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Unfolded protein response prevents blastocyst formation during preimplantation embryo development in vitro. Fertil Steril 2014; 102:1777-84. [PMID: 25305729 DOI: 10.1016/j.fertnstert.2014.09.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 08/16/2014] [Accepted: 09/04/2014] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To study the effect of increased endoplasmic reticulum (ER) stress as a major nongenomic mechanism for arrested blastocyst development. DESIGN Cell and animal study. SETTING The Ohio State University and Yale University. ANIMAL(S) Mice. INTERVENTION(S) Pregnant mare serum gonadotropin and hCG were administered IP; two cell embryos were collected 48 hours after hCG administration. MAIN OUTCOME MEASURE(S) Blastocyst development rate. RESULT(S) No morphological difference was detected in control versus tunicamycin- (TM) treated embryos until the blastocyst stage. On day 4 of embryonic development, TM treatment reduced blastocyst formation from 79% to 4% and induced nuclear fragmentation. TM treatment caused 2-fold and 2.6-fold increase in binding immunoglobulin protein and spliced-X-box binding protein 1 mRNA expression, respectively. By comparison, the tauroursodeoxycholic acid + TM combination reversed the effect of TM alone on blastocyst formation to near control levels. CONCLUSION(S) These results indicate that increased ER stress during in vitro embryo development triggers an unfolded protein response (UPR) that negatively affects blastocyst formation and suggests that activation of UPR signaling may account for low rates of blastocyst development.
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152
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Chen JH, Kuo HC, Lee KF, Tsai TH. Magnolol protects neurons against ischemia injury via the downregulation of p38/MAPK, CHOP and nitrotyrosine. Toxicol Appl Pharmacol 2014; 279:294-302. [DOI: 10.1016/j.taap.2014.07.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 01/17/2023]
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153
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de la Cadena SG, Hernández-Fonseca K, Camacho-Arroyo I, Massieu L. Glucose deprivation induces reticulum stress by the PERK pathway and caspase-7- and calpain-mediated caspase-12 activation. Apoptosis 2014; 19:414-27. [PMID: 24185830 DOI: 10.1007/s10495-013-0930-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Glucose is the main energy source in brain and it is critical for correct brain functioning. Type 1 diabetic patients might suffer from severe hypoglycemia if exceeding insulin administration, which can lead to acute brain injury if not opportunely corrected. The mechanisms leading to hypoglycemic brain damage are not completely understood and the role of endoplasmic reticulum (ER) stress has not been studied. ER stress resulting from the accumulation of unfolded or misfolded proteins in the ER is counteracted by the unfolded protein response (UPR). When the UPR is sustained, apoptotic death might take place. We have examined UPR activation during glucose deprivation (GD) in hippocampal cultured neurons and its role in the induction of apoptosis. Activation of the PERK pathway of the UPR was observed, as increased phosphorylation of eIF2α and elevated levels of the transcription factor ATF4, occurred 30 min after GD and the levels of the chaperone protein, GRP78 and the transcription factor CHOP, increased after 2 h of GD. In addition, we observed an early activation of caspase-7 and 12 during GD, while caspase-3 activity increased only transiently during glucose reintroduction. Inhibition of caspase-3/7 and the calcium-dependent protease, calpain, significantly decreased caspase-12 activity. The ER stress inhibitor, salubrinal prevented neuronal death and caspase-12 activity. Results suggest that the PERK pathway of the UPR is involved in GD-induced apoptotic neuronal death through the activation of caspase-12, rather than the mitochondrial-dependent caspase pathway. In addition, we show that calpain and caspase-7 are soon activated after GD and mediate caspase-12 activation and neuronal death.
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Affiliation(s)
- Selene García de la Cadena
- División de Neurociencias, Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP 70-253, Mexico, DF, 04510, Mexico
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154
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Cheng Z, Li L, Mo X, Zhang L, Xie Y, Guo Q, Wang Y. Non-invasive remote limb ischemic postconditioning protects rats against focal cerebral ischemia by upregulating STAT3 and reducing apoptosis. Int J Mol Med 2014; 34:957-66. [PMID: 25092271 PMCID: PMC4152138 DOI: 10.3892/ijmm.2014.1873] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 07/24/2014] [Indexed: 01/08/2023] Open
Abstract
The signal transducer and activator of transcription 3 (STAT3) signaling pathway has been implicated in cell apoptosis and inflammatory processes. Ischemic preconditioning (IPC) and ischemic postconditioning (IPTC) inhibit both of these processes. In the present study, we investigated the role of phosphorylated STAT3 (p-STAT3)-mediated apoptosis and inflammation following non-invasive remote limb IPTC (NRIPoC) using a classic rat model of focal cerebral ischemia. Forty-five adult male Sprague-Dawley rats were divided randomly into 3 groups (n=15 per group): the sham-operated, ischemia/reperfusion (I/R) and NRIPoC groups. NRIPoC was implemented at the beginning of reperfusion. At 24 h after cerebral reperfusion, we evaluated the neurological deficit score (NDS), assessed the cerebral infarct size and tissue morphology, and evaluated neuronal apoptosis. The protein expression levels of Bcl-2, Bax, nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α) and p-STAT3 in the penumbra region were assessed by western blot analysis. The cerebral infarct volume, the number of apoptotic cells and the protein expression levels of Bcl-2, Bax, NF-κB and TNF-α were all found to be increased in the I/R group compared with the sham-operated group. However, these levels were decreased in the NRIPoC group compared with the I/R group. The number of apoptotic cells in the penumbra in the I/R group was increased compared with that in the NRIPoC and sham-operated groups. The protein expression of p-STAT3 was increased in the NRIPoC group compared with the sham-operated and I/R groups. These results indicate that the protective effects of NRIPoC against cerebral I/R injury may be related to the attenuation of neuronal apoptosis and inflammation through the activation of STAT3.
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Affiliation(s)
- Zhigang Cheng
- Department of Anesthesiology, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Ling Li
- Department of Anesthesiology, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Xueying Mo
- Department of Anesthesiology, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Lu Zhang
- Department of Anesthesiology, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yongqiu Xie
- Department of Anesthesiology, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Qulian Guo
- Department of Anesthesiology, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yunjiao Wang
- Department of Anesthesiology, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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155
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Remote ischemic postconditioning alleviates cerebral ischemic injury by attenuating endoplasmic reticulum stress-mediated apoptosis. Transl Stroke Res 2014; 5:692-700. [PMID: 25043802 DOI: 10.1007/s12975-014-0359-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/04/2014] [Accepted: 07/08/2014] [Indexed: 02/07/2023]
Abstract
Remote ischemic postconditioning (RIPostC) has been proved to protect the brain from stroke, but the precise mechanism remains not fully understood. In the present study, we aimed to investigate whether RIPostC attenuates cerebral ischemia-reperfusion injury by abating endoplasmic reticulum (ER) stress response. CHOP, a multifunctional transcription factor in ER stress, regulates the expression of genes related to apoptosis, such as Bim and Bcl-2. Male SD rats were subjected to right middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion, and RIPostC was induced by three cycles of 10 min ischemia and 10 min reperfusion on bilateral femoral arteries immediately after ischemia. CHOP siRNA (CHOPi) and control siRNA (Coni) were injected into the right lateral ventricle 30 min before the beginning of ischemia. RIPostC, CHOPi, or RIPostC + CHOPi application reduced infarct volume, improved the neurological function, and decreased cell apoptosis. RIPostC increased the protein level of glucose-regulated protein 78 (GRP78) and decreased the protein level of phosphorylated-EIF2α, caspase-12, and CHOP. Furthermore, the expression of CHOP, Bim and cleaved-caspase-3 was decreased, while Bcl-2 expression was increased in response to application of RIPostC, CHOPi, or RIPostC + CHOPi. In sum, RIPostC protects against ischemia-reperfusion brain injury in rats by attenuating ER stress response-induced apoptosis.
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156
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Rao J, Yue S, Fu Y, Zhu J, Wang X, Busuttil RW, Kupiec-Weglinski JW, Lu L, Zhai Y. ATF6 mediates a pro-inflammatory synergy between ER stress and TLR activation in the pathogenesis of liver ischemia-reperfusion injury. Am J Transplant 2014; 14:1552-61. [PMID: 24903305 PMCID: PMC4074706 DOI: 10.1111/ajt.12711] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/07/2014] [Accepted: 02/15/2014] [Indexed: 01/25/2023]
Abstract
Although the roles of the metabolic stress in organ ischemia-reperfusion injury (IRI) have been well recognized, the question of whether and how these stress responses regulate innate immune activation against IR remains unclear. In a murine liver partial warm ischemia mode, we showed that prolonged ischemia triggered endoplasmic reticulum (ER) stress response, particularly, the activating transcription factor 6 (ATF6) branch, in liver Kupffer cells (KCs) and altered their responsiveness against Toll-like receptor (TLR) stimulation. Ischemia-primed cells increased pro-, but decreased anti-, inflammatory cytokine productions. Alleviation of ER stress in vivo by small chemical chaperon 4-phenylbutyrate or ATF6 small interfering RNA (siRNA) diminished the pro-inflammatory priming effect of ischemia in KCs, leading to the inhibition of liver immune response against IR and protection of livers from IRI. In vitro, ATF6 siRNA abrogated the ER stress-mediated pro-inflammatory enhancement of macrophage TLR4 response, by restricting NF-κB and restoring Akt activations. Thus, ischemia primes liver innate immune cells by ATF6-mediated ER stress response. The IR-induced metabolic stress and TLR activation function in synergy to activate tissue inflammatory immune response.
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Affiliation(s)
- Jianhua Rao
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA,Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiansu Province, China
| | - Shi Yue
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA
| | - Yuanfang Fu
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA
| | - Jianjun Zhu
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA,Department of Liver Surgery, Renji Hospital, Shanghai Jiaotong University Medical School, Shanghai, China
| | - Xuehao Wang
- Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiansu Province, China
| | - Ronald W. Busuttil
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA
| | - Jerzy W. Kupiec-Weglinski
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA
| | - Ling Lu
- Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiansu Province, China,Address correspondence: Yuan Zhai, MD, PhD. Dumont-UCLA Transplant Center 77-120 CHS, 10833 Le Conte Ave, Los Angeles, CA 90095. Phone: (310) 825-9426; Fax: (310) 267-2367, ; Ling Lu, MD, Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, 300 Guanzhou Road, Nanjing, P.R.China, Phone: 86-25-68136053; Fax:86-25-84630769;
| | - Yuan Zhai
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA, USA,Address correspondence: Yuan Zhai, MD, PhD. Dumont-UCLA Transplant Center 77-120 CHS, 10833 Le Conte Ave, Los Angeles, CA 90095. Phone: (310) 825-9426; Fax: (310) 267-2367, ; Ling Lu, MD, Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, 300 Guanzhou Road, Nanjing, P.R.China, Phone: 86-25-68136053; Fax:86-25-84630769;
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157
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Yang W, Shen Y, Chen Y, Chen L, Wang L, Wang H, Xu S, Fang S, Fu Y, Yu Y, Shen Y. Mesencephalic astrocyte-derived neurotrophic factor prevents neuron loss via inhibiting ischemia-induced apoptosis. J Neurol Sci 2014; 344:129-38. [PMID: 25001514 DOI: 10.1016/j.jns.2014.06.042] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 06/15/2014] [Accepted: 06/19/2014] [Indexed: 01/17/2023]
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF) has been shown to be up-regulated under the focal cerebral ischemia and protected against ischemic injury in rats. However, the underlying mechanisms are unclear. The aim of this study was to verify the protection of MANF on the cerebral ischemic injury and further investigate the possible mechanisms. Rat focal ischemic model was established by middle cerebral artery occlusion (MCAO). The recombinant human MANF was therapeutically administrated to the ipsilateral ventricle at 2 h after MCAO. MANF decreased the number of the propidium iodide (PI)- and TUNEL-positive neural cells. Contrarily, MANF protected the NeuN-positive cells in hippocampus and cortex from death induced by ischemia. The more interesting results in this study were that MANF repressed the cleavage of caspase-3 triggered by focal cerebral ischemia. MANF also reduced the elevated levels of BIP/Grp78, phosphorylated IRE1, and splicing XBP1 induced by focal cerebral ischemia, but not affect CHOP expression. Meanwhile, focal cerebral ischemia elevated the levels of XBP1 mRNA, including unspliced XBP1 (XBP1u) and spliced XBP1 (XBP1s). However, MANF did not affect the expression of XBP1 mRNA, neither XBP1u nor XBP1s. These results suggest that MANF can prevent the neuron loss via inhibiting ischemia-induced apoptosis and regulating unfolded protein response-related genes.
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Affiliation(s)
- Wen Yang
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China; Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
| | - Yujun Shen
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China; Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
| | - Ying Chen
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China; Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
| | - Lu Chen
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China; Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
| | - Le Wang
- Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, Anhui, PR China.
| | - Haiping Wang
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China; Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
| | - Shengchun Xu
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
| | - Shengyun Fang
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China; Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
| | - Yu Fu
- Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China
| | - Yongqiang Yu
- Department of Radiology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, Anhui, PR China.
| | - Yuxian Shen
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China; Biopharmaceutical Research Institute, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, PR China.
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158
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Li H, Zhu X, Fang F, Jiang D, Tang L. Down-regulation of GRP78 enhances apoptosis via CHOP pathway in retinal ischemia-reperfusion injury. Neurosci Lett 2014; 575:68-73. [PMID: 24880098 DOI: 10.1016/j.neulet.2014.05.042] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 02/26/2014] [Accepted: 05/19/2014] [Indexed: 12/25/2022]
Abstract
Ischemia/reperfusion (I/R) injury is the main cause of retinal apoptosis. But the mechanism remains elusive. During I/R injury, the intracellular calcium levels increase, resulting in the generation of reactive oxygen species, which have been shown to cause endoplasmic reticulum (ER) stress. However, little is known about the correlation between apoptosis and ER stress in retinal I/R injury. In the present study, we demonstrated that ER stress was activated in the retina of rat I/R models. The transcriptional expression of ER stress-associated molecules, glucose-regulated protein-78 (GRP78) and C/EBP-homologous protein (CHOP) were significantly increased in I/R retinas in a time-dependent manner. Partial inhibition of the endogenous expression of GRP78 with antisense oligonucleotide resulted in significant retinal damage and apoptosis in I/R injury rats. Also, the transcriptional expression of CHOP was persistently increased. Our findings indicate that ER stress may play a critical role in I/R injury induced retinal damage, and GRP78 may exert anti-apoptotic actions in I/R retina. Importantly, the persistent high expression of CHOP might serve as a possible mechanism that contributes to the enhanced the I/R-induced apoptosis after GRP78 down-regulation. These results may provide insight into the pathology of retinal I/R injury.
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Affiliation(s)
- Huiling Li
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Xiaohua Zhu
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Fang Fang
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | | | - Luosheng Tang
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China.
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159
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Logsdon AF, Lucke-Wold BP, Rosen CL, Huber JD. Disparity among neural injury models and the unfolded protein response. JOURNAL OF NEUROLOGICAL DISORDERS & STROKE 2014; 2. [PMID: 27284579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 09/28/2022]
Abstract
Endoplasmic reticulum stress is activated following both stroke and traumatic brain injury producing reactive oxgygen species, increasing intracellular calcium levels, and inducing inflammation; however, the timing and duration of activation varies between injuries. Preventing the immediate effects of ischemic/reperfusion injury or traumatic brain injury is challenging due to short onset of injury, but mitigating the secondary effects is a therapeutically targetable option. Preventative therapies using pharmacological agents have been utilized in pre-clinical models of neural injury to ameliorate secondary effects such as apoptosis and neurodegeneration. The connection between ER stress activation, apoptosis, and subsequent neurodegeneration has been proposed, but not yet causally linked. Researchers are now pursuing effective treatment strategies to suppress the secondary effects of neural injury in order to mitigate the development of chronic deficits. Secondary effects such as endoplasimic reticulum stress and neuroinflammation can be prevented in pre-clinical models, but the results have yet to translate to meaningful treatment options for patients. Evidence suggests that targeting the right transcription factors, at the right time, will aid in the prevention of apoptosis and neurodegenerative disease development following neural injury. In this review, we examine therapeutic approaches that target secondary injury and how these may correlate to better treatment options for patients.
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Affiliation(s)
- Aric Flint Logsdon
- Department of Pharmaceutical Sciences, West Virginia University, USA; Department of Neurosurgery, West Virginia University, USA
| | | | | | - Jason Delwyn Huber
- Department of Pharmaceutical Sciences, West Virginia University, USA; Department of Neurosurgery, West Virginia University, USA
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160
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Maier PJ, Zemoura K, Acuña MA, Yévenes GE, Zeilhofer HU, Benke D. Ischemia-like oxygen and glucose deprivation mediates down-regulation of cell surface γ-aminobutyric acidB receptors via the endoplasmic reticulum (ER) stress-induced transcription factor CCAAT/enhancer-binding protein (C/EBP)-homologous protein (CHOP). J Biol Chem 2014; 289:12896-907. [PMID: 24668805 DOI: 10.1074/jbc.m114.550517] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cerebral ischemia frequently leads to long-term disability and death. Excitotoxicity is believed to be the main cause for ischemia-induced neuronal death. Although a role of glutamate receptors in this process has been firmly established, the contribution of metabotropic GABAB receptors, which control excitatory neurotransmission, is less clear. A prominent characteristic of ischemic insults is endoplasmic reticulum (ER) stress associated with the up-regulation of the transcription factor CCAAT/enhancer-binding protein-homologous protein (CHOP). After inducing ER stress in cultured cortical neurons by sustained Ca(2+) release from intracellular stores or by a brief episode of oxygen and glucose deprivation (in vitro model of cerebral ischemia), we observed an increased expression of CHOP accompanied by a strong reduction of cell surface GABAB receptors. Our results indicate that down-regulation of cell surface GABAB receptors is caused by the interaction of the receptors with CHOP in the ER. Binding of CHOP prevented heterodimerization of the receptor subunits GABAB1 and GABAB2 and subsequent forward trafficking of the receptors to the cell surface. The reduced level of cell surface receptors diminished GABAB receptor signaling and, thus, neuronal inhibition. These findings indicate that ischemia-mediated up-regulation of CHOP down-regulates cell surface GABAB receptors by preventing their trafficking from the ER to the plasma membrane. This mechanism leads to diminished neuronal inhibition and may contribute to excitotoxicity in cerebral ischemia.
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Affiliation(s)
- Patrick J Maier
- From the Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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161
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Fessler EB, Chibane FL, Wang Z, Chuang DM. Potential roles of HDAC inhibitors in mitigating ischemia-induced brain damage and facilitating endogenous regeneration and recovery. Curr Pharm Des 2014; 19:5105-20. [PMID: 23448466 DOI: 10.2174/1381612811319280009] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 02/18/2013] [Indexed: 02/06/2023]
Abstract
Ischemic stroke is a leading cause of death and disability worldwide, with few available treatment options. The pathophysiology of cerebral ischemia involves both early phase tissue damage, characterized by neuronal death, inflammation, and blood-brain barrier breakdown, followed by late phase neurovascular recovery. It is becoming clear that any promising treatment strategy must target multiple points in the evolution of ischemic injury to provide substantial therapeutic benefit. Histone deacetylase (HDAC) inhibitors are a class of drugs that increase the acetylation of histone and non-histone proteins to activate transcription, enhance gene expression, and modify the function of target proteins. Acetylation homeostasis is often disrupted in neurological conditions, and accumulating evidence suggests that HDAC inhibitors have robust protective properties in many preclinical models of these disorders, including ischemic stroke. Specifically, HDAC inhibitors such as trichostatin A, valproic acid, sodium butyrate, sodium 4-phenylbutyrate, and suberoylanilide hydroxamic acid have been shown to provide robust protection against excitotoxicity, oxidative stress, ER stress, apoptosis, inflammation, and bloodbrain barrier breakdown. Concurrently, these agents can also promote angiogenesis, neurogenesis and stem cell migration to dramatically reduce infarct volume and improve functional recovery after experimental cerebral ischemia. In the following review, we discuss the mechanisms by which HDAC inhibitors exert these protective effects and provide evidence for their strong potential to ultimately improve stroke outcome in patients.
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Affiliation(s)
- Emily B Fessler
- Molecular Neurobiology Section, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, MSC 1363, Bethesda, MD 20892-1363, USA
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162
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Endoplasmic reticulum stress in cerebral ischemia. Neurochem Int 2014; 68:18-27. [DOI: 10.1016/j.neuint.2014.02.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 12/27/2013] [Accepted: 02/03/2014] [Indexed: 12/20/2022]
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163
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Adekeye A, Haeri M, Solessio E, Knox BE. Ablation of the proapoptotic genes CHOP or Ask1 does not prevent or delay loss of visual function in a P23H transgenic mouse model of retinitis pigmentosa. PLoS One 2014; 9:e83871. [PMID: 24523853 PMCID: PMC3921110 DOI: 10.1371/journal.pone.0083871] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/08/2013] [Indexed: 11/19/2022] Open
Abstract
The P23H mutation in rhodopsin (Rho(P23H)) is a prevalent cause of autosomal dominant retinitis pigmentosa. We examined the role of the ER stress proteins, Chop and Ask1, in regulating the death of rod photoreceptors in a mouse line harboring the Rho(P23H) rhodopsin transgene (GHL(+)). We used knockout mice models to determine whether Chop and Ask1 regulate rod survival or retinal degeneration. Electrophysiological recordings showed similar retinal responses and sensitivities for GHL(+), GHL(+)/Chop(-/-) and GHL(+)/Ask1(-/-) animals between 4-28 weeks, by which time all three mouse lines exhibited severe loss of retinal function. Histologically, ablation of Chop and Ask1 did not rescue photoreceptor loss in young animals. However, in older mice, a regional protective effect was observed in the central retina of GHL(+)/Chop(-/-) and GHL(+)/Ask1(-/-), a region that was severely degenerated in GHL(+) mice. Our results show that in the presence of the Rho(P23H) transgene, the rate of decline in retinal sensitivity is similar in Chop or Ask1 ablated and wild-type retinas, suggesting that these proteins do not play a major role during the acute phase of photoreceptor loss in GHL(+) mice. Instead they may be involved in regulating secondary pathological responses such as inflammation that are upregulated during later stages of disease progression.
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Affiliation(s)
- Adeseye Adekeye
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Mohammad Haeri
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Eduardo Solessio
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Barry E. Knox
- Departments of Neuroscience & Physiology, Biochemistry & Molecular Biology and Ophthalmology, Center for Vision Research, SUNY Upstate Medical University, Syracuse, New York, United States of America
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164
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Nakajima A, Tsuji M, Inagaki M, Tamura Y, Kato M, Niiya A, Usui Y, Oguchi K. Neuroprotective effects of propofol on ER stress-mediated apoptosis in neuroblastoma SH-SY5Y cells. Eur J Pharmacol 2014; 725:47-54. [DOI: 10.1016/j.ejphar.2014.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 12/20/2013] [Accepted: 01/07/2014] [Indexed: 11/27/2022]
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165
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Recombinant human thioredoxin-1 promotes neurogenesis and facilitates cognitive recovery following cerebral ischemia in mice. Neuropharmacology 2014; 77:453-64. [DOI: 10.1016/j.neuropharm.2013.10.027] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 10/18/2013] [Accepted: 10/23/2013] [Indexed: 11/22/2022]
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166
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Activated macrophage-like synoviocytes are resistant to endoplasmic reticulum stress-induced apoptosis in antigen-induced arthritis. Inflamm Res 2014; 63:335-46. [PMID: 24468888 DOI: 10.1007/s00011-013-0705-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 11/30/2013] [Accepted: 12/26/2013] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE To explore the characteristic expression of endoplasmic reticulum (ER) stress protein in antigen-induced arthritis models and the role of ER stress in arthritis. METHODS Effective animal models of rheumatoid arthritis in rabbits and rats were induced by methylated bovine serum albumin and Freund's complete adjuvant. Pathological changes were assessed by magnetic resonance imaging and histological analysis. The expression and localization of ER stress proteins in synovium and peritoneal macrophages (PMΦ) were analyzed by double immunofluorescence staining. RT-PCR was performed to detect mRNA expression of ER stress-related genes. Tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) levels in synoviocytes were measured by RT-PCR and radioimmunoassay. RESULTS We found that the ER stress marker BiP was highly up-regulated in arthritis synovium and extensively expressed in fibroblast-like synoviocytes (FLS) and macrophage-like synoviocytes (MLS). The expression of the pro-apoptotic factor CHOP/GADD153 was slightly elevated in inflammatory synovium and mainly localized in FLS, but insignificant in MLS. Unexpectedly, increased expression of CHOP was observed in PMΦ in arthritis rats. Likewise, cleaved caspase-3 was rarely expressed in MLS. In addition, induction of ER stress by tunicamycin resulted in significantly increased expression of pro-inflammatory molecules such as IL-1β and TNF-α in cultured inflammatory FLS. CONCLUSION Differential activation of the ER stress proteins in synovium MLS may contribute to the resistance of synoviocytes to ER stress-induced apoptosis. Furthermore, ER stress is a potential mediator of arthritis inflammation.
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Abstract
The endoplasmic reticulum (ER) is a central organelle for protein biosynthesis, folding, and traffic. Perturbations in ER homeostasis create a condition termed ER stress and lead to activation of the complex signaling cascade called the unfolded protein response (UPR). Recent studies have documented that the UPR coordinates multiple signaling pathways and controls various physiologies in cells and the whole organism. Furthermore, unresolved ER stress has been implicated in a variety of metabolic disorders, such as obesity and type 2 diabetes. Therefore, intervening in ER stress and modulating signaling components of the UPR would provide promising therapeutics for the treatment of human metabolic diseases.
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Affiliation(s)
- Jaemin Lee
- From the Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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168
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Expression of the CHOP-inducible carbonic anhydrase CAVI-b is required for BDNF-mediated protection from hypoxia. Brain Res 2013; 1543:28-37. [PMID: 24275196 DOI: 10.1016/j.brainres.2013.11.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 10/29/2013] [Accepted: 11/17/2013] [Indexed: 01/19/2023]
Abstract
Carbonic anhydrases (CAs) comprise a family of zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide. CAs contribute to a myriad of physiological processes, including pH regulation, anion transport and water balance. To date, 16 known members of the mammalian alpha-CA family have been identified. Given that the catalytic family members share identical reaction chemistry, their physiologic roles are influenced greatly by their tissue and sub-cellular locations. CAVI is the lone secreted CA and exists in both saliva and the gastrointestinal mucosa. An alternative, stress-inducible isoform of CAVI (CAVI-b) has been shown to be expressed from a cryptic promoter that is activated by the CCAAT/Enhancer-Binding Protein Homologous Protein (CHOP). The CAVI-b isoform is not secreted and is currently of unknown physiological function. Here we use neuronal models, including a model derived using Car6 and CHOP gene ablations, to delineate a role for CAVI-b in ischemic protection. Our results demonstrate that CAVI-b expression, which is increased through CHOP-signaling in response to unfolded protein stress, is also increased by oxygen-glucose deprivation (OGD). While enforced expression of CAVI-b is not sufficient to protect against ischemia, CHOP regulation of CAVI-b is necessary for adaptive changes mediated by BDNF that reduce subsequent ischemic damage. These results suggest that CAVI-b comprises a necessary component of a larger adaptive signaling pathway downstream of CHOP.
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169
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Cornejo VH, Pihán P, Vidal RL, Hetz C. Role of the unfolded protein response in organ physiology: Lessons from mouse models. IUBMB Life 2013; 65:962-75. [DOI: 10.1002/iub.1224] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/07/2013] [Indexed: 12/13/2022]
Affiliation(s)
- Víctor Hugo Cornejo
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
| | - Philippe Pihán
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
| | | | - Claudio Hetz
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
- Neurounion Biomedical Foundation; Santiago Chile
- Department of Immunology and Infectious Diseases; Harvard School of Public Health; Boston MA USA
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170
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YAO CHENGYE, ZHANG JIANCHENG, LIU GONGPING, CHEN FANG, LIN YUN. Neuroprotection by (−)-epigallocatechin-3-gallate in a rat model of stroke is mediated through inhibition of endoplasmic reticulum stress. Mol Med Rep 2013; 9:69-76. [DOI: 10.3892/mmr.2013.1778] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 10/25/2013] [Indexed: 11/06/2022] Open
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171
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Komita M, Jin H, Aoe T. The Effect of Endoplasmic Reticulum Stress on Neurotoxicity Caused by Inhaled Anesthetics. Anesth Analg 2013; 117:1197-204. [DOI: 10.1213/ane.0b013e3182a74773] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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172
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Katada R, Akdemir G, Asavapanumas N, Ratelade J, Zhang H, Verkman AS. Greatly improved survival and neuroprotection in aquaporin-4-knockout mice following global cerebral ischemia. FASEB J 2013; 28:705-14. [PMID: 24186965 DOI: 10.1096/fj.13-231274] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Aquaporin-4 (AQP4), the principal water channel in astrocytes, is involved in brain water movement, inflammation, and neuroexcitation. In this study, there was strong neuroprotection in mice lacking AQP4 in a model of global cerebral ischemia produced by transient, bilateral carotid artery occlusion (BCAO). Survival and neurological outcome were greatly improved in the AQP4(-/-) vs. AQP4(+/+) mice after occlusion, with large and robust differences in both outbred (CD1) and inbred (C57bl/6) mouse strains without or with mechanical ventilation. Improved survival was also seen in mice lacking the scaffold protein α-syntrophin, which manifest reduced astrocyte water permeability secondary to defective AQP4 plasma membrane targeting. Intracranial pressure elevation and brain water accumulation were much reduced in the AQP4(-/-) vs. AQP4(+/+) mice after carotid artery occlusion, as were blood-brain barrier (BBB) disruption and neuronal loss. Brain slices from AQP4(-/-) mice showed significantly reduced cell swelling and cytotoxicity in response to oxygen-glucose deprivation, compared with slices from AQP4(+/+) mice. Our findings suggest that the neuroprotective effect of AQP4 deletion in global cerebral ischemia involves reduced astrocyte swelling and brain water accumulation, resulting in reduced BBB disruption, inflammation, and neuron death. AQP4 water transport inhibition may improve survival and neurological outcome after cardiac arrest and in other conditions associated with global cerebral ischemia.
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Affiliation(s)
- Ryuichi Katada
- 1University of California, 1246 Health Sciences East Tower, Box 0521, San Francisco, CA 94143-0521, USA;
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173
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Caldeira MV, Salazar IL, Curcio M, Canzoniero LMT, Duarte CB. Role of the ubiquitin-proteasome system in brain ischemia: friend or foe? Prog Neurobiol 2013; 112:50-69. [PMID: 24157661 DOI: 10.1016/j.pneurobio.2013.10.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/08/2013] [Accepted: 10/15/2013] [Indexed: 11/26/2022]
Abstract
The ubiquitin-proteasome system (UPS) is a catalytic machinery that targets numerous cellular proteins for degradation, thus being essential to control a wide range of basic cellular processes and cell survival. Degradation of intracellular proteins via the UPS is a tightly regulated process initiated by tagging a target protein with a specific ubiquitin chain. Neurons are particularly vulnerable to any change in protein composition, and therefore the UPS is a key regulator of neuronal physiology. Alterations in UPS activity may induce pathological responses, ultimately leading to neuronal cell death. Brain ischemia triggers a complex series of biochemical and molecular mechanisms, such as an inflammatory response, an exacerbated production of misfolded and oxidized proteins, due to oxidative stress, and the breakdown of cellular integrity mainly mediated by excitotoxic glutamatergic signaling. Brain ischemia also damages protein degradation pathways which, together with the overproduction of damaged proteins and consequent upregulation of ubiquitin-conjugated proteins, contribute to the accumulation of ubiquitin-containing proteinaceous deposits. Despite recent advances, the factors leading to deposition of such aggregates after cerebral ischemic injury remain poorly understood. This review discusses the current knowledge on the role of the UPS in brain function and the molecular mechanisms contributing to UPS dysfunction in brain ischemia with consequent accumulation of ubiquitin-containing proteins. Chemical inhibitors of the proteasome and small molecule inhibitors of deubiquitinating enzymes, which promote the degradation of proteins by the proteasome, were both shown to provide neuroprotection in brain ischemia, and this apparent contradiction is also discussed in this review.
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Affiliation(s)
- Margarida V Caldeira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Ivan L Salazar
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Portugal
| | - Michele Curcio
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Science and Technology, University of Sannio, Benevento, Italy
| | | | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.
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174
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Srinivasan K, Sharma SS. Augmentation of endoplasmic reticulum stress in cerebral ischemia/reperfusion injury associated with comorbid type 2 diabetes. Neurol Res 2013; 33:858-65. [DOI: 10.1179/1743132811y.0000000015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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175
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Llorente IL, Burgin TC, Pérez-Rodríguez D, Martínez-Villayandre B, Pérez-García CC, Fernández-López A. Unfolded protein response to global ischemia following 48 h of reperfusion in the rat brain: the effect of age and meloxicam. J Neurochem 2013; 127:701-10. [DOI: 10.1111/jnc.12337] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 05/23/2013] [Accepted: 06/03/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Irene L. Llorente
- Área de Biología Celular; Instituto de Biomedicina; Universidad de León; León Spain
| | - Taiana C. Burgin
- Área de Biología Celular; Instituto de Biomedicina; Universidad de León; León Spain
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176
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Qiu B, Hu S, Liu L, Chen M, Wang L, Zeng X, Zhu S. CART attenuates endoplasmic reticulum stress response induced by cerebral ischemia and reperfusion through upregulating BDNF synthesis and secretion. Biochem Biophys Res Commun 2013; 436:655-9. [PMID: 23770418 DOI: 10.1016/j.bbrc.2013.05.142] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 05/28/2013] [Indexed: 01/11/2023]
Abstract
Cocaine and amphetamine regulated transcript (CART), a neuropeptide, has shown strong neuroprotective effects against cerebral ischemia and reperfusion (I/R) injury in vivo and in vitro. Here, we report a new effect of CART on ER stress which is induced by cerebral I/R in a rat model of middle cerebral artery occlusion (MCAO) or by oxygen and glucose deprivation (OGD) in cultured cortical neurons, as well as a new functionality of BDNF in the neuroprotection by CART against the ER stress in cerebral I/R. The results showed that CART was effective in reducing the neuronal apoptosis and expression of ER stress markers (GRP78, CHOP and cleaved caspase12), and increasing the BDNF expression in I/R injury rat cortex both in vivo and in vitro. In addition, the effects of CART on ischemia-induced neuronal apoptosis and ER stress were suppressed by tyrosine receptor kinase B (TrkB) IgG, whereas the effects of CART on BDNF transcription, synthesis and secretion were abolished by CREB siRNA. This work suggests that CART is functional in inhibiting the cerebral I/R-induced ER stress and neuronal apoptosis by facilitating the transcription, synthesis and secretion of BDNF in a CREB-dependent way.
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Affiliation(s)
- Bin Qiu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, People's Republic of China
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177
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Murata T, Kohno S, Ito C, Itoigawa M, Sugiura A, Hikita K, Kaneda N. Inhibitory effect of carbazolequinone derivatives on lipopolysaccharide and interferon-γ-induced nitric oxide production in mouse macrophage RAW264.7 cells. J Pharm Pharmacol 2013; 65:1204-13. [DOI: 10.1111/jphp.12087] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 04/24/2013] [Indexed: 01/02/2023]
Abstract
Abstract
Objectives
The aim of this study was to examine the mechanism underlying the inhibitory effect of our synthesized carbazolequinone derivatives on nitric oxide (NO) production in activated macrophages.
Methods
Lipopolysaccharide (LPS) and interferon-γ (IFN-γ)-stimulated RAW264.7 macrophages were treated with carbazolequinone derivatives. The NO and prostaglandin E2 (PGE2) levels in cell culture supernatants fractions were measured by Greiss and ELISA assay, respectively. The expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) was assessed by the real-time RT-PCR method. Nuclear factor kappa B (NF-κB) activation was detected by an NF-κB-dependent luciferase reporter assay.
Key findings
Our synthesized carbazolequinone derivatives (7-methoxy-2-methylcarbazole-1,4-quinone, 6-methoxy-2-methylcarbazole-1,4-quinone and 6-chloro-2-methylcarbazole-1,4-quinone) significantly inhibited LPS/IFN-γ-induced NO production and iNOS expression in RAW264.7 cells. They also inhibited the LPS/IFN-γ-mediated induction of COX-2 expression and PGE2 production. In addition, the LPS/IFN-γ-induced transcription activity of NF-κB was attenuated. Using the RAW264.7-tsAM5NE co-culture system, we found that these carbazolequinone derivatives protected neuronally differentiated tsAM5NE cells from NO-induced cell death by inhibiting the production of NO.
Conclusions
These results suggest that the three carbazolequinone derivatives inhibit LPS/IFN-γ-induced NO production via iNOS and COX-2 downregulation due to NF-κB inhibition. Therefore, these three carbazolequinone derivatives may be useful for developing a new drug against NO-mediated neurodegenerative diseases.
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Affiliation(s)
- Tomiyasu Murata
- Department of Analytical Neurobiology, Meijo University, Tempaku, Nagoya, Japan
| | - Susumu Kohno
- Division of Oncology and Molecular Biology, Cancer and Stem Cell Research Program, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | - Chihiro Ito
- Department of Medicinal Chemistry, Faculty of Pharmacy, Meijo University, Tempaku, Nagoya, Japan
| | - Masataka Itoigawa
- School of Sport and Health Science, Tokai Gakuen University, Tempaku, Nagoya, Japan
| | - Ayumi Sugiura
- Department of Analytical Neurobiology, Meijo University, Tempaku, Nagoya, Japan
| | - Kiyomi Hikita
- Department of Analytical Neurobiology, Meijo University, Tempaku, Nagoya, Japan
| | - Norio Kaneda
- Department of Analytical Neurobiology, Meijo University, Tempaku, Nagoya, Japan
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178
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Jain A. Endothelin-1–Induced Endoplasmic Reticulum Stress in Disease. J Pharmacol Exp Ther 2013; 346:163-72. [DOI: 10.1124/jpet.113.205567] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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179
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Wu CX, Liu R, Gao M, Zhao G, Wu S, Wu CF, Du GH. Pinocembrin protects brain against ischemia/reperfusion injury by attenuating endoplasmic reticulum stress induced apoptosis. Neurosci Lett 2013; 546:57-62. [PMID: 23669639 DOI: 10.1016/j.neulet.2013.04.060] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 04/23/2013] [Accepted: 04/27/2013] [Indexed: 12/18/2022]
Abstract
Endoplasmic reticulum stress (ER stress) is known to play a vital role in mediating ischemic reperfusion damage in brain. Our previous studies showed that pinocembrin alleviated cerebral ischemic injury in ischemia/reperfusion and vascular dementia animal models, but whether attenuation of ER stress-induced apoptosis contributes to the mechanisms remains to be elucidated. In this study, an attempt was therefore made to investigate the modulation effect of pinocembrin on ischemia/reperfusion-induced ER stress in brain. Focal cerebral ischemia/reperfusion rats were induced by middle cerebral artery occlusion (MCAO) for 2h followed by 6h reperfusion. Pinocembrin was administered in different doses (1mg/kg, 3mg/kg, and 10mg/kg, respectively) at the same time of onset of reperfusion. Neurological function and brain infarction were evaluated. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method, and flow cytometer (FCM) were used to investigate cell apoptosis in penumbra cortex. DNA fragmentation assay was also performed using electrophoresis. The expression of ER stress proteins of GRP78, CHOP/GADD153, ATF4, eIF2α phosphorylation was detected by western blot, and caspase-12 was evaluated by immunohistochemical analysis. Our results demonstrate that pinocembrin-treatment (3mg/kg and 10mg/kg) significantly reduced neurological deficit scores, infarct volume, and neuron apoptosis in the ischemia/reperfusion rats. It can also significantly modulate the protein levels by increasing GRP78 (10mg/kg) and attenuating CHOP/GADD153 expression along with caspase-12 activation (3mg/kg and 10mg/kg). At the same time, eIF2α phosphorylation was restrained and the expression of ATF4 was reduced (3mg/kg and 10mg/kg). These results suggest that the attenuation of ER stress induced apoptosis may be involved in the mechanisms of pinocembrin.
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Affiliation(s)
- Cai-Xia Wu
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
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180
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Zou XJ, Yang L, Yao SL. Endoplasmic reticulum stress and C/EBP homologous protein-induced Bax translocation are involved in angiotensin II-induced apoptosis in cultured neonatal rat cardiomyocytes. Exp Biol Med (Maywood) 2013; 237:1341-9. [PMID: 23239445 DOI: 10.1258/ebm.2012.012041] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to identify the roles and potential mechanisms of endoplasmic reticulum stress (ER stress), proapoptotic transcription factor C/EBP homologous protein (CHOP) and Bax in angiotensin II (Ang II)-induced cardiomyocyte apoptosis. Cultured neonatal rat cardiomyocytes were incubated with Ang II or antisense CHOP oligonucleotide which was used to inhibit CHOP expression. Expressions of ER chaperone immunoglobulin heavy chain-binding protein (BiP), CHOP and cytochrome c were examined by Western blotting. Mitochondrial membrane potential (MMP) was detected by a spectrofluorimeter. Apoptosis was analyzed with flow cytometry. Bax translocation was determined by double-labeling of immunofluorescence and Western blotting. Our results showed that Ang II-induced cardiomyocyte apoptosis was associated with the upregulations of BiP and CHOP, Bax translocation, MMP deplorization and cytochrome c release. These above effects were suppressed by antisense CHOP oligonucleotide. Furthermore, BiP and CHOP expressions, reactive oxygen species (ROS) production and cardiomyocyte apoptosis, which were upregulated by Ang II, were depressed by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin. From our results, ROS, ER stress and CHOP-mediated Bax translocation may be involved in Ang II-induced cardiomyocyte apoptosis.
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Affiliation(s)
- Xiao-Jing Zou
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, PR China
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181
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Potential for therapeutic manipulation of the UPR in disease. Semin Immunopathol 2013; 35:351-73. [PMID: 23572207 PMCID: PMC3641308 DOI: 10.1007/s00281-013-0370-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 03/13/2013] [Indexed: 12/16/2022]
Abstract
Increased endoplasmic reticulum (ER) stress and the activated unfolded protein response (UPR) signaling associated with it play key roles in physiological processes as well as under pathological conditions. The UPR normally protects cells and re-establishes cellular homeostasis, but prolonged UPR activation can lead to the development of various pathologies. These features make the UPR signaling pathway an attractive target for the treatment of diseases whose pathogenesis is characterized by chronic activation of this pathway. Here, we focus on the molecular signaling pathways of the UPR and suggest possible ways to target this response for therapeutic purposes.
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182
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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: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [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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183
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Binet F, Mawambo G, Sitaras N, Tetreault N, Lapalme E, Favret S, Cerani A, Leboeuf D, Tremblay S, Rezende F, Juan AM, Stahl A, Joyal JS, Milot E, Kaufman RJ, Guimond M, Kennedy TE, Sapieha P. Neuronal ER stress impedes myeloid-cell-induced vascular regeneration through IRE1α degradation of netrin-1. Cell Metab 2013; 17:353-71. [PMID: 23473031 DOI: 10.1016/j.cmet.2013.02.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 10/26/2012] [Accepted: 01/23/2013] [Indexed: 12/13/2022]
Abstract
In stroke and proliferative retinopathy, despite hypoxia driven angiogenesis, delayed revascularization of ischemic tissue aggravates the loss of neuronal function. What hinders vascular regrowth in the ischemic central nervous system remains largely unknown. Using the ischemic retina as a model of neurovascular interaction in the CNS, we provide evidence that the failure of reparative angiogenesis is temporally and spatially associated with endoplasmic reticulum (ER) stress. The canonical ER stress pathways of protein kinase RNA-like ER kinase (PERK) and inositol-requiring enzyme-1α (IRE1α) are activated within hypoxic/ischemic retinal ganglion neurons, initiating a cascade that results in angiostatic signals. Our findings demonstrate that the endoribonuclease IRE1α degrades the classical guidance cue netrin-1. This neuron-derived cue triggers a critical reparative-angiogenic switch in neural macrophage/microglial cells. Degradation of netrin-1, by persistent neuronal ER stress, thereby hinders vascular regeneration. These data identify a neuronal-immune mechanism that directly regulates reparative angiogenesis.
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Affiliation(s)
- François Binet
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada
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184
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Roussel BD, Kruppa AJ, Miranda E, Crowther DC, Lomas DA, Marciniak SJ. Endoplasmic reticulum dysfunction in neurological disease. Lancet Neurol 2013; 12:105-18. [PMID: 23237905 DOI: 10.1016/s1474-4422(12)70238-7] [Citation(s) in RCA: 340] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Endoplasmic reticulum (ER) dysfunction might have an important part to play in a range of neurological disorders, including cerebral ischaemia, sleep apnoea, Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, the prion diseases, and familial encephalopathy with neuroserpin inclusion bodies. Protein misfolding in the ER initiates the well studied unfolded protein response in energy-starved neurons during stroke, which is relevant to the toxic effects of reperfusion. The toxic peptide amyloid β induces ER stress in Alzheimer's disease, which leads to activation of similar pathways, whereas the accumulation of polymeric neuroserpin in the neuronal ER triggers a poorly understood ER-overload response. In other neurological disorders, such as Parkinson's and Huntington's diseases, ER dysfunction is well recognised but the mechanisms by which it contributes to pathogenesis remain unclear. By targeting components of these signalling responses, amelioration of their toxic effects and so the treatment of a range of neurodegenerative disorders might become possible.
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Affiliation(s)
- Benoit D Roussel
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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185
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Engel T, Sanz-Rodgriguez A, Jimenez-Mateos EM, Concannon CG, Jimenez-Pacheco A, Moran C, Mesuret G, Petit E, Delanty N, Farrell MA, O'Brien DF, Prehn JHM, Lucas JJ, Henshall DC. CHOP regulates the p53-MDM2 axis and is required for neuronal survival after seizures. ACTA ACUST UNITED AC 2013; 136:577-92. [PMID: 23361066 DOI: 10.1093/brain/aws337] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Hippocampal sclerosis is a frequent pathological finding in patients with temporal lobe epilepsy and can be caused by prolonged single or repeated brief seizures. Both DNA damage and endoplasmic reticulum stress have been implicated as underlying molecular mechanisms in seizure-induced brain injury. The CCAAT/enhancer-binding protein homologous protein (CHOP) is a transcriptional regulator induced downstream of DNA damage and endoplasmic reticulum stress, which can promote or inhibit apoptosis according to context. Recent work has proposed inhibition of CHOP as a suitable neuroprotective strategy. Here, we show that transcript and protein levels of CHOP increase in surviving subfields of the hippocampus after prolonged seizures (status epilepticus) in mouse models. CHOP was also elevated in the hippocampus from epileptic mice and patients with pharmacoresistant epilepsy. The hippocampus of CHOP-deficient mice was much more vulnerable to damage in mouse models of status epilepticus. Moreover, compared with wild-type animals, CHOP-deficient mice subject to status epilepticus developed more spontaneous seizures, displayed protracted hippocampal neurodegeneration and a deficit in a hippocampus-dependent object-place recognition task. The absence of CHOP was associated with a supra-maximal induction of p53 after status epilepticus, and inhibition of p53 abolished the cell death-promoting consequences of CHOP deficiency. The protective effect of CHOP could be partly explained by activating transcription of murine double minute 2 that targets p53 for degradation. These data demonstrate that CHOP is required for neuronal survival after seizures and caution against inhibition of CHOP as a neuroprotective strategy where excitotoxicity is an underlying pathomechanism.
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Affiliation(s)
- Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
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186
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Ji YL, Wang H, Zhang C, Zhang Y, Zhao M, Chen YH, Xu DX. N-acetylcysteine protects against cadmium-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in testes. Asian J Androl 2013; 15:290-6. [PMID: 23353715 DOI: 10.1038/aja.2012.129] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Cadmium (Cd) is a reproductive toxicant that induces germ cell apoptosis in the testes. Previous studies have demonstrated that endoplasmic reticulum (ER) stress is involved in Cd-induced germ cell apoptosis. The aim of the present study was to investigate the effects of N-acetylcysteine (NAC), an antioxidant, on Cd-induced ER stress and germ cell apoptosis in the testes. Male CD-1 mice were intraperitoneally injected with CdCl2 (2.0 mg kg(-1)). As expected, acute Cd exposure induced germ cell apoptosis in the testes, as determined by terminal dUTP nick-end labelling (TUNEL). However, the administration of NAC alleviated Cd-induced germ cell apoptosis in the testes. Further analysis showed that NAC attenuated the Cd-induced upregulation of testicular glucose-regulated protein 78 (GRP78), an important ER molecular chaperone. Moreover, NAC inhibited the Cd-induced phosphorylation of testicular eukaryotic translation initiation factor 2α (eIF2α), a downstream target of the double-stranded RNA-activated kinase-like ER kinase (PERK) pathway. In addition, NAC blocked the Cd-induced activation of testicular X binding protein (XBP)-1, indicating that NAC attenuates the Cd-induced ER stress and the unfolded protein response (UPR). Interestingly, NAC almost completely prevented the Cd-induced elevation of C/EBP homologous protein (CHOP) and phosphorylation of c-Jun N-terminal kinase (JNK), two components of the ER stress-mediated apoptotic pathway. In conclusion, NAC protects against Cd-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in the testes.
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Affiliation(s)
- Yan-Li Ji
- Department of Toxicology, Anhui Medical University, Hefei, China
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187
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Lafleur MA, Stevens JL, Lawrence JW. Xenobiotic perturbation of ER stress and the unfolded protein response. Toxicol Pathol 2013; 41:235-62. [PMID: 23334697 DOI: 10.1177/0192623312470764] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The proper folding, assembly, and maintenance of cellular proteins is a highly regulated process and is critical for cellular homeostasis. Multiple cellular compartments have adapted their own systems to ensure proper protein folding, and quality control mechanisms are in place to manage stress due to the accumulation of unfolded proteins. When the accumulation of unfolded proteins exceeds the capacity to restore homeostasis, these systems can result in a cell death response. Unfolded protein accumulation in the endoplasmic reticulum (ER) leads to ER stress with activation of the unfolded protein response (UPR) governed by the activating transcription factor 6 (ATF6), inositol requiring enzyme-1 (IRE1), and PKR-like endoplasmic reticulum kinase (PERK) signaling pathways. Many xenobiotics have been shown to influence ER stress and UPR signaling with either pro-survival or pro-death features. The ultimate outcome is dependent on many factors including the mechanism of action of the xenobiotic, concentration of xenobiotic, duration of exposure (acute vs. chronic), cell type affected, nutrient levels, oxidative stress, state of differentiation, and others. Assessing perturbations in activation or inhibition of ER stress and UPR signaling pathways are likely to be informative parameters to measure when analyzing mechanisms of action of xenobiotic-induced toxicity.
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Affiliation(s)
- Marc A Lafleur
- Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, California 91320, USA.
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188
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Ye Z, Wang N, Xia P, Wang E, Liao J, Guo Q. Parecoxib suppresses CHOP and Foxo1 nuclear translocation, but increases GRP78 levels in a rat model of focal ischemia. Neurochem Res 2013; 38:686-93. [PMID: 23325452 DOI: 10.1007/s11064-012-0953-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 12/07/2012] [Accepted: 12/19/2012] [Indexed: 11/26/2022]
Abstract
Parecoxib, a novel COX-2 inhibitor, functions as a neuroprotective agent and rescues neurons from cerebral ischemic reperfusion injury-induced apoptosis. However, the molecular mechanisms underlying parecoxib neuroprotection remain to be elucidated. There is growing evidence that endoplasmic reticulum (ER) stress plays an important role in neuronal death caused by brain ischemia. However, very little is known about the role of parecoxib in mediating pathophysiological reactions to ER stress induced by ischemic reperfusion injury. Therefore, in the present study, we investigated whether delayed administration of parecoxib attenuates brain damage via suppressing ER stress-induced cell death. Adult male Sprague-Dawley rats were administered parecoxib (10 or 30 mg kg(-1), IP) or isotonic saline twice a day starting 24 h after middle cerebral artery occlusion (MCAO) for three consecutive days. The expressions of glucose-regulated protein 78 (GRP78) and oxygen-regulated protein 150 (ORP150) and C/EBP-homologous protein (CHOP) and forkhead box protein O 1 (Foxo1) in cytoplasmic and nuclear fraction were determined by Western blotting. The levels of caspase-12 expression were checked by immunohistochemistry analysis, served as a marker for ER stress-induced apoptosis. Parecoxib significantly suppressed cerebral ischemic injury-induced nuclear translocation of CHOP and Foxo1 and attenuated the immunoreactivity of caspase-12 in ischemic penumbra. Furthermore, the protective effect of delayed administration of parecoxib was accompanied by an increased GRP78 and ORP150 expression. Therefore, our study suggested that elevation of GRP78 and ORP150, and suppression of CHOP and Foxo1 nuclear translocation may contribute to parecoxib-mediated neuroprotection during ER stress responses.
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Affiliation(s)
- Zhi Ye
- Department of Anesthesiology, The Affiliated Xiangya Hospital of Central South University, Changsha, 410078 Hunan Province, China
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189
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Liu X, Wang M, Chen H, Guo Y, Ma F, Shi F, Bi Y, Li Y. Hypothermia protects the brain from transient global ischemia/reperfusion by attenuating endoplasmic reticulum response-induced apoptosis through CHOP. PLoS One 2013; 8:e53431. [PMID: 23301071 PMCID: PMC3536702 DOI: 10.1371/journal.pone.0053431] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 11/28/2012] [Indexed: 01/09/2023] Open
Abstract
Endoplasmic reticulum (ER) stress has been implicated in the pathology of cerebral ischemia. Apoptotic cell death occurs during prolonged period of stress or when the adaptive response fails. Hypothermia blocked the TNF or Fas-mediated extrinsic apoptosis pathway and the mitochondria pathway of apoptosis, however, whether hypothermia can block endoplasmic reticulum mediated apoptosis is never known. This study aimed to elucidate whether hypothermia attenuates brain cerebral ischemia/reperfusion (I/R) damage by suppressing ER stress-induced apoptosis. A 15 min global cerebral ischemia rat model was used in this study. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) positive cells in hippocampus CA1 were assessed after reperfusion of the brain. The expressions of C/EBP-homologous protein (CHOP) and glucose-regulated protein 78 (GRP78) in ischemic hippocampus CA1 were measured at 6, 12, 24 and 48 h after reperfusion. The results showed that hypothermia significantly attenuated brain I/R injury, as shown by reduction in cell apoptosis, CHOP expression, and increase in GRP78 expression. These results suggest that hypothermia could protect brain from I/R injury by suppressing ER stress-induced apoptosis.
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Affiliation(s)
- Xiaojie Liu
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
| | - Mingshan Wang
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
| | - Huailong Chen
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
| | - Yunliang Guo
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
| | - Fuguo Ma
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
| | - Fei Shi
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
| | - Yanlin Bi
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
| | - Ying Li
- Department of Anesthesiology, Qingdao Municipal Hospital, Shandong, China
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190
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Loss of endoplasmic reticulum Ca2+ homeostasis: contribution to neuronal cell death during cerebral ischemia. Acta Pharmacol Sin 2013; 34:49-59. [PMID: 23103622 DOI: 10.1038/aps.2012.139] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The loss of Ca(2+) homeostasis during cerebral ischemia is a hallmark of impending neuronal demise. Accordingly, considerable cellular resources are expended in maintaining low resting cytosolic levels of Ca(2+). These include contributions by a host of proteins involved in the sequestration and transport of Ca(2+), many of which are expressed within intracellular organelles, including lysosomes, mitochondria as well as the endoplasmic reticulum (ER). Ca(2+) sequestration by the ER contributes to cytosolic Ca(2+) dynamics and homeostasis. Furthermore, within the ER Ca(2+) plays a central role in regulating a host of physiological processes. Conversely, impaired ER Ca(2+) homeostasis is an important trigger of pathological processes. Here we review a growing body of evidence suggesting that ER dysfunction is an important factor contributing to neuronal injury and loss post-ischemia. Specifically, the contribution of the ER to cytosolic Ca(2+) elevations during ischemia will be considered, as will the signalling cascades recruited as a consequence of disrupting ER homeostasis and function.
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191
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Schönthal AH. Endoplasmic reticulum stress: its role in disease and novel prospects for therapy. SCIENTIFICA 2012; 2012:857516. [PMID: 24278747 PMCID: PMC3820435 DOI: 10.6064/2012/857516] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 11/12/2012] [Indexed: 05/19/2023]
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle required for lipid biosynthesis, calcium storage, and protein folding and processing. A number of physiological and pathological conditions, as well as a variety of pharmacological agents, are able to disturb proper ER function and thereby cause ER stress, which severely impairs protein folding and therefore poses the risk of proteotoxicity. Specific triggers for ER stress include, for example, particular intracellular alterations (e.g., calcium or redox imbalances), certain microenvironmental conditions (e.g., hypoglycemia, hypoxia, and acidosis), high-fat and high-sugar diet, a variety of natural compounds (e.g., thapsigargin, tunicamycin, and geldanamycin), and several prescription drugs (e.g., bortezomib/Velcade, celecoxib/Celebrex, and nelfinavir/Viracept). The cell reacts to ER stress by initiating a defensive process, called the unfolded protein response (UPR), which is comprised of cellular mechanisms aimed at adaptation and safeguarding cellular survival or, in cases of excessively severe stress, at initiation of apoptosis and elimination of the faulty cell. In recent years, this dichotomic stress response system has been linked to several human diseases, and efforts are underway to develop approaches to exploit ER stress mechanisms for therapy. For example, obesity and type 2 diabetes have been linked to ER stress-induced failure of insulin-producing pancreatic beta cells, and current research efforts are aimed at developing drugs that ameliorate cellular stress and thereby protect beta cell function. Other studies seek to pharmacologically aggravate chronic ER stress in cancer cells in order to enhance apoptosis and achieve tumor cell death. In the following, these principles will be presented and discussed.
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Affiliation(s)
- Axel H. Schönthal
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, HMR-405, Los Angeles, CA 90033, USA
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192
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Liu CL, Li X, Hu GL, Li RJ, He YY, Zhong W, Li S, He KL, Wang LL. Salubrinal protects against tunicamycin and hypoxia induced cardiomyocyte apoptosis via the PERK-eIF2α signaling pathway. J Geriatr Cardiol 2012; 9:258-68. [PMID: 23097656 PMCID: PMC3470025 DOI: 10.3724/sp.j.1263.2012.02292] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 05/18/2012] [Accepted: 07/25/2012] [Indexed: 11/30/2022] Open
Abstract
Objectives This study examined the protective effect of salubrinal and the mechanism underlying this protection against tunicamycin (TM)- and hypoxia-induced apoptosis in rat cardiomyocytes. Methods Neonatal rat cardiomyocytes were cultured from the ventricles of 1-day-old Wistar rats. Cells were exposed to different concentrations of salubrinal (10, 20, and 40 µmol/L) for 30 min followed by TM treatment or hypoxia for 36 h. Apoptosis was measured by a multiparameter HCS (high content screening) apoptosis assay, TUNEL assay and flow cytometry. The phosphorylation of eukaryotic translation initiation factor 2 subunit alpha (eIF2α) and the expression of cleaved caspase-12 were determined by Western blotting. C/EBP homologous protein (CHOP) was detected by immunocytochemistry. Results HCS, TUNEL assays and flow cytometry showed that salubrinal protected cardiomyocytes against apoptosis induced by TM or hypoxia. Western blotting showed that salubrinal protected cardiomyocytes against apoptosis by inducing eIF2α phosphorylation and down-regulating the expression of the endoplasmic reticulum stress-mediated apoptotic proteins, CHOP and cleaved caspase-12. Conclusions Our study suggests that salubrinal protects rat cardiomyocytes against TM- or hypoxia-associated apoptosis via a mechanism involving the inhibition of ER stress-mediated apoptosis.
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Affiliation(s)
- Chun-Lei Liu
- Department of Cardiology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853, China ; Medical School of Nankai University, 74 Weijin Road, Tianjin 300074, China
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193
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Wang MD, Huang Y, Zhang GP, Mao L, Xia YP, Mei YW, Hu B. Exendin-4 improved rat cortical neuron survival under oxygen/glucose deprivation through PKA pathway. Neuroscience 2012; 226:388-96. [PMID: 23000625 DOI: 10.1016/j.neuroscience.2012.09.025] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 09/01/2012] [Accepted: 09/11/2012] [Indexed: 12/17/2022]
Abstract
Previous studies demonstrated that exendin-4 (Ex-4) may possess neurotrophic and neuroprotective functions in ischemia insults, but its mechanism remained unknown. Here, by using real-time PCR and ELISA, we identified the distribution of active GLP-1Rs in the rat primary cortical neurons. After establishment of an in vitro ischemia model by oxygen/glucose deprivation (OGD), neurons were treated with various dosages of Ex-4. The MTT assay showed that the relative survival rate increased with the dosage of Ex-4 ranging from 0.2 to 0.8 μg/ml (P<0.001, vs. OGD group). The apoptosis rate was reduced from (49.47±2.70)% to (14.61±0.81)% after Ex-4 treatment (0.4 μg/ml) 12h after OGD (P<0.001). Moreover, immunofluorescence staining indicated that Ex-4 increased glucose-regulated proteins 78 (GRP78) and reduced C/EBP-homologous protein (CHOP). Western blot analysis demonstrated that, after neurons were treated with Ex-4, GRP78 was up-regulated over time (P<0.01, vs. OGD group), while CHOP levels rose to a peak 8h after OGD and then decreased (P<0.05, vs. OGD group). This effect was changed by both the protein kinase A (PKA) inhibitor H89 (P<0.01, P<0.05, respectively, vs. Ex-4 group) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (P<0.01, P<0.01, respectively, vs. Ex-4 group) but not by the mitogen-activated protein kinase (MAPK) inhibitor U0126. Our study also revealed that, compared with the Ex-4 group, inhibition of the PKA signaling pathway significantly decreased the survival rate of neurons, down-regulated the expression of B-cell lymphoma 2 (Bcl-2) and up-regulated the Bax expression 3h after ODG (P<0.05, P<0.01, respectively), while neither PI3K nor MAPK inhibition exerted such effects. Furthermore, Western blotting exhibited that PKA expression was elevated in the presence or absence of OGD insults (P<0.05). This study indicated that Ex-4 protected neurons against OGD by modulating the unfolded protein response (UPR) through the PKA pathway and may serve as a novel therapeutic agent for stroke.
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Affiliation(s)
- M-D Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue, Wuhan 430022, PR China
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194
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Kang S, Louboutin JP, Datta P, Landel CP, Martinez D, Zervos AS, Strayer DS, Fernandes-Alnemri T, Alnemri ES. Loss of HtrA2/Omi activity in non-neuronal tissues of adult mice causes premature aging. Cell Death Differ 2012; 20:259-69. [PMID: 22976834 DOI: 10.1038/cdd.2012.117] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
mnd2 mice die prematurely as a result of neurodegeneration 30-40 days after birth due to loss of the enzymatic activity of the mitochondrial quality control protease HtrA2/Omi. Here, we show that transgenic expression of human HtrA2/Omi in the central nervous system of mnd2 mice rescues them from neurodegeneration and prevents their premature death. Interestingly, adult transgenic mnd2 mice develop accelerated aging phenotypes, such as premature weight loss, hair loss, reduced fertility, curvature of the spine, heart enlargement, increased autophagy, and death by 12-17 months of age. These mice also have elevated levels of clonally expanded mitochondrial DNA (mtDNA) deletions in their tissues. Our results provide direct genetic evidence linking mitochondrial protein quality control to mtDNA deletions and aging in mammals.
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Affiliation(s)
- S Kang
- Department of Biochemistry and Molecular Biology, The Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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195
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Liu J, Ren F, Cheng Q, Bai L, Shen X, Gao F, Busuttil RW, Kupiec-Weglinski JW, Zhai Y. Endoplasmic reticulum stress modulates liver inflammatory immune response in the pathogenesis of liver ischemia and reperfusion injury. Transplantation 2012; 94:211-7. [PMID: 22790388 PMCID: PMC3414672 DOI: 10.1097/tp.0b013e318259d38e] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Although endoplasmic reticulum (ER) stress has been implicated in the pathophysiology of organ ischemia-reperfusion injury (IRI), the underlying mechanisms have yet to be fully elucidated. In particular, because tissue proinflammatory immune response is the key mediator of local IRI, how ER stress impacts liver immune cell activation cascade remains to be determined. METHODS In vitro, ER stress in macrophages and hepatocytes were induced by pharmacological agents. Macrophage Toll-like receptor 4 and hepatocyte tumor necrosis factor α responses were studied. In vivo, the induction of ER stress by ischemia-reperfusion and the impact of ER stress amelioration by a small molecule chaperon 4-phenylbutyric acid on liver immune response were studied in a murine partial liver warm ischemia model. RESULTS ER-stressed macrophages generated a significantly enhanced proinflammatory immune response against Toll-like receptor 4 stimulation, whereas ER-stressed hepatocytes became more susceptible to tumor necrosis factor α-induced cell death. Ischemia-reperfusion resulted in up-regulations of spliced X-box binding protein 1 and activating transcription factor 6 levels in affected livers. Mice pretreated with 4-phenylbutyric acid were protected from liver IRI, in parallel with diminished local proinflammatory gene induction program. CONCLUSIONS Our study documents a potential immune regulatory role of ER stress in the mechanism of liver IRI and provides a rationale for targeting stress response as a new therapeutic means to ameliorate tissue inflammation in organ transplant recipients.
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Affiliation(s)
- Jun Liu
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
- Department of General Surgery, Beijing Friendship Hospital, Affiliated to Capital Medical University, Beijing, China
| | - Feng Ren
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
- Institute of Liver Diseases, Beijing You'an Hospital, Affiliated to Capital Medical University, Beijing, China
| | - Qiao Cheng
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Li Bai
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
- Institute of Liver Diseases, Beijing You'an Hospital, Affiliated to Capital Medical University, Beijing, China
| | - Xiuda Shen
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Feng Gao
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Ronald W. Busuttil
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Jerzy W. Kupiec-Weglinski
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Yuan Zhai
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
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196
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Guo FJ, Liu Y, Zhou J, Luo S, Zhao W, Li X, Liu C. XBP1S protects cells from ER stress-induced apoptosis through Erk1/2 signaling pathway involving CHOP. Histochem Cell Biol 2012; 138:447-60. [PMID: 22669460 DOI: 10.1007/s00418-012-0967-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2012] [Indexed: 01/14/2023]
Abstract
The mammalian unfolded protein response (UPR) protects the cell against the stress of misfolded proteins in the endoplasmic reticulum (ER), and the transcription factor X-box binding protein 1 spliced (XBP1S), a regulator of the UPR, is known to be important for ER stress (ERS)-mediated apoptosis and cell growth, but the molecular mechanism underlying these processes remains unexplored. Here, we report that knockdown of XBP1S by an siRNA silencing approach increased the expression of ERS-associated molecules. The overexpression of XBP1S stimulated, whereas its knockdown inhibited, cell proliferation in chondrocytes and chondrosarcoma cells; in addition, overexpression of XBP1S inhibited, while its repression enhanced, ERS-mediated apoptosis in chondrocytes and chondrosarcoma cells. Furthermore, XBP1S-mediated inhibition of apoptosis in response to ERS is through the Erk1/2 signaling pathway and down-regulation CHOP transcription factor. CHOP is one of the key downstream molecules known to be involved in ERS-mediated apoptosis. Collectively, these findings reveal a novel critical role of XBP1S in ERS-mediated apoptosis and the molecular mechanisms involved.
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Affiliation(s)
- Feng-Jin Guo
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China.
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197
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Ji YL, Wang Z, Wang H, Zhang C, Zhang Y, Zhao M, Chen YH, Meng XH, Xu DX. Ascorbic acid protects against cadmium-induced endoplasmic reticulum stress and germ cell apoptosis in testes. Reprod Toxicol 2012; 34:357-63. [PMID: 22569276 DOI: 10.1016/j.reprotox.2012.04.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 04/07/2012] [Accepted: 04/27/2012] [Indexed: 11/29/2022]
Abstract
Cadmium (Cd) is a testicular toxicant which induces endoplasmic reticulum (ER) stress and germ cell apoptosis in testes. This study investigated the effects of ascorbic acid on Cd-evoked ER stress and germ cell apoptosis in testes. Male mice were intraperitoneally injected with CdCl(2) (2.0 mg/kg). As expected, a single dose of Cd induced testicular germ cell apoptosis. Interestingly, Cd-triggered testicular germ cell apoptosis was almost completely inhibited in mice treated with ascorbic acid. Interestingly, ascorbic acid significantly attenuated Cd-induced upregulation of GRP78 in testes. In addition, ascorbic acid significantly attenuated Cd-triggered testicular IRE1α and eIF2α phosphorylation and XBP-1 activation, indicating that this antioxidant counteracts Cd-induced unfolded protein response (UPR) in testes. Finally, ascorbic acid significantly attenuated Cd-evoked upregulation of CHOP and JNK phosphorylation, two components in ER stress-mediated apoptotic pathway. In conclusion, ascorbic acid protects mice from Cd-triggered germ cell apoptosis via inhibiting ER stress and UPR in testes.
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Affiliation(s)
- Yan-Li Ji
- Department of Toxicology, School of Public Health, Anhui Medical University, Hefei 230032, China
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198
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Kolattukudy PE, Niu J. Inflammation, endoplasmic reticulum stress, autophagy, and the monocyte chemoattractant protein-1/CCR2 pathway. Circ Res 2012; 110:174-89. [PMID: 22223213 DOI: 10.1161/circresaha.111.243212] [Citation(s) in RCA: 193] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Numerous inflammatory cytokines have been implicated in the pathogenesis of cardiovascular diseases. Monocyte chemoattractant protein (MCP)-1/CCL2 is expressed by mainly inflammatory cells and stromal cells such as endothelial cells, and its expression is upregulated after proinflammatory stimuli and tissue injury. MCP-1 can function as a traditional chemotactic cytokine and also regulates gene transcription. The recently discovered novel zinc-finger protein, called MCPIP (MCP-1-induced protein), initiates a series of signaling events that causes oxidative and endoplasmic reticulum (ER) stress, leading to autophagy that can result in cell death or differentiation, depending on the cellular context. After a brief review of the basic processes involved in inflammation, ER stress, and autophagy, the recently elucidated role of MCP-1 and MCPIP in inflammatory diseases is reviewed. MCPIP was found to be able to control inflammatory response by inhibition of nuclear factor-κB activation through its deubiquitinase activity or by degradation of mRNA encoding a set of inflammatory cytokines through its RNase activity. The potential inclusion of such a novel deubiquitinase in the emerging anti-inflammatory strategies for the treatment of inflammation-related diseases such as cardiovascular diseases and type 2 diabetes is briefly discussed.
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Affiliation(s)
- Pappachan E Kolattukudy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816, USA.
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199
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Abstract
Given the functional importance of the endoplasmic reticulum (ER), an organelle that performs folding, modification, and trafficking of secretory and membrane proteins to the Golgi compartment, the maintenance of ER homeostasis in insulin-secreting β-cells is very important. When ER homeostasis is disrupted, the ER generates adaptive signaling pathways, called the unfolded protein response (UPR), to maintain homeostasis of this organelle. However, if homeostasis fails to be restored, the ER initiates death signaling pathways. New observations suggest that both chronic hyperglycemia and hyperlipidemia, known as important causative factors of type 2 diabetes (T2D), disrupt ER homeostasis to induce unresolvable UPR activation and β-cell death. This review examines how the UPR pathways, induced by high glucose and free fatty acids (FFAs), interact to disrupt ER function and cause β-cell dysfunction and death.
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Affiliation(s)
- Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea 680-749
| | - Randal J. Kaufman
- Degenerative Disease Research Program, Neuroscience, Aging, and Stem Cell Research Center, Sanford Burnham Medical Research Institute, La Jolla, California 92037
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200
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Refined Qingkailing Protects MCAO Mice from Endoplasmic Reticulum Stress-Induced Apoptosis with a Broad Time Window. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:567872. [PMID: 22536287 PMCID: PMC3320064 DOI: 10.1155/2012/567872] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 01/02/2012] [Accepted: 01/03/2012] [Indexed: 11/18/2022]
Abstract
In the current study, we are investigating effect of refined QKL on ischemia-reperfusion-induced brain injury in mice. Methods. Mice were employed to induce ischemia-reperfusion injury of brain by middle cerebral artery occlusion (MCAO). RQKL solution was administered with different doses (0, 1.5, 3, and 6 mL/kg body weight) at the same time of onset of ischemia, and with the dose of 1.5 mL/kg at different time points (0, 1.5, 3, 6, and 9 h after MCAO). Neurological function and brain infarction were examined and cell apoptosis and ROS at prefrontal cortex were evaluated 24 h after MCAO, and western blot and intracellular calcium were also researched, respectively. Results. RQKL of all doses can improve neurological function and decrease brain infarction, and it performed significant effect in 0, 1.5, 3, and 6 h groups. Moreover, RQKL was able to reduce apoptotic process by reduction of caspase-3 expression, or restraint of eIF2a phosphorylation and caspase-12 activation. It was also able to reduce ROS and modulate intracellular calcium in the brain. Conclusion. RQKL can prevent ischemic-induced brain injury with a time window of 6 h, and its mechanism might be related to suppress ER stress-mediated apoptotic signaling.
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