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Solvay M, Holfelder P, Klaessens S, Pilotte L, Stroobant V, Lamy J, Naulaerts S, Spillier Q, Frédérick R, De Plaen E, Sers C, Opitz CA, Van den Eynde BJ, Zhu J. Tryptophan depletion sensitizes the AHR pathway by increasing AHR expression and GCN2/LAT1-mediated kynurenine uptake, and potentiates induction of regulatory T lymphocytes. J Immunother Cancer 2023; 11:e006728. [PMID: 37344101 DOI: 10.1136/jitc-2023-006728] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/12/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan-dioxygenase (TDO) are enzymes catabolizing the essential amino acid tryptophan into kynurenine. Expression of these enzymes is frequently observed in advanced-stage cancers and is associated with poor disease prognosis and immune suppression. Mechanistically, the respective roles of tryptophan shortage and kynurenine production in suppressing immunity remain unclear. Kynurenine was proposed as an endogenous ligand for the aryl hydrocarbon receptor (AHR), which can regulate inflammation and immunity. However, controversy remains regarding the role of AHR in IDO1/TDO-mediated immune suppression, as well as the involvement of kynurenine. In this study, we aimed to clarify the link between IDO1/TDO expression, AHR pathway activation and immune suppression. METHODS AHR expression and activation was analyzed by RT-qPCR and western blot analysis in cells engineered to express IDO1/TDO, or cultured in medium mimicking tryptophan catabolism by IDO1/TDO. In vitro differentiation of naïve CD4+ T cells into regulatory T cells (Tregs) was compared in T cells isolated from mice bearing different Ahr alleles or a knockout of Ahr, and cultured in medium with or without tryptophan and kynurenine. RESULTS We confirmed that IDO1/TDO expression activated AHR in HEK-293-E cells, as measured by the induction of AHR target genes. Unexpectedly, AHR was also overexpressed on IDO1/TDO expression. AHR overexpression did not depend on kynurenine but was triggered by tryptophan deprivation. Multiple human tumor cell lines overexpressed AHR on tryptophan deprivation. AHR overexpression was not dependent on general control non-derepressible 2 (GCN2), and strongly sensitized the AHR pathway. As a result, kynurenine and other tryptophan catabolites, which are weak AHR agonists in normal conditions, strongly induced AHR target genes in tryptophan-depleted conditions. Tryptophan depletion also increased kynurenine uptake by increasing SLC7A5 (LAT1) expression in a GCN2-dependent manner. Tryptophan deprivation potentiated Treg differentiation from naïve CD4+ T cells isolated from mice bearing an AHR allele of weak affinity similar to the human AHR. CONCLUSIONS Tryptophan deprivation sensitizes the AHR pathway by inducing AHR overexpression and increasing cellular kynurenine uptake. As a result, tryptophan catabolites such as kynurenine more potently activate AHR, and Treg differentiation is promoted. Our results propose a molecular explanation for the combined roles of tryptophan deprivation and kynurenine production in mediating IDO1/TDO-induced immune suppression.
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Affiliation(s)
- Marie Solvay
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | - Pauline Holfelder
- Faculty of Bioscience, Heidelberg University, Heidelberg, Germany
- DKTK Division of Metabolic Crosstalk in Cancer, German Cancer Research Center, DKFZ, INF 280, 69120 Heidelberg, Germany
| | - Simon Klaessens
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | - Luc Pilotte
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | - Vincent Stroobant
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | - Juliette Lamy
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | - Stefan Naulaerts
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | | | | | - Etienne De Plaen
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | - Christine Sers
- Partner Site Berlin, German Cancer Consortium, Heidelberg, Germany
- German Cancer Consortium Partner Site Berlin, German Cancer Research Center, Heidelberg, Germany
| | - Christiane A Opitz
- DKTK Division of Metabolic Crosstalk in Cancer, German Cancer Research Center, DKFZ, INF 280, 69120 Heidelberg, Germany
- Neurology Clinic and National Center for Tumor Diseases, Heidelberg, Germany
| | - Benoit J Van den Eynde
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
| | - Jingjing Zhu
- de Duve Institute, UCLouvain, Brussels, Belgium
- Ludwig Institute for Cancer Research, de Duve Institute, Brussels, Belgium
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Lv R, Liu X, Zhang Y, Dong N, Wang X, He Y, Yue H, Yin Q. Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome. Signal Transduct Target Ther 2023; 8:218. [PMID: 37230968 DOI: 10.1038/s41392-023-01496-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.
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Affiliation(s)
- Renjun Lv
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Xueying Liu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Yue Zhang
- Department of Geriatrics, the 2nd Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
| | - Na Dong
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Xiao Wang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Yao He
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, 730000, China
| | - Hongmei Yue
- Department of Pulmonary and Critical Care Medicine, The First Hospital of Lanzhou University, Lanzhou, 730000, China.
| | - Qingqing Yin
- Department of Geriatric Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China.
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Advances in Molecular Pathology of Obstructive Sleep Apnea. Molecules 2022; 27:molecules27238422. [PMID: 36500515 PMCID: PMC9739159 DOI: 10.3390/molecules27238422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 12/03/2022] Open
Abstract
Obstructive sleep apnea (OSA) is a common syndrome that features a complex etiology and set of mechanisms. Here we summarized the molecular pathogenesis of OSA, especially the prospective mechanism of upper? airway dilator fatigue and the current breakthroughs. Additionally, we also introduced the molecular mechanism of OSA in terms of related studies on the main signaling pathways and epigenetics alterations, such as microRNA, long non-coding RNA, and DNA methylation. We also reviewed small molecular compounds, which are potential targets for gene regulations in the future, that are involved in the regulation of OSA. This review will be beneficial to point the way for OSA research within the next decade.
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Yang Z, Zhang X, Li C, Chi S, Xie A. Molecular Mechanisms Underlying Reciprocal Interactions Between Sleep Disorders and Parkinson's Disease. Front Neurosci 2021; 14:592989. [PMID: 33642969 PMCID: PMC7902929 DOI: 10.3389/fnins.2020.592989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 11/27/2020] [Indexed: 01/11/2023] Open
Abstract
Sleep-wake disruptions are among the most prevalent and burdensome non-motor symptoms of Parkinson's disease (PD). Clinical studies have demonstrated that these disturbances can precede the onset of typical motor symptoms by years, indicating that they may play a primary function in the pathogenesis of PD. Animal studies suggest that sleep facilitates the removal of metabolic wastes through the glymphatic system via convective flow from the periarterial space to the perivenous space, upregulates antioxidative defenses, and promotes the maintenance of neuronal protein homeostasis. Therefore, disruptions to the sleep-wake cycle have been associated with inefficient metabolic clearance and increased oxidative stress in the central nervous system (CNS). This leads to excessive accumulation of alpha-synuclein and the induction of neuronal loss, both of which have been proposed to be contributing factors to the pathogenesis and progression of PD. Additionally, recent studies have suggested that PD-related pathophysiological alterations during the prodromal phase disrupt sleep and circadian rhythms. Taken together, these findings indicate potential mechanistic interactions between sleep-wake disorders and PD progression as proposed in this review. Further research into the hypothetical mechanisms underlying these interactions would be valuable, as positive findings may provide promising insights into novel therapeutic interventions for PD.
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Affiliation(s)
- Zhengjie Yang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaona Zhang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Chengqian Li
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Song Chi
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Anmu Xie
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
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Zadorozhnii PV, Kiselev VV, Kharchenko AV. In silico toxicity evaluation of Salubrinal and its analogues. Eur J Pharm Sci 2020; 155:105538. [PMID: 32889087 DOI: 10.1016/j.ejps.2020.105538] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/14/2020] [Accepted: 08/30/2020] [Indexed: 02/06/2023]
Abstract
This paper reports on a comprehensive in silico toxicity assessment of Salubrinal and its analogues containing a cinnamic acid residue or quinoline ring using the online servers admetSAR, ADMETlab, ProTox, ADVERPred, Pred-hERG and Vienna LiverTox. Apart from rare exceptions, in all 55 studied structures, mild or practical absence of acute toxicity was predicted for rats (III or IV toxicity class). Cardiotoxic, hepatotoxic and immunotoxic effects were predicted for Salubrinal and its analogues. We constructed models of the main predicted anti-targets hERG, BSEP, MRP3, MRP4 and AhR using the principle of homologous modeling. Molecular docking studies were carried out with the obtained models. We carried out molecular docking for all targets using AutoDock Vina, implemented in the PyRx 0.8 software package. According to the results of molecular docking, the compounds analyzed are potential moderate or weak hERG blockers. Induction of cholestasis and, as a consequence, liver damage by these drugs, directly related to inhibition of BSEP, MRP3 and MRP4, most likely will not be observed. Interaction with AhR for the studied compounds is impossible for steric reasons and, as a consequence, toxic effects on the immune and other organ systems associated with the activation of the AhR signaling pathway are excluded.
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Affiliation(s)
- Pavlo V Zadorozhnii
- Department of pharmacy and technology of organic substances, Ukrainian State University of Chemical Technology, Gagarin Ave., 8, Dnipro 49005, Ukraine.
| | - Vadym V Kiselev
- Department of pharmacy and technology of organic substances, Ukrainian State University of Chemical Technology, Gagarin Ave., 8, Dnipro 49005, Ukraine
| | - Aleksandr V Kharchenko
- Department of pharmacy and technology of organic substances, Ukrainian State University of Chemical Technology, Gagarin Ave., 8, Dnipro 49005, Ukraine
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Li M, Li X, Lu Y. Obstructive Sleep Apnea Syndrome and Metabolic Diseases. Endocrinology 2018; 159:2670-2675. [PMID: 29788220 DOI: 10.1210/en.2018-00248] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/14/2018] [Indexed: 12/24/2022]
Abstract
With the rapid changes in lifestyle in modern society, including the high nutritional intake and reduced physical activity, the incidence of metabolic diseases has been increasing year by year. Obstructive sleep apnea syndrome (OSAS) is a sleep disorder, usually characterized by sudden pauses of breathing during sleep and an interrupted sleep rhythm. Although the pathological mechanism remains poorly understood, it has been strongly associated with metabolic diseases, including obesity, insulin resistance, type 2 diabetes mellitus (T2DM), and nonalcoholic fatty liver disease (NAFLD). In the present mini-review, we briefly summarize the connections between OSAS, obesity, T2DM, and NAFLD, which might help us to better understand the pathogenesis of human diseases.
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Affiliation(s)
- Min Li
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Xiaoying Li
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Yan Lu
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
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Kaempferol mitigates Endoplasmic Reticulum Stress Induced Cell Death by targeting caspase 3/7. Sci Rep 2018; 8:2189. [PMID: 29391535 PMCID: PMC5794799 DOI: 10.1038/s41598-018-20499-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 01/17/2018] [Indexed: 12/12/2022] Open
Abstract
The Endoplasmic Reticulum (ER) plays a fundamental role in executing multiple cellular processes required for normal cellular function. Accumulation of misfolded/unfolded proteins in the ER triggers ER stress which contributes to progression of multiple diseases including neurodegenerative disorders. Recent reports have shown that ER stress inhibition could provide positive response against neuronal injury, ischemia and obesity in in vivo models. Our search towards finding an ER stress inhibitor has led to the functional discovery of kaempferol, a phytoestrogen possessing ER stress inhibitory activity in cultured mammalian cells. We have shown that kaempferol pre-incubation significantly inhibits the expression of GRP78 (a chaperone) and CHOP (ER stress associated pro-apoptotic transcription factor) under stressed condition. Also, our investigation in the inhibitory specificity of kaempferol has revealed that it inhibits cell death induced by diverse stimuli. Further study on exploring the molecular mechanism implied that kaempferol renders protection by targeting caspases. Both the in silico docking and in vitro assay using recombinant caspase-3 enzyme confirmed the binding of kaempferol to caspases, through an allosteric mode of competitive inhibition. Altogether, we have demonstrated the ability of kaempferol to alleviate ER stress in in vitro model.
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Rescue of Glaucomatous Neurodegeneration by Differentially Modulating Neuronal Endoplasmic Reticulum Stress Molecules. J Neurosci 2017; 36:5891-903. [PMID: 27225776 DOI: 10.1523/jneurosci.3709-15.2016] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 04/26/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Axon injury is an early event in neurodegenerative diseases that often leads to retrograde neuronal cell death and progressive permanent loss of vital neuronal functions. The connection of these two obviously sequential degenerative events, however, is elusive. Deciphering the upstream signals that trigger the neurodegeneration cascades in both neuronal soma and axon would be a key step toward developing the effective neuroprotectants that are greatly needed in the clinic. We showed previously that optic nerve injury-induced neuronal endoplasmic reticulum (ER) stress plays an important role in retinal ganglion cell (RGC) death. Using two in vivo mouse models of optic neuropathies (traumatic optic nerve injury and glaucoma) and adeno-associated virus-mediated RGC-specific gene targeting, we now show that differential manipulation of unfolded protein response pathways in opposite directions-inhibition of eukaryotic translation initiation factor 2α-C/EBP homologous protein and activation of X-box binding protein 1-promotes both RGC axons and somata survival and preserves visual function. Our results indicate that axon injury-induced neuronal ER stress plays an important role in both axon degeneration and neuron soma death. Neuronal ER stress is therefore a promising therapeutic target for glaucoma and potentially other types of neurodegeneration. SIGNIFICANCE STATEMENT Neuron soma and axon degeneration have distinct molecular mechanisms although they are clearly connected after axon injury. We previously demonstrated that axon injury induces neuronal endoplasmic reticulum (ER) stress and that manipulation of ER stress molecules synergistically promotes neuron cell body survival. Here we investigated the possibility that ER stress also plays a role in axon degeneration and whether ER stress modulation preserves neuronal function in neurodegenerative diseases. Our results suggest that neuronal ER stress is a general mechanism of degeneration for both neuronal cell body and axon, and that therapeutic targeting of ER stress produces significant functional recovery.
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Integrated Stress Response as a Therapeutic Target for CNS Injuries. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6953156. [PMID: 28536699 PMCID: PMC5425910 DOI: 10.1155/2017/6953156] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 02/24/2017] [Accepted: 04/05/2017] [Indexed: 11/25/2022]
Abstract
Central nervous system (CNS) injuries, caused by cerebrovascular pathologies or mechanical contusions (e.g., traumatic brain injury, TBI) comprise a diverse group of disorders that share the activation of the integrated stress response (ISR). This pathway is an innate protective mechanism, with encouraging potential as therapeutic target for CNS injury repair. In this review, we will focus on the progress in understanding the role of the ISR and we will discuss the effects of various small molecules that target the ISR on different animal models of CNS injury.
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Tempaku PF, Tufik S, Hirotsu C. Commentary: Stress Signal Network between Hypoxia and ER Stress in Chronic Kidney Disease. Front Physiol 2017; 8:243. [PMID: 28487661 PMCID: PMC5403942 DOI: 10.3389/fphys.2017.00243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 04/05/2017] [Indexed: 11/17/2022] Open
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Trzepizur W, Khalyfa A, Qiao Z, Popko B, Gozal D. Integrated stress response activation by sleep fragmentation during late gestation in mice leads to emergence of adverse metabolic phenotype in offspring. Metabolism 2017; 69:188-198. [PMID: 28139216 DOI: 10.1016/j.metabol.2017.01.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 12/16/2016] [Accepted: 01/16/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Late gestational sleep fragmentation (SF) is highly prevalent particularly in obese women, and induces metabolic dysfunction in adult offspring mice. SF induces activation of the integrated stress response (ISR), which might be involved in metabolic disorders. We hypothesized that adult offspring of double mutant mice (DM) involving the critical ISR genes CHOP and GADD34 would be protected from developing obesity and insulin resistance following SF. METHODS Time-pregnant CHOP/GADD34 DM and wild type (WT) mice were randomly assigned to sleep control (SC) or SF conditions during the last 5days of gestation. At 24-weeks of age, body weight, fat mass, and HOMA-IR were assessed in the offspring. Tregs lymphocytes, Lyc6chigh, M1 and M2 macrophages were examined in visceral white adipose tissues (vWAT) using flow cytometry. The effects of plasma exosomes on adipocyte cell line proliferation, differentiation and insulin sensitivity were also evaluated. RESULTS SF-WT male showed significant increases in body weight, vWAT mass and HOMA-IR compared to SC-WT mice, while SF had no effect in SF-DM mice. Inflammatory macrophages (Ly-6chigh) and the ratio of M1/M2 macrophages were increased while FoxP3+ Tregs counts were decreased in SF-WT but not in SF-DM mice. Exosomes from SF-WT, but not from the SF-DM offspring increased pre-adipocyte proliferation and differentiation, and decreased in vitro adipocyte insulin sensitivity. CONCLUSION Activation of the ISR during late gestation, as induced by late gestational SF, appears to underlie some of the transgenerational modifications in metabolic genes ultimately contributing to a metabolic syndrome phenotype in adult offspring.
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Affiliation(s)
- Wojciech Trzepizur
- Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Abdelnaby Khalyfa
- Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Zhuanhong Qiao
- Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Brian Popko
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, IL 60637, United States
| | - David Gozal
- Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA.
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Kobylewski SE, Henderson KA, Yamada KE, Eckhert CD. Activation of the EIF2α/ATF4 and ATF6 Pathways in DU-145 Cells by Boric Acid at the Concentration Reported in Men at the US Mean Boron Intake. Biol Trace Elem Res 2017; 176:278-293. [PMID: 27587023 PMCID: PMC5344959 DOI: 10.1007/s12011-016-0824-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 08/15/2016] [Indexed: 02/06/2023]
Abstract
Fruits, nuts, legumes, and vegetables are rich sources of boron (B), an essential plant nutrient with chemopreventive properties. Blood boric acid (BA) levels reflect recent B intake, and men at the US mean intake have a reported non-fasting level of 10 μM. Treatment of DU-145 prostate cancer cells with physiological concentrations of BA inhibits cell proliferation without causing apoptosis and activates eukaryotic initiation factor 2 (eIF2α). EIF2α induces cell differentiation and protects cells by redirecting gene expression to manage endoplasmic reticulum stress. Our objective was to determine the temporal expression of endoplasmic reticulum (ER) stress-activated genes in DU-145 prostate cells treated with 10 μM BA. Immunoblots showed post-treatment increases in eIF2α protein at 30 min and ATF4 and ATF6 proteins at 1 h and 30 min, respectively. The increase in ATF4 was accompanied by an increase in the expression of its downstream genes growth arrest and DNA damage-induced protein 34 (GADD34) and homocysteine-induced ER protein (Herp), but a decrease in GADD153/CCAAT/enhancer-binding protein homologous protein (CHOP), a pro-apoptotic gene. The increase in ATF6 was accompanied by an increase in expression of its downstream genes GRP78/BiP, calreticulin, Grp94, and EDEM. BA did not activate IRE1 or induce cleavage of XBP1 mRNA, a target of IRE1. Low boron status has been associated with increased cancer risk, low bone mineralization, and retinal degeneration. ATF4 and BiP/GRP78 function in osteogenesis and bone remodeling, calreticulin is required for tumor suppressor p53 function and mineralization of teeth, and BiP/GRP78 and EDEM prevent the aggregation of misfolded opsins which leads to retinal degeneration. The identification of BA-activated genes that regulate its phenotypic effects provides a molecular underpinning for boron nutrition and biology.
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Affiliation(s)
- Sarah E Kobylewski
- Interdepartmental Program in Molecular Toxicology, University of California, Los Angeles, CA, USA
| | - Kimberly A Henderson
- Interdepartmental Program in Molecular Toxicology, University of California, Los Angeles, CA, USA
| | - Kristin E Yamada
- Interdepartmental Program in Molecular Toxicology, University of California, Los Angeles, CA, USA
| | - Curtis D Eckhert
- Interdepartmental Program in Molecular Toxicology, University of California, Los Angeles, CA, USA.
- Department of Environmental Health Sciences, University of California, Fielding School of Public Health, 650 Charles E. Young Dr., Los Angeles, CA, 90095, USA.
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Barreda-Manso MA, Yanguas-Casás N, Nieto-Sampedro M, Romero-Ramírez L. Neuroprotection and Blood-Brain Barrier Restoration by Salubrinal After a Cortical Stab Injury. J Cell Physiol 2016; 232:1501-1510. [PMID: 27753092 DOI: 10.1002/jcp.25655] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/17/2016] [Indexed: 01/02/2023]
Abstract
Following a central nervous system (CNS) injury, restoration of the blood-brain barrier (BBB) integrity is essential for recovering homeostasis. When this process is delayed or impeded, blood substances and cells enter the CNS parenchyma, initiating an additional inflammatory process that extends the initial injury and causes so-called secondary neuronal loss. Astrocytes and profibrotic mesenchymal cells react to the injury and migrate to the lesion site, creating a new glia limitans that restores the BBB. This process is beneficial for the resolution of the inflammation, neuronal survival, and the initiation of the healing process. Salubrinal is a small molecule with neuroprotective properties in different animal models of stroke and trauma to the CNS. Here, we show that salubrinal increased neuronal survival in the neighbourhood of a cerebral cortex stab injury. Moreover, salubrinal reduced cortical blood leakage into the parenchyma of injured animals compared with injured controls. Adjacent to the site of injury, salubrinal induced immunoreactivity for platelet-derived growth factor subunit B (PDGF-B), a specific mitogenic factor for mesenchymal cells. This effect might be responsible for the increased immunoreactivity for fibronectin and the decreased activation of microglia and macrophages in injured mice treated with salubrinal, compared with injured controls. The immunoreactivity for PDGF-B colocalized with neuronal nuclei (NeuN), suggesting that cortical neurons in the proximity of the injury were the main source of PDGF-B. Our results suggest that after an injury, neurons play an important role in both, the healing process and the restoration of the BBB integrity. J. Cell. Physiol. 232: 1501-1510, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- M Asunción Barreda-Manso
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain.,Unidad de Neurología Experimental, Hospital Nacional de Parapléjicos (SESCAM), Madrid, Spain
| | - Natalia Yanguas-Casás
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain
| | - Manuel Nieto-Sampedro
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain.,Unidad de Neurología Experimental, Hospital Nacional de Parapléjicos (SESCAM), Madrid, Spain
| | - Lorenzo Romero-Ramírez
- Unidad de Neurología Experimental, Hospital Nacional de Parapléjicos (SESCAM), Madrid, Spain
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Romero-Ramírez L, Nieto-Sampedro M, Barreda-Manso MA. All roads go to Salubrinal: endoplasmic reticulum stress, neuroprotection and glial scar formation. Neural Regen Res 2016; 10:1926-7. [PMID: 26889171 PMCID: PMC4730807 DOI: 10.4103/1673-5374.169619] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
| | - Manuel Nieto-Sampedro
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain; Instituto Cajal, CSIC, Avda. Doctor Arce 37, 28002 Madrid, Spain
| | - M Asunción Barreda-Manso
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain; Instituto Cajal, CSIC, Avda. Doctor Arce 37, 28002 Madrid, Spain
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Belaidi E, Thomas A, Bourdier G, Moulin S, Lemarié E, Levy P, Pépin JL, Korichneva I, Godin-Ribuot D, Arnaud C. Endoplasmic reticulum stress as a novel inducer of hypoxia inducible factor-1 activity: its role in the susceptibility to myocardial ischemia-reperfusion induced by chronic intermittent hypoxia. Int J Cardiol 2016; 210:45-53. [PMID: 26922713 DOI: 10.1016/j.ijcard.2016.02.096] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 02/09/2016] [Accepted: 02/14/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Obstructive sleep apnea (OSA) is a highly prevalent disease and a risk factor for myocardial infarction expansion in humans. Intermittent hypoxia (IH) is known to be the most important OSA feature in terms of cardiovascular morbi-mortality. Since ER stress and HIF-1 are known to be involved in cardiomyocyte life or death, this study investigates the role of ER stress on HIF-1 activation in myocardial susceptibility to ischemia-reperfusion (I/R) induced by IH. METHODS C57Bl6J, HIF-1α(+/-) and their respective control mice were exposed to 14 days of IH (21-5% FiO2, 60 scycle, 8h/day). Myocardial inter-organelle calcium exchanges, ER stress and HIF-1 activity were investigated and in vivo I/R was performed to measure infarct size. In additional groups, tauroursodeoxycholic acid (TUDCA, 75 mg·kg(-1)), an ER stress inhibitor, was administered daily during exposure. RESULTS In C57Bl6J mice, chronic IH induced an increase in ER-Ca(2+) content, ER stress markers and HIF-1 activity, associated with an enhanced infarct size (33.7 ± 9.4 vs. 61.0 ± 5.6% in N and IH, respectively, p<0.05). IH failed to increase infarct size in HIF-1α deficient mice (42.4 ± 2.7 and 24.7 ± 3.4% N and IH, respectively). Finally, TUDCA totally abolished the IH-induced increase in HIF-1 activity (1.3 ± 0.04 vs. 0.14 ± 0.02 fold increase in IH vs. IH-TUDCA respectively, p<0.0001) and in infarct size (55.5 ± 7.6 vs. 49.9 ± 3.0 in N-TUDCA and IH-TUDCA, respectively). CONCLUSION This novel regulatory mechanism of HIF-1 activity by ER stress should be considered as a potential diagnostic tool for cardiovascular complications in OSA patients as well as a therapeutic target to limit myocardial ischemic damage.
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Affiliation(s)
- Elise Belaidi
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France.
| | - Amandine Thomas
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
| | - Guillaume Bourdier
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
| | - Sophie Moulin
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
| | - Emeline Lemarié
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
| | - Patrick Levy
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
| | - Jean-Louis Pépin
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
| | - Irina Korichneva
- Université Picardie, Laboratoire de biologie cellulaire moléculaire, Amiens 80000, France
| | - Diane Godin-Ribuot
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
| | - Claire Arnaud
- Université Grenoble Alpes, Laboratoire HP2, Grenoble F-38042, France; INSERM, U1042, Grenoble F-38042, France
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Bourdier G, Flore P, Sanchez H, Pepin JL, Belaidi E, Arnaud C. High-intensity training reduces intermittent hypoxia-induced ER stress and myocardial infarct size. Am J Physiol Heart Circ Physiol 2015; 310:H279-89. [PMID: 26566725 DOI: 10.1152/ajpheart.00448.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 11/09/2015] [Indexed: 12/25/2022]
Abstract
Chronic intermittent hypoxia (IH) is described as the major detrimental factor leading to cardiovascular morbimortality in obstructive sleep apnea (OSA) patients. OSA patients exhibit increased infarct size after a myocardial event, and previous animal studies have shown that chronic IH could be the main mechanism. Endoplasmic reticulum (ER) stress plays a major role in the pathophysiology of cardiovascular disease. High-intensity training (HIT) exerts beneficial effects on the cardiovascular system. Thus, we hypothesized that HIT could prevent IH-induced ER stress and the increase in infarct size. Male Wistar rats were exposed to 21 days of IH (21-5% fraction of inspired O2, 60-s cycle, 8 h/day) or normoxia. After 1 wk of IH alone, rats were submitted daily to both IH and HIT (2 × 24 min, 15-30m/min). Rat hearts were either rapidly frozen to evaluate ER stress by Western blot analysis or submitted to an ischemia-reperfusion protocol ex vivo (30 min of global ischemia/120 min of reperfusion). IH induced cardiac proapoptotic ER stress, characterized by increased expression of glucose-regulated protein kinase 78, phosphorylated protein kinase-like ER kinase, activating transcription factor 4, and C/EBP homologous protein. IH-induced myocardial apoptosis was confirmed by increased expression of cleaved caspase-3. These IH-associated proapoptotic alterations were associated with a significant increase in infarct size (35.4 ± 3.2% vs. 22.7 ± 1.7% of ventricles in IH + sedenary and normoxia + sedentary groups, respectively, P < 0.05). HIT prevented both the IH-induced proapoptotic ER stress and increased myocardial infarct size (28.8 ± 3.9% and 21.0 ± 5.1% in IH + HIT and normoxia + HIT groups, respectively, P = 0.28). In conclusion, these findings suggest that HIT could represent a preventive strategy to limit IH-induced myocardial ischemia-reperfusion damages in OSA patients.
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Affiliation(s)
- Guillaume Bourdier
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France; Institut National de la Santé et de la Recherche Médicale, U1042, Grenoble, France; and
| | - Patrice Flore
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France; Institut National de la Santé et de la Recherche Médicale, U1042, Grenoble, France; and
| | - Hervé Sanchez
- Institut de Recherche Biomédicale des Armées, Operational Environments, Brétigny/Orge, France
| | - Jean-Louis Pepin
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France; Institut National de la Santé et de la Recherche Médicale, U1042, Grenoble, France; and
| | - Elise Belaidi
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France; Institut National de la Santé et de la Recherche Médicale, U1042, Grenoble, France; and
| | - Claire Arnaud
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France; Institut National de la Santé et de la Recherche Médicale, U1042, Grenoble, France; and
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Xu LH, Xie H, Shi ZH, Du LD, Wing YK, Li AM, Ke Y, Yung WH. Critical Role of Endoplasmic Reticulum Stress in Chronic Intermittent Hypoxia-Induced Deficits in Synaptic Plasticity and Long-Term Memory. Antioxid Redox Signal 2015; 23:695-710. [PMID: 25843188 PMCID: PMC4580307 DOI: 10.1089/ars.2014.6122] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIMS This study examined the role of endoplasmic reticulum (ER) stress in mediating chronic intermittent hypoxia (IH)-induced neurocognitive deficits. We designed experiments to demonstrate that ER stress is initiated in the hippocampus under chronic IH and determined its role in apoptotic cell death, impaired synaptic structure and plasticity, and memory deficits. RESULTS Two weeks of IH disrupted ER fine structure and upregulated ER stress markers, glucose-regulated protein 78, caspase-12, and C/EBP homologous protein, in the hippocampus, which could be suppressed by ER stress inhibitors, tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid. Meanwhile, ER stress induced apoptosis via decreased Bcl-2, promoted reactive oxygen species production, and increased malondialdehyde formation and protein carbonyl, as well as suppressed mitochondrial function. These effects were largely prevented by ER stress inhibitors. On the other hand, suppression of oxidative stress could reduce ER stress. In addition, the length of the synaptic active zone and number of mature spines were reduced by IH. Long-term recognition memory and spatial memory were also impaired, which was accompanied by reduced long-term potentiation in the Schaffer collateral pathway. These effects were prevented by coadministration of the TUDCA. INNOVATION AND CONCLUSION These results show that ER stress plays a critical role in underlying memory deficits in obstructive sleep apnea (OSA)-associated IH. Attenuators of ER stress may serve as novel adjunct therapeutic agents for ameliorating OSA-induced neurocognitive impairment.
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Affiliation(s)
- Lin-Hao Xu
- 1 Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong , Shatin, Hong Kong, China
| | - Hui Xie
- 1 Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong , Shatin, Hong Kong, China
| | - Zhi-Hui Shi
- 1 Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong , Shatin, Hong Kong, China
| | - Li-Da Du
- 1 Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong , Shatin, Hong Kong, China
| | - Yun-Kwok Wing
- 2 Department of Psychiatry, Prince of Wales Hospital , Shatin, Hong Kong, China
| | - Albert M Li
- 3 Department of Pediatrics, Prince of Wales Hospital , Shatin, Hong Kong, China
| | - Ya Ke
- 1 Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong , Shatin, Hong Kong, China
| | - Wing-Ho Yung
- 1 Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong , Shatin, Hong Kong, China
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Strategies to optimize kidney recovery and preservation in transplantation: specific aspects in pediatric transplantation. Pediatr Nephrol 2015; 30:1243-54. [PMID: 25185880 DOI: 10.1007/s00467-014-2924-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 07/09/2014] [Accepted: 07/21/2014] [Indexed: 01/08/2023]
Abstract
In renal transplantation, live donor kidney grafts are associated with optimum success rates due to the shorter period of ischemia during the surgical procedure. The current shortage of donor organs for adult patients has caused a shift towards deceased donors, often with co-morbidity factors, whose organs are more sensitive to ischemia-reperfusion injury, which is unavoidable during transplantation. Donor management is pivotal to kidney graft survival through the control of the ischemia-reperfusion sequence, which is known to stimulate numerous deleterious or regenerative pathways. Although the key role of endothelial cells has been established, the complexity of the injury, associated with stimulation of different cell signaling pathways, such as unfolded protein response and cell death, prevents the definition of a unique therapeutic target. Preclinical transplant models in large animals are necessary to establish relationships and kinetics and have already contributed to the improvement of organ preservation. Therapeutic strategies using mesenchymal stem cells to induce allograft tolerance are promising advances in the treatment of the pediatric recipient in terms of reducing/withdrawing immunosuppressive therapy. In this review we focus on the different donor management strategies in kidney graft conditioning and on graft preservation consequences by highlighting the role of endothelial cells. We also propose strategies for preventing ischemia-reperfusion, such as cell therapy.
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Li RJ, He KL, Li X, Wang LL, Liu CL, He YY. Salubrinal protects cardiomyocytes against apoptosis in a rat myocardial infarction model via suppressing the dephosphorylation of eukaryotic translation initiation factor 2α. Mol Med Rep 2015; 12:1043-9. [PMID: 25816071 PMCID: PMC4438964 DOI: 10.3892/mmr.2015.3508] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 02/19/2015] [Indexed: 01/04/2023] Open
Abstract
The aim of the present study was to examine the role of eIF2α in cardiomyocyte apoptosis and evaluate the cardioprotective role of salubrinal in a rat myocardial infarction (MI) model. Rat left anterior descending coronary arteries were ligated and the classical proteins involved in the endoplasmic reticulum stress (ERS)-induced apoptotic pathway were analyzed using quantitative polymerase chain reaction and western blot analysis. Salubrinal was administered to the rats and cardiomyocyte apoptosis and infarct size were evaluated by a specific staining method. Compared with the sham surgery group, the rate of cardiomyocyte apoptosis in the MI group was increased with the development of the disease. It was also demonstrated that the mRNA and protein levels of GRP78, caspase-12, CHOP and the protein expression of p-eIF2α were increased in the MI group. Furthermore, the results showed that treatment with salubrinal can decrease cardiomyocyte apoptosis and infarct size by increasing eIF2α phosphorylation and decreasing the expression of caspase-12 and CHOP. The present study suggests that salubrinal protects against ER stress-induced rat cadiomyocyte apoptosis via suppressing the dephosphorylation of eIF2α in the ERS-associated pathway.
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Affiliation(s)
- Rui-Jun Li
- Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Kun-Lun He
- Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Xin Li
- Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Li-Li Wang
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P.R. China
| | - Chun-Lei Liu
- Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Yun-Yun He
- Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
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Lam CS, Tipoe GL, So KF, Fung ML. Neuroprotective mechanism of Lycium barbarum polysaccharides against hippocampal-dependent spatial memory deficits in a rat model of obstructive sleep apnea. PLoS One 2015; 10:e0117990. [PMID: 25714473 PMCID: PMC4340928 DOI: 10.1371/journal.pone.0117990] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 01/03/2015] [Indexed: 01/01/2023] Open
Abstract
Chronic intermittent hypoxia (CIH) is a hallmark of obstructive sleep apnea (OSA), which induces hippocampal injuries mediated by oxidative stress. This study aims to examine the neuroprotective mechanism of Lycium barbarum polysaccharides (LBP) against CIH-induced spatial memory deficits. Adult Sprague–Dawley rats were exposed to hypoxic treatment resembling a severe OSA condition for a week. The animals were orally fed with LBP solution (1mg/kg) daily 2 hours prior to hypoxia or in air for the control. The effect of LBP on the spatial memory and levels of oxidative stress, inflammation, endoplasmic reticulum (ER) stress, apoptosis and neurogenesis in the hippocampus was examined. There was a significant deficit in the spatial memory and an elevated level of malondialdehyde with a decreased expression of antioxidant enzymes (SOD, GPx-1) in the hypoxic group when compared with the normoxic control. In addition, redox-sensitive nuclear factor kappa B (NFКB) canonical pathway was activated with a translocation of NFКB members (p65, p50) and increased expression levels of NFКB-dependent inflammatory cytokines and mediator (TNFα, IL-1β, COX-2); also, a significantly elevated level of ER stress (GRP78/Bip, PERK, CHOP) and autophagic flux in the hypoxic group, leading to neuronal apoptosis in hippocampal subfields (DG, CA1, CA3). Remarkably, LBP administration normalized the elevated level of oxidative stress, neuroinflammation, ER stress, autophagic flux and apoptosis induced by hypoxia. Moreover, LBP significantly mitigated both the caspase-dependent intrinsic (Bax, Bcl2, cytochrome C, cleaved caspase-3) and extrinsic (FADD, cleaved caspase-8, Bid) signaling apoptotic cascades. Furthermore, LBP administration prevented the spatial memory deficit and enhanced the hippocampal neurogenesis induced by hypoxia. Our results suggest that LBP is neuroprotective against CIH-induced hippocampal-dependent spatial memory deficits by promoting hippocampal neurogenesis and negatively modulating the apoptotic signaling cascades activated by oxidative stress and inflammation.
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Affiliation(s)
- Chun-Sing Lam
- Department of Physiology, University of Hong Kong, Hong Kong, PR China
| | - George Lim Tipoe
- Department of Anatomy, University of Hong Kong, Hong Kong, PR China
- Research Centre of Heart, Brain, Hormone & Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, PR China
| | - Kwok-Fai So
- Department of Anatomy, University of Hong Kong, Hong Kong, PR China
- Department of Ophthalmology, University of Hong Kong, Hong Kong, PR China
- Research Centre of Heart, Brain, Hormone & Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, PR China
- State Key Laboratory of Brain and Cognitive Science, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, PR China
- Guangdong-HongKong-Macau Institute of CNS Regeneration, Jinan University, Guangdong, PR China
- Guangdong Key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou 510632, China
| | - Man-Lung Fung
- Department of Physiology, University of Hong Kong, Hong Kong, PR China
- Research Centre of Heart, Brain, Hormone & Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, PR China
- * E-mail:
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Rubovitch V, Barak S, Rachmany L, Goldstein RB, Zilberstein Y, Pick CG. The Neuroprotective Effect of Salubrinal in a Mouse Model of Traumatic Brain Injury. Neuromolecular Med 2015; 17:58-70. [DOI: 10.1007/s12017-015-8340-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 01/06/2015] [Indexed: 12/15/2022]
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Effects of PP1-12, a Novel Protein Phosphatase-1 Inhibitor, on Ventricular Function and Remodeling After Myocardial Infarction in Rats. J Cardiovasc Pharmacol 2014; 64:360-7. [DOI: 10.1097/fjc.0000000000000128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Chaudhari N, Talwar P, Parimisetty A, Lefebvre d'Hellencourt C, Ravanan P. A molecular web: endoplasmic reticulum stress, inflammation, and oxidative stress. Front Cell Neurosci 2014; 8:213. [PMID: 25120434 PMCID: PMC4114208 DOI: 10.3389/fncel.2014.00213] [Citation(s) in RCA: 424] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 07/15/2014] [Indexed: 12/13/2022] Open
Abstract
Execution of fundamental cellular functions demands regulated protein folding homeostasis. Endoplasmic reticulum (ER) is an active organelle existing to implement this function by folding and modifying secretory and membrane proteins. Loss of protein folding homeostasis is central to various diseases and budding evidences suggest ER stress as being a major contributor in the development or pathology of a diseased state besides other cellular stresses. The trigger for diseases may be diverse but, inflammation and/or ER stress may be basic mechanisms increasing the severity or complicating the condition of the disease. Chronic ER stress and activation of the unfolded-protein response (UPR) through endogenous or exogenous insults may result in impaired calcium and redox homeostasis, oxidative stress via protein overload thereby also influencing vital mitochondrial functions. Calcium released from the ER augments the production of mitochondrial Reactive Oxygen Species (ROS). Toxic accumulation of ROS within ER and mitochondria disturbs fundamental organelle functions. Sustained ER stress is known to potentially elicit inflammatory responses via UPR pathways. Additionally, ROS generated through inflammation or mitochondrial dysfunction could accelerate ER malfunction. Dysfunctional UPR pathways have been associated with a wide range of diseases including several neurodegenerative diseases, stroke, metabolic disorders, cancer, inflammatory disease, diabetes mellitus, cardiovascular disease, and others. In this review, we have discussed the UPR signaling pathways, and networking between ER stress-induced inflammatory pathways, oxidative stress, and mitochondrial signaling events, which further induce or exacerbate ER stress.
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Affiliation(s)
- Namrata Chaudhari
- Apoptosis and Cell Death Research Lab, School of Biosciences and Technology, Vellore Institute of Technology University , Vellore , India
| | - Priti Talwar
- Apoptosis and Cell Death Research Lab, School of Biosciences and Technology, Vellore Institute of Technology University , Vellore , India
| | - Avinash Parimisetty
- Groupe d'Etude sur l'Inflammation Chronique et l'Obésité, EA 41516, Plateforme CYROI, Université de La Réunion , Saint Denis de La Réunion , France
| | - Christian Lefebvre d'Hellencourt
- Groupe d'Etude sur l'Inflammation Chronique et l'Obésité, EA 41516, Plateforme CYROI, Université de La Réunion , Saint Denis de La Réunion , France
| | - Palaniyandi Ravanan
- Apoptosis and Cell Death Research Lab, School of Biosciences and Technology, Vellore Institute of Technology University , Vellore , India
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Endoplasmic reticulum stress plays critical role in brain damage after chronic intermittent hypoxia in growing rats. Exp Neurol 2014; 257:148-56. [PMID: 24810321 DOI: 10.1016/j.expneurol.2014.04.029] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 04/17/2014] [Accepted: 04/28/2014] [Indexed: 01/08/2023]
Abstract
Obstructive sleep apnea hypopnea syndrome (OSAHS) in children is associated with multiple system morbidities. Cognitive dysfunction as a result of central nervous system complication has been reported in children with OSAHS. However, the underlying mechanisms are poorly understood. Endoplasmic reticulum stress (ERS)-related apoptosis plays an important role in various diseases of the central nervous system, but very little is known about the role of ERS in mediating pathophysiological reactions to cognitive dysfunction in OSAHS. Chronic intermittent hypoxia (CIH) exposures, modeling OSAHS, across 2 and 4weeks in growing rats made more reference memory errors, working memory errors and total memory errors in the 8-Arm radial maze task, increased significantly TUNEL positive cells, upregulated the unfolded protein response in the hippocampus and prefrontal cortex as evidenced by increased phosphorylation of PKR-like endoplasmic reticulum kinase, inositol-requiring enzyme l and some downstream products. A selective inhibitor of eukaryotic initiation factor-2a dephosphorylation, salubrinal, prevented C/EBP-homologous protein activation in the hippocampus and prefrontal cortex throughout hypoxia/reoxygenation exposure. Our findings suggest that ERS mediated cell apoptosis may be one of the underlying mechanisms of cognitive dysfunction in OSAHS children. Further, a specific ERS inhibitor Salubrinal should be tested for neuroprotection against CIH-induced injury.
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Docosahexaenoic acid reduces ER stress and abnormal protein accumulation and improves neuronal function following traumatic brain injury. J Neurosci 2014; 34:3743-55. [PMID: 24599472 DOI: 10.1523/jneurosci.2872-13.2014] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In this study, we investigated the development of endoplasmic reticulum (ER) stress after traumatic brain injury (TBI) and the efficacy of post-TBI administration of docosahexaenoic acid (DHA) in reducing ER stress. TBI was induced by cortical contusion injury in Sprague-Dawley rats. Either DHA (16 mg/kg in DMSO) or vehicle DMSO (1 ml/kg) was administered intraperitoneally at 5 min after TBI, followed by a daily dose for 3-21 d. TBI triggered sustained expression of the ER stress marker proteins including phosphorylated eukaryotic initiation factor-2α, activating transcription factor 4, inositol requiring kinase 1, and C/EBP homologous protein in the ipsilateral cortex at 3-21 d after TBI. The prolonged ER stress was accompanied with an accumulation of abnormal ubiquitin aggregates and increased expression of amyloid precursor protein (APP) and phosphorylated tau (p-Tau) in the frontal cortex after TBI. The ER stress marker proteins were colocalized with APP accumulation in the soma. Interestingly, administration of DHA attenuated all ER stress marker proteins and reduced the accumulation of both ubiquitinated proteins and APP/p-Tau proteins. In addition, the DHA-treated animals exhibited early recovery of their sensorimotor function after TBI. In summary, our study demonstrated that TBI induces a prolonged ER stress, which is positively correlated with abnormal APP accumulation. The sustained ER stress may play a role in chronic neuronal damage after TBI. Our findings illustrate that post-TBI administration of DHA has therapeutic potentials in reducing ER stress, abnormal protein accumulation, and neurological deficits.
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Li S, Yang L, Selzer ME, Hu Y. Neuronal endoplasmic reticulum stress in axon injury and neurodegeneration. Ann Neurol 2013; 74:768-77. [PMID: 23955583 PMCID: PMC3963272 DOI: 10.1002/ana.24005] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 08/04/2013] [Accepted: 08/07/2013] [Indexed: 12/13/2022]
Abstract
Injuries to central nervous system axons result not only in Wallerian degeneration of the axon distal to the injury, but also in death or atrophy of the axotomized neurons, depending on injury location and neuron type. No method of permanently avoiding these changes has been found, despite extensive knowledge concerning mechanisms of secondary neuronal injury. The autonomous endoplasmic reticulum (ER) stress pathway in neurons has recently been implicated in retrograde neuronal degeneration. In addition to the emerging role of ER morphology in axon maintenance, we propose that ER stress is a common neuronal response to disturbances in axon integrity and a general mechanism for neurodegeneration. Thus, manipulation of the ER stress pathway could have important therapeutic implications for neuroprotection.
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Affiliation(s)
- Shaohua Li
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Liu Yang
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
| | - Michael E. Selzer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
- Department of Neurology, Temple University School of Medicine, Philadelphia, PA, USA
| | - Yang Hu
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
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Lupachyk S, Watcho P, Obrosov AA, Stavniichuk R, Obrosova IG. Endoplasmic reticulum stress contributes to prediabetic peripheral neuropathy. Exp Neurol 2013; 247:342-8. [DOI: 10.1016/j.expneurol.2012.11.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 10/29/2012] [Accepted: 11/02/2012] [Indexed: 01/06/2023]
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Chou YT, Zhan G, Zhu Y, Fenik P, Panossian L, Li Y, Zhang J, Veasey S. C/EBP homologous binding protein (CHOP) underlies neural injury in sleep apnea model. Sleep 2013; 36:481-92. [PMID: 23564995 DOI: 10.5665/sleep.2528] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Obstructive sleep apnea (OSA) is associated with cognitive impairment and neuronal injury. Long-term exposure to intermittent hypoxia (LTIH) in rodents, modeling the oxygenation patterns in sleep apnea, results in NADPH oxidase 2 (Nox2) oxidative injury to many neuronal populations. Brainstem motoneurons susceptible to LTIH injury show uncompensated endoplasmic reticulum stress responses with increased (CCAAT/enhancer binding protein homologous protein (CHOP). We hypothesized that CHOP underlies LTIH oxidative injury. In this series of studies, we first determined whether CHOP is upregulated in other brain regions susceptible to LTIH oxidative Nox2 injury and then determined whether CHOP plays an adaptive or injurious role in the LTIH response. To integrate these findings with previous studies examining LTIH neural injury, we examined the role of CHOP in Nox2, hypoxia-inducible factor-1α (HIF-1α) responses, oxidative injury and apoptosis, and neuron loss. DESIGN Within/between mice subjects. SETTING Laboratory setting. PARTICIPANTSSUBJECTS: CHOP null and wild-type adult male mice. INTERVENTIONS LTIH or sham LTIH. MEASUREMENTS AND MAIN RESULTS Relative to wild-type mice, CHOP-/- mice conferred resistance to oxidative stress (superoxide production/ carbonyl proteins) in brain regions examined: cortex, hippocampus, and motor nuclei. CHOP deletion prevented LTIH upregulation of Nox2 and HIF-1α in the hippocampus, cortex, and brainstem motoneurons and protected mice from neuronal apoptosis and motoneuron loss. CONCLUSIONS Endogenous CHOP is necessary for LTIH-induced HIF-1α, Nox2 upregulation, and oxidative stress; CHOP influences LTIH-induced apoptosis in neurons and loss of neurons. Findings support the concept that minimizing CHOP may provide neuroprotection in OSA.
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Affiliation(s)
- Yu-Ting Chou
- Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan
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Torres-Peraza JF, Engel T, Martín-Ibáñez R, Sanz-Rodríguez A, Fernández-Fernández MR, Esgleas M, Canals JM, Henshall DC, Lucas JJ. Protective neuronal induction of ATF5 in endoplasmic reticulum stress induced by status epilepticus. Brain 2013; 136:1161-76. [DOI: 10.1093/brain/awt044] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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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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31
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Zhang J, Veasey S. Making sense of oxidative stress in obstructive sleep apnea: mediator or distracter? Front Neurol 2012; 3:179. [PMID: 23293626 PMCID: PMC3530694 DOI: 10.3389/fneur.2012.00179] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/03/2012] [Indexed: 01/01/2023] Open
Abstract
Obstructive sleep apnea is increasingly recognized as an important contributor to cognitive impairment, metabolic derangements, and cardiovascular disease and mortality. Identifying the mechanisms by which this prevalent disorder influences health outcomes is now of utmost importance. As the prevalence of this disorder steadily increases, therapies are needed to prevent or reverse sleep apnea morbidities now more than ever before. Oxidative stress is implicated in cardiovascular morbidities of sleep apnea. What role oxidative stress plays in neural injury and cognitive impairments has been difficult to understand without readily accessible tissue to biopsy in persons with and without sleep apnea. An improved understanding of the role oxidative stress plays in neural injury in sleep apnea may be developed by integrating information gained examining neural tissue in animal models of sleep apnea with key features of redox biochemistry and clinical sleep apnea studies where extra-neuronal oxidative stress characterizations have been performed. Collectively, this information sets the stage for developing and testing novel therapeutic approaches to treat and prevent, not only central nervous system injury and dysfunction in sleep apnea, but also the cardiovascular and potentially metabolic conditions associated with this prevalent, disabling disorder.
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Affiliation(s)
- Jing Zhang
- Department of Pulmonary Medicine, Peking University First Hospital Beijing, China ; Center for Sleep and Circadian Neurobiology, School of Medicine, University of Pennsylvania Philadelphia, PA, USA
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32
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Pellegrino R, Sunaga DY, Guindalini C, Martins RCS, Mazzotti DR, Wei Z, Daye ZJ, Andersen ML, Tufik S. Whole blood genome-wide gene expression profile in males after prolonged wakefulness and sleep recovery. Physiol Genomics 2012; 44:1003-12. [DOI: 10.1152/physiolgenomics.00058.2012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Although the specific functions of sleep have not been completely elucidated, the literature has suggested that sleep is essential for proper homeostasis. Sleep loss is associated with changes in behavioral, neurochemical, cellular, and metabolic function as well as impaired immune response. Using high-resolution microarrays we evaluated the gene expression profiles of healthy male volunteers who underwent 60 h of prolonged wakefulness (PW) followed by 12 h of sleep recovery (SR). Peripheral whole blood was collected at 8 am in the morning before the initiation of PW (Baseline), after the second night of PW, and one night after SR. We identified over 500 genes that were differentially expressed. Notably, these genes were related to DNA damage and repair and stress response, as well as diverse immune system responses, such as natural killer pathways including killer cell lectin-like receptors family, as well as granzymes and T-cell receptors, which play important roles in host defense. These results support the idea that sleep loss can lead to alterations in molecular processes that result in perturbation of cellular immunity, induction of inflammatory responses, and homeostatic imbalance. Moreover, expression of multiple genes was downregulated following PW and upregulated after SR compared with PW, suggesting an attempt of the body to re-establish internal homeostasis. In silico validation of alterations in the expression of CETN3, DNAJC, and CEACAM genes confirmed previous findings related to the molecular effects of sleep deprivation. Thus, the present findings confirm that the effects of sleep loss are not restricted to the brain and can occur intensely in peripheral tissues.
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Affiliation(s)
- R. Pellegrino
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - D. Y. Sunaga
- Human Genome Research Center, Biosciences Institute of University of Sao Paulo, São Paulo, Brazil
| | - C. Guindalini
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - R. C. S. Martins
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - D. R. Mazzotti
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Z. Wei
- Department of Computer Science, New Jersey Institute of Technology, Newark, New Jersey; and
| | - Z. J. Daye
- Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - M. L. Andersen
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - S. Tufik
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
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Zhang P, Hamamura K, Jiang C, Zhao L, Yokota H. Salubrinal promotes healing of surgical wounds in rat femurs. J Bone Miner Metab 2012; 30:568-79. [PMID: 22610062 DOI: 10.1007/s00774-012-0359-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Accepted: 04/02/2012] [Indexed: 10/28/2022]
Abstract
Phosphorylation of eukaryotic initiation factor 2α (eIF2α), transiently activated by various cellular stresses, is known to alleviate stress-induced cellular damage. Here, we addressed a question: does elevation of eIF2α phosphorylation by salubrinal (a pharmacological inhibitor of eIF2α dephosphorylation) enhance healing of bone wounds? We hypothesized that salubrinal would accelerate a closure of surgically generated bone holes by modifying expression of stress-sensitive genes. To examine this hypothesis, we employed a rat wound model. Surgical wounds were generated on anterior and posterior femoral cortexes, and salubrinal was locally administered on the anterior side. The results showed that, compared to a contralateral control, the size of surgical wounds was reduced by 10.8 % (day 10) and 18.0 % (day 20) on the anterior side (both p < 0.001), and 4.1 % (day 10; p < 0.05) and 11.1 % (day 20; p < 0.001) on the posterior side. In addition, salubrinal locally elevated cortical thickness and increased BMD and BMC. Pharmacokinetic analysis revealed that subcutaneous injection of salubrinal transiently increased its concentration in plasma followed by a rapid decrease within 24 h, and its half-life in plasma was 1.2 h. Salubrinal altered the phosphorylation level of eIF2α as well as the mRNA levels of ATF3, ATF4, and CHOP, and suppressed cell death induced by stress to the endoplasmic reticulum. In summary, the results herein demonstrate that subcutaneous administration of salubrinal accelerates healing of surgically generated bone holes through the modulation of eIF2α phosphorylation.
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Affiliation(s)
- Ping Zhang
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, SL220, 723 West Michigan Street, Indianapolis, IN, 46202, USA
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34
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Sustained translational repression by eIF2α-P mediates prion neurodegeneration. Nature 2012; 485:507-11. [PMID: 22622579 DOI: 10.1038/nature11058] [Citation(s) in RCA: 469] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 03/16/2012] [Indexed: 12/11/2022]
Abstract
The mechanisms leading to neuronal death in neurodegenerative disease are poorly understood. Many of these disorders, including Alzheimer's, Parkinson's and prion diseases, are associated with the accumulation of misfolded disease-specific proteins. The unfolded protein response is a protective cellular mechanism triggered by rising levels of misfolded proteins. One arm of this pathway results in the transient shutdown of protein translation, through phosphorylation of the α-subunit of eukaryotic translation initiation factor, eIF2. Activation of the unfolded protein response and/or increased eIF2α-P levels are seen in patients with Alzheimer's, Parkinson's and prion diseases, but how this links to neurodegeneration is unknown. Here we show that accumulation of prion protein during prion replication causes persistent translational repression of global protein synthesis by eIF2α-P, associated with synaptic failure and neuronal loss in prion-diseased mice. Further, we show that promoting translational recovery in hippocampi of prion-infected mice is neuroprotective. Overexpression of GADD34, a specific eIF2α-P phosphatase, as well as reduction of levels of prion protein by lentivirally mediated RNA interference, reduced eIF2α-P levels. As a result, both approaches restored vital translation rates during prion disease, rescuing synaptic deficits and neuronal loss, thereby significantly increasing survival. In contrast, salubrinal, an inhibitor of eIF2α-P dephosphorylation, increased eIF2α-P levels, exacerbating neurotoxicity and significantly reducing survival in prion-diseased mice. Given the prevalence of protein misfolding and activation of the unfolded protein response in several neurodegenerative diseases, our results suggest that manipulation of common pathways such as translational control, rather than disease-specific approaches, may lead to new therapies preventing synaptic failure and neuronal loss across the spectrum of these disorders.
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35
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Endoplasmic reticulum stress is important for the manifestations of α-synucleinopathy in vivo. J Neurosci 2012; 32:3306-20. [PMID: 22399753 DOI: 10.1523/jneurosci.5367-11.2012] [Citation(s) in RCA: 286] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Accumulation of misfolded α-synuclein (αS) is mechanistically linked to neurodegeneration in Parkinson's disease (PD) and other α-synucleinopathies. However, how αS causes neurodegeneration is unresolved. Because cellular accumulation of misfolded proteins can lead to endoplasmic reticulum stress/unfolded protein response (ERS/UPR), chronic ERS could contribute to neurodegeneration in α-synucleinopathy. Using the A53T mutant human αS transgenic (A53TαS Tg) mouse model of α-synucleinopathy, we show that disease onset in the αS Tg model is coincident with induction of ER chaperones in neurons exhibiting αS pathology. However, the neuronal ER chaperone induction was not accompanied by the activation of phospho-eIF2α, indicating that α-synucleinopathy is associated with abnormal UPR that could promote cell death. Induction of ERS/UPR was associated with increased levels of ER/microsomal (ER/M) associated αS monomers and aggregates. Significantly, human PD cases also exhibit higher relative levels of ER/M αS than the control cases. Moreover, αS interacts with ER chaperones and overexpression of αS sensitizes neuronal cells to ERS-induced toxicity, suggesting that αS may have direct impact on ER function. This view is supported by the presence of ERS-activated caspase-12 and the accumulation of ER-associated polyubiquitin. More important, treatment with Salubrinal, an anti-ERS compound, significantly attenuates disease manifestations in both the A53TαS Tg mouse model and the adeno-associated virus-transduced rat model of A53TαS-dependent dopaminergic neurodegeneration. Our data indicate that the accumulation αS within ER leads to chronic ER stress conditions that contribute to neurodegeneration in α-synucleinopathies. Attenuating chronic ERS could be an effective therapy for PD and other α-synucleinopathies.
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36
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Naidoo N. Roles of endoplasmic reticulum and energetic stress in disturbed sleep. Neuromolecular Med 2012; 14:213-9. [PMID: 22527792 DOI: 10.1007/s12017-012-8179-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 03/23/2012] [Indexed: 11/26/2022]
Abstract
Sleep disturbances are contributing factors to health risk for several diseases including hypertension, diabetes, obesity, depression, and stroke. On a molecular level, sleep disturbances that incur sleep loss and sleep fragmentation result in cellular stress, inflammation, and an impaired immune system. It has been hypothesized that sleep deprivation or prolonged waking leads to increased energy demand and thus energetic stress. Sleep loss and sleep fragmentation are also known to lead to cellular stress specifically endoplasmic reticulum (ER) stress. This review will summarize the current knowledge of the roles of ER and energetic stress during sleep loss and fragmentation that are characteristics of many sleep disturbances. Sleep research pertinent to these specific pathways will be discussed.
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Affiliation(s)
- Nirinjini Naidoo
- Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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37
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Methippara M, Mitrani B, Schrader FX, Szymusiak R, McGinty D. Salubrinal, an endoplasmic reticulum stress blocker, modulates sleep homeostasis and activation of sleep- and wake-regulatory neurons. Neuroscience 2012; 209:108-18. [PMID: 22387272 DOI: 10.1016/j.neuroscience.2012.02.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 10/28/2022]
Abstract
Endoplasmic reticulum (ER) stress has been associated with the regulation of sleep and wake. We have previously shown that i.c.v. administration of a specific ER stress modulator, Salubrinal (SALUB), which inhibits global protein translation by blocking the dephosphorylation of eukaryotic initiation factor 2α (p-eIF2α), increased non-rapid eye movement (NREM) sleep. Here we report on the relationship between ER stress response and sleep homeostasis by measuring the amount and intensity of homeostatic recovery sleep in response to the i.c.v. administration of SALUB in adult freely behaving rats. We have also tested the hypothesis that SALUB induces sleep by activating sleep-promoting neurons and inhibiting wake-promoting neurons in the basal forebrain (BF) and hypothalamus by quantifying the effects of SALUB treatment on c-Fos expression in those neuronal groups. The present study found that i.c.v. administration of SALUB significantly modified the homeostatic sleep response. SALUB administered during sleep deprivation increased sleep intensity, indicated by slow-wave activity (SWA), during recovery sleep, whereas its administration during recovery sleep increased the amount of recovery sleep. We also found that SALUB induced c-Fos activation of GABAergic neurons in the sleep-promoting rostral median preoptic nucleus while simultaneously reducing c-Fos activation of wake-promoting lateral hypothalamic orexin-expressing neurons and magnocellular BF cholinergic neurons. The current findings suggest that ER stress pathway plays a role in the homeostatic control of NREM sleep in response to sleep deprivation and provides a mechanistic explanation for the sleep modulation by molecules signaling the need for brain protein synthesis.
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Affiliation(s)
- M Methippara
- Department of Psychology, UCLA, 405 Hilgard, Los Angeles, CA 90095, USA
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38
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Dalal S, Foster CR, Das BC, Singh M, Singh K. Β-adrenergic receptor stimulation induces endoplasmic reticulum stress in adult cardiac myocytes: role in apoptosis. Mol Cell Biochem 2012; 364:59-70. [PMID: 22270541 DOI: 10.1007/s11010-011-1205-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/15/2011] [Indexed: 02/06/2023]
Abstract
Accumulation of misfolded proteins and alterations in calcium homeostasis induces endoplasmic reticulum (ER) stress, leading to apoptosis. In this study, we tested the hypothesis that β-AR stimulation induces ER stress, and induction of ER stress plays a pro-apoptotic role in cardiac myocytes. Using thapsigargin and brefeldin A, we demonstrate that ER stress induces apoptosis in adult rat ventricular myocytes (ARVMs). β-AR-stimulation (isoproterenol; 3h) significantly increased expression of ER stress proteins, such as GRP-78, Gadd-153, and Gadd-34, while activating caspase-12 in ARVMs. In most parts, these effects were mimicked by thapsigargin. β-AR stimulation for 15 min increased PERK and eIF-2α phosphorylation. PERK phosphorylation remained higher, while eIF-2α phosphorylation declined thereafter, reaching to ~50% below basal levels at 3 h after β-AR stimulation. This decline in eIF-2α phosphorylation was prevented by β1-AR, not by β2-AR antagonist. Forskolin, adenylyl cyclase activator, simulated the effects of ISO on eIF-2α phosphorylation. Salubrinal (SAL), an ER stress inhibitor, maintained eIF-2α phosphorylation and inhibited β-AR-stimulated apoptosis. Furthermore, inhibition of caspase-12 using z-ATAD inhibited β-AR-stimulated and thapsigargin-induced apoptosis. In vivo, β-AR stimulation induced ER stress in the mouse heart as evidenced by increased expression of GRP-78 and Gadd-153, activation of caspase-12, and dephosphorylation of eIF-2α. SAL maintained phosphorylation of eIF-2α, inhibited activation of caspase-12, and decreased β-AR-stimulated apoptosis in the heart. Thus, β-AR stimulation induces ER stress in cardiac myocytes and in the heart, and induction of ER stress plays a pro-apoptotic role.
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Affiliation(s)
- Suman Dalal
- Department of Physiology, James H Quillen College of Medicine, James H Quillen Veterans Affairs Medical Center, East Tennessee State University, PO Box 70576, Johnson City, TN 37614, USA
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39
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Stockwell SR, Platt G, Barrie SE, Zoumpoulidou G, te Poele RH, Aherne GW, Wilson SC, Sheldrake P, McDonald E, Venet M, Soudy C, Elustondo F, Rigoreau L, Blagg J, Workman P, Garrett MD, Mittnacht S. Mechanism-based screen for G1/S checkpoint activators identifies a selective activator of EIF2AK3/PERK signalling. PLoS One 2012; 7:e28568. [PMID: 22253692 PMCID: PMC3257223 DOI: 10.1371/journal.pone.0028568] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 11/10/2011] [Indexed: 01/08/2023] Open
Abstract
Human cancers often contain genetic alterations that disable G1/S checkpoint control and loss of this checkpoint is thought to critically contribute to cancer generation by permitting inappropriate proliferation and distorting fate-driven cell cycle exit. The identification of cell permeable small molecules that activate the G1/S checkpoint may therefore represent a broadly applicable and clinically effective strategy for the treatment of cancer. Here we describe the identification of several novel small molecules that trigger G1/S checkpoint activation and characterise the mechanism of action for one, CCT020312, in detail. Transcriptional profiling by cDNA microarray combined with reverse genetics revealed phosphorylation of the eukaryotic initiation factor 2-alpha (EIF2A) through the eukaryotic translation initiation factor 2-alpha kinase 3 (EIF2AK3/PERK) as the mechanism of action of this compound. While EIF2AK3/PERK activation classically follows endoplasmic reticulum (ER) stress signalling that sets off a range of different cellular responses, CCT020312 does not trigger these other cellular responses but instead selectively elicits EIF2AK3/PERK signalling. Phosphorylation of EIF2A by EIF2A kinases is a known means to block protein translation and hence restriction point transit in G1, but further supports apoptosis in specific contexts. Significantly, EIF2AK3/PERK signalling has previously been linked to the resistance of cancer cells to multiple anticancer chemotherapeutic agents, including drugs that target the ubiquitin/proteasome pathway and taxanes. Consistent with such findings CCT020312 sensitizes cancer cells with defective taxane-induced EIF2A phosphorylation to paclitaxel treatment. Our work therefore identifies CCT020312 as a novel small molecule chemical tool for the selective activation of EIF2A-mediated translation control with utility for proof-of-concept applications in EIF2A-centered therapeutic approaches, and as a chemical starting point for pathway selective agent development. We demonstrate that consistent with its mode of action CCT020312 is capable of delivering potent, and EIF2AK3 selective, proliferation control and can act as a sensitizer to chemotherapy-associated stresses as elicited by taxanes.
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Affiliation(s)
- Simon R. Stockwell
- Research Department of Cancer Biology, UCL Cancer Institute, London, United Kingdom
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - Georgina Platt
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - S. Elaine Barrie
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - Georgia Zoumpoulidou
- Research Department of Cancer Biology, UCL Cancer Institute, London, United Kingdom
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
| | - Robert H. te Poele
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - G. Wynne Aherne
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Stuart C. Wilson
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Peter Sheldrake
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Edward McDonald
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Mathilde Venet
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Christelle Soudy
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Frédéric Elustondo
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Laurent Rigoreau
- Cancer Research Technology Discovery Laboratories London, Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Julian Blagg
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Paul Workman
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Michelle D. Garrett
- Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, United Kingdom
| | - Sibylle Mittnacht
- Research Department of Cancer Biology, UCL Cancer Institute, London, United Kingdom
- Division of Cancer Biology, The Institute of Cancer Research, London, United Kingdom
- * E-mail:
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Dysfunctional nucleus tractus solitarius: its crucial role in promoting neuropathogenetic cascade of Alzheimer's dementia--a novel hypothesis. Neurochem Res 2012; 37:846-68. [PMID: 22219130 DOI: 10.1007/s11064-011-0680-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/16/2011] [Accepted: 12/15/2011] [Indexed: 12/22/2022]
Abstract
The pathophysiological mechanism(s) underlying Alzheimer's disease (AD) still remain unclear, and no disease-modifying or prophylactic therapies are currently available. Unraveling the fundamental neuropathogenesis of AD is an important challenge. Several studies on AD have suggested lesions in a number of CNS areas including the basal forebrain, hippocampus, entorhinal cortex, amygdale/insula, and the locus coeruleus. However, plausible unifying studies on the upstream factors that involve these heterogeneous regions and herald the onset of AD pathogenesis are not available. The current article presents a novel nucleus tractus solitarius (NTS) vector hypothesis that underpins several disparate biological mechanisms and neural circuits, and identifies relevant hallmarks of major presumptive causative factor(s) linked to the NTS, in older/aging individuals. Aging, obesity, infection, sleep apnea, smoking, neuropsychological states, and hypothermia-all activate inflammatory cytokines and oxidative stress. The synergistic impact of systemic proinflammatory mediators activates microglia and promotes neuroinflammation. Acutely, the innate immune response is protective defending against pathogens/toxins; however, when chronic, it causes neuroinflammation and neuronal dysfunction, particularly in brainstem and neocortex. The NTS in the brainstem is an essential multiple signaling hub, and an extremely important central integration site of baroreceptor, chemoreceptor, and a multitude of sensory afferents from gustatory, gastrointestinal, cardiac, pulmonary, and upper airway systems. Owing to persistent neuroinflammation, the dysfunctional NTS exerts deleterious impact on nucleus ambiguus, dorsal motor nucleus of vagus, hypoglossal, parabrachial, locus coeruleus and many key nuclei in the brainstem, and the hippocampus, entorhinal cortex, prefrontal cortex, amygdala, insula, and basal forebrain in the neocortex. The neuronal and synaptic dysfunction emanating from the inflamed NTS may affect its interconnected pathways impacting almost the entire CNS--which is already primed by neuroinflammation, thus promoting cognitive and neuropsychiatric symptoms. The upstream factors discussed here may underpin the neuropathopgenesis of AD. AD pathology is multifactorial; the current perspective underscores the value of attenuating disparate upstream factors--in conjunction with anticholinesterase, anti-inflammatory, immunosuppressive, and anti-oxidant pharmacotherapy. Amelioration of the NTS pathology may be of central importance in countering the neuropathological cascade of AD. The NTS, therefore, may be a potential target of novel therapeutic strategies.
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41
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Neurobiology and Neuropathophysiology of Obstructive Sleep Apnea. Neuromolecular Med 2011; 14:168-79. [DOI: 10.1007/s12017-011-8165-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 11/19/2011] [Indexed: 10/14/2022]
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42
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Cai J, Tuong CM, Zhang Y, Shields CB, Guo G, Fu H, Gozal D. Mouse intermittent hypoxia mimicking apnoea of prematurity: effects on myelinogenesis and axonal maturation. J Pathol 2011; 226:495-508. [PMID: 21953180 DOI: 10.1002/path.2980] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/24/2011] [Accepted: 08/04/2011] [Indexed: 01/09/2023]
Abstract
Premature babies are at high risk for both infantile apnoea and long-term neurobehavioural deficits. Recent studies suggest that diffuse structural changes in brain white matter are a positive predictor of poor cognitive outcomes. Since oligodendrocyte maturation, myelination, axon development, and synapse formation mainly occur in the third trimester of gestation and first postnatal year, infantile apnoea could lead to and/or exaggerate white matter impairments in preterm neonates. Therefore, we investigated oligodendroglia and axon development in a neonatal mouse model of intermittent hypoxia between postnatal days 2 and 10. During critical phases of central nervous system development, intermittent hypoxia induced hypomyelination in the corpus callosum, striatum, fornix, and cerebellum, but not in the pons or spinal cord. Intermittent hypoxia-elicited alterations in myelin-forming processes were reflected by decreased expression of myelin proteins, including MBP, PLP, MAG, and CNPase, possibly due to arrested maturation of oligodendrocytes. Ultrastructural abnormalities were apparent in the myelin sheath and axon. Immature oligodendrocytes were more vulnerable to neonatal intermittent hypoxia exposures than developing axons, suggesting that hypomyelination may contribute, at least partially, to axonal deficits. Insufficient neurofilament synthesis with anomalous components of neurofilament subunits, β-tubulin, and MAP2 isoforms indicated immaturity of axons in intermittent hypoxia-exposed mouse brains. In addition, down-regulation of synapsin I, synaptophysin, and Gap-43 phosphorylation suggested a potential stunt in axonogenesis and synaptogenesis. The region-selective and complex impairment in brain white matter induced by intermittent hypoxia was further associated with electrophysiological changes that may underlie long-term neurobehavioural sequelae.
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Affiliation(s)
- Jun Cai
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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Pae EK, Yoon AJ, Ahuja B, Lau GW, Nguyen DD, Kim Y, Harper RM. Perinatal intermittent hypoxia alters γ-aminobutyric acid: a receptor levels in rat cerebellum. Int J Dev Neurosci 2011; 29:819-26. [PMID: 21964325 DOI: 10.1016/j.ijdevneu.2011.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 09/06/2011] [Accepted: 09/09/2011] [Indexed: 01/13/2023] Open
Abstract
Perinatal hypoxia commonly causes brain injury in infants, but the time course and mechanisms underlying the preferential male injury are unclear. Intermittent hypoxia disturbs cerebellar γ-aminobutyric (GABA)-A receptor profiles during the perinatal period, possibly responding to transient excitatory processes associated with GABA(A) receptors. We examined whether hypoxic insults were particularly damaging to the male rodent cerebellum during a specific developmental time window. We evaluated cerebellar injury and GABA(A) receptor profiles following 5-h intermittent hypoxia (IH: 20.8% and 10.3% ambient oxygen, switched every 240s) or room-air control in groups of male and female rat pups on postnatal d 1-2, wk 1, or wk 3. The cerebella were harvested and compared between groups. The mRNA levels of GABA(A) receptors α6, normalized to a house-keeping gene GAPDH, and assessed using real-time reverse-transcriptase PCR assays were up-regulated by IH at wk 1, more extensively in male rats, with sex influencing the regulatory time-course. In contrast, GABA(A) α6 receptor protein expression levels, assessed using Western blot assays, reached a nadir at wk 1 in both male and female rats, possibly indicating involvement of a post-transcriptional mechanism. The extent of cerebellar damage and level of apoptosis, assessed by DNA fragmentation, were greatest in the wk 3 IH-exposed group. The findings suggest partial protection for female rats against early hypoxic insult in the cerebellum, and that down-regulation of GABA(A) receptors, rather than direct neural injury assessed by DNA fragmentation may modify cerebellar function, with potential later motor and other deficits.
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Affiliation(s)
- Eung-Kwon Pae
- UCLA School of Dentistry, Los Angeles, CA 90095, USA.
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Naidoo N, Zhu J, Zhu Y, Fenik P, Lian J, Galante R, Veasey S. Endoplasmic reticulum stress in wake-active neurons progresses with aging. Aging Cell 2011; 10:640-9. [PMID: 21388495 PMCID: PMC3125474 DOI: 10.1111/j.1474-9726.2011.00699.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Fragmentation of wakefulness and sleep are expected outcomes of advanced aging. We hypothesize that wake neurons develop endoplasmic reticulum dyshomeostasis with aging, in parallel with impaired wakefulness. In this series of experiments, we sought to more fully characterize age-related changes in wakefulness and then, in relevant wake neuronal populations, explore functionality and endoplasmic reticulum homeostasis. We report that old mice show greater sleep/wake transitions in the active period with markedly shortened wake periods, shortened latencies to sleep, and less wake time in the subjective day in response to a novel social encounter. Consistent with sleep/wake instability and reduced social encounter wakefulness, orexinergic and noradrenergic wake neurons in aged mice show reduced c-fos response to wakefulness and endoplasmic reticulum dyshomeostasis with increased nuclear translocation of CHOP and GADD34. We have identified an age-related unfolded protein response injury to and dysfunction of wake neurons. It is anticipated that these changes contribute to sleep/wake fragmentation and cognitive impairment in aging.
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Affiliation(s)
- Nirinjini Naidoo
- Division of Sleep Medicine, Center for Sleep & Circadian Neurobiology, School of Medicine, University of Pennsylvania, 125 S. 31st Street, Philadelphia, PA 19104, USA.
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Chen A, Zhang P, Duan Z, Wang G, Yokota H. Modelling the Molecular Transportation of Subcutaneously Injected Salubrinal. Biomed Eng Comput Biol 2011. [DOI: 10.4137/becb.s7050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
For the subcutaneous administration of a chemical agent (salubrinal), we constructed a mathematical model of molecule transportation and subsequently evaluated the kinetics of diffusion, convection, and molecular turnover. Salubrinal is a potential therapeutic agent that can reduce cellular damage and death. The understanding of its temporal profiles in local tissue as well as in a whole body is important to develop a proper strategy for its administration. Here, the diffusion and convection kinetics was formulated using partial and ordinary differential equations in one- and three-dimensional (semi-spherical) coordinates. Several key parameters including an injection velocity, a diffusion coefficient, thickness of subcutaneous tissue, and a permeability factor at the tissue-blood boundary were estimated from experimental data in rats. With reference to analytical solutions in a simplified model without convection, numerical solutions revealed that the diffusion coefficient and thickness of subcutaneous tissue determined the timing of the peak concentration in the plasma, and its magnitude was dictated by the permeability factor. Furthermore, the initial velocity, induced by needle injection, elevated an immediate transport of salubrinal at t < 1h. The described analysis with a combination of partial and ordinary differential equations contributes to the prediction of local and systemic effects and the understanding of the transportation mechanism of salubrinal and other agents.
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Affiliation(s)
- Andy Chen
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92092, USA
| | - Ping Zhang
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Zhiyao Duan
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Guofeng Wang
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Hiroki Yokota
- Department of Biomedical Engineering, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA
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Michinaga S, Hisatsune A, Isohama Y, Katsuki H. Orexin neurons in hypothalamic slice cultures are vulnerable to endoplasmic reticulum stress. Neuroscience 2011; 190:289-300. [PMID: 21712074 DOI: 10.1016/j.neuroscience.2011.06.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/18/2011] [Accepted: 06/07/2011] [Indexed: 01/09/2023]
Abstract
Narcolepsy results from disruption of orexin neurons in the hypothalamus that play a key role in maintenance of the arousal state. Underlying mechanisms leading to selective loss of orexin neurons remain unknown. On the other hand, endoplasmic reticulum stress, namely, conditions associated with impairment of endoplasmic reticulum functions such as proper folding and sorting of newly synthesized proteins, is implicated in pathogenesis of several types of neurodegenerative disorders. Here we found that application of endoplasmic reticulum stress inducers such as tunicamycin (that prevents protein N-glycosylation) and thapsigargin (that inhibits Ca²⁺-ATPase) to organotypic slice cultures of the hypothalamus caused preferential loss of orexin-immunoreactive neurons, as compared to melanin-concentrating hormone- or calcitonin gene-related peptide-immunoreactive neurons. The decrease in orexin-immunoreactive neurons at early time points (6-24 h) was not accompanied by induction of cell death as indicated by the absence of caspase-3 activation and no significant change in the number of NeuN-positive cells, whereas sustained treatment with tunicamycin for 72 h induced cell death. At 24-h treatment, tunicamycin and thapsigargin did not decrease expression of prepro-orexin mRNA, suggesting that post-transcriptional mechanisms were responsible for depletion of orexin peptides. In addition, inhibition of axonal transport by colchicine and inhibition of proteasomal activity by MG132 significantly prevented the decrease in orexin immunoreactivity by tunicamycin. Comparative examinations of expression of unfolded protein response-related proteins revealed that C/EBP-homologous protein (a transcription factor that promotes induction of apoptosis) as well as phosphorylated form of RNA-dependent protein kinase-like endoplasmic reticulum kinase (a protein kinase that mediates inhibition of protein translation) was expressed more prominently in orexin neurons than in melanin-concentrating hormone neurons, in response to tunicamycin. These results indicate that orexin neurons are particularly sensitive to endoplasmic reticulum stress, which may be relevant to pathogenic events in narcolepsy.
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Affiliation(s)
- S Michinaga
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan
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Abstract
The ability to respond to perturbations in endoplasmic reticulum (ER) function is a fundamentally important property of all cells, but ER stress can also lead to apoptosis. In settings of chronic ER stress, the associated apoptosis may contribute to pathophysiological processes involved in a number of prevalent diseases, including neurodegenerative diseases, diabetes, atherosclerosis and renal disease. The molecular mechanisms linking ER stress to apoptosis are the topic of this review, with emphases on relevance to pathophysiology and integration and complementation among the various apoptotic pathways induced by ER stress.
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Affiliation(s)
- Ira Tabas
- Department of Medicine, Anatomy & Cell Biology, Columbia University, New York, NY 10032, USA.
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ER stress response plays an important role in aggregation of α-synuclein. Mol Neurodegener 2010; 5:56. [PMID: 21144044 PMCID: PMC3016345 DOI: 10.1186/1750-1326-5-56] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 12/13/2010] [Indexed: 01/04/2023] Open
Abstract
Background Accumulation of filamentous α-synuclein as Lewy bodies is a hallmark of Parkinson's disease. To identify the mechanisms involved in α-synuclein assembly and determine whether the assemblies are cytotoxic, we developed a cell model (3D5) that inducibly expresses wild-type human α-synuclein and forms inclusions that reproduce many morphological and biochemical characteristics of Lewy bodies. In the present study, we evaluated the effects of several histone deacetylase inhibitors on α-synuclein aggregation in 3D5 cells and primary neuronal cultures. These drugs have been demonstrated to protect cells transiently overexpressing α-synuclein from its toxicity. Results Contrary to transient transfectants, the drug treatment did not benefit 3D5 cells and primary cultures. The treated were less viable and contained more α-synuclein oligomers, active caspases 3 and 9, as well as ER stress markers than non-treated counterparts. The drug-treated, induced-3D5 cells, or primary cultures from transgenic mice overexpressing (<2 fold) α-synuclein, displayed more α-synuclein oligomers and ER stress markers than non-induced or non-transgenic counterparts. Similar effects were demonstrated in cultures treated with tunicamycin, an ER stressor. These effects were blocked by co-treatment with salubrinal, an ER stress inhibitor. In comparison, co-treatment with a pan caspase inhibitor protected cells from demise but did not reduce α-synuclein oligomer accumulation. Conclusions Our results indicate that an increase of wild-type α-synuclein can elicit ER stress response and sensitize cells to further insults. Most importantly, an increase of ER stress response can promote the aggregation of wild type α-synuclein.
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Thompson CL, Wisor JP, Lee CK, Pathak SD, Gerashchenko D, Smith KA, Fischer SR, Kuan CL, Sunkin SM, Ng LL, Lau C, Hawrylycz M, Jones AR, Kilduff TS, Lein ES. Molecular and anatomical signatures of sleep deprivation in the mouse brain. Front Neurosci 2010; 4:165. [PMID: 21088695 PMCID: PMC2981377 DOI: 10.3389/fnins.2010.00165] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Accepted: 08/23/2010] [Indexed: 11/13/2022] Open
Abstract
Sleep deprivation (SD) leads to a suite of cognitive and behavioral impairments, and yet the molecular consequences of SD in the brain are poorly understood. Using a systematic immediate-early gene (IEG) mapping to detect neuronal activation, the consequences of SD were mapped primarily to forebrain regions. SD was found to both induce and suppress IEG expression (and thus neuronal activity) in subregions of neocortex, striatum, and other brain regions. Laser microdissection and cDNA microarrays were used to identify the molecular consequences of SD in seven brain regions. In situ hybridization (ISH) for 222 genes selected from the microarray data and other sources confirmed that robust molecular changes were largely restricted to the forebrain. Analysis of the ISH data for 222 genes (publicly accessible at http://sleep.alleninstitute.org) provided a molecular and anatomic signature of the effects of SD on the brain. The suprachiasmatic nucleus (SCN) and the neocortex exhibited differential regulation of the same genes, such that in the SCN genes exhibited time-of-day effects while in the neocortex, genes exhibited only SD and waking (W) effects. In the neocortex, SD activated gene expression in areal-, layer-, and cell type-specific manner. In the forebrain, SD preferentially activated excitatory neurons, as demonstrated by double-labeling, except for striatum which consists primarily of inhibitory neurons. These data provide a characterization of the anatomical and cell type-specific signatures of SD on neuronal activity and gene expression that may account for the associated cognitive and behavioral effects.
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Abstract
Sleepiness has long been recognized as a presenting symptom in obstructive sleep apnea syndrome, but persistent neurocognitive injury from sleep apnea has been appreciated only recently. Although therapy for sleep apnea markedly improves daytime symptoms, cognitive impairments may persist despite long-term therapy with continuous positive airway pressure. We know now that certain groups of neurons, typically those that are more metabolically active, are more vulnerable to injury than others. Animal models of sleep apnea oxygenation patterns have been instrumental in elucidating mechanisms of injury. The hypoxia/reoxygenation events result in oxidative, inflammatory, and endoplasmic reticulum stress responses in susceptible neural groups. With molecular pathways being fleshed out in animal models, it is time to carefully and systematically examine neural injury in humans and test the applicability of findings from animal models. To succeed, however, we cannot view sleep apnea as an isolated process. Rather, injury in sleep apnea is more likely the consequence of overlapping injuries from comorbid conditions. The progress in elucidating mechanisms of neural injury is palpable, and it now seems we indeed are closer to developing therapies to prevent and treat neural injury in obstructive sleep apnea.
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Affiliation(s)
- Diane C Lim
- Center for Sleep and Neurobiology, University of Pennsylvania School of Medicine, Translational Research Building, Room 2115, 125 South 31st Street, Philadelphia, PA, 19104, USA
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