1
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Alarmins and c-Jun N-Terminal Kinase (JNK) Signaling in Neuroinflammation. Cells 2020; 9:cells9112350. [PMID: 33114371 PMCID: PMC7693759 DOI: 10.3390/cells9112350] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/08/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023] Open
Abstract
Neuroinflammation is involved in the progression or secondary injury of multiple brain conditions, including stroke and neurodegenerative diseases. Alarmins, also known as damage-associated molecular patterns, are released in the presence of neuroinflammation and in the acute phase of ischemia. Defensins, cathelicidin, high-mobility group box protein 1, S100 proteins, heat shock proteins, nucleic acids, histones, nucleosomes, and monosodium urate microcrystals are thought to be alarmins. They are released from damaged or dying cells and activate the innate immune system by interacting with pattern recognition receptors. Being principal sterile inflammation triggering agents, alarmins are considered biomarkers and therapeutic targets. They are recognized by host cells and prime the innate immune system toward cell death and distress. In stroke, alarmins act as mediators initiating the inflammatory response after the release from the cellular components of the infarct core and penumbra. Increased c-Jun N-terminal kinase (JNK) phosphorylation may be involved in the mechanism of stress-induced release of alarmins. Putative crosstalk between the alarmin-associated pathways and JNK signaling seems to be inherently interwoven. This review outlines the role of alarmins/JNK-signaling in cerebral neurovascular inflammation and summarizes the complex response of cells to alarmins. Emerging anti-JNK and anti-alarmin drug treatment strategies are discussed.
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2
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Lin J, Fang Y, Zhang M, Wang X, Li L, He M, Xue A, Zhu K, Shen Y, Li B. Phosphorylation of PRAS40 contributes to the activation of the PI3K/AKT/mTOR signaling pathway and the inhibition of autophagy following status epilepticus in rats. Exp Ther Med 2020; 20:3625-3632. [PMID: 32855714 PMCID: PMC7444373 DOI: 10.3892/etm.2020.9085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 06/02/2020] [Indexed: 12/30/2022] Open
Abstract
Status epilepticus (SE) is a neurological disorder associated with high morbidity and mortality rates, and is often difficult to treat. Moreover, the underlying mechanism of SE remains unknown. The lithium-pilocarpine model is a validated animal model that can reproduce the main clinical and neuropathological features of SE. In the present study, this SE model was utilized and SE was successfully established in rats, as determined by the corresponding epileptic electroencephalogram. Histology, immunohistochemistry, western blot analysis and co-immunoprecipitation were used to detect the phosphorylation (p-) of AKT substrate of 40 kDa (PRAS40), the combination of p-PRAS40 and 14-3-3 protein and the activation of the PI3K/mTOR signaling pathway in SE. In addition, the present study analyzed the dynamics of the expression of autophagy-associated factors in the hippocampus after SE induction, and the influence of suppressing the p- of PRAS40 on the autophagy process was detected in the pathogenesis of SE. The results indicated that increased p-PRAS40 expression could activate the mTOR pathway to decrease the level of autophagy. However, inhibition of the mTOR signaling pathway promoted autophagy flux. These results may provide further understanding of p-PRAS40 functions in SE.
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Affiliation(s)
- Junyi Lin
- School of Policing Studies, Shanghai University of Political Science and Law, Shanghai 201701, P.R. China.,Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Youxin Fang
- General Family Medicine Clinic, Xuhui District Xietu Subdistrict Community Healthcare Center, Shanghai 200120, P.R. China
| | - Mingchang Zhang
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Xiang Wang
- Institute of Forensic Science, Jiading Branch of Shanghai Public Security Bureau, Shanghai 201800, P.R. China
| | - Liliang Li
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Meng He
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Aimin Xue
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Keming Zhu
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Yiwen Shen
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Beixu Li
- School of Policing Studies, Shanghai University of Political Science and Law, Shanghai 201701, P.R. China.,Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
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3
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Gao Y, Luo C, Yao Y, Huang J, Fu H, Xia C, Ye G, Yu L, Han J, Fan Y, Tao L. IL-33 Alleviated Brain Damage via Anti-apoptosis, Endoplasmic Reticulum Stress, and Inflammation After Epilepsy. Front Neurosci 2020; 14:898. [PMID: 32982679 PMCID: PMC7487557 DOI: 10.3389/fnins.2020.00898] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/31/2020] [Indexed: 12/12/2022] Open
Abstract
Interleukin (IL)-33 belongs to a novel chromatin-associated cytokine newly recognized by the IL-1 family, and its specific receptor is the orphan IL-1 receptor (ST2). Cumulative evidence suggests that IL-33 plays a crucial effect on the pathological changes and pathogenesis of central nervous system (CNS) diseases and injuries, such as recurrent neonatal seizures (RNS). However, the specific roles of IL-33 and its related molecular mechanisms in RNS remain confused. In the present study, we investigated the protein expression changes and co-localized cell types of IL-33 or ST2, as well as the effect of IL-33 on RNS-induced neurobehavioral defects, weight loss, and apoptosis. Moreover, an inhibitor of IL-33, anti-IL-33 was performed to further exploited underlying mechanisms. We found that administration of IL-33 up-regulated the expression levels of IL-33 and ST2, and increased the number of its co-localization with Olig-2-positive oligodendrocytes and NeuN-positive neurons at 72 h post-RNS. Noteworthily, RNS-induced neurobehavioral deficits, bodyweight loss, and spatial learning and memory impairment, as well as cell apoptosis, were reversed by IL-33 pretreatment. Additionally, the increase in IL-1β and TNF-α levels, up-regulation of ER stress, as well as a decrease in anti-apoptotic protein Bcl-2 and an increase in pro-apoptotic protein CC-3 induced by RNS are prevented by administration of IL-33. Moreover, IL-33 in combination with Anti-IL-33 significantly inverted the effects of IL-33 or Anti-IL-33 alone on apoptosis, ER stress, and inflammation. Collectively, these data suggest that IL-33 attenuates RNS-induced neurobehavioral disorders, bodyweight loss, and spatial learning and memory deficits, at least in part through mechanisms involved in inhibition of apoptosis, ER stress, and neuro-inflammation.
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Affiliation(s)
- Yuan Gao
- Department of Forensic Science, Medical College of Soochow University, Suzhou, China.,Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China.,Shanghai Key Laboratory of Forensic Medicine, Department of Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai, China
| | - Chengliang Luo
- Department of Forensic Science, Medical College of Soochow University, Suzhou, China
| | - Yi Yao
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Junjie Huang
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Huifang Fu
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,Department of Pathology, Traditional Chinese Medicine Hospital, Nanjing, China
| | - Chongjian Xia
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Guanghua Ye
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Linsheng Yu
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Junge Han
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Yanyan Fan
- Department of Forensic Science, Wenzhou Medical University, Wenzhou, China.,The Forensic Center, Wenzhou Medical University, Wenzhou, China.,Center of Basic Medical Experiment, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, China
| | - Luyang Tao
- Department of Forensic Science, Medical College of Soochow University, Suzhou, China
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4
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Jung S, Ballheimer YE, Brackmann F, Zoglauer D, Geppert CI, Hartmann A, Trollmann R. Seizure-induced neuronal apoptosis is related to dysregulation of the RNA-edited GluR2 subunit in the developing mouse brain. Brain Res 2020; 1735:146760. [PMID: 32142720 DOI: 10.1016/j.brainres.2020.146760] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 02/27/2020] [Accepted: 03/02/2020] [Indexed: 12/28/2022]
Abstract
Ca2+-permeable AMPA receptors (AMPAR) which crucially modify maturational programs of the developing brain are involved in seizure-induced glutamate excitotoxicity and apoptosis. Regulatory effects on AMPAR subunit composition and RNA-editing in the developing brain and their significance as therapeutic targets are not well understood. Here, we analyzed acute effects of recurrent pilocarpine-induced neonatal seizures on age- and region-specific expression of AMPAR subunits and adenosine deaminases (ADAR) in the developing mouse brain (P10). After recurrent seizure activity and regeneration periods of 6-72 h cerebral mRNA levels of GluR (glutamate receptor subunit) 1, GluR2, GluR3, and GluR4 were unaffected compared to controls. However, ratio of GluR2 and GluR4 to pooled GluR1-4 mRNA concentration significantly decreased in seizure-exposed brains in comparison to controls. After a regeneration period of 24-72 h ADAR1 and ADAR2 mRNA expression was significantly lower in seizure-exposed brains than in those of controls. This was confirmed at the protein level in the hippocampal CA3 region. We observed a regionally increased apoptosis (TUNEL+ and CC3+ cells) in the hippocampus, parietal cortex and subventricular zone of seizure-exposed brains in comparison to controls. Together, present in vivo data demonstrate the maturational age-specific, functional role of RNA-edited GluR2 in seizure-induced excitotoxicity in the developing mouse brain. In response to recurrent seizure activity, we observed reduced expression of GluR2 and the GluR2 mRNA-editing enzymes ADAR1 and ADAR2 accompanied by increased apoptosis in a region-specific manner. Thus, AMPA receptor subtype-specific mRNA editing is assessed as a promising target of novel neuroprotective treatment strategies in consideration of age-related developmental mechanisms.
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Affiliation(s)
- Susan Jung
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Yili E Ballheimer
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Florian Brackmann
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Daniel Zoglauer
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Carol-Immanuel Geppert
- Institute of Pathology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Arndt Hartmann
- Institute of Pathology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Regina Trollmann
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
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5
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Li Q, Han Y, Du J, Jin H, Zhang J, Niu M, Qin J. Alterations of apoptosis and autophagy in developing brain of rats with epilepsy: Changes in LC3, P62, Beclin-1 and Bcl-2 levels. Neurosci Res 2018; 130:47-55. [DOI: 10.1016/j.neures.2017.08.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/20/2017] [Accepted: 08/07/2017] [Indexed: 01/10/2023]
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6
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Ketogenic diet attenuates neuronal injury via autophagy and mitochondrial pathways in pentylenetetrazol-kindled seizures. Brain Res 2018; 1678:106-115. [DOI: 10.1016/j.brainres.2017.10.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 09/20/2017] [Accepted: 10/07/2017] [Indexed: 11/24/2022]
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7
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Gao Y, Luo CL, Li LL, Ye GH, Gao C, Wang HC, Huang WW, Wang T, Wang ZF, Ni H, Chen XP, Tao LY. IL-33 Provides Neuroprotection through Suppressing Apoptotic, Autophagic and NF-κB-Mediated Inflammatory Pathways in a Rat Model of Recurrent Neonatal Seizure. Front Mol Neurosci 2017; 10:423. [PMID: 29311813 PMCID: PMC5742123 DOI: 10.3389/fnmol.2017.00423] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/04/2017] [Indexed: 12/19/2022] Open
Abstract
Interleukin-33 (IL-33) is a novel identified chromatin-associated cytokine of IL-1 family cytokines. It signals through a heterodimer comprised of ST2L and IL-1RAcp, and plays a crucial role in many diseases. However, very little is known about the role and underlying intricate mechanisms of IL-33 in recurrent neonatal seizure (RNS). To determine whether IL-33 plays an important regulatory role, we established a neonatal seizure model in this study. Rats were subjected to recurrent seizures induced by inhaling volatile flurothyl. Recombinant IL-33 or PBS were also administered by intraperitoneally (IP) before surgery, respectively. Here, our current results indicated that RNS contributed to a significant reduction in IL-33 and its specific receptor (ST2L) expressions in cortex. While, in hippocampus, RNS induced an increase in IL-33 and ST2L evidently, compared with Sham group. After injection with IL-33, however, a remarkable increase in total IL-33 was detected both in brain cortex and hippocampus. In addition, IL-33 was mainly co-localized in the nuclear of GFAP+ astrocytes and the cytoplasm of the Iba-1+ microglia and IL-33+/NeuN+ merged cells. In parallel, ST2L was expressed mainly in the membrane of GFAP+ astrocytes, Iba-1+ microglia and NeuN+ neurons, respectively. Furthermore, administration of IL-33 improved RNS-induced behavioral deficits, promoted bodyweight gain, and ameliorated spatial learning and memory ability. Moreover, IL-33 pretreatment blocked the activation of NF-κB, resisted inflammatory cytokines IL-1β and TNF-α increase, as well as suppressed apoptosis and autophagy activation after RNS. Collectively, IL-33 provides potential neuroprotection through suppressing apoptosis, autophagy and at least in part by NF-κB-mediated inflammatory pathways after RNS.
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Affiliation(s)
- Yuan Gao
- Department of Forensic Medicine, Wenzhou Medical University, Wenzhou, China.,Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Cheng-Liang Luo
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Li-Li Li
- Department of Neurology Laboratory, Children's Hospital of Soochow University, Suzhou, China
| | - Guang-Hua Ye
- Department of Forensic Medicine, Wenzhou Medical University, Wenzhou, China
| | - Cheng Gao
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Hao-Chen Wang
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Wen-Wen Huang
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Tao Wang
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Zu-Feng Wang
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Hong Ni
- Department of Neurology Laboratory, Children's Hospital of Soochow University, Suzhou, China
| | - Xi-Ping Chen
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
| | - Lu-Yang Tao
- Department of Forensic Medicine, Medical School of Soochow University, Suzhou, China
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8
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Li Q, Han Y, Du J, Jin H, Zhang J, Niu M, Qin J. Recombinant Human Erythropoietin Protects Against Hippocampal Damage in Developing Rats with Seizures by Modulating Autophagy via the S6 Protein in a Time-Dependent Manner. Neurochem Res 2017; 43:465-476. [PMID: 29238892 DOI: 10.1007/s11064-017-2443-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/19/2017] [Accepted: 11/30/2017] [Indexed: 12/16/2022]
Abstract
Epilepsy is among the most common neurological disorders. Recurrent seizures result in neuronal death, cognitive deficits and intellectual disabilities in children. Currently, recombinant human erythropoietin (rhEPO) is considered to play a neuroprotective role in nervous system disorders. However, the precise mechanisms through which rhEPO modulates epilepsy remain unknown. Based on results from numerous studies, we hypothesized that rhEPO protects against hippocampal damage in developing rats with seizures probably by modulating autophagy via the ribosomal protein S6 (S6) in a time-dependent manner. First, we observed that rats with recurrent seizures displayed neuronal loss in the hippocampal CA1 region. Second, rhEPO injection reduced neuronal loss and decreased the number of apoptotic cells in the hippocampal CA1 region. Moreover, rhEPO increased the Bcl-2 protein expression levels and decreased the ratio of cleaved caspase-3/caspase-3 in the hippocampus. Finally, rhEPO modulated autophagy in the hippocampus in a time-dependent manner, probably via the S6 protein. In summary, rhEPO protects against hippocampal damage in developing rats with seizures by modulating autophagy in a time-dependent manner, probably via the S6 protein. Consequently, rhEPO is a likely drug candidate that is capable of attenuating brain injury.
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Affiliation(s)
- Qinrui Li
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi-An Men Street, Beijing, 100034, People's Republic of China
| | - Ying Han
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi-An Men Street, Beijing, 100034, People's Republic of China.
| | - Junbao Du
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi-An Men Street, Beijing, 100034, People's Republic of China
| | - Hongfang Jin
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi-An Men Street, Beijing, 100034, People's Republic of China
| | - Jing Zhang
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi-An Men Street, Beijing, 100034, People's Republic of China
| | - Manman Niu
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi-An Men Street, Beijing, 100034, People's Republic of China
| | - Jiong Qin
- Department of Pediatrics, Peking University People's Hospital, No. 11, Xi Zhi Men Street, Beijing, 100044, People's Republic of China.
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9
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Okerlund ND, Schneider K, Leal-Ortiz S, Montenegro-Venegas C, Kim SA, Garner LC, Waites CL, Gundelfinger ED, Reimer RJ, Garner CC. Bassoon Controls Presynaptic Autophagy through Atg5. Neuron 2017; 93:897-913.e7. [DOI: 10.1016/j.neuron.2017.01.026] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 06/28/2016] [Accepted: 01/25/2017] [Indexed: 12/22/2022]
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10
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Xia L, Lei Z, Shi Z, Guo D, Su H, Ruan Y, Xu ZC. Enhanced autophagy signaling in diabetic rats with ischemia-induced seizures. Brain Res 2016; 1643:18-26. [DOI: 10.1016/j.brainres.2016.04.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/15/2016] [Accepted: 04/22/2016] [Indexed: 10/21/2022]
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11
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Cannabidiol Post-Treatment Alleviates Rat Epileptic-Related Behaviors and Activates Hippocampal Cell Autophagy Pathway Along with Antioxidant Defense in Chronic Phase of Pilocarpine-Induced Seizure. J Mol Neurosci 2016; 58:432-40. [DOI: 10.1007/s12031-015-0703-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 12/15/2015] [Indexed: 12/13/2022]
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12
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Maiese K. Targeting molecules to medicine with mTOR, autophagy and neurodegenerative disorders. Br J Clin Pharmacol 2015; 82:1245-1266. [PMID: 26469771 DOI: 10.1111/bcp.12804] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 10/11/2015] [Accepted: 10/13/2015] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are significantly increasing in incidence as the age of the global population continues to climb with improved life expectancy. At present, more than 30 million individuals throughout the world are impacted by acute and chronic neurodegenerative disorders with limited treatment strategies. The mechanistic target of rapamycin (mTOR), also known as the mammalian target of rapamycin, is a 289 kDa serine/threonine protein kinase that offers exciting possibilities for novel treatment strategies for a host of neurodegenerative diseases that include Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, stroke and trauma. mTOR governs the programmed cell death pathways of apoptosis and autophagy that can determine neuronal stem cell development, precursor cell differentiation, cell senescence, cell survival and ultimate cell fate. Coupled to the cellular biology of mTOR are a number of considerations for the development of novel treatments involving the fine control of mTOR signalling, tumourigenesis, complexity of the apoptosis and autophagy relationship, functional outcome in the nervous system, and the intimately linked pathways of growth factors, phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), AMP activated protein kinase (AMPK), silent mating type information regulation two homologue one (Saccharomyces cerevisiae) (SIRT1) and others. Effective clinical translation of the cellular signalling mechanisms of mTOR offers provocative avenues for new drug development in the nervous system tempered only by the need to elucidate further the intricacies of the mTOR pathway.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey, 07101, USA.
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13
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Rami A, Benz AP, Niquet J, Langhagen A. Axonal Accumulation of Lysosomal-Associated Membrane Protein 1 (LAMP1) Accompanying Alterations of Autophagy Dynamics in the Rat Hippocampus Upon Seizure-Induced Injury. Neurochem Res 2015; 41:53-63. [PMID: 26329516 DOI: 10.1007/s11064-015-1704-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/11/2015] [Accepted: 08/18/2015] [Indexed: 02/02/2023]
Abstract
We found a dramatic upregulation in the expression of LC3 in the hippocampus of rats upon status epilepticus (SE). However, the enhancement in LC3 expression might be caused by a reduction in lysosomal activity or by alterations in autophagosome-lysosome fusion leading to a cytosolic vesicular retention. In order to dissect this aspect, we monitored the spatial and temporal expression of LC3 and LAMP1 in the hippocampus of rats with SE. The Western blot analysis showed that the expression of LAMP1 was slightly increased in hippocampal cells at 6, 24, and 48 h post-SE. However, immunofluorescence analysis showed dramatic spatial changes in LAMP1 distribution within the hippocampus. LAMP1 in controls was localised only in cytosol as dot like staining, however at 24 h post-SE LAMP1 was not only highly expressed, but accumulated in mossy fibers of dentate gyrus. In parallel, we found few scattered LC3-positive-dots in neurites of dentate gyrus which co-localise with LAMP1-positive structures. We conclude that SE not only increased autophagosomal abundance, but also lysosomal activities and a massive accumulation of LAMP1 in axons of dentate gyrus. This could support the hypothesis that the marked increased autophagosomal abundance in cytosol reflects an increase in the autophagic activity more than an inhibition of autophagosomal clearance. Although LAMP1 may have contributed to cell damage in the selective vulnerable hippocampal CA1-subfield, it is also possible that lysosomal/autophagic mechanisms in mossy fibers were compensatory and reflected an attempt to survive the epileptic insult by breaking down non-essential components.
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Affiliation(s)
- A Rami
- Institut für Zelluläre und Molekulare Anatomie (Anatomie III), Klinikum der Johann Wolfgang von Goethe-Universität, Theodor-Stern-Kai 7, 60590, Frankfurt/Main, Germany.
| | - A P Benz
- Institut für Zelluläre und Molekulare Anatomie (Anatomie III), Klinikum der Johann Wolfgang von Goethe-Universität, Theodor-Stern-Kai 7, 60590, Frankfurt/Main, Germany
| | - J Niquet
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - A Langhagen
- Institut für Zelluläre und Molekulare Anatomie (Anatomie III), Klinikum der Johann Wolfgang von Goethe-Universität, Theodor-Stern-Kai 7, 60590, Frankfurt/Main, Germany
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