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Lipinski MM, Wu J, Faden AI, Sarkar C. Function and Mechanisms of Autophagy in Brain and Spinal Cord Trauma. Antioxid Redox Signal 2015; 23:565-77. [PMID: 25808205 PMCID: PMC4545370 DOI: 10.1089/ars.2015.6306] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
SIGNIFICANCE Traumatic brain injury (TBI) and spinal cord injury (SCI) are major causes of death and long-term disability worldwide. Despite important pathophysiological differences between these disorders, in many respects, mechanisms of injury are similar. During both TBI and SCI, some cells are directly mechanically injured, but more die as a result of injury-induced biochemical changes (secondary injury). Autophagy, a lysosome-dependent cellular degradation pathway with neuroprotective properties, has been implicated both clinically and experimentally in the delayed response to TBI and SCI. However, until recently, its mechanisms and function remained unknown, reflecting in part the difficulty of isolating autophagic processes from ongoing cell death and other cellular events. RECENT ADVANCES Emerging data suggest that depending on the location and severity of traumatic injury, autophagy flux--defined as the progress of cargo through the autophagy system and leading to its degradation--may be either increased or decreased after central nervous system trauma. CRITICAL ISSUES While increased autophagy flux may be protective after mild injury, after more severe trauma inhibition of autophagy flux may contribute to neuronal cell death, indicating disruption of autophagy as a part of the secondary injury mechanism. FUTURE DIRECTIONS Augmentation and/or restoration of autophagy flux may provide a potential therapeutic target for treatment of TBI and SCI. Development of those treatments will require thorough characterization of changes in autophagy flux, its mechanisms and function over time after injury.
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Affiliation(s)
- Marta M Lipinski
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine , Baltimore, Maryland
| | - Junfang Wu
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine , Baltimore, Maryland
| | - Alan I Faden
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine , Baltimore, Maryland
| | - Chinmoy Sarkar
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine , Baltimore, Maryland
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102
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Lopez MS, Dempsey RJ, Vemuganti R. Resveratrol neuroprotection in stroke and traumatic CNS injury. Neurochem Int 2015; 89:75-82. [PMID: 26277384 DOI: 10.1016/j.neuint.2015.08.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/07/2015] [Accepted: 08/08/2015] [Indexed: 02/02/2023]
Abstract
Resveratrol, a stilbene formed in many plants in response to various stressors, elicits multiple beneficial effects in vertebrates. Particularly, resveratrol was shown to have therapeutic properties in cancer, atherosclerosis and neurodegeneration. Resveratrol-induced benefits are modulated by multiple synergistic pathways that control oxidative stress, inflammation and cell death. Despite the lack of a definitive mechanism, both in vivo and in vitro studies suggest that resveratrol can induce a neuroprotective state when administered acutely or prior to experimental injury to the CNS. In this review, we discuss the neuroprotective potential of resveratrol in stroke, traumatic brain injury and spinal cord injury, with a focus on the molecular pathways responsible for this protection.
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Affiliation(s)
- Mary S Lopez
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Robert J Dempsey
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Raghu Vemuganti
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA.
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103
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Park Y, Liu C, Luo T, Dietrich WD, Bramlett H, Hu B. Chaperone-Mediated Autophagy after Traumatic Brain Injury. J Neurotrauma 2015; 32:1449-57. [PMID: 25891649 DOI: 10.1089/neu.2014.3694] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chaperone-mediated autophagy (CMA) and the ubiquitin-proteasomal system (UPS) are two major protein degradation systems responsible for maintaining cellular homeostasis, but how these two systems are regulated after traumatic brain injury (TBI) remains unknown. TBI produces primary mechanical damage that must be repaired to maintain neuronal homeostasis. The level of lysosomal-associated membrane protein type 2A (LAMP2A) is the hallmark of CMA activity. The level of polyubiquitinated proteins (ubi-proteins) reflects UPS activity. This study utilized a moderate fluid percussion injury model in rats to investigate the changes in CMA and the UPS after TBI. Induction of CMA was manifested by significant upregulation of LAMP2A and secondary lysosomes during the periods of 1-15 days of recovery after TBI. In comparison, the levels of ubi-proteins were increased only moderately after TBI. The increases in the levels of LAMP2A and 70 kDa heat-shock protein for CMA after TBI were seen mainly in the secondary lysosome-containing fractions. Confocal and electron microscopy further showed that increased LAMP2A or lysosomes were found mainly in neurons and proliferated microglia. Because CMA and the UPS are two major routes for elimination of different types of cellular aberrant proteins, the consecutive activation of these two pathways may serve as a protective mechanism for maintaining cellular homeostasis after TBI.
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Affiliation(s)
- Yujung Park
- 1 Neurochemistry Laboratory of Brain Injury, Shock Trauma and Anesthesiology Research Center; University of Maryland School of Medicine , Baltimore, Maryland
| | - Chunli Liu
- 1 Neurochemistry Laboratory of Brain Injury, Shock Trauma and Anesthesiology Research Center; University of Maryland School of Medicine , Baltimore, Maryland
| | - Tianfei Luo
- 1 Neurochemistry Laboratory of Brain Injury, Shock Trauma and Anesthesiology Research Center; University of Maryland School of Medicine , Baltimore, Maryland
| | - W Dalton Dietrich
- 2 Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami School of Medicine , Miami, Florida
| | - Helen Bramlett
- 2 Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami School of Medicine , Miami, Florida
| | - Bingren Hu
- 1 Neurochemistry Laboratory of Brain Injury, Shock Trauma and Anesthesiology Research Center; University of Maryland School of Medicine , Baltimore, Maryland
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104
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Zhang L, Ding K, Wang H, Wu Y, Xu J. Traumatic Brain Injury-Induced Neuronal Apoptosis is Reduced Through Modulation of PI3K and Autophagy Pathways in Mouse by FTY720. Cell Mol Neurobiol 2015; 36:131-42. [PMID: 26099903 DOI: 10.1007/s10571-015-0227-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/12/2015] [Indexed: 01/13/2023]
Abstract
FTY720 is a synthetic compound produced by modification of metabolite from Isaria sinclairii. It is a novel type of immunosuppressive agent inhibiting lymphocyte egress from secondary lymphoid tissues, thereby causing peripheral lymphopenia. Growing evidences have suggested that apoptosis and autophagy were involved in the secondary brain injury after traumatic brain injury (TBI) although FTY720 exerted neuroprotective effects in a variety of neurological diseases except TBI. The present study was aimed to investigate the role of FTY720 in a mouse model of TBI. In experiment 1, ICR mice were divided into four groups: sham group, TBI group, TBI + vehicle group, and TBI + FTY720 group. And the injured cerebral cortex (including both contused and penumbra) was used for analysis. We found that FTY720 administration after TBI improved neurobehavioral function, alleviated brain edema, accompanied by modulation of apoptotic indicators such as Bcl-2, Bcl-xL, Bax, and cytochrome c. In experiment 2, ICR mice were also divided into four groups: sham group, TBI + vehicle group, TBI + FTY720 group, and TBI + FTY720 + inhibitors group. And the injured cerebral cortex (including both contused and penumbra) was used for analysis. We found that FTY720 increased the expression of phospho-protein kinase B (AKT) and some autophagy markers such as LC3 and Beclin 1. In addition, the apoptosis inhibition effect of FTY720 was partly abrogated by the phosphatidylinositide 3-kinases (PI3K)/AKT pathway inhibitor LY294002 and autophagy inhibitor 3-methyladenine. Collectively, our data provide the first evidence that FTY720 exerted neuroprotective effects after TBI, at least in part, through the activation of PI3K/AKT pathway and autophagy.
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Affiliation(s)
- Li Zhang
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, 210002, Jiangsu, China
| | - Ke Ding
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, 210002, Jiangsu, China
| | - Handong Wang
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, 210002, Jiangsu, China.
| | - Yong Wu
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, 210002, Jiangsu, China
| | - Jianguo Xu
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, 210002, Jiangsu, China
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105
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Zhou Y, Zhou Y, Yu S, Wu J, Chen Y, Zhao Y. Sulfiredoxin-1 exerts anti-apoptotic and neuroprotective effects against oxidative stress-induced injury in rat cortical astrocytes following exposure to oxygen-glucose deprivation and hydrogen peroxide. Int J Mol Med 2015; 36:43-52. [PMID: 25955519 PMCID: PMC4494579 DOI: 10.3892/ijmm.2015.2205] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 04/21/2015] [Indexed: 01/05/2023] Open
Abstract
Sulfiredoxin 1 (Srxn1), an endogenous antioxidant protein, plays an important neuroprotective role in cerebral ischemia. However, the exact mechanisms of action of Srxn1 in cerebral ischemia have not yet been fully elucidated. Therefore, in the present study, rat primary cortical astrocytes transfected with a lentiviral vector encoding short hairpin RNA (shRNA) were exposed to oxygen-glucose deprivation (OGD) for 4 h or to 100 μM hydrogen peroxide (H2O2) for 6 h, in order to construct an in vitro model of cerebral ischemia-induced damage. We found that following exposure to OGD or H2O2, the knockdown of Srxn1 resulted in a decrease in cell viability, as shown by MTS assay, an increase in cell damage, as shown by lactate dehydrogenase assay and an increase in cellular apoptosis, as shown by Hoechst 33342 staining and flow cytometry. Furthermore, we found that following exposure to OGD or H2O2, the knockdown of Srxn1 resulted in a decrease in mitochondrial transmembrane potential (Δψm) as indicated by JC-1 staining, an increase in the cytoplasmic expression of cytochrome c (Cyt.C), caspase-3, caspase-9, poly(ADP-ribose) polymerase (PARP) and Bax protein at the protein level, but a decrease in the expression of the anti-apoptotic Bcl-2 protein; these effects were tightly associated with the mitochondrial apoptotic pathway. However, we found that there was no obvious change in the intracellular calcium ([Ca2+]i) levels and caspase-12 expression following the knockdown of Srxn1. Taken together, the results from the present study demonstrate that Srxn1 protects primary rat cortical astrocytes from OGD- or H2O2-induced apoptosis and that involves the activation of the mitochondrial apoptotic pathway, which suggests that Srxn1 may be a potential target in the treatment of cerebral ischemia.
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Affiliation(s)
- Yunchuan Zhou
- Department of Pathology, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Yang Zhou
- Department of Pathology, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Shanshan Yu
- Department of Pathology, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Jingxian Wu
- Department of Pathology, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Yanlin Chen
- Department of Pathology, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Yong Zhao
- Department of Pathology, Chongqing Medical University, Chongqing 400016, P.R. China
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106
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Demarest TG, McCarthy MM. Sex differences in mitochondrial (dys)function: Implications for neuroprotection. J Bioenerg Biomembr 2014; 47:173-88. [PMID: 25293493 DOI: 10.1007/s10863-014-9583-7] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/14/2014] [Indexed: 12/12/2022]
Abstract
Decades of research have revealed numerous differences in brain structure size, connectivity and metabolism between males and females. Sex differences in neurobehavioral and cognitive function after various forms of central nervous system (CNS) injury are observed in clinical practice and animal research studies. Sources of sex differences include early life exposure to gonadal hormones, chromosome compliment and adult hormonal modulation. It is becoming increasingly apparent that mitochondrial metabolism and cell death signaling are also sexually dimorphic. Mitochondrial metabolic dysfunction is a common feature of CNS injury. Evidence suggests males predominantly utilize proteins while females predominantly use lipids as a fuel source within mitochondria and that these differences may significantly affect cellular survival following injury. These fundamental biochemical differences have a profound impact on energy production and many cellular processes in health and disease. This review will focus on the accumulated evidence revealing sex differences in mitochondrial function and cellular signaling pathways in the context of CNS injury mechanisms and the potential implications for neuroprotective therapy development.
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Affiliation(s)
- Tyler G Demarest
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA,
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107
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Posada-Duque RA, Barreto GE, Cardona-Gomez GP. Protection after stroke: cellular effectors of neurovascular unit integrity. Front Cell Neurosci 2014; 8:231. [PMID: 25177270 PMCID: PMC4132372 DOI: 10.3389/fncel.2014.00231] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/24/2014] [Indexed: 12/16/2022] Open
Abstract
Neurological disorders are prevalent worldwide. Cerebrovascular diseases (CVDs), which account for 55% of all neurological diseases, are the leading cause of permanent disability, cognitive and motor disorders and dementia. Stroke affects the function and structure of blood-brain barrier, the loss of cerebral blood flow regulation, oxidative stress, inflammation and the loss of neural connections. Currently, no gold standard treatments are available outside the acute therapeutic window to improve outcome in stroke patients. Some promising candidate targets have been identified for the improvement of long-term recovery after stroke, such as Rho GTPases, cell adhesion proteins, kinases, and phosphatases. Previous studies by our lab indicated that Rho GTPases (Rac and RhoA) are involved in both tissue damage and survival, as these proteins are essential for the morphology and movement of neurons, astrocytes and endothelial cells, thus playing a critical role in the balance between cell survival and death. Treatment with a pharmacological inhibitor of RhoA/ROCK blocks the activation of the neurodegeneration cascade. In addition, Rac and synaptic adhesion proteins (p120 catenin and N-catenin) play critical roles in protection against cerebral infarction and in recovery by supporting the neurovascular unit and cytoskeletal remodeling activity to maintain the integrity of the brain parenchyma. Interestingly, neuroprotective agents, such as atorvastatin, and CDK5 silencing after cerebral ischemia and in a glutamate-induced excitotoxicity model may act on the same cellular effectors to recover neurovascular unit integrity. Therefore, future efforts must focus on individually targeting the structural and functional roles of each effector of neurovascular unit and the interactions in neural and non-neural cells in the post-ischemic brain and address how to promote the recovery or prevent the loss of homeostasis in the short, medium and long term.
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Affiliation(s)
- Rafael Andres Posada-Duque
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana Bogotá D.C., Colombia
| | - Gloria Patricia Cardona-Gomez
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
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