.g., cFLIP and survivin) and increased the expression of proapoptotic proteins (e.g., Bax and p53). Together, our results indicate that capsazepine potentiates the apoptotic effects of TRAIL through downregulation of cell survival proteins and upregulation of death receptors via the ROS-JNK-CHOP-mediated pathway.
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217
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Chan JY, Biden TJ, Laybutt DR. Cross-talk between the unfolded protein response and nuclear factor-κB signalling pathways regulates cytokine-mediated beta cell death in MIN6 cells and isolated mouse islets. Diabetologia 2012; 55:2999-3009. [PMID: 22893028 DOI: 10.1007/s00125-012-2657-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 06/12/2012] [Indexed: 01/07/2023]
Abstract
AIMS/HYPOTHESIS Pancreatic beta cell destruction in type 1 diabetes may be mediated by cytokines such as IL-1β, IFN-γ and TNF-α. Endoplasmic reticulum (ER) stress and nuclear factor-κB (NFκB) signalling are activated by cytokines, but their significance in beta cells remains unclear. Here, we investigated the role of cytokine-induced ER stress and NFκB signalling in beta cell destruction. METHODS Isolated mouse islets and MIN6 beta cells were incubated with IL-1β, IFN-γ and TNF-α. The chemical chaperone 4-phenylbutyric acid (PBA) was used to inhibit ER stress. Protein production and gene expression were assessed by western blot and real-time RT-PCR. RESULTS We found in beta cells that inhibition of cytokine-induced ER stress with PBA unexpectedly potentiated cell death and NFκB-regulated gene expression. These responses were dependent on NFκB activation and were associated with a prolonged decrease in the inhibitor of κB-α (IκBα) protein, resulting from increased IκBα protein degradation. Cytokine-mediated NFκB-regulated gene expression was also potentiated after pre-induction of ER stress with thapsigargin, but not tunicamycin. Both PBA and thapsigargin treatments led to preferential upregulation of ER degradation genes over ER-resident chaperones as part of the adaptive unfolded protein response (UPR). In contrast, tunicamycin activated a balanced adaptive UPR in association with the maintenance of Xbp1 splicing. CONCLUSIONS/INTERPRETATION These data suggest a novel mechanism by which cytokine-mediated ER stress interacts with NFκB signalling in beta cells, by regulating IκBα degradation. The cross-talk between the UPR and NFκB signalling pathways may be important in the regulation of cytokine-mediated beta cell death.
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Affiliation(s)
- J Y Chan
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, 384 Victoria St, Darlinghurst, NSW 2010, Australia
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218
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Todorov SS, Kit OI. [Current idea of the morphogenetic features of liposarcomas]. Arkh Patol 2012; 74:61-63. [PMID: 23383449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The paper considers the current aspects of the morphology, immunohistochemistry, molecular biology of liposarcomas. Particular attention is given to the embryogenesis of liposarcomas and to problems in the immunohistochemical diagnosis of these neoplasms. There is evidence that TLS-CHOP is involved in the PNA processing of liposarcoma cells. Prospects for the diagnosis and treatment of malignant mesenchymal tumors are discussed.
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219
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Polman JAE, Hunter RG, Speksnijder N, van den Oever JME, Korobko OB, McEwen BS, de Kloet ER, Datson NA. Glucocorticoids modulate the mTOR pathway in the hippocampus: differential effects depending on stress history. Endocrinology 2012; 153:4317-27. [PMID: 22778218 DOI: 10.1210/en.2012-1255] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glucocorticoid (GC) hormones, released by the adrenals in response to stress, are key regulators of neuronal plasticity. In the brain, the hippocampus is a major target of GC, with abundant expression of the GC receptor. GC differentially affect the hippocampal transcriptome and consequently neuronal plasticity in a subregion-specific manner, with consequences for hippocampal information flow and memory formation. Here, we show that GC directly affect the mammalian target of rapamycin (mTOR) signaling pathway, which plays a central role in translational control and has long-lasting effects on the plasticity of specific brain circuits. We demonstrate that regulators of the mTOR pathway, DNA damage-induced transcript (DDIT)4 and FK506-binding protein 51 are transcriptionally up-regulated by an acute GC challenge in the dentate gyrus (DG) subregion of the rat hippocampus, most likely via a GC-response element-driven mechanism. Furthermore, two other mTOR pathway members, the mTOR regulator DDIT4-like and the mTOR target DDIT3, are down-regulated by GC in the rat DG. Interestingly, the GC responsiveness of DDIT4 and DDIT3 was lost in animals with a recent history of chronic stress. Basal hippocampal mTOR protein levels were higher in animals exposed to chronic stress than in controls. Moreover, an acute GC challenge significantly reduced mTOR protein levels in the hippocampus of animals with a chronic stress history but not in unstressed controls. Based on these findings, we propose that direct regulation of the mTOR pathway by GC represents an important mechanism regulating neuronal plasticity in the rat DG, which changes after exposure to chronic stress.
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Affiliation(s)
- J Annelies E Polman
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, 2300 RA Leiden, The Netherlands
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220
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Narayanapillai S, Agarwal C, Tilley C, Agarwal R. Silibinin is a potent sensitizer of UVA radiation-induced oxidative stress and apoptosis in human keratinocyte HaCaT cells. Photochem Photobiol 2012; 88:1135-40. [PMID: 22118157 PMCID: PMC3925450 DOI: 10.1111/j.1751-1097.2011.01050.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
UVA radiation (315-400 nm), which constitutes ca 95% of the UV irradiation in natural sunlight reaching earth surface, is a major environmental risk factor associated with human skin cancer pathogenesis. UVA is an oxidizing agent that causes significant damage to cellular components through the release of reactive oxygen species (ROS) and leads to photoaging and photocarcinogenesis. Here we investigate the effect of silibinin, the flavonolignan from Silybum marianum, on UVA-induced ROS and cell death in human keratinocyte cell line HaCaT. In addition, the effect of silibinin on UVA-induced intracellular ROS-mediated endoplasmic reticulum (ER) stress was also analyzed. UVA irradiation resulted in ROS production and apoptosis in HaCaT cells in a dose-dependent manner, and the ROS levels and apoptotic index were found to be elevated significantly when the cells were treated with 75 μmsilibinin for 2 h before UVA exposure. When the cells were pretreated with 10 mmN-acetyl cysteine, the enhancement of UVA-induced apoptosis by silibinin was compromised. Furthermore, we found that silibinin enhances ER stress-mediated apoptosis in HaCaT cells by increasing the expression of CHOP protein. These results suggest that silibinin may be beneficial in the removal of UVA-damaged cells and the prevention of skin cancer.
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Affiliation(s)
- Sreekanth Narayanapillai
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Chapla Agarwal
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, United States of America
- University of Colorado Cancer Center, Aurora, Colorado, United States of America
| | - Cynthia Tilley
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Rajesh Agarwal
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, United States of America
- University of Colorado Cancer Center, Aurora, Colorado, United States of America
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221
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He Z, Ostrowski RP, Sun X, Ma Q, Tang J, Zhang JH. Targeting C/EBP homologous protein with siRNA attenuates cerebral vasospasm after experimental subarachnoid hemorrhage. Exp Neurol 2012; 238:218-24. [PMID: 22944263 DOI: 10.1016/j.expneurol.2012.08.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/15/2012] [Accepted: 08/21/2012] [Indexed: 11/18/2022]
Abstract
Endothelial apoptosis plays a major role in the development of cerebral vascular spasm after subarachnoid hemorrhage (SAH). C/EBP homologous protein (CHOP) orchestrates apoptosis in a variety of cell types in response to endoplasmic reticulum (ER) stress, implicated in the brain injury after SAH. However, the role of CHOP in the mechanism of cerebral vasospasm (CVS) after SAH remains unexplored. The aim of this study was to evaluate the effect of CHOP silencing on endothelial apoptosis and CVS following subarachnoid hemorrhage in the rat. The study was conducted on 65 rats and employed endovascular perforation model of SAH. CHOP siRNAs were injected 24 h prior to the hemorrhage. At 72 h after SAH brains with basilar arteries (BA) were collected from euthanized rats for laboratory investigations. Triple fluorescence stain revealed expression of CHOP in cerebral vascular endothelia after SAH. Marked reduction of CHOP protein and the reduction of its downstream signaling effectors, bim and caspase-3, were found in BA with Western blot analysis. CHOP silencing reduced number of apoptotic endothelial cells in BA, and increased BA diameter after SAH. The amelioration of CVS was associated with reduced neuronal injury in cerebral tissues. In conclusion, CHOP siRNA treatment can effectively combat apoptotic mechanisms of cerebral vasospasm set in motion by subarachnoid bleeding.
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Affiliation(s)
- Zhaohui He
- Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University, 1 Friendship Road, 400016 Chongqing, China
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222
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Chen CM, Wu CT, Chiang CK, Liao BW, Liu SH. C/EBP homologous protein (CHOP) deficiency aggravates hippocampal cell apoptosis and impairs memory performance. PLoS One 2012; 7:e40801. [PMID: 22815824 PMCID: PMC3397964 DOI: 10.1371/journal.pone.0040801] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 06/13/2012] [Indexed: 01/20/2023] Open
Abstract
Neurodegenerative disorders are growing burdens in modern societies because of increased life expectancy. Most neurodegenerative disorders commonly possess a similar neuropathological feature - the accumulation of abnormal protein aggregates or inclusions (misfolded proteins) in the brain. One of the main functions of endoplasmic reticulum (ER) is to initiate proper protein folding to facilitate protein secretion through the induction of unfolded protein response (UPR). C/EBP homologous protein (CHOP) induction has been demonstrated to be a signaling event underlying ER stress-induced cell apoptosis. In this study, we explored the role of CHOP in the hippocampal cell apoptosis and memory performance injury under an induced ER stress condition. Adult male wild type (C57BL/6J) and CHOP knockout (CHOP−/−) mice were intracerebroventricularly injected with tunicamycin. Tunicamycin can induce ER stress and cell apoptosis in mouse hippocampus. Compared with wild type mice, CHOP−/− mice showed an enhanced hippocampal cell apoptosis, worse performance in memory-related behavioral tests, and attenuated IRE-1 expression under tunicamycin treatment. The aggravated cell apoptosis and worse memory performance in CHOP−/− mice might be due to the deficiency of CHOP protein resulted in the impaired adaptive/pathological transcriptional response, the decreased IRE-1 and XBP-1 expressions, and the increased JNK phosphorylation to cope with ER stress. Taken together, these results suggest that CHOP may play a protective role in the hippocampal cell apoptosis and impairment of memory performance.
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Affiliation(s)
- Chang-Mu Chen
- Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan
- * E-mail: (CMC); (SHL)
| | - Cheng-Tien Wu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chih-Kang Chiang
- Department of Integrated Diagnostics & Therapeutics, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan
| | - Bor-Wu Liao
- Department of Otolaryngology, Cardinal Tien Hospital, Yung Ho Branch, New Taipei City, Taiwan
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail: (CMC); (SHL)
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223
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O'Brien A, Barber JEB, Reid S, Niknejad N, Dimitroulakos J. Enhancement of cisplatin cytotoxicity by disulfiram involves activating transcription factor 3. Anticancer Res 2012; 32:2679-2688. [PMID: 22753726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND Activating transcription factor 3 (ATF3), a stress-inducible gene, is a regulator of cisplatin-induced cytotoxicity, and enhancement of the ATF3 expression potentiates this cytotoxicity. MATERIALS AND METHODS ATF3 expression and its binding to the transcription target CHOP were evaluated by western blot and chromatin immunoprecipitation (ChIP), respectively, in a panel of five cell lines (WI38, MCF7, PC3, A549). MTT assays were employed to assess the effects of many drugs, including disulfiram, on cell viability. RESULTS ATF3 protein expression was up-regulated after cytotoxic doses of cisplatin treatment and it directly bound to the CHOP gene promoter, increasing this pro-apoptotic protein's expression. In a library screen of 1200 compounds, disulfiram, a dithiocarbamate drug, was identified as an enhancer of the cytotoxic effects of cisplatin. This increased cytotoxic action was synergistic and likely due to their ability to induce ATF3 independently. CONCLUSION Understanding the role of ATF3 in cisplatin-induced cytotoxicity will lead to novel therapeutic approaches that could improve this drug's efficacy.
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Affiliation(s)
- Anna O'Brien
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, 501 Smyth Road, Box 926, Ottawa, ON, K1H 8L6, Canada
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Qin W, Yang L, Zhang X, Zhang Z, Xu L, Wu J, An J, Wang Y. Cyanobacteria-blooming water samples from Lake Taihu induce endoplasmic reticulum stress in liver and kidney of mice. Ecotoxicology 2012; 21:1495-1503. [PMID: 22526928 DOI: 10.1007/s10646-012-0903-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/29/2012] [Indexed: 05/31/2023]
Abstract
To investigate whether endoplasmic reticulum (ER) stress was involved in apoptosis induced by cyanobacteria-blooming water, healthy male ICR mice were fed with water samples from cyanobacteria-blooming regions of Lake Taihu (China), including Meiliang Bay (M1 and M2), central lake region (H), macrophyte-dominated Xukou Bay (X), and tap water (control group) for three consecutive months. Hepatic and renal mRNA and protein expression of ER stress signaling molecules were measured with quantitative real-time PCR and western blotting. Compared to macrophyte-dominated and control water samples, cyanobacteria-blooming water changed hepatic ER stress signaling molecules. M1 water treatment increased the mRNA and protein levels of glucose regulation protein 78 (GRP78) and C/EBP homologous protein (CHOP), and decreased the mRNA levels of B-cell lymphoma 2 (Bcl-2). M2 water treatment up-regulated GRP78 mRNA and protein expression, whereas H water treatment up-regulated mRNA and protein expression of GRP78 and caspase-12. Cyanobacteria-blooming water exposure also changed mRNA and protein expression of ER stress signaling molecules in the kidneys. M1 water exposure up-regulated GRP78 mRNA and protein expression and CHOP mRNA expression, whereas M2 water treatment up-regulated caspase-12 and Bcl-2 mRNA expression. M1 and M2 cyanobacteria-blooming water exposure significantly increased relative liver weights, and induced hepatic cell apoptosis. However, cyanobacteria-blooming water treatment did not change kidney weights, and did not induce renal apoptosis compared to macrophyte-dominated and control water samples. Hence, cyanobacteria-blooming water induces hepatic apoptosis via ER stress, and ER stress may play an important role in the apparent anti-apoptotic effects on renal cells exposed to cyanobacteria-blooming water.
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Affiliation(s)
- Wendi Qin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing 210046, People's Republic of China
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225
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Ghosh AP, Klocke BJ, Ballestas ME, Roth KA. CHOP potentially co-operates with FOXO3a in neuronal cells to regulate PUMA and BIM expression in response to ER stress. PLoS One 2012; 7:e39586. [PMID: 22761832 PMCID: PMC3386252 DOI: 10.1371/journal.pone.0039586] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 05/28/2012] [Indexed: 12/23/2022] Open
Abstract
Endoplasmic reticulum (ER) stress-induced apoptosis has been implicated in various neurodegenerative diseases including Parkinson Disease, Alzheimer Disease and Huntington Disease. PUMA (p53 upregulated modulator of apoptosis) and BIM (BCL2 interacting mediator of cell death), pro-apoptotic BH3 domain-only, BCL2 family members, have previously been shown to regulate ER stress-induced cell death, but the upstream signaling pathways that regulate this response in neuronal cells are incompletely defined. Consistent with previous studies, we show that both PUMA and BIM are induced in response to ER stress in neuronal cells and that transcriptional induction of PUMA regulates ER stress-induced cell death, independent of p53. CHOP (C/EBP homologous protein also known as GADD153; gene name Ddit3), a critical initiator of ER stress-induced apoptosis, was found to regulate both PUMA and BIM expression in response to ER stress. We further show that CHOP knockdown prevents perturbations in the AKT (protein kinase B)/FOXO3a (forkhead box, class O, 3a) pathway in response to ER stress. CHOP co-immunoprecipitated with FOXO3a in tunicamycin treated cells, suggesting that CHOP may also regulate other pro-apoptotic signaling cascades culminating in PUMA and BIM activation and cell death. In summary, CHOP regulates the expression of multiple pro-apoptotic BH3-only molecules through multiple mechanisms, making CHOP an important therapeutic target relevant to a number of neurodegenerative conditions.
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Affiliation(s)
- Arindam P Ghosh
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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226
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Xu M, Lu N, Sun Z, Zhang H, Dai Q, Wei L, Li Z, You Q, Guo Q. Activation of the unfolded protein response contributed to the selective cytotoxicity of oroxylin A in human hepatocellular carcinoma HepG2 cells. Toxicol Lett 2012; 212:113-25. [PMID: 22609744 DOI: 10.1016/j.toxlet.2012.05.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/05/2012] [Accepted: 05/08/2012] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is a refractory malignancy with a high incidence and large mortality. Current strategy for the chemotherapy of HCC focuses on developing agents with better efficacy and lower toxicity. In this study, we demonstrated that the natural flavonoid oroxylin A preferentially inhibited the viability of HCC cell line HepG2 but not the normal hepatic cell line L02. In HepG2 but not L02 cells, oroxylin A induced substantial production of intracellular H₂O₂ and inordinate activation of the PERK-eIF2α-ATF4-CHOP branch of the unfolded protein response (UPR) pathway, which resulted in the induction of TRB3 and causal reduction of p-AKT1/2/3 (Ser473). Moreover, these effects were eliminated by either the stable knockdown of CHOP or the pretreatment and then co-incubation with the specific H₂O₂ scavenger catalase. These results indicated that the H₂O₂-triggered overactivation of the UPR pathway and causal inactivation of AKT signaling contributed to the preferential cytotoxicity of oroxylin A in malignant HepG2 cells. Therefore, present study proposed an underlying molecular mechanism that implicated the selective antitumor effect of oroxylin A and recommended oroxylin A as a prospect for improving the current chemotherapeutic strategy for the treatment of HCC.
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Affiliation(s)
- Min Xu
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, PR China
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227
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Jauhiainen A, Thomsen C, Strömbom L, Grundevik P, Andersson C, Danielsson A, Andersson MK, Nerman O, Rörkvist L, Ståhlberg A, Åman P. Distinct cytoplasmic and nuclear functions of the stress induced protein DDIT3/CHOP/GADD153. PLoS One 2012; 7:e33208. [PMID: 22496745 PMCID: PMC3322118 DOI: 10.1371/journal.pone.0033208] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 02/10/2012] [Indexed: 11/29/2022] Open
Abstract
DDIT3, also known as GADD153 or CHOP, encodes a basic leucine zipper transcription factor of the dimer forming C/EBP family. DDIT3 is known as a key regulator of cellular stress response, but its target genes and functions are not well characterized. Here, we applied a genome wide microarray based expression analysis to identify DDIT3 target genes and functions. By analyzing cells carrying tamoxifen inducible DDIT3 expression constructs we show distinct gene expression profiles for cells with cytoplasmic and nuclear localized DDIT3. Of 175 target genes identified only 3 were regulated by DDIT3 in both cellular localizations. More than two thirds of the genes were downregulated, supporting a role for DDIT3 as a dominant negative factor that could act by either cytoplasmic or nuclear sequestration of dimer forming transcription factor partners. Functional annotation of target genes showed cell migration, proliferation and apoptosis/survival as the most affected categories. Cytoplasmic DDIT3 affected more migration associated genes, while nuclear DDIT3 regulated more cell cycle controlling genes. Cell culture experiments confirmed that cytoplasmic DDIT3 inhibited migration, while nuclear DDIT3 caused a G1 cell cycle arrest. Promoters of target genes showed no common sequence motifs, reflecting that DDIT3 forms heterodimers with several alternative transcription factors that bind to different motifs. We conclude that expression of cytoplasmic DDIT3 regulated 94 genes. Nuclear translocation of DDIT3 regulated 81 additional genes linked to functions already affected by cytoplasmic DDIT3. Characterization of DDIT3 regulated functions helps understanding its role in stress response and involvement in cancer and degenerative disorders.
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Affiliation(s)
- Alexandra Jauhiainen
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden
| | - Christer Thomsen
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
| | - Linda Strömbom
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
| | - Pernilla Grundevik
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
| | - Carola Andersson
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
| | - Anna Danielsson
- Department of Oncology, Institute of Clinical Sciences, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Mattias K. Andersson
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
| | - Olle Nerman
- Department of Mathematical Statistics, Chalmers University of Technology, Gothenburg, Sweden
- Department of Mathematical Statistics, University of Gothenburg, Gothenburg, Sweden
| | - Linda Rörkvist
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
| | - Anders Ståhlberg
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
| | - Pierre Åman
- Sahlgrenska Cancer Center, Department of Pathology, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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Chen CY, Yiin SJ, Hsu JL, Wang WC, Lin SC, Chern CL. Isoobtusilactone A sensitizes human hepatoma Hep G2 cells to TRAIL-induced apoptosis via ROS and CHOP-mediated up-regulation of DR5. J Agric Food Chem 2012; 60:3533-3539. [PMID: 22400995 DOI: 10.1021/jf2051224] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Hepatoma cells are relatively resistant to TRAIL. We have previously shown that isoobtusilactone A (IOA), a potent anticancer agent isolated from Cinnamomum kotoense, induced mitochondria-mediated apoptosis in hepatoma cells. Here, we report that IOA could potentiate TRAIL-induced apoptosis in Hep G2 cells. The combined treatment with IOA and TRAIL significantly induced caspase-dependent apoptosis. This correlated with the up-regulation of C/EBP homologous protein (CHOP) and death receptor 5 (DR5) protein levels. Gene silencing of the DR5 by small interfering RNA abrogated the apoptosis induced by the combined regimen of IOA and TRAIL, suggesting that the sensitization to TRAIL was mediated through DR5. By analyzing the DR5 promoter, we found that IOA induced a CHOP-dependent DR5 transactivation. DR5 expression after IOA treatment was accompanied by provoking intracellular reactive oxygen species (ROS) generation. Pretreatment with N-acetyl-L-cysteine (NAC) attenuated IOA-induced CHOP and DR5 expression and inhibited TRAIL-induced apoptosis. Taken together, our data suggested that ROS-dependent and CHOP-regulated DR5 expression played a pivotal role in the synergistic enhancement of TRAIL-induced apoptosis instigated by IOA in Hep G2 cells.
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Affiliation(s)
- Chung-Yi Chen
- Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan, Republic of China
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229
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Maris M, Overbergh L, Gysemans C, Waget A, Cardozo AK, Verdrengh E, Cunha JPM, Gotoh T, Cnop M, Eizirik DL, Burcelin R, Mathieu C. Deletion of C/EBP homologous protein (Chop) in C57Bl/6 mice dissociates obesity from insulin resistance. Diabetologia 2012; 55:1167-78. [PMID: 22237685 DOI: 10.1007/s00125-011-2427-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 11/29/2011] [Indexed: 01/23/2023]
Abstract
AIMS/HYPOTHESIS Endoplasmic reticulum (ER) stress has been implicated in the development of type 2 diabetes, via effects on obesity, insulin resistance and pancreatic beta cell health. C/EBP homologous protein (CHOP) is induced by ER stress and has a central role in apoptotic execution pathways triggered by ER stress. The aim of this study was to characterise the role of CHOP in obesity and insulin resistance. METHODS Metabolic studies were performed in Chop ( -/- ) and wild-type C57Bl/6 mice, and included euglycaemic-hyperinsulinaemic clamps and indirect calorimetry. The inflammatory state of liver and adipose tissue was determined by quantitative RT-PCR, immunohistology and macrophage cultures. Viability and absence of ER stress in islets of Langerhans was determined by electron microscopy, islet culture and quantitative RT-PCR. RESULTS Systemic deletion of Chop induced abdominal obesity and hepatic steatosis. Despite marked obesity, Chop ( -/- ) mice had preserved normal glucose tolerance and insulin sensitivity. This discrepancy was accompanied by lower levels of pro-inflammatory cytokines and less infiltration of immune cells into fat and liver. CONCLUSIONS/INTERPRETATION These observations suggest that insulin resistance is not induced by fat accumulation per se, but rather by the inflammation induced by ectopic fat. CHOP may play a key role in the crosstalk between excessive fat deposition and induction of inflammation-mediated insulin resistance.
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Affiliation(s)
- M Maris
- Catholic University of Leuven, Leuven, Belgium
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230
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Sage AT, Holtby-Ottenhof S, Shi Y, Damjanovic S, Sharma AM, Werstuck GH. Metabolic syndrome and acute hyperglycemia are associated with endoplasmic reticulum stress in human mononuclear cells. Obesity (Silver Spring) 2012; 20:748-55. [PMID: 21633399 DOI: 10.1038/oby.2011.144] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Endoplasmic reticulum (ER) stress and the activation of the unfolded protein response (UPR) have been implicated in a number of complications associated with diabetes mellitus including micro- and macrovascular dysfunction. In this study we examine ER stress levels in blood cells isolated from human subjects with metabolic syndrome and in healthy controls. Total RNA and protein were isolated from leukocytes and the levels of specific ER stress markers were quantified by real-time-PCR and immunoblot analysis. Our results indicate that, compared to healthy controls, individuals with metabolic syndrome have elevated mRNA levels of genes indicative of ER stress; including spliced XBP-1 (sXBP-1), Grp78, and CHOP. Induced ER stress levels correlate with blood glucose but not plasma lipid concentration. Furthermore, in healthy individuals, a standard 75 g oral glucose challenge produced a significant elevation in spliced XBP-1 (1.3 fold), Grp78 (2.0 fold), and calreticulin (3.5 fold) mRNA 60 min post challenge and a significant increase in Grp78 (2.0 fold), calreticulin (2.7 fold) protein levels 2 h postchallenge, relative to fasting levels. The UPR was also activated ex vivo, in human leukocytes cultured in the presence of 15 mmol/l glucose, supporting a specific role for glucose. The oral glucose challenge was associated with a significant increase in the expression of inflammatory cytokines, including interleukin (IL)-1α/β, IL-6, and IL-8, that may result from ER stress. These findings suggest that there is an association between both acute and chronic dysglycemia and ER stress in humans.
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Affiliation(s)
- Andrew T Sage
- Thrombosis and Atherosclerosis Research Institute, Hamilton, Ontario, Canada
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231
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Chiu SC, Chen SP, Huang SY, Wang MJ, Lin SZ, Harn HJ, Pang CY. Induction of apoptosis coupled to endoplasmic reticulum stress in human prostate cancer cells by n-butylidenephthalide. PLoS One 2012; 7:e33742. [PMID: 22470469 PMCID: PMC3314677 DOI: 10.1371/journal.pone.0033742] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 02/16/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND N-butylidenephthalide (BP) exhibits antitumor effect in a variety of cancer cell lines. The objective of this study was to obtain additional insights into the mechanisms involved in BP induced cell death in human prostate cancer cells. METHODS/PRINCIPAL FINDINGS Two human prostate cancer cell lines, PC-3 and LNCaP, were treated with BP, and subsequently evaluated for their viability and cell cycle profiles. BP caused cell cycle arrest and cell death in both cell lines. The G0/G1 phase arrest was correlated with increase levels of CDK inhibitors (p16, p21 and p27) and decrease of the checkpoint proteins. To determine the mechanisms of BP-induced growth arrest and cell death in prostate cancer cell lines, we performed a microarray study to identify alterations in gene expression induced by BP in the LNCaP cells. Several BP-induced genes, including the GADD153/CHOP, an endoplasmic reticulum stress (ER stress)-regulated gene, were identified. BP-induced ER stress was evidenced by increased expression of the downstream molecules GRP78/BiP, IRE1-α and GADD153/CHOP in both cell lines. Blockage of IRE1-α or GADD153/CHOP expression by siRNA significantly reduced BP-induced cell death in LNCaP cells. Furthermore, blockage of JNK1/2 signaling by JNK siRNA resulted in decreased expression of IRE1-α and GADD153/CHOP genes, implicating that BP-induced ER stress may be elicited via JNK1/2 signaling in prostate cancer cells. BP also suppressed LNCaP xenograft tumor growth in NOD-SCID mice. It caused 68% reduction in tumor volume after 18 days of treatment. CONCLUSIONS Our results suggest that BP can cause G0/G1 phase arrest in prostate cancer cells and its cytotoxicity is mediated by ER stress induction. Thus, BP may serve as an anticancer agent by inducing ER stress in prostate cancer.
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Affiliation(s)
- Sheng-Chun Chiu
- Department of Medical Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Shee-Ping Chen
- Tzu Chi Stem Cells Center, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Sung-Ying Huang
- Department of Ophthalmology, Mackay Memorial Hospital, Hsinchu, Taiwan
| | - Mei-Jen Wang
- Department of Medical Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Shinn-Zong Lin
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan
| | - Horng-Jyh Harn
- Department of Pathology, China Medical University Hospital, Taichung, Taiwan
| | - Cheng-Yoong Pang
- Department of Medical Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
- Institute of Medical Sciences, School of Medicine, Tzu Chi University, Hualien, Taiwan
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232
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Thomas KC, Roberts JK, Deering-Rice CE, Romero EG, Dull RO, Lee J, Yost GS, Reilly CA. Contributions of TRPV1, endovanilloids, and endoplasmic reticulum stress in lung cell death in vitro and lung injury. Am J Physiol Lung Cell Mol Physiol 2012; 302:L111-9. [PMID: 21949157 PMCID: PMC3349369 DOI: 10.1152/ajplung.00231.2011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 09/21/2011] [Indexed: 12/31/2022] Open
Abstract
Endogenous agonists of transient receptor potential vanilloid-1 (TRPV1) (endovanilloids) are implicated as mediators of lung injury during inflammation. This study tested the hypothesis that endovanilloids produced following lipopolysaccharide (LPS) treatment activate TRPV1 and cause endoplasmic reticulum stress/GADD153 expression in lung cells, representing a mechanistic component of lung injury. The TRPV1 agonist nonivamide induced GADD153 expression and caused cytotoxicity in immortalized and primary human bronchial, bronchiolar/alveolar, and microvascular endothelial cells, proportional to TRPV1 mRNA expression. In CF-1 mice, Trpv1 mRNA was most abundant in the alveoli, and intratracheal nonivamide treatment promoted Gadd153 expression in the alveolar region. Treatment of CF-1 mice with LPS increased Gadd153 in the lung, lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid, and lung wet-to-dry weight ratio. Cotreating mice with LPS and the TRPV1 antagonist LJO-328 reduced Gadd153 induction and LDH in BAL but did not inhibit increases in lung wet-to-dry ratio. In Trpv1(-/-) mice treated with LPS, Gadd153 induction and LDH in BAL were reduced relative to wild-type mice, and the wet-to-dry weight ratios of lungs from both wild-type and Trpv1(-/-) mice decreased. Organic extracts of blood collected from LPS-treated mice were more cytotoxic to TRPV1-overexpressing cells compared with BEAS-2B cells and extracts from control mice, however, most pure endovanilloids did not produce cytotoxicity in a characteristic TRPV1-dependent manner. Collectively, these data indicate a role for TRPV1, and endogenous TRPV1 agonists, in ER stress and cytotoxicity in lung cells but demonstrate that ER stress and cytotoxicity are not essential for pulmonary edema.
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Affiliation(s)
- Karen C Thomas
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
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233
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Chen T, Fei F, Jiang XF, Zhang L, Qu Y, Huo K, Fei Z. Down-regulation of Homer1b/c attenuates glutamate-mediated excitotoxicity through endoplasmic reticulum and mitochondria pathways in rat cortical neurons. Free Radic Biol Med 2012; 52:208-17. [PMID: 22080088 DOI: 10.1016/j.freeradbiomed.2011.10.451] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/18/2011] [Accepted: 10/18/2011] [Indexed: 11/28/2022]
Abstract
Glutamate-mediated excitotoxicity is involved in many acute and chronic brain diseases. Homer proteins, a new member of the postsynaptic scaffolding proteins, regulate glutamatergic signaling and intracellular calcium mobilization in the central nervous system. Here we investigated the effects of down-regulating Homer1b/c, a constitutively expressed long form of Homer proteins, on glutamate excitotoxicity-induced neuronal injury. In our in vitro excitotoxic models, we demonstrated that glutamate insults led to a dose-dependent neuronal injury, which was mediated by the intracellular calcium-dependent reactive oxygen species (ROS) production. We found that down-regulation of Homer1b/c with specific small interfering RNA (siRNA) improved neuronal survival, inhibited intracellular ROS production, and reduced apoptotic cell death after neurotoxicity. Homer1b/c knockdown decreased the intracellular calcium overload through inhibition of the group I metabotropic glutamate receptor (mGluR)/inositol 1,4,5-trisphosphate receptor (IP3R)-mediated Ca2+ release from the endoplasmic reticulum (ER) in injured neurons. In addition, Homer1b/c siRNA transfection attenuated the activation of eukaryotic initiation factor 2α (eIF2α), RNA-dependent protein kinase-like ER kinase (PERK) and caspase-12, and inhibited the up-regulation of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) after glutamate treatment. Homer1b/c knockdown also preserved the mitochondrial membrane potential (MMP), reduced cytochrome c (Cyt. c) release, and partly blocked the increase of capase-9 activity and Bax/Bcl-2 ratio. Taken together, these results suggest that down-regulation of Homer1b/c protects cortical neurons against glutamate-induced excitatory damage, and this neuroprotection may be dependent at least in part on the inhibition of calcium-dependent ROS production and the preservation of the ER and mitochondrial function.
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Affiliation(s)
- Tao Chen
- Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
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Prasanthi JRP, Larson T, Schommer J, Ghribi O. Silencing GADD153/CHOP gene expression protects against Alzheimer's disease-like pathology induced by 27-hydroxycholesterol in rabbit hippocampus. PLoS One 2011; 6:e26420. [PMID: 22046282 PMCID: PMC3194795 DOI: 10.1371/journal.pone.0026420] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 09/26/2011] [Indexed: 02/07/2023] Open
Abstract
Endoplasmic reticulum (ER) stress is suggested to play a key role in the pathogenesis of neurodegenerative diseases including Alzheimer's disease (AD). Sustained ER stress leads to activation of the growth arrest and leucine zipper transcription factor, DNA damage inducible gene 153 (gadd153; also called CHOP). Activated gadd153 can generate oxidative damage and reactive oxygen species (ROS), increase β-amyloid (Aβ) levels, disturb iron homeostasis and induce inflammation as well as cell death, which are all pathological hallmarks of AD. Epidemiological and laboratory studies suggest that cholesterol dyshomeostasis contributes to the pathogenesis of AD. We have previously shown that the cholesterol oxidized metabolite 27-hydroxycholesterol (27-OHC) triggers AD-like pathology in organotypic slices. However, the extent to which gadd153 mediates 27-OHC effects has not been determined. We silenced gadd153 gene with siRNA and determined the effects of 27-OHC on AD hallmarks in organotypic slices from adult rabbit hippocampus. siRNA to gadd153 reduced 27-OHC-induced Aβ production by mechanisms involving reduction in levels of β-amyloid precursor protein (APP) and β-secretase (BACE1), the enzyme that initiates cleavage of APP to yield Aβ peptides. Additionally, 27-OHC-induced tau phosphorylation, ROS generation, TNF-α activation, and iron and apoptosis-regulatory protein levels alteration were also markedly reduced by siRNA to gadd153. These data suggest that ER stress-mediated gadd153 activation plays a central role in the triggering of AD pathological hallmarks that result from incubation of hippocampal slices with 27-OHC. Our results add important insights into cellular mechanisms that underlie the potential contribution of cholesterol metabolism in AD pathology, and suggest that preventing gadd153 activation protects against AD related to cholesterol oxidized products.
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Affiliation(s)
- Jaya R. P. Prasanthi
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Tyler Larson
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Jared Schommer
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Othman Ghribi
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
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Yu Z, Wang AM, Adachi H, Katsuno M, Sobue G, Yue Z, Robins DM, Lieberman AP. Macroautophagy is regulated by the UPR-mediator CHOP and accentuates the phenotype of SBMA mice. PLoS Genet 2011; 7:e1002321. [PMID: 22022281 PMCID: PMC3192827 DOI: 10.1371/journal.pgen.1002321] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 08/10/2011] [Indexed: 12/11/2022] Open
Abstract
Altered protein homeostasis underlies degenerative diseases triggered by misfolded proteins, including spinal and bulbar muscular atrophy (SBMA), a neuromuscular disorder caused by a CAG/glutamine expansion in the androgen receptor. Here we show that the unfolded protein response (UPR), an ER protein quality control pathway, is induced in skeletal muscle from SBMA patients, AR113Q knock-in male mice, and surgically denervated wild-type mice. To probe the consequence of UPR induction, we deleted CHOP (C/EBP homologous protein), a transcription factor induced following ER stress. CHOP deficiency accentuated atrophy in both AR113Q and surgically denervated muscle through activation of macroautophagy, a lysosomal protein quality control pathway. Conversely, impaired autophagy due to Beclin-1 haploinsufficiency decreased muscle wasting and extended lifespan of AR113Q males, producing a significant and unexpected amelioration of the disease phenotype. Our findings highlight critical cross-talk between the UPR and macroautophagy, and they indicate that autophagy activation accentuates aspects of the SBMA phenotype. In many age-dependent neurodegenerative diseases, the accumulation of misfolded or mutant proteins drives pathogenesis. Several protein quality control pathways have emerged as central regulators of the turnover of these toxic proteins and therefore impact phenotypic severity. In spinal and bulbar muscular atrophy (SBMA), the mutant androgen receptor with an expanded glutamine tract undergoes hormone-dependent nuclear translocation, unfolding, and oligomerization—steps that are critical to the development of progressive proximal limb and bulbar muscle weakness in men. Here we show that the unfolded protein response (UPR), an endoplasmic reticulum stress response, is triggered in skeletal muscle from SBMA patients and knock-in mice. We find that disruption of the UPR exacerbates skeletal muscle atrophy through the induction of macroautophagy, a lysosomal protein quality pathway. In contrast, impaired autophagy diminishes muscle wasting and prolongs lifespan of SBMA mice. Our findings highlight cross-talk between the UPR and autophagy, and they suggest that limited activation of the autophagic pathway may be beneficial in certain neuromuscular diseases such as SBMA where the nucleus is the essential site of toxicity.
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Affiliation(s)
- Zhigang Yu
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Adrienne M. Wang
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Neuroscience Graduate Program, The University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Hiroaki Adachi
- Department of Neurology, Nagoya University, Nagoya, Japan
| | | | - Gen Sobue
- Department of Neurology, Nagoya University, Nagoya, Japan
| | - Zhenyu Yue
- Departments of Neurology and Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Diane M. Robins
- Department of Human Genetics, The University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Andrew P. Lieberman
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Neuroscience Graduate Program, The University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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John L, Thomas S, Herchenröder O, Pützer BM, Schaefer S. Hepatitis E virus ORF2 protein activates the pro-apoptotic gene CHOP and anti-apoptotic heat shock proteins. PLoS One 2011; 6:e25378. [PMID: 21966512 PMCID: PMC3179511 DOI: 10.1371/journal.pone.0025378] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 09/02/2011] [Indexed: 12/11/2022] Open
Abstract
Background Hepatitis E virus (HEV) is a non-enveloped plus-strand RNA virus that causes acute hepatitis. The capsid protein open reading frame 2 (ORF2) is known to induce endoplasmic reticulum stress in ORF2 expressing cells. Methodology/Principal Findings In this study we found that HEV ORF2 activates the expression of the pro-apoptotic gene C/EBP homologous protein (CHOP). ORF2 stimulates the CHOP promoter mainly through AARE (amino acid response elements) and to a minor extent the ERSE (endoplasmic reticulum stress response elements). Activating transcription factor 4 (ATF4) protein binds and activates the AARE regulatory sites of the CHOP promoter. ORF2 expression also leads to increased phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α) that in turn initiates the translation of ATF4 mRNA. The pro-apoptotic gene CHOP is an important trigger to initiate endoplasmic reticulum stress induced apoptosis. However, the activation of CHOP by ORF2 in this study did not induce apoptosis, nor did BCL2-associated X protein (Bax) translocate to mitochondria. Microarray analysis revealed an ORF2 specific increased expression of chaperones Hsp72, Hsp70B', and co-chaperone Hsp40. Co-immunoprecipitation (Co-IP) and in silico molecular docking analysis suggests that HEV ORF2 interacts with Hsp72. In addition, Hsp72 shows nuclear accumulation in ORF2 expressing cells. Conclusions/Significance These data provide new insight into simultaneously occurring counter-acting effects of HEV ORF2 that may be part of a strategy to prevent host suicide before completion of the viral replication cycle.
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Affiliation(s)
- Lijo John
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock Medical School, Rostock, Germany
| | - Saijo Thomas
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock Medical School, Rostock, Germany
| | - Ottmar Herchenröder
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock Medical School, Rostock, Germany
| | - Brigitte M. Pützer
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock Medical School, Rostock, Germany
- * E-mail:
| | - Stephan Schaefer
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock Medical School, Rostock, Germany
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Hou LL, Jin L, Han CC, Cheng B, Wang L, Zhang XD, Zhang LJ. [Role of dysregulation of Bim in resistance of melanoma cells to endoplasmic reticulum stress-induced apoptosis]. Zhonghua Zhong Liu Za Zhi 2011; 33:494-498. [PMID: 22093624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE To establish a model of ER stress-induced apoptosis with tunicamycin and to examine whether Bim is dysregulated and its potential role in resistance of melanoma cells to apoptosis under endoplasmic reticulum (ER) stress. METHODS A model of ER stress-induced apoptosis was established with tunicamycin. Apoptotic cells were quantitated using the annexin V/propidium iodide method by flow cytometry. Hoechst staining was also used to confirm the apoptotic cell death. Western blotting was used to measure the activation of caspase-3 and -9, and the expression of Bim, GRP78, CHOP, and Foxo1 at the protein level. The expression of Bim, CHOP and Foxo1 at the mRNA level was quantitated by qPCR. The siRNA technique was used to inhibit the expression of Bim. RESULTS Treatment of the melanoma cells with tunicamycin did not induce significant apoptosis and activation of caspase cascade, whereas it caused marked activation of caspase-3 and -9, and apoptosis in HEK293 cells which were used as a control. With exposure to tunicamycin (3 µmol/L) for 12, 24, 36 hours the Bim protein levels were not increased in Mel-RM and MM200 cells. Its mRNA levels were 0.37 ± 0.05, 0.13 ± 0.02 and 0.02 ± 0.01 in Mel-RM cells, while 0.41 ± 0.06, 0.16 ± 0.04 and 0.21 ± 0.03 in MM200 cells, respectively. The expression of Bim mRNA was significantly reduced compared with that in the control groups of the two cell lines (P < 0.01). siRNA knockdown of Bim protected HEK293 cells against activation of caspase-3. The cell apoptosis of Bim siRNA group was (5.69 ± 0.38)%, significantly lower than that of the siRNA control group (40.32 ± 1.64)% and blank control group (35.46 ± 2.01)% (P < 0.01). In the melanoma cells after exposure to tunicamycin (3 µmol/L) for 6, 12, 24, and 36 hours the transcription factor CHOP at mRNA level were significantly increased and the expressions at protein level were also up-regulated. The expressions of another transcription factor Foxo1 at mRNA level significantly decreased and the expressions at protein level were down-regulated, too. CONCLUSIONS The lack of Bim up-regulation contributes to the resistance of melanoma cells to ER stress-induced apoptosis and may be a mechanism by which melanoma cells adapt to ER stress conditions. Transcription factors CHOP and Foxo1 may be responsible for the dysregulation of Bim in melanoma cells upon ER stress.
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Affiliation(s)
- Li-li Hou
- Department of Immunology, Anhui Medical University, Hefei, China
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Wang L, Li H, Wang J, Gao W, Lin Y, Jin W, Chang G, Wang R, Li Q, Ma L, Pang T. C/EBP ζ targets to neutrophil gelatinase-associated lipocalin (NGAL) as a repressor for metastasis of MDA-MB-231 cells. Biochim Biophys Acta 2011; 1813:1803-13. [PMID: 21741997 DOI: 10.1016/j.bbamcr.2011.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 06/23/2011] [Accepted: 06/23/2011] [Indexed: 01/04/2023]
Abstract
Breast cancer is a leading cause of morbidity in women worldwide. neutrophil gelatinase-associated lipocalin (NGAL), a useful biomarker of ER negative (ER(-)) breast cancer, promotes local tumor invasion and lymph node metastasis. We first identified the distinctive expression of NGAL in two breast cancer cell lines MCF7 and MDA-MB-231 cells, and then confirmed NGAL as a critical inducer of metastasis. Finally, the transcriptional factor CCAAT enhancer-binding proteins ζ (C/EBP ζ) was overexpressed in MDA-MB-231 cells. Consistent with the effect of NGAL knockdown, C/EBP ζ overexpression caused the significant changes that could prevent cell metastasis. C/EBP ζ overexpression induced a strong decrease in NGAL and matrix metalloproteinases (MMPs) expressions as determined by quantitative real time PCR and Western blotting. To identify the potential role of C/EBP ζ on regulating of NGAL in breast cancer, we established the dual-luciferase reporter assay for NGAL in MDA-MB-231 cells cotransfected with C/EBP ζ. Promoter reporter assays determined that C/EBP ζ directly repressed the human NGAL gene promoter activity by inhibiting the NGAL transcription. Taken together, this work identified that the C/EBP ζ overexpression downregulated NGAL to inhibit migration and invasion of breast cancer, which could be used as a novel strategy for breast cancer therapy.
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Affiliation(s)
- Lihong Wang
- Chinese Academy of Medical Sciences, Tianjing, People's Republic of China
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Geraghty P, Wallace A, D’Armiento JM. Induction of the unfolded protein response by cigarette smoke is primarily an activating transcription factor 4-C/EBP homologous protein mediated process. Int J Chron Obstruct Pulmon Dis 2011; 6:309-19. [PMID: 21697995 PMCID: PMC3119106 DOI: 10.2147/copd.s19599] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Cigarette smoke is the major risk factor associated with the development of chronic obstructive pulmonary disease (COPD). Recent studies propose a link between endoplasmic reticulum (ER) stress and emphysema, demonstrated by increased ER stress markers under smoking conditions. Here, we investigate whether cigarette smoke-induced ER stress is cell specific and correlates with acute and chronic cigarette smoke exposure. METHODS Gene and protein expression changes in human primary lung cell cultures following cigarette smoke extract (CSE) exposure were monitored by qPCR and Western blot analysis. Mice and guinea pigs were exposed to cigarette smoke and ER stress markers examined in whole lung homogenates. Inflammatory cells from the bronchoalveolar lavage fluid of 10 days smoke exposed mice were also examined. RESULTS Cigarette smoke induced a trend increase in the ER stress response through an activating transcription factor 4 (ATF4) mediated induction of C/EBP homologous protein (CHOP) in primary small airway epithelial cells. Bronchial epithelial cells and macrophages responded similarly to CSE. Wild-type mice and guinea pigs exposed to acute levels of cigarette smoke exhibited increased levels of CHOP but not at significant levels. However, after long-term chronic cigarette smoke exposure, CHOP expression was reduced. Interestingly, inflammatory cells from smoke exposed mice had a significant increase in CHOP/ATF4 expression. CONCLUSION A trend increase in CHOP levels appear in multiple human lung cell types following acute cigarette smoke exposure in vitro. In vivo, inflammatory cells, predominately macrophages, demonstrate significant cigarette smoke-induced ER stress. Early induction of CHOP in cigarette smoke may play a pivotal role in early induction of lung disease, however in vivo long-term cigarette smoke exposure exhibited a reduction in the ER stress response.
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Affiliation(s)
- Patrick Geraghty
- Department of Medicine, Divisions of Molecular and Pulmonary Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Alison Wallace
- Department of Medicine, Divisions of Molecular and Pulmonary Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Jeanine M D’Armiento
- Department of Medicine, Divisions of Molecular and Pulmonary Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
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Zhang R, Niu YJ, Zhang ZJ, Chen Q, Guo HC, Zhao J, Li Y, Fan LG. [The effects of the cadmium chloride on the DNA damage and the expression level of gadd gene in HepG2 cell line]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2011; 29:409-412. [PMID: 22096849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE To investigate the effects of the cadmium chloride on the DNA damage and the expression of the gadd153 and gadd45beta promoter and mRNA in HepG2 cells. METHODS DNA damage induced by cadmium chloride was detected by comet assay. The plasmids (pGADD153-Luc and pG45-Luc) containing DNA damage and repair inducible gene 153 and 45 (gadd153 and gadd45beta) promoter and luciferase and gadd45beta reporter gene were constructed. The activity of gadd153 and gadd45beta promoter were represented by the luciferase activity, the inducible luciferase activities was detected by bioluminescence. The expression of gadd153 and gadd45beta mRNA was detected by RT-PCR. RESULTS The results of comet assay indicated that Olive Tail Moment induced by the cadmium chloride increased significantly at the dose of 100, 300 micromol/L, compared with the control (P < 0.05). The luciferase activity analysis showed that the expression levels of gadd153 promoter increased significantly in 1, 5, 10 micromol/L treatment group, compared with the control (P < 0.05). The expression levels of gadd45beta promoter in 5, 10 micromol/L treatment group were significantly higher than that in control group (P < 0.05). The expression levels of gadd153 mRNA induced by cadmium chloride at the doses of 1, 5, 10 micromol/L and the expression levels of gadd45beta mRNA induced at the doses of 5, 10 micromol/L were significantly higher than thoae in control group (P < 0.05). CONCLUSION The cadmium chloride can induce the DNA damage and increase the expression levels of the gadd153 and gadd45beta promoters in HepG2 cells.
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Affiliation(s)
- Rong Zhang
- Department of Occupational and Environmental Health, School of Public Health, Hebei Medical University, Shijiazhuang 050017, China
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241
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Li B, Wang HS, Li GG, Zhao MJ, Zhao MH. The role of endoplasmic reticulum stress in the early stage of diabetic retinopathy. Acta Diabetol 2011; 48:103-11. [PMID: 19924374 DOI: 10.1007/s00592-009-0170-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 11/09/2009] [Indexed: 02/01/2023]
Abstract
The aim of this study was to evaluate the role of endoplasmic reticulum (ER) stress in diabetic retinopathy (DR) using in vitro and in vivo models. For the in vivo studies, diabetes was induced in rats, and retinal expression of glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), and vascular endothelial growth factor (VEGF) in groups of rats at 1, 3, and 6 months was assessed. For the in vitro studies, human retinal capillary endothelial cells (HRCECs) were cultured in the presence of varying glucose concentrations, and the expression of mRNA and protein for GRP78, ATF4, CHOP, and VEGF was assessed. The chosen glucose concentrations were reflective of those apparent in diabetic patients. Expression of VEGF and CHOP mRNA levels were significantly increased in diabetic rats compared to control rats at 1, 3, and 6 months (P < 0.05). In HRCECs cultured in the presence of high as well as variable glucose concentrations, CHOP expression and apoptosis were significantly increased (P < 0.05). However, GRP78 and ATF4 expression levels were unchanged. Our findings suggest that early progression of DR may be mediated by ER stress, but probably does not involve changes in ATF4 or GRP78.
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Affiliation(s)
- Bin Li
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China.
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Lee SJ, Kim SH, Kang JG, Kim CS, Ihm SH, Choi MG, Yoo HJ. Effects of all-trans retinoic acid on sodium/iodide symporter and CCAAT/enhancer-binding protein-homologous protein under condition of endoplasmic reticulum stress in FRTL5 thyroid cells. Horm Metab Res 2011; 43:331-6. [PMID: 21225541 DOI: 10.1055/s-0030-1269907] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In thyroid cells, the effects of all- TRANS retinoic acid (ATRA) on sodium/iodide symporter (NIS) and CCAAT/enhancer-binding protein-homologous protein (CHOP) under condition of endoplasmic reticulum (ER) stress have not been evaluated. In the present study, the relationships between NIS, CHOP, and p38 MAPK, and the effects of ATRA on NIS and CHOP expression as well as on p38 MAPK activation under condition of ER stress in thyroid cells were investigated. In FRTL5 thyroid cells, NIS mRNA and protein levels decreased following tunicamycin (TN) treatment, while CHOP mRNA and protein levels increased. In addition, while CHOP mRNA levels decreased after administration of tauro-UDCA and siCHOP, NIS mRNA levels were not altered. After pretreatment with SB203580, NIS mRNA levels decreased in non-TN-treated cells but increased in TN-treated cells. In contrast, CHOP mRNA levels decreased in both non-TN-treated and TN-treated cells. Exposure to ATRA decreased NIS mRNA levels in non-TN-treated cells but increased NIS mRNA levels in TN-treated cells. ATRA decreased CHOP mRNA levels in both non-TN-treated and TN-treated cells although the response was significant only in TN-treated cells. Phospho-p38 MAPK protein levels but not total p38 MAPK protein levels increased in TN-treated cells. ATRA attenuated this increase in phopho-p38 MAPK protein levels. In conclusion, our results demonstrate that ER stress may induce reciprocal changes in NIS and CHOP expression via p38 MAPK in FRTL5 thyroid cells, and that ATRA may attenuate ER stress-induced alterations in NIS and CHOP expression by modulating the phosphorylation of p38 MAPK in FRTL5 thyroid cells.
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Affiliation(s)
- S J Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea.
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243
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Li D, Liu J, Li J. Genotoxic evaluation of the insecticide endosulfan based on the induced GADD153-GFP reporter gene expression. Environ Monit Assess 2011; 176:251-258. [PMID: 20625822 DOI: 10.1007/s10661-010-1580-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 06/15/2010] [Indexed: 05/29/2023]
Abstract
Endosulfan is one of the few organochlorine insecticides still in use in China for protecting crops from a variety of insects. Endosulfan is toxic in fishes and rodents in the in vivo assays, but its genotoxicity in mammalian cells has not been well tested. In this work, a genotoxic testing system has been developed based on the induction of a HepG2/GADD153-GFP reporter gene expression in response to the DNA-damaging agents. Methyl methanesulfonate, a known carcinogenic and genotoxic agent, was used to test the effects of damage dose and post-treatment incubation time on GADD153-GFP expression. Subsequently, the system was applied to the genotoxicity evaluation of endosulfan. Endosulfan was able to cause the increase of GADD153-GFP expression at a sublethal dose (0.02-20 mg/L). In particular, it induced a maximum green fluorescent protein expression at the tested concentration of 0.2 mg/L, with 4.07-fold inflorescence relative to untreated cells. The results suggest that endosulfan has the potential genotoxicity for HepG2 cell line by inducing DNA damage. The study also confirms that the induced GADD153-GFP expression system is an appropriate and sensitive method for the assessment of genotoxicity from a broad range of pesticides with the DNA-damaging potential.
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Affiliation(s)
- Dahui Li
- College of Life Sciences, Graduate University of Chinese Academy of Sciences, Beijing, 100049, China.
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Abstract
Melatonin has recently gained attention as a regulator of biologic processes in addition to its effects on circadian rhythms. The mechanisms whereby melatonin regulates the apoptotic program remain poorly understood. In this study, we investigated the combined effect of melatonin and kahweol on apoptosis of cancer cells, but not in most normal human cell types, thus presenting an attractive novel strategy for cancer treatment. In our experiments, treatment with a combination of melatonin and kahweol induced apoptosis, stimulated DEVDase activity, and DNA fragmentation. Co-treatment with melatonin and kahweol induced up-regulation of p53-upregulated modulator of apoptosis (PUMA) while down-regulation of PUMA expression using small interfering RNAs attenuated melatonin plus kahweol-induced apoptosis. In addition, co-treatment with kahweol and melatonin induced PUMA up-regulation through endoplasmic reticulum stress-mediated C/EBP homologous protein induction and the p53-independent pathway. Our results collectively demonstrate that up-regulation of PUMA contributes to the sensitizing effect of melatonin plus kahweol on apoptosis in cancer cells.
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Affiliation(s)
- Hee Jung Um
- Department of Immunology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu, Korea
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Wang L, Wang L, Song R, Shen Y, Sun Y, Gu Y, Shu Y, Xu Q. Targeting Sarcoplasmic/Endoplasmic Reticulum Ca2+-ATPase 2 by Curcumin Induces ER Stress-Associated Apoptosis for Treating Human Liposarcoma. Mol Cancer Ther 2011; 10:461-71. [PMID: 21282356 DOI: 10.1158/1535-7163.mct-10-0812] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Lu Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Han Kou Road, Nanjing 210093, China
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Choi MJ, Park EJ, Min KJ, Park JW, Kwon TK. Endoplasmic reticulum stress mediates withaferin A-induced apoptosis in human renal carcinoma cells. Toxicol In Vitro 2011; 25:692-8. [PMID: 21266191 DOI: 10.1016/j.tiv.2011.01.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/15/2010] [Accepted: 01/18/2011] [Indexed: 02/04/2023]
Abstract
The accumulation of misfolded proteins in the lumen of the endoplasmic reticulum (ER) results in cellular stress that initiates a specialized response designated as the unfolded protein response. ER stress has been implicated in a variety of common diseases, such as diabetes, ischemia and neurodegenerative disorders. Withaferin A, a major chemical constituent of Withania somnifera, has been reported to inhibit tumor cell growth. We show that withaferin A induced a dose-dependent apoptotic cell death in several types of human cancer cells, as measured by FACS analysis and PARP cleavage. Treatment of Caki cells with withaferin A induced a number of signature ER stress markers, including phosphorylation of eukaryotic initiation factor-2α (eIF-2 α), ER stress-specific XBP1 splicing, and up-regulation of glucose-regulated protein (GRP)-78. In addition, withaferin A caused up-regulation of CAAT/enhancer-binding protein-homologous protein (CHOP), suggesting the induction of ER stress. Pretreatment with N-acetyl cysteine (NAC) significantly inhibited withaferin A-mediated ER stress proteins and cell death, suggesting that reactive oxygen species (ROS) mediate withaferin A-induced ER stress. Furthermore, CHOP siRNA or inhibition of caspase-4 activity attenuated withaferin A-induced apoptosis. Taken together, the present study provides strong evidence supporting an important role of the ER stress response in mediating withaferin A-induced apoptosis.
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Affiliation(s)
- Min Jung Choi
- Department of Immunology, School of Medicine, Keimyung University, 2800 Dalgubeoldaero, Dalseo-Gu, Daegu 704-701, South Korea
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Abstract
The unfolded protein response (UPR) is a conserved, intracellular signaling pathway activated by endoplasmic reticulum (ER) stress. In mammalian cells, the UPR is controlled by three ER-resident transmembrane proteins: inositol-requiring enyzme-1 (IRE1), PKR-like ER kinase (PERK), and activating transcription factor-6 (ATF6), by which cytoprotective mechanisms are initiated to restore ER functions. However, if cellular homeostasis is not restored by the UPR's initial events, UPR signaling triggers apoptotic cell death, which correlates with the pathogenesis of a wide range of human diseases. The intrinsic function of the UPR in regulating cell survival and death suggests its importance as a mechanistic link between ER stress and disease pathogenesis. Understanding UPR regulatory molecules or signaling pathways involved in disease pathogenesis is critical to establishing therapeutic strategies. For this purpose, several experimental tools have been developed to evaluate individual UPR components. In this chapter, we present methods to monitor and quantify activation of individual UPR signaling pathways in mammalian cells and tissues, and we review strategies to artificially and selectively activate individual UPR signaling pathways using chemical-genetic approaches.
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Affiliation(s)
- Nobuhiko Hiramatsu
- Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, California, USA
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Ke PY, Chen SSL. Activation of the unfolded protein response and autophagy after hepatitis C virus infection suppresses innate antiviral immunity in vitro. J Clin Invest 2011; 121:37-56. [PMID: 21135505 PMCID: PMC3007134 DOI: 10.1172/jci41474] [Citation(s) in RCA: 266] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 10/06/2010] [Indexed: 12/11/2022] Open
Abstract
Autophagy, a process for catabolizing cytoplasmic components, has been implicated in the modulation of interactions between RNA viruses and their host. However, the mechanism underlying the functional role of autophagy in the viral life cycle still remains unclear. Hepatitis C virus (HCV) is a single-stranded, positive-sense, membrane-enveloped RNA virus that can cause chronic liver disease. Here we report that HCV induces the unfolded protein response (UPR), which in turn activates the autophagic pathway to promote HCV RNA replication in human hepatoma cells. Further analysis revealed that the entire autophagic process through to complete autolysosome maturation was required to promote HCV RNA replication and that it did so by suppressing innate antiviral immunity. Gene silencing or activation of the UPR-autophagy pathway activated or repressed, respectively, IFN-β activation mediated by an HCV-derived pathogen-associated molecular pattern (PAMP). Similar results were achieved with a PAMP derived from Dengue virus (DEV), indicating that HCV and DEV may both exploit the UPR-autophagy pathway to escape the innate immune response. Taken together, these results not only define the physiological significance of HCV-induced autophagy, but also shed light on the knowledge of host cellular responses upon HCV infection as well as on exploration of therapeutic targets for controlling HCV infection.
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Affiliation(s)
- Po-Yuan Ke
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Robbins RD, Tersey SA, Ogihara T, Gupta D, Farb TB, Ficorilli J, Bokvist K, Maier B, Mirmira RG. Inhibition of deoxyhypusine synthase enhances islet {beta} cell function and survival in the setting of endoplasmic reticulum stress and type 2 diabetes. J Biol Chem 2010; 285:39943-52. [PMID: 20956533 PMCID: PMC3000976 DOI: 10.1074/jbc.m110.170142] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 10/04/2010] [Indexed: 01/09/2023] Open
Abstract
Islet β cell dysfunction resulting from inflammation, ER stress, and oxidative stress is a key determinant in the progression from insulin resistance to type 2 diabetes mellitus. It was recently shown that the enzyme deoxyhypusine synthase (DHS) promotes early cytokine-induced inflammation in the β cell. DHS catalyzes the conversion of lysine to hypusine, an amino acid that is unique to the translational elongation factor eIF5A. Here, we sought to determine whether DHS activity contributes to β cell dysfunction in models of type 2 diabetes in mice and β cell lines. A 2-week treatment of obese diabetic C57BLKS/J-db/db mice with the DHS inhibitor GC7 resulted in improved glucose tolerance, increased insulin release, and enhanced β cell mass. Thapsigargin treatment of β cells in vitro induces a picture of ER stress and apoptosis similar to that seen in db/db mice; in this setting, DHS inhibition led to a block in CHOP (CAAT/enhancer binding protein homologous protein) production despite >30-fold activation of Chop gene transcription. Blockage of CHOP translation resulted in reduction of downstream caspase-3 cleavage and near-complete protection of cells from apoptotic death. DHS inhibition appeared to prevent the cytoplasmic co-localization of eIF5A with the ER, possibly precluding the participation of eIF5A in translational elongation at ER-based ribosomes. We conclude that hypusination by DHS is required for the ongoing production of proteins, particularly CHOP, in response to ER stress in the β cell.
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Affiliation(s)
- Reiesha D. Robbins
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22904
| | - Sarah A. Tersey
- the Department of Pediatrics and the Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Takeshi Ogihara
- the Department of Pediatrics and the Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Dhananjay Gupta
- the Department of Pediatrics and the Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Thomas B. Farb
- the Lilly Research Labs, Eli Lilly and Company, Indianapolis, Indiana 46285, and
| | - James Ficorilli
- the Lilly Research Labs, Eli Lilly and Company, Indianapolis, Indiana 46285, and
| | - Krister Bokvist
- the Lilly Research Labs, Eli Lilly and Company, Indianapolis, Indiana 46285, and
| | - Bernhard Maier
- the Department of Pediatrics and the Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Raghavendra G. Mirmira
- the Department of Pediatrics and the Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
- the Departments of Medicine and of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
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Suzuki K, Matsui Y, Endo K, Kubo T, Hasegawa T, Kimura T, Ohtani O, Yasui N. Myxoid liposarcoma with EWS-CHOP type 1 fusion gene. Anticancer Res 2010; 30:4679-4683. [PMID: 21115923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
BACKGROUND In myxoid liposarcoma (MLS), the t(12;16)(q13;p11) chromosomal translocation and its resultant fusion transcript, the human translocation liposarcoma (TLS)-CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP), are found in the majority of cases. On the other hand, the variant translocation, t(12;22)(q13;q12) creating the Ewing sarcoma (EWS)-CHOP fusion transcript, is detectable in a limited number of cases. PATIENTS AND METHODS Tissue from MLS arising in the left thigh of a 19-year-old female was analyzed for possible detection of chromosome translocation and fusion transcript. Fluorescent in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR) methods were used. RESULTS FISH analysis demonstrated a rearrangement in the CHOP gene. RT-PCR analysis confirmed the presence of EWS-CHOP chimeric transcript type 1, in which exon 7 of EWS was in-frame fused to exon 2 of CHOP with a serine (AGT) to methionine (ATG) transition at the junction. The patient underwent a radical segmental resection including a left vastus medialis musclectomy. Sixty months following the surgical resection, the patient was alive with no evidence of disease. CONCLUSION Analysis of MLS with EWS-CHOP variant transcripts, type 1 through type 4, including this case together with 15 cases in the literature, indicated that MLS with type 1 fusion transcript may show a more favorable clinical behavior than MLS with other types of fusion transcript.
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MESH Headings
- Adult
- Chromosomes, Human, Pair 12/genetics
- Chromosomes, Human, Pair 22/genetics
- Female
- Humans
- In Situ Hybridization, Fluorescence
- Liposarcoma, Myxoid/diagnosis
- Liposarcoma, Myxoid/genetics
- Magnetic Resonance Imaging
- Oncogene Proteins, Fusion/genetics
- RNA, Messenger/genetics
- RNA-Binding Protein EWS/genetics
- Retrospective Studies
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription Factor CHOP/genetics
- Transcription, Genetic
- Translocation, Genetic
- Young Adult
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Affiliation(s)
- Kayo Suzuki
- Departments of Orthopaedic Surgery, University of Toyama, Toyama 930-0194, Japan
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