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Wang LC, Wei WY, Ho PC. Short-Term Cortical Electrical Stimulation during the Acute Stage of Traumatic Brain Injury Improves Functional Recovery. Biomedicines 2022; 10:biomedicines10081965. [PMID: 36009512 PMCID: PMC9405844 DOI: 10.3390/biomedicines10081965] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/03/2022] [Accepted: 08/10/2022] [Indexed: 11/16/2022] Open
Abstract
Functional restoration is an important issue in the treatment of traumatic brain injury (TBI). Various electrical stimulation devices and protocols have been applied in preclinical studies and have shown therapeutic potential for brain trauma. Short-term invasive cortical electrical stimulation during the acute stage of TBI might be a feasible adjuvant therapy for patients with moderate-to-severe brain injury receiving neurosurgical treatment in the intensive care unit. However, the therapeutic effects of short-term multisession cortical electrical stimulation for brain trauma are not clear. This study explored the therapeutic effects of acute-stage short-term cortical electrical stimulation on TBI. We conducted seven sessions of one-hour cortical electrical stimulation from day 0 to day 6 in rats after brain trauma by controlled cortical impact and then evaluated the functional outcome and histopathological changes. Our data showed that short-term cortical electrical stimulation improved motor coordination, short-term memory, and learning ability and attenuated neurological severity after brain trauma. Lesion volume, apoptosis, and gliosis after brain trauma were reduced, and trauma-induced neurogenesis in the hippocampus for the innate neural reparative response was increased. Our study demonstrated that short-term cortical electrical stimulation applied in the acute stage of traumatic brain injury is a potential adjuvant therapy to improve the recovery of neurological deficits.
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Affiliation(s)
- Liang-Chao Wang
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
- Division of Neurosurgery, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
- Correspondence: ; Tel.: +886-6-2353535 (ext. 5284)
| | - Wei-Yen Wei
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Pei-Chuan Ho
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
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Zhang B, Yang M, Yan Q, Xu X, Niu F, Dong J, Zhuang Y, Lu S, Ge Q, Liu B. The Dual Dose-Dependent Effects of Corticosterone on Hippocampal Cell Apoptosis After Traumatic Brain Injury Depend on the Activation Ratio of Mineralocorticoid Receptors to Glucocorticoid Receptors. Front Pharmacol 2021; 12:713715. [PMID: 34381366 PMCID: PMC8350576 DOI: 10.3389/fphar.2021.713715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/13/2021] [Indexed: 01/11/2023] Open
Abstract
In our recent studies, we reported that mineralocorticoid receptor (MR) had the opposite effects of glucocorticoid receptor (GR) on neural cell survival after traumatic brain injury (TBI). However, whether short-term use of high-dose natural glucocorticoids, which are mixed agonists of both MR and GR, leads to neurotoxic effects by inducing excessive GR activation is unclear, as is the threshold GR activation level and the possible signaling pathways remain unclear. In this study, we examined the dual dose-dependent effects of corticosterone (CORT) on spatial memory, hippocampal cell survival and receptor-mediated downstream signaling pathways after TBI. We found that different doses of CORT exhibited dual effects on hippocampal cell survival and rat spatial memory. Low doses of CORT (0.3 and 3 mg/kg) significantly increased MR activation, upregulated Akt/CREB/Bad phosphorylation and Bcl-2 concentration, reduced the number of apoptotic neural cells, and subsequently improved rat spatial memory. In contrast, a high dose of CORT (30 mg/kg) exerted the opposite effects by overactivating GR, upregulating P53/Bax levels, and inhibiting Erk/CREB activity. The results suggest that the neuroprotective and neurotoxic effects of endogenous GC depend on a threshold level and that a higher dose of GC, even for short-term use, should be avoided after TBI.
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Affiliation(s)
- Bin Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Mengshi Yang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Qiongyu Yan
- Department of Pharmacy, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiaojian Xu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Fei Niu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Jinqian Dong
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yuan Zhuang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Shenghua Lu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Qianqian Ge
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Baiyun Liu
- Department of Neurosurgery and Beijing Key Laboratory of Central Nervous System Injury, Beijing Tiantan Hospital and Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Nerve Injury and Repair Center of Beijing Institute for Brain Disorders, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China
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Vita SM, Redell JB, Maynard ME, Zhao J, Grill RJ, Dash PK, Grayson BE. P-glycoprotein Expression Is Upregulated in a Pre-Clinical Model of Traumatic Brain Injury. Neurotrauma Rep 2020; 1:207-217. [PMID: 33274346 PMCID: PMC7703495 DOI: 10.1089/neur.2020.0034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Athletes participating in contact sports are at risk for sustaining repeat mild traumatic brain injury (rmTBI). Unfortunately, no pharmacological treatment to lessen the pathophysiology of brain injury has received U.S. Food and Drug Administration (FDA) approval. One hurdle to overcome for potential candidate agents to reach effective therapeutic concentrations in the brain is the blood-brain barrier (BBB). Adenosine triphosphate (ATP)-binding cassette (ABC) transporters, such as P-glycoprotein (Pgp), line the luminal membrane of the brain capillary endothelium facing the vascular space. Although these transporters serve to protect the central nervous system (CNS) from damage by effluxing neurotoxicants before they can reach the brain, they may also limit the accumulation of therapeutic drugs in the brain parenchyma. Thus, increased Pgp expression following brain injury may result in reduced brain availability of therapeutic agents. We therefore questioned if repeat concussive injury increases Pgp expression in the brain. To answer this question, we used a rodent model of repeat mild closed head injury (rmCHI) and examined the messenger RNA (mRN) and protein expression of both isoforms of rodent Pgp (Abcb1a and Abcb1b). Compared with sham-operated controls (n = 5), the mRNA levels of both Abcb1a and Abcb1b were found to be increased in the hippocampus at day 1 (n = 5) and at day 5 (n = 5) post-injury. Using a validated antibody, we show increased immunolabeling for Pgp in the dorsal cortex at day 5 and in the hippocampus at day 1 (n = 5) and at day 5 (n = 5) post-injury compared with sham controls (n = 6). Taken together, these results suggest that increased expression of Pgp after rmCHI may reduce the brain accumulation of therapeutic drugs that are Pgp substrates. It is plausible that including a Pgp inhibitor with a candidate therapeutic agent may be an effective approach to treat the pathophysiology of rmCHI.
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Affiliation(s)
- Sydney M Vita
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - John B Redell
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, Texas, USA
| | - Mark E Maynard
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, Texas, USA
| | - Jing Zhao
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, Texas, USA
| | - Raymond J Grill
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Pramod K Dash
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, Texas, USA
| | - Bernadette E Grayson
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, USA
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Zhang B, Bai M, Xu X, Yang M, Niu F, Gao F, Liu B. Corticosteroid receptor rebalancing alleviates critical illness-related corticosteroid insufficiency after traumatic brain injury by promoting paraventricular nuclear cell survival via Akt/CREB/BDNF signaling. J Neuroinflammation 2020; 17:318. [PMID: 33100225 PMCID: PMC7586672 DOI: 10.1186/s12974-020-02000-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/16/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND We previously found that high-dose methylprednisolone increased the incidence of critical illness-related corticosteroid insufficiency (CIRCI) and mortality in rats with traumatic brain injury (TBI), whereas low-dose hydrocortisone but not methylprednisolone exerted protective effects. However, the receptor-mediated mechanism remains unclear. This study investigated the receptor-mediated mechanism of the opposite effects of different glucocorticoids on the survival of paraventricular nucleus (PVN) cells and the incidence of CIRCI after TBI. METHODS Based on controlled cortical impact (CCI) and treatments, male SD rats (n = 300) were randomly divided into the sham, CCI, CCI + GCs (methylprednisolone 1 or 30 mg/kg/day; corticosterone 1 mg/kg/day), CCI + methylprednisolone+RU486 (RU486 50 mg/kg/day), and CCI + corticosterone+spironolactone (spironolactone 50 mg/kg/day) groups. Blood samples were collected 7 days before and after CCI. Brain tissues were collected on postinjury day 7 and processed for histology and western blot analysis. RESULTS We examined the incidence of CIRCI, mortality, apoptosis in the PVN, the receptor-mediated mechanism, and downstream signaling pathways on postinjury day 7. We found that methylprednisolone and corticosterone exerted opposite effects on the survival of PVN cells and the incidence of CIRCI by activating different receptors. High-dose methylprednisolone increased the nuclear glucocorticoid receptor (GR) level and subsequently increased cell loss in the PVN and the incidence of CIRCI. In contrast, low-dose corticosterone but not methylprednisolone played a protective role by upregulating mineralocorticoid receptor (MR) activation. The possible downstream receptor signaling mechanism involved the differential effects of GR and MR on the activity of the Akt/CREB/BDNF pathway. CONCLUSION The excessive activation of GR by high-dose methylprednisolone exacerbated apoptosis in the PVN and increased CIRCI. In contrast, refilling of MR by corticosterone protects PVN neurons and reduces the incidence of CIRCI by promoting GR/MR rebalancing after TBI.
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Affiliation(s)
- Bin Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Miao Bai
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Xiaojian Xu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Mengshi Yang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Fei Niu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Fei Gao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Baiyun Liu
- Beijing Key Laboratory of Central Nervous System Injury and Department of Neurosurgery, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, No.119 South Fourth Ring West Road, Fengtai District, Beijing, 100070, People's Republic of China.
- Nerve Injury and Repair Center of Beijing Institute for Brain Disorders, Beijing, China.
- China National Clinical Research Center for Neurological Diseases, Beijing, China.
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Carlson SW, Saatman KE. Central Infusion of Insulin-Like Growth Factor-1 Increases Hippocampal Neurogenesis and Improves Neurobehavioral Function after Traumatic Brain Injury. J Neurotrauma 2018; 35:1467-1480. [PMID: 29455576 PMCID: PMC5998830 DOI: 10.1089/neu.2017.5374] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Traumatic brain injury (TBI) produces neuronal dysfunction and cellular loss that can culminate in lasting impairments in cognitive and motor abilities. Therapeutic agents that promote repair and replenish neurons post-TBI hold promise in improving recovery of function. Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor capable of mediating neuroprotective and neuroplasticity mechanisms. Targeted overexpression of IGF-1 enhances the generation of hippocampal newborn neurons in brain-injured mice; however, the translational neurogenic potential of exogenously administered IGF-1 post-TBI remains unknown. In a mouse model of controlled cortical impact, continuous intracerebroventricular infusion of recombinant human IGF-1 (hIGF) for 7 days, beginning 15 min post-injury, resulted in a dose-dependent increase in the number of immature neurons in the hippocampus. Infusion of 10 μg/day of IGF-1 produced detectable levels of hIGF-1 in the cortex and hippocampus and a concomitant increase in protein kinase B activation in the hippocampus. Both motor function and cognition were improved over 7 days post-injury in IGF-1-treated cohorts. Vehicle-treated brain-injured mice showed reduced hippocampal immature neuron density relative to sham controls at 7 days post-injury. In contrast, the density of hippocampal immature neurons in brain-injured mice receiving acute onset IGF-1 infusion was significantly higher than in injured mice receiving vehicle and equivalent to that in sham-injured control mice. Importantly, the neurogenic effect of IGF-1 was maintained with as much as a 6-h delay in the initiation of infusion. These data suggest that central infusion of IGF-1 enhances the generation of immature neurons in the hippocampus, with a therapeutic window of at least 6 h post-injury, and promotes neurobehavioral recovery post-TBI.
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Affiliation(s)
- Shaun W. Carlson
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
| | - Kathryn E. Saatman
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky
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Zuo W, Yan F, Zhang B, Hu X, Mei D. Salidroside improves brain ischemic injury by activating PI3K/Akt pathway and reduces complications induced by delayed tPA treatment. Eur J Pharmacol 2018; 830:128-138. [PMID: 29626425 DOI: 10.1016/j.ejphar.2018.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/29/2018] [Accepted: 04/03/2018] [Indexed: 10/17/2022]
Abstract
Cerebral ischemia causes blood-brain barrier (BBB) injury and thus increases the risk of complications secondary to thrombolysis, which limited its clinical application. This study aims to clarify the role and mechanism of salidroside (SALD) in alleviating brain ischemic injury and whether pretreatment of it could improve prognosis of delayed treatment of tissue plasminogen activator (t-PA). Rats were subjected to 3 h of middle cerebral artery occlusion (MCAO) and were intraperitoneally administered with 10, 20 or 40 mg/kg SALD before ischemia. 1.5% 5-triphenyl-2H-tetrazolium chloride (TTC) staining and neurological studies were performed to observe the effectiveness of SALD. The expressions and the distribution of phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) signaling were analyzed. Experiments were further conducted in isolated microvessels and human brain microvascular endothelial cells (HBMECs) to explore the protective mechanism of SALD. Finally, rats were subjected to 6 h of MCAO and 24 h of reperfusion. tPA was given with or without the pretreatment of SALD. Various approaches including gelatin zymography, western blot and immunofluorescence were used to evaluate the effect of this combination therapy. SALD could reduce cerebral ischemic injury and enhance HBMECs viability subjected to OGD. In vivo and in vitro studies showed the mechanism might be related to the activation of PI3K/Akt signaling by phosphorylating Akt on Ser473. Pretreatment of SALD could alleviate BBB injury and improve the outcome of delayed treatment of tPA. These results provide evidence that SALD might be an effective adjuvant to reduce the complications induced by delayed tPA treatment for brain ischemia.
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Affiliation(s)
- Wei Zuo
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China
| | - Feng Yan
- Center for Brain Disorders Research, Capital Mexical University, PR China; Beijing Institute for Brain Disorders, PR China; Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, Beijing, PR China
| | - Bo Zhang
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China
| | - Xiaomin Hu
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China
| | - Dan Mei
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China.
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Wang Y, Sawyer TW, Tse YC, Fan C, Hennes G, Barnes J, Josey T, Weiss T, Nelson P, Wong TP. Primary Blast-Induced Changes in Akt and GSK 3β Phosphorylation in Rat Hippocampus. Front Neurol 2017; 8:413. [PMID: 28868045 PMCID: PMC5563325 DOI: 10.3389/fneur.2017.00413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/31/2017] [Indexed: 12/30/2022] Open
Abstract
Traumatic brain injury (TBI) due to blast from improvised explosive devices has been a leading cause of morbidity and mortality in recent conflicts in Iraq and Afghanistan. However, the mechanisms of primary blast-induced TBI are not well understood. The Akt signal transduction pathway has been implicated in various brain pathologies including TBI. In the present study, the effects of simulated primary blast waves on the phosphorylation status of Akt and its downstream effector kinase, glycogen synthase kinase 3β (GSK3β), in rat hippocampus, were investigated. Male Sprague-Dawley (SD) rats (350–400 g) were exposed to a single pulse shock wave (25 psi; ~7 ms duration) and sacrificed 1 day, 1 week, or 6 weeks after exposure. Total and phosphorylated Akt, as well as phosphorylation of its downstream effector kinase GSK3β (at serine 9), were detected with western blot analysis and immunohistochemistry. Results showed that Akt phosphorylation at both serine 473 and threonine 308 was increased 1 day after blast on the ipsilateral side of the hippocampus, and this elevation persisted until at least 6 weeks postexposure. Similarly, phosphorylation of GSK3β at serine 9, which inhibits GSK3β activity, was also increased starting at 1 day and persisted until at least 6 weeks after primary blast on the ipsilateral side. In contrast, p-Akt was increased at 1 and 6 weeks on the contralateral side, while p-GSK3β was increased 1 day and 1 week after primary blast exposure. No significant changes in total protein levels of Akt and GSK were observed on either side of the hippocampus at any time points. Immunohistochemical results showed that increased p-Akt was mainly of neuronal origin in the CA1 region of the hippocampus and once phosphorylated, the majority was translocated to the dendritic and plasma membranes. Finally, electrophysiological data showed that evoked synaptic N-methyl-d-aspartate (NMDA) receptor activity was significantly increased 6 weeks after primary blast, suggesting that increased Akt phosphorylation may enhance synaptic NMDA receptor activation, or that enhanced synaptic NMDA receptor activation may increase Akt phosphorylation.
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Affiliation(s)
- Yushan Wang
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Thomas W Sawyer
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Yiu Chung Tse
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
| | - Changyang Fan
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Grant Hennes
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Julia Barnes
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Tyson Josey
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Tracy Weiss
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Peggy Nelson
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Tak Pan Wong
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
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Sarkis GA, Mangaonkar MD, Moghieb A, Lelling B, Guertin M, Yadikar H, Yang Z, Kobeissy F, Wang KKW. The Application of Proteomics to Traumatic Brain and Spinal Cord Injuries. Curr Neurol Neurosci Rep 2017; 17:23. [DOI: 10.1007/s11910-017-0736-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Labroo P, Shea J, Sant H, Gale B, Agarwal J. Effect Of combining FK506 and neurotrophins on neurite branching and elongation. Muscle Nerve 2016; 55:570-581. [PMID: 27503321 DOI: 10.1002/mus.25370] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 07/28/2016] [Accepted: 08/05/2016] [Indexed: 12/21/2022]
Abstract
INTRODUCTION There is a clinical need to improve the outcomes of peripheral nerve regeneration and repair after injury. In addition to its immunosuppressive effects, FK506 (tacrolimus) has been shown to have neuroregenerative properties. To determine biologically relevant local FK506 and growth factor concentrations, we performed an in vitro bioassay using dorsal root ganglion (DRG) from chicken embryos. METHODS Neurite elongation and neurite branching were analyzed microscopically after addition of FK506, glial cell line-derived neurotrophic factor (GDNF), and nerve growth factor (NGF), each alone and in combination. RESULTS FK506 induced modest neurite elongation (∼500-800 µm) without improving neurite branching significantly. The combination of FK506 with NGF, GDNF, or both, exerted a potentiating or competitive effect on neurite elongation (∼700-1100 µm) based on dosage and competitive effect on neurite branching (∼0.2-0.4). CONCLUSIONS These results strongly suggest that the interaction of FK506 with GDNF and NGF mediates distinct enhancement of neurite growth. Muscle Nerve 55: 570-581, 2017.
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Affiliation(s)
- Pratima Labroo
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Jill Shea
- Department of Surgery, University of Utah, 30 N 1900 E, 3b400, Salt Lake City, Utah, 84132, USA
| | - Himanshu Sant
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Bruce Gale
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Jayant Agarwal
- Department of Surgery, University of Utah, 30 N 1900 E, 3b400, Salt Lake City, Utah, 84132, USA
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Ahn SM, Kim HN, Kim YR, Choi YW, Kim CM, Shin HK, Choi BT. Emodin from Polygonum multiflorum ameliorates oxidative toxicity in HT22 cells and deficits in photothrombotic ischemia. JOURNAL OF ETHNOPHARMACOLOGY 2016; 188:13-20. [PMID: 27151150 DOI: 10.1016/j.jep.2016.04.058] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/15/2016] [Accepted: 04/30/2016] [Indexed: 06/05/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Polygonum multiflorum Thunb. has been used widely in East Asia in treatment of diseases associated with aging. Emodin, an active component from Polygonum multiflorum Thunb., provides benefits for brain disturbances induced by severe cerebral injury. AIM OF THE STUDY We investigated the neuroprotective effect of emodin from Polygonum multiflorum Thunb. against glutamate-induced oxidative toxicity and cerebral ischemia. MATERIALS AND METHODS For examination of neuroprotective effects of emodin, cell viability, cytotoxicity, flow cytometry, and Western blot were performed in HT22 cells and infarct volume, behavioral tests and Western blot in a mouse model of photothrombotic ischemic stroke. RESULTS Pretreatment with emodin resulted in significantly reduced glutamate-induced apoptotic cell death in HT22 cells. However, blocking of phosphatidylinositol-3 kinase (PI3K) activity with LY294002 resulted in significantly inhibited cell survival by emodin. Exposure of glutamate-treated cells to emodin induced an increase in the level of Bcl-2 expression, whereas the expression of Bax and active caspase-3 proteins was significantly reduced. In addition, treatment with emodin resulted in increased phosphorylation of Akt and cAMP response element binding protein (CREB), and expression of mature brain-derived neurotrophic factor (BDNF). This expression by emodin was also significantly inhibited by blocking of PI3K activity. In a photothrombotic ischemic stroke model, treatment with emodin resulted in significantly reduced infarct volume and improved motor function. We confirmed the critical role of the expression levels of Bcl-2/Bax, active caspase-3, phosphorylated (p)Akt, p-CREB, and mature BDNF for potent neuroprotective effects of emodin in cerebral ischemia. CONCLUSIONS These results suggest that emodin may afford a significant neuroprotective effect against glutamate-induced apoptosis through activation of the PI3K/Akt signaling pathway, and subsequently enhance behavioral function in cerebral ischemia.
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Affiliation(s)
- Sung Min Ahn
- Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea; Research Center for Anti-aging Technology Development, Pusan National University, Busan 46241, Republic of Korea
| | - Ha Neui Kim
- Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea; Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan 50612, Republic of Korea
| | - Yu Ri Kim
- Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea
| | - Young Whan Choi
- Research Center for Anti-aging Technology Development, Pusan National University, Busan 46241, Republic of Korea; Department of Horticultural Bioscience, College of Natural Resource and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - Cheol Min Kim
- Research Center for Anti-aging Technology Development, Pusan National University, Busan 46241, Republic of Korea; Department of Biochemistry, College of Medicine, Pusan National University, Yangsan 50612, Republic of Korea
| | - Hwa Kyoung Shin
- Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea; Research Center for Anti-aging Technology Development, Pusan National University, Busan 46241, Republic of Korea; Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan 50612, Republic of Korea; Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea
| | - Byung Tae Choi
- Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea; Research Center for Anti-aging Technology Development, Pusan National University, Busan 46241, Republic of Korea; Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan 50612, Republic of Korea; Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea.
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Dorsett CR, McGuire JL, Niedzielko TL, DePasquale EAK, Meller J, Floyd CL, McCullumsmith RE. Traumatic Brain Injury Induces Alterations in Cortical Glutamate Uptake without a Reduction in Glutamate Transporter-1 Protein Expression. J Neurotrauma 2016; 34:220-234. [PMID: 27312729 DOI: 10.1089/neu.2015.4372] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We hypothesize that the primary mechanism for removal of glutamate from the extracellular space is altered after traumatic brain injury (TBI). To evaluate this hypothesis, we initiated TBI in adult male rats using a 2.0 atm lateral fluid percussion injury (LFPI) model. In the ipsilateral cortex and hippocampus, we found no differences in expression of the primary glutamate transporter in the brain (GLT-1) 24 h after TBI. In contrast, we found a decrease in glutamate uptake in the cortex, but not the hippocampus, 24 h after injury. Because glutamate uptake is potently regulated by protein kinases, we assessed global serine-threonine protein kinase activity using a kinome array platform. Twenty-five kinome array peptide substrates were differentially phoshorylated between LFPI and controls in the cortex, whereas 19 peptide substrates were differentially phosphorylated in the hippocampus (fold change ≥ ± 1.15). We identified several kinases as likely to be involved in acute TBI, including protein kinase B (Akt) and protein kinase C (PKC), which are well-characterized modulators of GLT-1. Exploratory studies using an inhibitor of Akt suggest selective activation of kinases in LFPI versus controls. Ingenuity pathway analyses of implicated kinases from our network model found apoptosis and cell death pathways as top functions in acute LFPI. Taken together, our data suggest diminished activity of glutamate transporters in the prefrontal cortex, with no changes in protein expression of the primary glutamate transporter GLT-1, and global alterations in signaling networks that include serine-threonine kinases that are known modulators of glutamate transport activity.
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Affiliation(s)
- Christopher R Dorsett
- 1 Biological and Biomedical Sciences Doctoral Program, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Jennifer L McGuire
- 2 Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati , Cincinnati, Ohio
| | - Tracy L Niedzielko
- 3 Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham , Birmingham, Alabama
| | - Erica A K DePasquale
- 2 Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati , Cincinnati, Ohio
| | - Jaroslaw Meller
- 4 Departments of Environmental Health, Electrical Engineering & Computing Systems, and Biomedical Informatics, University of Cincinnati College of Medicine , Cincinnati, Ohio.,5 Department of Biomedical Informatics, Cincinnati Children's Hospital Medical Center , Cincinnati, Ohio
| | - Candace L Floyd
- 3 Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham , Birmingham, Alabama
| | - Robert E McCullumsmith
- 2 Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati , Cincinnati, Ohio
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12
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Shim SS, Stutzmann GE. Inhibition of Glycogen Synthase Kinase-3: An Emerging Target in the Treatment of Traumatic Brain Injury. J Neurotrauma 2016; 33:2065-2076. [PMID: 26979735 DOI: 10.1089/neu.2015.4177] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although traumatic brain injury (TBI) has been a major public health concern for decades, the pathophysiological mechanism of TBI is not clearly understood, and an effective medical treatment of TBI is not available at present. Of particular concern is sustained TBI, which has a strong tendency to take a deteriorating neurodegenerative course into chronic traumatic encephalopathy (CTE) and dementia, including Alzheimer's disease. Tauopathy and beta amyloid (Aβ) plaques are known to be the key pathological markers of TBI, which contribute to the progressive deterioration associated with TBI such as CTE and Alzheimer's disease. The multiple lines of evidence strongly suggest that the inhibition of glycogen synthase kinase-3 (GSK-3) is a potential target in the treatment of TBI. GSK-3 constitutively inhibits neuroprotective processes and promotes apoptosis. After TBI, GSK-3 is inhibited through the receptor tyrosine kinase (RTK) and canonical Wnt signaling pathways as an innate neuroprotective mechanism against TBI. GSK-3 inhibition via GSK-3 inhibitors and drugs activating RTK or Wnt signaling is likely to reinforce the innate neuroprotective mechanism. GSK-3 inhibition studies using rodent TBI models demonstrate that GSK-3 inhibition produces diverse neuroprotective actions such as reducing the size of the traumatic injury, tauopathy, Aβ accumulation, and neuronal death, by releasing and activating neuroprotective substrates from GSK-3 inhibition. These effects are correlated with reduced TBI-induced behavioral and cognitive symptoms. Here, we review studies on the therapeutic effects of GSK-3 inhibition in TBI rodent models, and critically discuss the issues that these studies address.
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Affiliation(s)
- Seong S Shim
- 1 Atlanta VA Medical Center, Mental Health Service Line , Decatur, Georgia
| | - Grace E Stutzmann
- 2 Department of Neuroscience, Rosalind Franklin University/The Chicago Medical School , North Chicago, Illinois
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13
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White TE, Surles-Zeigler MC, Ford GD, Gates AS, Davids B, Distel T, LaPlaca MC, Ford BD. Bilateral gene interaction hierarchy analysis of the cell death gene response emphasizes the significance of cell cycle genes following unilateral traumatic brain injury. BMC Genomics 2016; 17:130. [PMID: 26912237 PMCID: PMC4765060 DOI: 10.1186/s12864-016-2412-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 01/26/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Delayed or secondary cell death that is caused by a cascade of cellular and molecular processes initiated by traumatic brain injury (TBI) may be reduced or prevented if an effective neuroprotective strategy is employed. Microarray and subsequent bioinformatic analyses were used to determine which genes, pathways and networks were significantly altered 24 h after unilateral TBI in the rat. Ipsilateral hemi-brain, the corresponding contralateral hemi-brain, and naïve (control) brain tissue were used for microarray analysis. RESULTS Ingenuity Pathway Analysis showed cell death and survival (CD) to be a top molecular and cellular function associated with TBI on both sides of the brain. One major finding was that the overall gene expression pattern suggested an increase in CD genes in ipsilateral brain tissue and suppression of CD genes contralateral to the injury which may indicate an endogenous protective mechanism. We created networks of genes of interest (GOI) and ranked the genes by the number of direct connections each had in the GOI networks, creating gene interaction hierarchies (GIHs). Cell cycle was determined from the resultant GIHs to be a significant molecular and cellular function in post-TBI CD gene response. CONCLUSIONS Cell cycle and apoptosis signalling genes that were highly ranked in the GIHs and exhibited either the inverse ipsilateral/contralateral expression pattern or contralateral suppression were identified and included STAT3, CCND1, CCND2, and BAX. Additional exploration into the remote suppression of CD genes may provide insight into neuroprotective mechanisms that could be used to develop therapies to prevent cell death following TBI.
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Affiliation(s)
- Todd E White
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA, 30310, USA.
| | - Monique C Surles-Zeigler
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA, 30310, USA.
| | - Gregory D Ford
- Division of Natural Sciences and Physical Education, Georgia Highlands College, 5441 Highway 20, NE, Cartersville, GA, 30121, USA.
| | - Alicia S Gates
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA, 30310, USA.
| | - Benem Davids
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA, 30310, USA.
| | - Timothy Distel
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA, 30310, USA.
- University of California-Riverside School of Medicine, 900 University Ave., Riverside, CA, 92521, USA.
| | - Michelle C LaPlaca
- Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Drive, Atlanta, GA, 30332, USA.
| | - Byron D Ford
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA, 30310, USA.
- University of California-Riverside School of Medicine, 900 University Ave., Riverside, CA, 92521, USA.
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14
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Sabirzhanov B, Stoica BA, Zhao Z, Loane DJ, Wu J, Dorsey SG, Faden AI. miR-711 upregulation induces neuronal cell death after traumatic brain injury. Cell Death Differ 2015; 23:654-68. [PMID: 26470728 DOI: 10.1038/cdd.2015.132] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/18/2015] [Accepted: 09/03/2015] [Indexed: 11/09/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of mortality and disability. MicroRNAs (miRs) are small noncoding RNAs that negatively regulate gene expression at post-transcriptional level and may be key modulators of neuronal apoptosis, yet their role in secondary injury after TBI remains largely unexplored. Changes in miRs after controlled cortical impact (CCI) in mice were examined during the first 72 h using miR arrays and qPCR. One selected miR (711) was examined with regard to its regulation and relation to cell death; effects of miR-711 modulation were evaluated after CCI and using in vitro cell death models of primary cortical neurons. Levels of miR-711 were increased in the cortex early after TBI and in vitro models through rapid upregulation of miR-711 transcription (pri-miR-711) rather than catabolism. Increases coincided with downregulation of the pro-survival protein Akt, a predicted target of miR-711, with sequential activation of forkhead box O3 (FoxO3)a/glycogen synthase kinase 3 (GSK3)α/β, pro-apoptotic BH3-only molecules PUMA (Bcl2-binding component 3) and Bim (Bcl2-like 11 (apoptosis facilitator)), and mitochondrial release of cytochrome c and AIF. miR-711 and Akt (mRNA) co-immunoprecipitated with the RNA-induced silencing complex (RISC). A miR-711 hairpin inhibitor attenuated the apoptotic mechanisms and decreased neuronal death in an Akt-dependent manner. Conversely, a miR-711 mimic enhanced neuronal apoptosis. Central administration of the miR-711 hairpin inhibitor after TBI increased Akt expression and attenuated apoptotic pathways. Treatment reduced cortical lesion volume, neuronal cell loss in cortex and hippocampus, and long-term neurological dysfunction. miR-711 changes contribute to neuronal cell death after TBI, in part by inhibiting Akt, and may serve as a novel therapeutic target.
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Affiliation(s)
- B Sabirzhanov
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA.,Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, USA
| | - B A Stoica
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA.,Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, USA
| | - Z Zhao
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA.,Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, USA
| | - D J Loane
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA.,Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, USA
| | - J Wu
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA.,Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, USA
| | - S G Dorsey
- University of Maryland School of Nursing, Baltimore, MD, USA.,Program in Neuroscience, University of Maryland, Baltimore, MD, USA
| | - A I Faden
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA.,Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, USA
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15
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Zhu X, Park J, Golinski J, Qiu J, Khuman J, Lee CCH, Lo EH, Degterev A, Whalen MJ. Role of Akt and mammalian target of rapamycin in functional outcome after concussive brain injury in mice. J Cereb Blood Flow Metab 2014; 34:1531-9. [PMID: 24938400 PMCID: PMC4158669 DOI: 10.1038/jcbfm.2014.113] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 05/19/2014] [Accepted: 05/30/2014] [Indexed: 11/09/2022]
Abstract
Akt (protein kinase B) and mammalian target of rapamycin (mTOR) have been implicated in the pathogenesis of cell death and cognitive outcome after cerebral contusion in mice; however, a role for Akt/mTOR in concussive brain injury has not been well characterized. In a mouse closed head injury (CHI) concussion traumatic brain injury (TBI) model, phosphorylation of Akt (p-Akt), mTOR (p-mTOR), and S6RP (p-S6RP) was increased by 24 hours in cortical and hippocampal brain homogenates (P<0.05 versus sham for each), and p-S6RP was robustly induced in IBA-1+ microglia and glial fibrillary acidic protein-positive (GFAP+) astrocytes. Pretreatment with inhibitors of Akt or mTOR individually by the intracerebroventricular route reduced phosphorylation of their respective direct substrates FOXO1 (P<0.05) or S6RP (P<0.05) after CHI, confirming the activity of inhibitors. Rapamycin pretreatment significantly worsened hidden platform (P<0.01) and probe trial (P<0.05) performance in CHI mice. Intracerebroventricular administration of necrostatin-1 (Nec-1) before CHI increased hippocampal Akt and S6RP phosphorylation and improved place learning (probe trials, P<0.001 versus vehicle), whereas co-administration of rapamycin or Akt inhibitor with Nec-1 eliminated improved probe trial performance. These data suggest a beneficial role for Akt/mTOR signaling after concussion TBI independent of cell death that may contribute to improved outcome by Nec-1.
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Affiliation(s)
- Xiaoxia Zhu
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [3] Department of Rheumatology, Huashan Hospital, Fudan University, Shanghai, China
| | - Juyeon Park
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Julianne Golinski
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Jianhua Qiu
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Jugta Khuman
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Christopher C H Lee
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Eng H Lo
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Alexei Degterev
- Department of Developmental, Molecular and Chemical Biology, Tufts University, Boston, Massachusetts, USA
| | - Michael J Whalen
- 1] Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
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16
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Wilson SM, Ki Yeon S, Yang XF, Park KD, Khanna R. Differential regulation of collapsin response mediator protein 2 (CRMP2) phosphorylation by GSK3ß and CDK5 following traumatic brain injury. Front Cell Neurosci 2014; 8:135. [PMID: 24904280 PMCID: PMC4035569 DOI: 10.3389/fncel.2014.00135] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/29/2014] [Indexed: 11/13/2022] Open
Abstract
Aberrant ion channel function has been heralded as a main underlying mechanism driving epilepsy and its symptoms. However, it has become increasingly clear that treatment strategies targeting voltage-gated sodium or calcium channels merely mask the symptoms of epilepsy without providing disease-modifying benefits. Ion channel function is likely only one important cog in a highly complex machine. Gross morphological changes, such as reactive sprouting and outgrowth, may also play a role in epileptogenesis. Mechanisms responsible for these changes are not well-understood. Here we investigate the potential involvement of the neurite outgrowth-promoting molecule collapsin response mediator protein 2 (CRMP2). CRMP2 activity, in this respect, is regulated by phosphorylation state, where phosphorylation by a variety of kinases, including glycogen synthase kinase 3 β (GSK3β) renders it inactive. Phosphorylation (inactivation) of CRMP2 was decreased at two distinct phases following traumatic brain injury (TBI). While reduced CRMP2 phosphorylation during the early phase was attributed to the inactivation of GSK3β, the sustained decrease in CRMP2 phosphorylation in the late phase appeared to be independent of GSK3β activity. Instead, the reduction in GSK3β-phosphorylated CRMP2 was attributed to a loss of priming by cyclin-dependent kinase 5 (CDK5), which allows for subsequent phosphorylation by GSK3β. Based on the observation that the proportion of active CRMP2 is increased for up to 4 weeks following TBI, it was hypothesized that it may drive neurite outgrowth, and therefore, circuit reorganization during this time. Therefore, a novel small-molecule tool was used to target CRMP2 in an attempt to determine its importance in mossy fiber sprouting following TBI. In this report, we demonstrate novel differential regulation of CRMP2 phosphorylation by GSK3β and CDK5 following TBI.
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Affiliation(s)
- Sarah M Wilson
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine Indianapolis, IN, USA
| | - Seul Ki Yeon
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology Seoul, Korea
| | - Xiao-Fang Yang
- Department of Pharmacology, College of Medicine, University of Arizona Tucson, AZ, USA
| | - Ki Duk Park
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology Seoul, Korea
| | - Rajesh Khanna
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine Indianapolis, IN, USA ; Department of Pharmacology, College of Medicine, University of Arizona Tucson, AZ, USA
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17
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Liu Q, Qiu J, Liang M, Golinski J, van Leyen K, Jung JE, You Z, Lo EH, Degterev A, Whalen MJ. Akt and mTOR mediate programmed necrosis in neurons. Cell Death Dis 2014; 5:e1084. [PMID: 24577082 PMCID: PMC3944276 DOI: 10.1038/cddis.2014.69] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 01/05/2014] [Accepted: 01/28/2014] [Indexed: 12/23/2022]
Abstract
Necroptosis is a newly described form of regulated necrosis that contributes to neuronal death in experimental models of stroke and brain trauma. Although much work has been done elucidating initiating mechanisms, signaling events governing necroptosis remain largely unexplored. Akt is known to inhibit apoptotic neuronal cell death. Mechanistic target of rapamycin (mTOR) is a downstream effector of Akt that controls protein synthesis. We previously reported that dual inhibition of Akt and mTOR reduced acute cell death and improved long term cognitive deficits after controlled-cortical impact in mice. These findings raised the possibility that Akt/mTOR might regulate necroptosis. To test this hypothesis, we induced necroptosis in the hippocampal neuronal cell line HT22 using concomitant treatment with tumor necrosis factor α (TNFα) and the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. TNFα/zVAD treatment induced cell death within 4 h. Cell death was preceded by RIPK1–RIPK3–pAkt assembly, and phosphorylation of Thr-308 and Thr473 of AKT and its direct substrate glycogen synthase kinase-3β, as well as mTOR and its direct substrate S6 ribosomal protein (S6), suggesting activation of Akt/mTOR pathways. Pretreatment with Akt inhibitor viii and rapamycin inhibited Akt and S6 phosphorylation events, mitochondrial reactive oxygen species production, and necroptosis by over 50% without affecting RIPK1–RIPK3 complex assembly. These data were confirmed using small inhibitory ribonucleic acid-mediated knockdown of AKT1/2 and mTOR. All of the aforementioned biochemical events were inhibited by necrostatin-1, including Akt and mTOR phosphorylation, generation of oxidative stress, and RIPK1–RIPK3–pAkt complex assembly. The data suggest a novel, heretofore unexpected role for Akt and mTOR downstream of RIPK1 activation in neuronal cell death.
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Affiliation(s)
- Q Liu
- 1] Department of Pediatric Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [3] Department of Anatomy, Histology and Embryology, Shanghai Medical College, Fudan University, Shanghai, China
| | - J Qiu
- 1] Department of Pediatric Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - M Liang
- 1] Department of Pediatric Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [3] Department of Rheumatology, Huashan Hospital, Fudan University, Shanghai, China
| | - J Golinski
- 1] Department of Pediatric Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - K van Leyen
- 1] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroprotection Research Laboratory, Departments of Neurology and Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - J E Jung
- 1] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroprotection Research Laboratory, Departments of Neurology and Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Z You
- Department of Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, USA
| | - E H Lo
- 1] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroprotection Research Laboratory, Departments of Neurology and Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - A Degterev
- Department of Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, USA
| | - M J Whalen
- 1] Department of Pediatric Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA [2] Neuroscience Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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18
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Zhang X, Yan X, Gorman J, Hoffman SN, Zhang L, Boscarino JA. Perioperative hyperglycemia is associated with postoperative neurocognitive disorders after cardiac surgery. Neuropsychiatr Dis Treat 2014; 10:361-70. [PMID: 24570589 PMCID: PMC3933727 DOI: 10.2147/ndt.s57761] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE Neurocognitive disorders commonly occur following cardiac surgery. However, the underlying etiology of these disorders is not well understood. The current study examined the association between perioperative glucose levels and other risk factors and the onset of neurocognitive disorders in adult patients following coronary artery bypass and/or valvular surgery. METHODS Adult patients who underwent their first cardiac surgery at a large tertiary care medical center were identified and those with neurocognitive disorders prior to surgery were excluded. Demographic, perioperative, and postoperative neurocognitive outcome data were extracted from the Society for Thoracic Surgery database, and from electronic medical records, between January 2004 and June 2009. Multiple clinical risk factors and measures associated with insulin resistance, such as hyperglycemia, were assessed. Multivariable Cox competing risk survival models were used to assess hyperglycemia and postoperative neurocognitive disorders at follow up, adjusting for other risk factors and confounding variables. RESULTS Of the 855 patients included in the study, 271 (31.7%) had new onset neurocognitive disorders at follow-up. Age, sex, New York Heart Failure (NYHF) Class, length of postoperative intensive care unit stay, perioperative blood product transfusion, and other key factors were identified and assessed as potential risk factors (or confounders) for neurocognitive disorders at follow-up. Bivariate analyses suggested that new onset neurocognitive disorders were associated with NYHF Class, cardiopulmonary bypass, history of diabetes, intraoperative blood product use, and number of diseased coronary vessels, which are commonly-accepted risk factors in cardiac surgery. In addition, higher first glucose level (median =116 mg/dL) and higher peak glucose >169 mg/dL were identified as risk factors. Male sex and nonuse of intra-operative blood products appeared to be protective. Controlling for potential risk factors and confounders, multivariable Cox survival models suggested that increased perioperative first glucose measured in 20 unit increments, was significantly associated with the onset of postoperative neurocognitive disorders at follow-up (hazard ratio [HR] =1.16, P<0.001) and that women had an elevated risk for this outcome (HR =4.18, P=0.01). CONCLUSION Our study suggests that perioperative hyperglycemia was associated with new onset of postoperative neurocognitive disorders in adult patients after cardiac surgery, and that men tended to be protected from these outcomes. These findings may suggest a need for the revision of clinical protocols for perioperative insulin therapy to prevent long-term neurocognitive complications.
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Affiliation(s)
- Xiaopeng Zhang
- Department of Anesthesiology, Geisinger Medical Center, Danville, PA, USA
| | - Xiaowei Yan
- Center for Health Research, Geisinger Clinic, Danville, PA, USA
| | - Jennifer Gorman
- Center for Health Research, Geisinger Clinic, Danville, PA, USA
| | - Stuart N Hoffman
- Department of Neurology, Geisinger Medical Center, Danville, PA, USA
| | - Li Zhang
- Department of Anesthesiology, Geisinger Medical Center, Danville, PA, USA
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19
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Madathil SK, Carlson SW, Brelsfoard JM, Ye P, D’Ercole AJ, Saatman KE. Astrocyte-Specific Overexpression of Insulin-Like Growth Factor-1 Protects Hippocampal Neurons and Reduces Behavioral Deficits following Traumatic Brain Injury in Mice. PLoS One 2013; 8:e67204. [PMID: 23826235 PMCID: PMC3695083 DOI: 10.1371/journal.pone.0067204] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 05/16/2013] [Indexed: 11/19/2022] Open
Abstract
Traumatic brain injury (TBI) survivors often suffer from long-lasting cognitive impairment that stems from hippocampal injury. Systemic administration of insulin-like growth factor-1 (IGF-1), a polypeptide growth factor known to play vital roles in neuronal survival, has been shown to attenuate posttraumatic cognitive and motor dysfunction. However, its neuroprotective effects in TBI have not been examined. To this end, moderate or severe contusion brain injury was induced in mice with conditional (postnatal) overexpression of IGF-1 using the controlled cortical impact (CCI) injury model. CCI brain injury produces robust reactive astrocytosis in regions of neuronal damage such as the hippocampus. We exploited this regional astrocytosis by linking expression of hIGF-1 to the astrocyte-specific glial fibrillary acidic protein (GFAP) promoter, effectively targeting IGF-1 delivery to vulnerable neurons. Following brain injury, IGF-1Tg mice exhibited a progressive increase in hippocampal IGF-1 levels which was coupled with enhanced hippocampal reactive astrocytosis and significantly greater GFAP levels relative to WT mice. IGF-1 overexpression stimulated Akt phosphorylation and reduced acute (1 and 3d) hippocampal neurodegeneration, culminating in greater neuron survival at 10d after CCI injury. Hippocampal neuroprotection achieved by IGF-1 overexpression was accompanied by improved motor and cognitive function in brain-injured mice. These data provide strong support for the therapeutic efficacy of increased brain levels of IGF-1 in the setting of TBI.
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Affiliation(s)
- Sindhu K. Madathil
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Shaun W. Carlson
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Jennifer M. Brelsfoard
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Ping Ye
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - A. Joseph D’Ercole
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kathryn E. Saatman
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail:
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20
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Jackson TC, Verrier JD, Kochanek PM. Anthraquinone-2-sulfonic acid (AQ2S) is a novel neurotherapeutic agent. Cell Death Dis 2013; 4:e451. [PMID: 23303125 PMCID: PMC3563977 DOI: 10.1038/cddis.2012.187] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 11/04/2012] [Accepted: 11/12/2012] [Indexed: 11/09/2022]
Abstract
Anthraquinone derivatives such as emodin have recently been shown to protect in models of beta amyloid β (Aβ) and tau aggregation-induced cell death. The mechanisms of action possibly involve preconditioning effects, anti-aggregation properties, and/or enhancing the phosphatidylinositol-3-kinase (PI3K)/AKT survival mechanism. We studied several natural (emodin, rhein, and aloin) and synthetic (AQ2S) anthraquinones, to screen for post-treatment therapeutic benefit in two models of neuronal death, namely hydrogen peroxide (H(2)O(2)) and staurosporine (STS)-induced injury. Treatment with emodin, rhein, or aloin failed to reduce H(2)O(2) injury. Moreover, consistent with emodin behaving like a mild toxin, it exacerbated oxidative injury at the highest concentration used (50 μM) in our post-treatment paradigm, and potently inhibited AKT. In contrast, AQ2S was neuroprotective. It reduced H(2)O(2) injury at 50 and 75 μM. In addition, AQ2S potently inhibited staurosporine (STS)-induced injury. The mechanisms of action involve caspase inhibition and AKT activation. However, blockade of AKT signaling with LY294002 failed to abolish AQ2S-mediated protection on the STS assay. This is the first study to report that AQ2S is a new neuroprotective compound and a novel caspase inhibitor.
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Affiliation(s)
- T C Jackson
- Department of Critical Care Medicine, University of Pittsburgh, School of Medicine, Safar Center for Resuscitation Research, Pittsburgh, PA 15260, USA.
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21
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Abstract
The molecular mechanisms governing the spontaneous recovery seen following brain injury remain elusive, but recent studies indicate that injury-induced stimulation of hippocampal neurogenesis contributes to the repair process. The therapeutic potential of endogenous neurogenesis is tempered by the demonstration that traumatic brain injury (TBI) results in the selective death of adult-born immature neurons, compromising the cell population poised to compensate for trauma-induced neuronal loss. Here, we identify the Ras-related GTPase, Rit, as a critical player in the survival of immature hippocampal neurons following brain injury. While Rit knock-out (Rit(-/-)) did not alter hippocampal development, hippocampal neural cultures derived from Rit(-/-) mice display increased cell death and blunted MAPK cascade activation in response to oxidative stress, without affecting BDNF-dependent signaling. When compared with wild-type hippocampal cultures, Rit loss rendered immature (Dcx(+)) neurons susceptible to oxidative damage, without altering the survival of neural progenitor (Nestin(+)) cells. Oxidative stress is a major contributor to neuronal cell death following brain injury. Consistent with the enhanced vulnerability of cultured Rit(-/-) immature neurons, Rit(-/-) mice exhibited a significantly greater loss of adult-born immature neurons within the dentate gyrus after TBI. In addition, post-TBI neuronal remodeling was blunted. Together, these data identify a new and unexpected role for Rit in injury-induced neurogenesis, functioning as a selective survival mechanism for immature hippocampal neurons within the subgranular zone of the dentate gyrus following TBI.
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Chen SF, Tsai HJ, Hung TH, Chen CC, Lee CY, Wu CH, Wang PY, Liao NC. Salidroside improves behavioral and histological outcomes and reduces apoptosis via PI3K/Akt signaling after experimental traumatic brain injury. PLoS One 2012; 7:e45763. [PMID: 23029230 PMCID: PMC3454376 DOI: 10.1371/journal.pone.0045763] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Accepted: 08/24/2012] [Indexed: 11/18/2022] Open
Abstract
Background Traumatic brain injury (TBI) induces a complex sequence of apopototic cascades that contribute to secondary tissue damage. The aim of this study was to investigate the effects of salidroside, a phenolic glycoside with potent anti-apoptotic properties, on behavioral and histological outcomes, brain edema, and apoptosis following experimental TBI and the possible involvement of the phosphoinositide 3-kinase/protein kinase B (PI3K)/Akt signaling pathway. Methodology/Principal Findings Mice subjected to controlled cortical impact injury received intraperitoneal salidroside (20, or 50 mg/kg) or vehicle injection 10 min after injury. Behavioral studies, histology analysis and brain water content assessment were performed. Levels of PI3K/Akt signaling-related molecules, apoptosis-related proteins, cytochrome C (CytoC), and Smac/DIABLO were also analyzed. LY294002, a PI3K inhibitor, was administered to examine the mechanism of protection. The protective effect of salidroside was also investigated in primary cultured neurons subjected to stretch injury. Treatment with 20 mg/kg salidroside_significantly improved functional recovery and reduced brain tissue damage up to post-injury day 28. Salidroside_also significantly reduced neuronal death, apoptosis, and brain edema at day 1. These changes were associated with significant decreases in cleaved caspase-3, CytoC, and Smac/DIABLO at days 1 and 3. Salidroside increased phosphorylation of Akt on Ser473 and the mitochondrial Bcl-2/Bax ratio at day 1, and enhanced phosphorylation of Akt on Thr308 at day 3. This beneficial effect was abolished by pre-injection of LY294002. Moreover, delayed administration of salidroside at 3 or 6 h post-injury reduced neuronal damage at day 1. Salidroside treatment also decreased neuronal vulnerability to stretch-induced injury in vitro. Conclusions/Significance Post-injury salidroside improved long-term behavioral and histological outcomes and reduced brain edema and apoptosis following TBI, at least partially via the PI3K/Akt signaling pathway.
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Affiliation(s)
- Szu-Fu Chen
- Departments of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan, Republic of China.
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Mild traumatic brain injury in the rat alters neuronal number in the limbic system and increases conditioned fear and anxiety-like behaviors. Exp Neurol 2012; 235:574-87. [DOI: 10.1016/j.expneurol.2012.03.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 02/13/2012] [Accepted: 03/25/2012] [Indexed: 12/23/2022]
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Involvement of the glycogen synthase kinase-3 signaling pathway in TBI pathology and neurocognitive outcome. PLoS One 2011; 6:e24648. [PMID: 21935433 PMCID: PMC3174188 DOI: 10.1371/journal.pone.0024648] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 08/17/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) sets in motion cascades of biochemical changes that result in delayed cell death and altered neuronal architecture. Studies have demonstrated that inhibition of glycogen synthase kinase-3 (GSK-3) effectively reduces apoptosis following a number of stimuli. The Wnt family of proteins, and growth factors are two major factors that regulate GSK-3 activity. In the absence of stimuli, GSK-3 is constitutively active and is complexed with Axin, adenomatous polyposis coli (APC), and casein kinase Iα (CK1α) and phosphorylates ß-Catenin leading to its degradation. Binding of Wnt to Frizzled receptors causes the translocation of GSK-3 to the plasma membrane, where it phosphorylates and inactivates the Frizzled co-receptor lipoprotein-related protein 6 (LRP6). Furthermore, the translocation of GSK-3 reduces ß-Catenin phosphorylation and degradation, leading to ß-Catenin accumulation and gene expression. Growth factors activate Akt, which in turn inhibits GSK-3 activity by direct phosphorylation, leading to a reduction in apoptosis. METHODOLOGY/PRINCIPAL FINDINGS Using a rodent model, we found that TBI caused a rapid, but transient, increase in LRP6 phosphorylation that is followed by a modest decrease in ß-Catenin phosphorylation. Phospho-GSK-3β immunoreactivity was found to increase three days post injury, a time point at which increased Akt activity following TBI has been observed. Lithium influences several neurochemical cascades, including inhibiting GSK-3. When the efficacy of daily lithium was assessed, reduced hippocampal neuronal cell loss and learning and memory improvements were observed. These influences were partially mimicked by administration of the GSK-3-selective inhibitor SB-216763, as this drug resulted in improved motor function, but only a modest improvement in memory retention and no overt neuroprotection. CONCLUSION/SIGNIFICANCE Taken together, our findings suggest that selective inhibition of GSK-3 may offer partial cognitive improvement. As a broad spectrum inhibitor of GSK-3, lithium offers neuroprotection and robust cognitive improvement, supporting its clinical testing as a treatment for TBI.
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Tokuda S, Mahaffey CL, Monks B, Faulkner CR, Birnbaum MJ, Danzer SC, Frankel WN. A novel Akt3 mutation associated with enhanced kinase activity and seizure susceptibility in mice. Hum Mol Genet 2010; 20:988-99. [PMID: 21159799 DOI: 10.1093/hmg/ddq544] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In a phenotype-driven mutagenesis screen, a novel, dominant mouse mutation, Nmf350, caused low seizure threshold, sporadic tonic-clonic seizures, brain enlargement and ectopic neurons in the dentate hilus and molecular layer of the hippocampus. Genetic mapping implicated Akt3, one of four candidates within the critical interval. Sequencing analysis revealed that mutants have a missense mutation in Akt3 (encoding one of three AKT/protein kinase B molecules), leading to a non-synonymous amino acid substitution in the highly conserved protein kinase domain. Previous knockout studies showed that Akt3 is pivotal in postnatal brain development, including a smaller brain, although seizures were not observed. In contrast to Akt3(Nmf350), we find that Akt3 null mice exhibit an elevated seizure threshold. An in vitro kinase assay revealed that Akt3(Nmf350) confers higher enzymatic activity, suggesting that Akt3(Nmf350) might enhance AKT signaling in the brain. In the dentate gyrus of Akt3(Nmf350) homozygotes, we also observed a modest increase in immunoreactivity of phosphorylated ribosomal protein S6, an AKT pathway downstream target. Together these findings suggest that Akt3(Nmf350) confers an increase of AKT3 activity in specific neuronal populations in the brain, and a unique dominant phenotype. Akt3(Nmf350) mice provide a new tool for studying physiological roles of AKT signaling in the brain, and potentially novel mechanisms for epilepsy.
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Madathil SK, Evans HN, Saatman KE. Temporal and regional changes in IGF-1/IGF-1R signaling in the mouse brain after traumatic brain injury. J Neurotrauma 2010; 27:95-107. [PMID: 19751099 DOI: 10.1089/neu.2009.1002] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Although neurotrophic factors such as nerve growth factor, basic fibroblast growth factor, brain-derived neurotrophic factor, and neurotrophin 4/5 are elevated after traumatic brain injury (TBI), little is known about the endogenous response of insulin-like growth factor-1 (IGF-1). We evaluated IGF-1, IGF-1 receptor (IGF-1R), and total and phosphorylated Akt (p-Akt), a known downstream mediator of IGF-1 signaling, using ELISA, Western blotting, and immunohistochemistry at 1, 6, 24, 48, and 72 h following 0.5-mm controlled cortical impact brain injury in adult mice. IGF-1 was transiently upregulated in homogenates of injured cortex at 1 h, and cells with increased IGF-1 immunoreactivity were observed in and around the cortical contusion site up to 48 h. IGF-1R and total Akt levels in cortical homogenates were unchanged, although immunohistochemistry revealed regional changes. In contrast, serine p-Akt levels increased significantly in homogenates at 6 h post-injury. Interestingly, delayed increases in vascular IGF-1R, total Akt, and p-Akt immunostaining were observed in and around the cortical contusion. IGF-1 and its downstream mediators were also upregulated in the subcortical white matter. Our findings indicate that moderate TBI results in a brief induction of IGF-1 and its signaling components in the acute post-traumatic period. This may reflect an attempt at endogenous neuroprotection or repair.
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Affiliation(s)
- Sindhu Kizhakke Madathil
- Spinal Cord and Brain Injury Research Center, Department of Physiology, University of Kentucky, Lexington, Kentucky 40536-0509, USA
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Rubovitch V, Edut S, Sarfstein R, Werner H, Pick CG. The intricate involvement of the Insulin-like growth factor receptor signaling in mild traumatic brain injury in mice. Neurobiol Dis 2010; 38:299-303. [PMID: 20138993 DOI: 10.1016/j.nbd.2010.01.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 01/26/2010] [Accepted: 01/27/2010] [Indexed: 12/28/2022] Open
Abstract
Insulin-like growth factor-1 (IGF-1) was suggested as a potential neuroprotective treatment for traumatic brain injury (TBI) induced damage (cognitive as well as cellular). The main goal of the present study was to evaluate the role of the IGF-1R activation in spatial memory outcome following mild traumatic brain injury. mTBI-induced phosphorylation of IGF-1R, AKT and ERK1/2, in mice hippocampus, which was inhibited when mice were pretreated with the selective IGF-1R inhibitor AG1024. IGF-1 administration prevented spatial memory deficits following mTBI. Surprisingly, blocking the IGF-1R signaling in mTBI mice did not augment the spatial memory deficit. In addition, this data imply an intriguing and complex role of the IGF-1 signaling axis in the cellular and behavioral events following mTBI.
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Affiliation(s)
- Vardit Rubovitch
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Israel
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PH domain leucine-rich repeat protein phosphatase 1 contributes to maintain the activation of the PI3K/Akt pro-survival pathway in Huntington's disease striatum. Cell Death Differ 2009; 17:324-35. [PMID: 19745829 DOI: 10.1038/cdd.2009.127] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dysregulation of gene expression is one of the mechanisms involved in the pathophysiology of Huntington's disease (HD). Here, we examined whether mutant huntingtin regulates the levels of PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1), a phosphatase that specifically dephosphorylates Akt at Ser473. Our results show decreased PHLPP1 protein levels in knock-in models (Hdh(Q111/Q111) mouse striatum and STHdh(Q111/Q111) cells), in the striatum of N-terminal exon-1 mutant huntingtin transgenic mouse models (R6/1; R6/1 : BDNF + or - , R6/2 and Tet/HD94) and in the putamen of HD patients. Quantitative PCR analysis revealed a reduction in PHLPP1 mRNA levels in the striatum of R6/1 compared with wild-type mice. Coincident with reduced PHLPP1 protein levels, we observed increased phosphorylated Akt (Ser473) levels specifically in the striatum. The analysis of the conditional mouse model Tet/HD94 disclosed that after mutant huntingtin shutdown PHLPP1 levels returned to wild-type levels whereas phospho-Akt levels were partially reduced. In conclusion, our results show that mutant huntingtin downregulates PHLPP1 expression. In the striatum, these reduced levels of PHLPP1 can contribute to maintain high levels of activated Akt that may delay cell death and allow the recovery of neuronal viability after mutant huntingtin silencing.
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Biomarkers of primary and evolving damage in traumatic and ischemic brain injury: diagnosis, prognosis, probing mechanisms, and therapeutic decision making. Curr Opin Crit Care 2008; 14:135-41. [PMID: 18388674 DOI: 10.1097/mcc.0b013e3282f57564] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Emerging data suggest that biomarkers of brain injury have potential utility as diagnostic, prognostic, and therapeutic adjuncts in the setting of traumatic and ischemic brain injury. Two approaches are being used, namely, assessing markers of structural damage and quantifying mediators of the cellular, biochemical, or molecular cascades in secondary injury or repair. Novel proteomic, multiplex, and lipidomic methods are also being applied. RECENT FINDINGS Biochemical markers of neuronal, glial, and axonal damage such as neuron-specific enolase, S100B, and myelin basic protein, respectively, are readily detectable in biological samples such as serum or cerebrospinal fluid and are being studied in patients with ischemic and traumatic brain injury. In addition, a number of studies have demonstrated that novel tools to assess simultaneously multiple biomarkers can provide unique insight such as details on specific molecular participants in cell death cascades, inflammation, or oxidative stress. SUMMARY Multifaceted cellular, biochemical, and molecular monitoring of proteins and lipids is logical as an adjunct to guiding therapies and improving outcomes in traumatic and ischemic brain injury and we appear to be on the verge of a breakthrough with the use of these markers as diagnostic, prognostic, and monitoring adjuncts, in neurointensive care.
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Shapira M, Licht A, Milman A, Pick CG, Shohami E, Eldar-Finkelman H. Role of glycogen synthase kinase-3beta in early depressive behavior induced by mild traumatic brain injury. Mol Cell Neurosci 2006; 34:571-7. [PMID: 17289399 DOI: 10.1016/j.mcn.2006.12.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2006] [Revised: 12/14/2006] [Accepted: 12/19/2006] [Indexed: 11/16/2022] Open
Abstract
Traumatic brain injury (TBI) is a triggering event for a set of pathophysiological changes and concomitant depressive behavior. Glycogen synthase kinase-3 (GSK-3) is a potent in vivo regulator of cell apoptosis and, in addition, is implicated in depressive behavior. In this study, we investigated the role of GSK-3 in the physiological model of mild TBI (mTBI) at both the cellular and behavior levels. mTBI resulted in increased phosphorylation of inhibitory site serine(9) of GSK-3beta, which coincided with increased serine(473) phosphorylation of its upstream kinase PKB and accumulation of its downstream target beta-catenin in the hippocampus. mTBI induced a depressive behavior which was evident as early as 24 h post-injury. Pretreatment with GSK-3 inhibitors, lithium, or L803-mts prevented mTBI-induced depression. We suggest that mTBI elicits a pro-survival cascade of PKB/GSK-3beta/beta-catenin as part of a rehabilitation program. Furthermore, the use of selective GSK-3 inhibitors may have therapeutic benefits in treatment conditions associated with brain injury.
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Affiliation(s)
- Moran Shapira
- Department of Molecular Human Genetics and Biochemistry, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
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