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Kang JB, Koh PO. Retinoic acid alleviates the reduction of Akt and Bad phosphorylation and regulates Bcl-2 family protein interactions in animal models of ischemic stroke. PLoS One 2024; 19:e0303213. [PMID: 38753710 PMCID: PMC11098415 DOI: 10.1371/journal.pone.0303213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 04/21/2024] [Indexed: 05/18/2024] Open
Abstract
Ischemic stroke causes a lack of oxygen and glucose supply to brain, eventually leads to severe neurological disorders. Retinoic acid is a major metabolic product of vitamin A and has various biological effects. The PI3K-Akt signaling pathway is an important survival pathway in brain. Phosphorylated Akt is important in regulating survival and apoptosis. We examined whether retinoic acid has neuroprotective effects in stroke model by regulating Akt and its downstream protein, Bad. Moreover, we investigated the relationship between retinoic acid and Bcl-2 family protein interactions. Animals were intraperitoneally administered vehicle or retinoic acid (5 mg/kg) for four days before surgery and ischemic stroke was induced by middle cerebral artery occlusion (MCAO) surgery. Neurobehavioral tests were performed 24 h after MCAO and cerebral cortical tissues were collected. Cresyl violet staining and TUNEL histochemistry were performed, Western blot and immunoprecipitation analysis were performed to elucidate the expression of various proteins. Retinoic acid reduced neurological deficits and histopathological changes, decreased the number of TUNEL-positive cells, and alleviated reduction of phospho-PDK1, phospho-Akt, and phospho-Bad expression caused by MCAO damage. Immunoprecipitation analysis showed that MCAO damage reduced the interaction between phospho-Bad and 14-3-3, which was attenuated by retinoic acid. Furthermore, retinoic acid mitigated the increase in Bcl-2/Bad and Bcl-xL/Bad binding levels and the reduction in Bcl-2/Bax and Bcl-xL/Bax binding levels caused by MCAO damage. Retinoic acid alleviated MCAO-induced increase of caspase-3 and cleaved caspase-3 expression. We demonstrate that retinoic acid prevented apoptosis against cerebral ischemia through phosphorylation of Akt and Bad, maintenance of phospho-Bad and 14-3-3 binding, and regulation of Bcl-2 family protein interactions. .
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Affiliation(s)
- Ju-Bin Kang
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea
| | - Phil-Ok Koh
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea
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2
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Nguyen H, Zhu W, Baltan S. Casein Kinase 2 Signaling in White Matter Stroke. Front Mol Biosci 2022; 9:908521. [PMID: 35911974 PMCID: PMC9325966 DOI: 10.3389/fmolb.2022.908521] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/21/2022] [Indexed: 11/27/2022] Open
Abstract
The growth of the aging population, together with improved stroke care, has resulted in an increase in stroke survivors and a rise in recurrent events. Axonal injury and white matter (WM) dysfunction are responsible for much of the disability observed after stroke. The mechanisms of WM injury are distinct compared to gray matter and change with age. Therefore, an ideal stroke therapeutic must restore neuronal and axonal function when applied before or after a stroke, and it must also protect across age groups. Casein kinase 2 (CK2), is expressed in the brain, including WM, and is regulated during the development and numerous disease conditions such as cancer and ischemia. CK2 activation in WM mediates ischemic injury by activating the Cdk5 and AKT/GSK3β signaling pathways. Consequently, CK2 inhibition using the small molecule inhibitor CX-4945 (Silmitasertib) correlates with preservation of oligodendrocytes, conservation of axon structure, and axonal mitochondria, leading to improved functional recovery. Remarkably, CK2 inhibition promotes WM function when applied after ischemic injury by specifically regulating the AKT/GSK3β pathways. The blockade of the active conformation of AKT confers post-ischemic protection to young and old WM by preserving mitochondria, implying AKT as a common therapeutic target across age groups. Using a NanoString nCounter miRNA expression profiling, comparative analyses of ischemic WM with or without CX-4945 treatment reveal that miRNAs are expressed at high levels in WM after ischemia, and CX-4945 differentially regulates some of these miRNAs. Therefore, we propose that miRNA regulation may be one of the protective actions of CX-4945 against WM ischemic injury. Silmitasertib is FDA approved and currently in use for cancer and Covid patients; therefore, it is plausible to repurpose CK2 inhibitors for stroke patients.
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Affiliation(s)
| | | | - Selva Baltan
- Anesthesiology and Peri-Operative Medicine (APOM), Oregon Health and Science University, Portland, OR, United States
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3
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Baltan S, Sandau US, Brunet S, Bastian C, Tripathi A, Nguyen H, Liu H, Saugstad JA, Zarnegarnia Y, Dutta R. Identification of miRNAs That Mediate Protective Functions of Anti-Cancer Drugs During White Matter Ischemic Injury. ASN Neuro 2021; 13:17590914211042220. [PMID: 34619990 PMCID: PMC8642107 DOI: 10.1177/17590914211042220] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We have previously shown that two anti-cancer drugs, CX-4945 and MS-275, protect and preserve white matter (WM) architecture and improve functional recovery in a model of WM ischemic injury. While both compounds promote recovery, CX-4945 is a selective Casein kinase 2 (CK2) inhibitor and MS-275 is a selective Class I histone deacetylase (HDAC) inhibitor. Alterations in microRNAs (miRNAs) mediate some of the protective actions of these drugs. In this study, we aimed to (1) identify miRNAs expressed in mouse optic nerves (MONs); (2) determine which miRNAs are regulated by oxygen glucose deprivation (OGD); and (3) determine the effects of CX-4945 and MS-275 treatment on miRNA expression. RNA isolated from MONs from control and OGD-treated animals with and without CX-4945 or MS-275 treatment were quantified using NanoString nCounter® miRNA expression profiling. Comparative analysis of experimental groups revealed that 12 miRNAs were expressed at high levels in MONs. OGD upregulated five miRNAs (miR-1959, miR-501-3p, miR-146b, miR-201, and miR-335-3p) and downregulated two miRNAs (miR-1937a and miR-1937b) compared to controls. OGD with CX-4945 upregulated miR-1937a and miR-1937b, and downregulated miR-501-3p, miR-200a, miR-1959, and miR-654-3p compared to OGD alone. OGD with MS-275 upregulated miR-2134, miR-2141, miR-2133, miR-34b-5p, miR-153, miR-487b, miR-376b, and downregulated miR-717, miR-190, miR-27a, miR-1959, miR-200a, miR-501-3p, and miR-200c compared to OGD alone. Interestingly, miR-501-3p and miR-1959 were the only miRNAs upregulated by OGD, and downregulated by OGD plus CX-4945 and MS-275. Therefore, we suggest that protective functions of CX-4945 or MS-275 against WM injury maybe mediated, in part, through miRNA expression.
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Affiliation(s)
- Selva Baltan
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, USA
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
- Selva Baltan, Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Mackenzie Hall 2140A, L459, 3181 S.W. Sam Jackson Park Rd., Portland, OR 97239, USA.
| | - Ursula S. Sandau
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, USA
| | - Sylvain Brunet
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Chinthasagar Bastian
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Ajai Tripathi
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Hung Nguyen
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, USA
| | - Helen Liu
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, USA
| | - Julie A. Saugstad
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, USA
| | - Yalda Zarnegarnia
- Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, USA
| | - Ranjan Dutta
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Li CY, Ma W, Liu KP, Yang JW, Wang XB, Wu Z, Zhang T, Wang JW, Liu W, Liu J, Liang Y, Zhang XK, Li JJ, Guo JH, Li LY. Advances in intervention methods and brain protection mechanisms of in situ and remote ischemic postconditioning. Metab Brain Dis 2021; 36:53-65. [PMID: 33044640 DOI: 10.1007/s11011-020-00562-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/05/2020] [Indexed: 01/01/2023]
Abstract
Ischemic postconditioning (PostC) conventionally refers to a series of brief blood vessel occlusions and reperfusions, which can induce an endogenous neuroprotective effect and reduce cerebral ischemia/reperfusion (I/R) injury. Depending on the site of adaptive ischemic intervention, PostC can be classified as in situ ischemic postconditioning (ISPostC) and remote ischemic postconditioning (RIPostC). Many studies have shown that ISPostC and RIPostC can reduce cerebral IS injury through protective mechanisms that increase cerebral blood flow after reperfusion, decrease antioxidant stress and anti-neuronal apoptosis, reduce brain edema, and regulate autophagy as well as Akt, MAPK, PKC, and KATP channel cell signaling pathways. However, few studies have compared the intervention methods, protective mechanisms, and cell signaling pathways of ISPostC and RIPostC interventions. Thus, in this article, we compare the history, common intervention methods, neuroprotective mechanisms, and cell signaling pathways of ISPostC and RIPostC.
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Affiliation(s)
- Chun-Yan Li
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Wei Ma
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Kuang-Pin Liu
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Jin-Wei Yang
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China
| | - Xian-Bin Wang
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Zhen Wu
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China
| | - Tong Zhang
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China
| | - Jia-Wei Wang
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China
| | - Wei Liu
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Jie Liu
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Yu Liang
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Xing-Kui Zhang
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Jun-Jun Li
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China
| | - Jian-Hui Guo
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, 650032, Yunnan, China.
| | - Li-Yan Li
- Institute of Neuroscience, Kunming Medical University, Kunming, 650500, Yunnan, China.
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Sasaki K, Yamamoto S, Mutoh T, Tsuru Y, Taki Y, Kawashima R. Rapamycin protects against early brain injury independent of cerebral blood flow changes in a mouse model of subarachnoid haemorrhage. Clin Exp Pharmacol Physiol 2019; 45:859-862. [PMID: 29676052 DOI: 10.1111/1440-1681.12950] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 01/05/2023]
Abstract
We evaluated the neuroprotective role of rapamycin, a mammalian target of rapamycin (mTOR) kinase inhibitor, in cerebral ischaemia and locomotor function in a mouse model of subarachnoid haemorrhage (SAH). Pretreatment with rapamycin, an mTOR kinase inhibitor, resulted in better recovery from cerebral hypoxia early after SAH than control (P < .05), while the values of peak flow velocity in the middle cerebral artery did not change significantly (P > .05). Average distance travelled and the ratio of central-area distance/total travelled distance determined by open-field test after day 14 was significantly higher in mice pretreated with rapamycin than in control mice (P < .05). Inhibition of the mTOR pathway could be protective against post-SAH early brain injury, ameliorating brain tissue hypoxia and locomotor hypoactivity.
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Affiliation(s)
- Kazumasu Sasaki
- Institute of Development, Aging and Cancer (IDAC), Tohoku University, Sendai, Japan
| | - Shuzo Yamamoto
- Institute of Development, Aging and Cancer (IDAC), Tohoku University, Sendai, Japan
| | - Tatsushi Mutoh
- Institute of Development, Aging and Cancer (IDAC), Tohoku University, Sendai, Japan
| | - Yoshiharu Tsuru
- Primetech Life Science Laboratory, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yasuyuki Taki
- Institute of Development, Aging and Cancer (IDAC), Tohoku University, Sendai, Japan
| | - Ryuta Kawashima
- Institute of Development, Aging and Cancer (IDAC), Tohoku University, Sendai, Japan
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Cheng CY, Kao ST, Lee YC. Ferulic acid ameliorates cerebral infarction by activating Akt/mTOR/4E‑BP1/Bcl‑2 anti‑apoptotic signaling in the penumbral cortex following permanent cerebral ischemia in rats. Mol Med Rep 2018; 19:792-804. [PMID: 30569126 DOI: 10.3892/mmr.2018.9737] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 11/23/2018] [Indexed: 11/05/2022] Open
Abstract
The aim of the present study was to determine the effects of ferulic acid (FerA) administered immediately following the onset of permanent middle cerebral artery occlusion (MCAo) and then 7 days of ischemia, and also to explore the involvement of protein kinase B (Akt)‑induced signaling in the penumbral cortex. Immediately following the onset of MCAo, FerA was intravenously administered to rats at a dose of 60 mg/kg (FerA‑60 mg), 80 mg/kg (FerA‑80 mg), or 100 mg/kg (FerA‑100 mg). FerA‑80 mg and FerA‑100 mg effectively ameliorated cerebral infarction and neurological deficits 7 days following permanent cerebral ischemia. FerA‑80 mg and FerA‑100 mg significantly upregulated the expression of phospho‑Akt (p‑Akt), phospho‑mammalian target of rapamycin (p‑mTOR), and eukaryotic initiation factor 4E (eIF4E)‑binding protein 1 (4E‑BP1), and the phospho‑4E‑BP1 (p‑4E‑BP1)/4E‑BP1 and mitochondrial Bcl‑2/Bax ratios, and markedly downregulated the levels of cytochrome c‑, cleaved caspase‑3‑, and terminal deoxynucleotidyl transferase‑mediated dUTP‑biotin nick‑end labeling‑immunoreactive cells in the penumbral cortex at 7 days post‑ischemia. LY294002, a selective inhibitor of phosphoinositide 3‑kinase/Akt signaling, was administered 30 min prior to ischemia, which abrogated the upregulating effects of FerA‑100 mg on the expression of p‑Akt, p‑mTOR, 4E‑BP1, p‑4E‑BP1 and eIF4E, the mitochondrial Bcl‑2/Bax ratio and the ameliorating effect of FerA‑100 mg on cerebral infarction. FerA administered at doses of 80 and 100 mg/kg exerted beneficial effects against cerebral ischemia by activating Akt‑induced signaling. The effects of FerA at doses of 80 and 100 mg/kg on mitochondrial B‑cell lymphoma-2 (Bcl‑2)‑associated X protein‑related apoptosis were attributed to the activation of Akt/mTOR/4E‑BP1/Bcl‑2 anti‑apoptotic signaling, and eventually contributed to suppression of the cytochrome c/caspase‑3 activation pathway in the penumbral cortex 7 days following permanent cerebral ischemia.
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Affiliation(s)
- Chin-Yi Cheng
- School of Post‑Baccalaureate Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Shung-Te Kao
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Yu-Chen Lee
- Department of Chinese Medicine, China Medical University Hospital, Taichung 40447, Taiwan, R.O.C
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7
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Wang P, Xie R, Cheng M, Sapolsky R, Ji X, Zhao H. The mTOR cell signaling pathway is crucial to the long-term protective effects of ischemic postconditioning against stroke. Neurosci Lett 2018; 676:58-65. [PMID: 29605662 DOI: 10.1016/j.neulet.2018.03.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/14/2018] [Accepted: 03/28/2018] [Indexed: 01/23/2023]
Abstract
Ischemic postconditioning (IPostC) protects against stroke, but few have studied the pathophysiological mechanisms of its long-term protective effects. Here, we investigated whether the mTOR pathway is involved in the long-term protective effects of IPostC. Stroke was induced in rats by distal middle cerebral artery occlusion (dMCAo) combined with 30 min of bilateral common carotid artery (CCA) occlusion, and IPostC was induced after the CCA release. Injury size and behavioral tests were measured up to 3 weeks post stroke. We used rapamycin and mTOR shRNA lentiviral vectors to inhibit mTOR activities, while S6K1 viral vectors, a main downstream mTOR gene, were used to promote mTOR activities. We found that rapamycin administration abolished the long-term protective effects of IPostC. In addition, IPostC promoted the presynaptic growth associated protein 43 (GAP-43) and the postsynaptic protein 95 (PSD-95) levels at 1 week post-stroke, which were reduced by rapamycin. Furthermore, rapamycin reduced phosphorylated mTOR (p-mTOR) protein levels measured at 3 weeks after stroke. These results were confirmed by mTOR shRNA transfection. Moreover, we found that injection of S6K1 viral vectors promoted GAP-43 and PSD-95 protein levels. We conclude that mTOR may play a crucial, protective role in brain damage after stroke and contribute to the protective effects of IPostC.
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Affiliation(s)
- Peng Wang
- Departments of Neurosurgery, Stanford University, Stanford, CA 94305, United States
| | - Rong Xie
- Departments of Neurosurgery, Stanford University, Stanford, CA 94305, United States; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Michelle Cheng
- Departments of Neurosurgery, Stanford University, Stanford, CA 94305, United States; Departments of Biological Sciences, Stanford University, Stanford, CA 94305, United States
| | - Robert Sapolsky
- Departments of Biological Sciences, Stanford University, Stanford, CA 94305, United States
| | - Xunming Ji
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical School, Beijing 100053, China.
| | - Heng Zhao
- Departments of Neurosurgery, Stanford University, Stanford, CA 94305, United States.
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Park JA, Lee CH. Neuroprotective Effect of Duloxetine on Chronic Cerebral Hypoperfusion-Induced Hippocampal Neuronal Damage. Biomol Ther (Seoul) 2018; 26:115-120. [PMID: 28365975 PMCID: PMC5839489 DOI: 10.4062/biomolther.2016.248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/19/2016] [Accepted: 01/09/2017] [Indexed: 01/08/2023] Open
Abstract
Chronic cerebral hypoperfusion (CCH), which is associated with onset of vascular dementia, causes cognitive impairment and neuropathological alterations in the brain. In the present study, we examined the neuroprotective effect of duloxetine (DXT), a potent and balanced serotonin/norepinephrine reuptake inhibitor, on CCH-induced neuronal damage in the hippocampal CA1 region using a rat model of permanent bilateral common carotid arteries occlusion. We found that treatment with 20 mg/kg DXT could attenuate the neuronal damage, the reduction of phosphorylations of mTOR and p70S6K as well as the elevations of TNF-α and IL-1β levels in the hippocampal CA1 region at 28 days following CCH. These results indicate that DXT displays the neuroprotective effect against CCH-induced hippocampal neuronal death, and that neuroprotective effect of DXT may be closely related with the attenuations of CCH-induced decrease of mTOR/p70S6K signaling pathway as well as CCH-induced neuroinflammatory process.
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Affiliation(s)
- Jin-A Park
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, Republic of Korea
| | - Choong-Hyun Lee
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, Republic of Korea
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Wu M, Zhang H, Kai J, Zhu F, Dong J, Xu Z, Wong M, Zeng LH. Rapamycin prevents cerebral stroke by modulating apoptosis and autophagy in penumbra in rats. Ann Clin Transl Neurol 2017; 5:138-146. [PMID: 29468175 PMCID: PMC5817831 DOI: 10.1002/acn3.507] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 12/13/2022] Open
Abstract
Objective Whether activation or inhibition of the mTOR pathway is beneficial to ischemic injury remains controversial. It may result from the different reaction of ischemic penumbra and core to modulation of mTOR pathway after cerebral ischemia-reperfusion injury in rats. Methods Longa's middle cerebral artery occlusion (MCAO) method was conducted to induce the focal cerebral ischemia-reperfusion. Western blot analysis was used to examine the protein expression involving mTOR pathway, apoptosis, and autophagy-related proteins. TTC staining and Fluoro-Jade B staining was conducted to detect the infarct volume and cell apoptosis, respectively. Neurological function was measured by modified neurological severity score and left-biased swing. Results mTOR signaling pathway was activated in ischemic penumbra and decreased in ischemic core after ischemia and ischemia-reperfusion. Ischemia-reperfusion injury induced the increase in cleaved caspase 9 and caspase 3 both in ischemic penumbra and in ischemic core, whereas the expression of phosphorylated ULK1, Beclin 1 and LC3-II was decreased. Rapamycin pre or postadministration inhibited the overactivation of mTOR pathway in ischemic penumbra. Ameliorated neurological function and reduced infarct volume were observed after pre or postrapamycin treatment. Rapamycin markedly decreased the number of FJB-positive cells and the expression of cleaved caspase-3 and cleaved caspase-9 proteins as well as increased the activation of autophagy reflected by ULK1, Beclin-1 and LC3. Interpretation mTOR signaling pathway was activated in ischemic penumbra after cerebral ischemia-reperfusion injury in rats. mTOR inhibitor rapamycin significantly decreased the mTOR activation and infarct volume and subsequently improved neurological function. These results may relate to inhibition of neuron apoptosis and activation of autophagy.
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Affiliation(s)
- Meiling Wu
- Department of Pharmacology School of Medicine Zhejiang University City College Hangzhou Zhejiang 310015 China
| | - Huadan Zhang
- Department of Pharmacology School of Medicine Zhejiang University City College Hangzhou Zhejiang 310015 China
| | - Jiejing Kai
- Department of Pharmacology School of Medicine Zhejiang University City College Hangzhou Zhejiang 310015 China
| | - Feng Zhu
- Department of Pharmacology School of Medicine Zhejiang University City College Hangzhou Zhejiang 310015 China
| | - Jingyin Dong
- Department of Pharmacology School of Medicine Zhejiang University City College Hangzhou Zhejiang 310015 China
| | - Ziwei Xu
- Department of Pharmacology School of Medicine Zhejiang University City College Hangzhou Zhejiang 310015 China
| | - Michael Wong
- Department of Neurology School of Medicine Washington University in St. Louis Saint Louis Missouri 63110
| | - Ling-Hui Zeng
- Department of Pharmacology School of Medicine Zhejiang University City College Hangzhou Zhejiang 310015 China
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Rezaei R, Nourshahi M, Khodagholi F, Haghparast A, Nasoohi S, Bigdeli M, Ashabi G. Differential impact of treadmill training on stroke-induced neurological disorders. Brain Inj 2017; 31:1910-1917. [DOI: 10.1080/02699052.2017.1346287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Rasoul Rezaei
- Department of Sport Physiology, Faculty of Physical Education and Sport Sciences, Shahid Beheshti University, G.C., Evin 198396113, Tehran, Iran
| | - Maryam Nourshahi
- Department of Sport Physiology, Faculty of Physical Education and Sport Sciences, Shahid Beheshti University, G.C., Evin 198396113, Tehran, Iran
| | - Fariba Khodagholi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sanaz Nasoohi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Ghorbangol Ashabi
- Department of Physiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Arabian M, Aboutaleb N, Soleimani M, Ajami M, Habibey R, Rezaei Y, Pazoki-Toroudi H. Preconditioning with morphine protects hippocampal CA1 neurons from ischemia-reperfusion injury via activation of the mTOR pathway. Can J Physiol Pharmacol 2017; 96:80-87. [PMID: 28881154 DOI: 10.1139/cjpp-2017-0245] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The signaling pathway of chronic morphine treatment to prevent neuronal damage following transient cerebral ischemia is not clear. In this study, we examined the role of mammalian target of rapamycin (mTOR) to identify the neuroprotective effects of chronic morphine preconditioning on the hippocampus following ischemia-reperfusion (I/R) injury. Morphine was administered for 5 days, twice a day, before inducing I/R injury. The possible role of mTOR was evaluated by the injection of rapamycin (5 mg/kg body weight, by intraperitoneal injection) before I/R was induced. The passive avoidance test was used to evaluate memory performance. Neuronal density and apoptosis were measured in the CA1 region, 72 h after I/R injury. The expressions of mTOR and phosphorylated mTOR (p-mTOR), as well as superoxide dismutase (SOD) activity were determined 24 h after I/R injury. Chronic morphine treatment attenuated apoptosis and neuronal loss in the hippocampus after I/R injury, which led to improvement in memory (P < 0.05 vs. untreated I/R) and increase in the expression of p-mTOR (P < 0.05 vs. untreated I/R) and SOD activity (P < 0.05 vs. untreated I/R) in the hippocampus. Pretreatment with rapamycin abolished all the above-mentioned protective effects. These results describe novel findings whereby chronic morphine preconditioning in hippocampal CA1 neurons is mediated by the mTOR pathway, and through increased phosphorylation of mTOR can alleviate oxidative stress and apoptosis, and eventually protect the hippocampus from I/R injury.
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Affiliation(s)
- Maedeh Arabian
- a Rajaie Cardiovascular, Medical, and Research Centre, Iran University of Medical Sciences, Tehran, Iran
| | - Nahid Aboutaleb
- b Physiology Research Center, Physiology Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mansoureh Soleimani
- c Cellular and Molecular Research Centre, Department of Anatomy, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Marjan Ajami
- d Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rouhollah Habibey
- e Department of Neuroscience and Brain Technologies-Istituto Italiano di Technologia, Via Morego, 30, 16163 Genova, Italy
| | - Yousef Rezaei
- f Heart Valve Disease Research Center, Rajaie Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Hamidreza Pazoki-Toroudi
- b Physiology Research Center, Physiology Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Park JA, Lee CH. Temporal changes in mammalian target of rapamycin (mTOR) and phosphorylated-mTOR expressions in the hippocampal CA1 region of rat with vascular dementia. J Vet Sci 2017; 18:11-16. [PMID: 27297423 PMCID: PMC5366295 DOI: 10.4142/jvs.2017.18.1.11] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/21/2016] [Accepted: 05/12/2016] [Indexed: 01/08/2023] Open
Abstract
Mammalian target of rapamycin (mTOR) has an important role in various biological processes in cells. In the present study, we investigated temporal changes in mTOR and phosphorylated-mTOR (p-mTOR) expressions in the rat hippocampal CA1 region following chronic cerebral hypoperfusion (CCH) induced by permanent bilateral common carotid arteries occlusion (2VO). The mTOR immunoreactivity in the pyramidal neurons and mTOR protein level in the hippocampal CA1 region were markedly decreased at 21 and 28 days after 2VO surgery. However, p-mTOR protein expression was significantly increased at 7 days following CCH but then decreased with time. The results indicate that mTOR and p-mTOR expressions change in the hippocampal CA1 region after 2VO surgery and that reduced expressions of mTOR and p-mTOR may be closely related to the CCH-induced neuronal damage in the hippocampal CA1 region.
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Affiliation(s)
- Jin-A Park
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, Korea
| | - Choong-Hyun Lee
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, Korea
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Impaired autophagosome clearance contributes to neuronal death in a piglet model of neonatal hypoxic-ischemic encephalopathy. Cell Death Dis 2017; 8:e2919. [PMID: 28703794 DOI: 10.1038/cddis.2017.318] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/29/2017] [Accepted: 06/07/2017] [Indexed: 01/21/2023]
Abstract
To examine the temporal relationship of cortical autophagic flux with delayed neuronal cell death after hypoxia-ischemia (HI) in neonatal piglets. HI was produced with 45-min hypoxia and 7-min airway occlusion in 3-5-day-old piglets. Markers of autophagic, lysosomal and cell death signaling were studied via immunohistochemistry, immunoblotting, and histochemistry in piglet brains. In vitro, autophagy was impaired in cultured mouse cortical neurons treated with chloroquine with or without rapamycin for 1 d in the presence of Z-VAD-fmk, cyclosporine A, or vehicle control, and cell viability was assessed with the MTT assay. In vivo, neuronal cell death of sensorimotor cortex was delayed by 1-2 days after HI, whereas LC3-II, Beclin-1, PI3KC3, ATG12-ATG-5, and p-ULK1 increased by 1.5-6 h. Autophagosomes accumulated in cortical neurons by 1 d owing to enhanced autophagy and later to decreased autophagosome clearance, as indicated by LC3, Beclin-1, and p62 accumulation. Autophagy flux impairment was attributable to lysosomal dysfunction, as indicated by low lysosomal-associated membrane protein 2, cathepsin B, and cathepsin D levels at 1 d. Ubiquitin levels increased at 1 d. Autophagosome and p62 accumulated predominantly in neurons at 1 d, with p62 puncta occurring in affected cells. Beclin-1 colocalized with markers of caspase-dependent and caspase-independent apoptosis and necrosis in neurons. In vitro, mouse neonatal cortical neurons treated with rapamycin and chloroquine showed increased autophagosomes, but not autolysosomes, and increased cell death that was attenuated by cyclosporine A. Neonatal HI initially increases autophagy but later impairs autophagosome clearance, coinciding with delayed cortical neuronal death.
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Saeedi Saravi SS, Arefidoust A, Saeedi Saravi SS, Yaftian R, Bayati M, Salehi M, Dehpour AR. Mammalian target of rapamycin (mTOR)/nitric oxide system possibly modulate antidepressant-like effect of 17α-ethinyl estradiol in ovariectomized mice. Biomed Pharmacother 2017; 89:591-604. [DOI: 10.1016/j.biopha.2017.02.078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 02/07/2023] Open
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Yang H, Li L, Zhou K, Wang Y, Guan T, Chai C, Kou J, Yu B, Yan Y. Shengmai injection attenuates the cerebral ischemia/reperfusion induced autophagy via modulation of the AMPK, mTOR and JNK pathways. PHARMACEUTICAL BIOLOGY 2016; 54:2288-2297. [PMID: 26983890 DOI: 10.3109/13880209.2016.1155625] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Context Shengmai injection (SMI) is a patented Chinese medicine originated from the ancient Chinese herbal compound Shengmai san, which is used extensively for the treatment of cardiovascular and cerebrovascular disease in the clinic. Objective To determine the neuroprotective effect of SMI, we investigated the effect of SMI on cerebral ischemia/reperfusion (I/R) injury in mice as well as the mechanisms underlying this effect. Materials and methods Right middle cerebral artery was occluded by inserting a thread through internal carotid artery for 1 h, and then reperfused for 24 h in mice. The neuroprotective effects were determined using transmission electron microscopic examination, the evaluation of infarct volume, neurological deficits and water brain content. Related mechanisms were evaluated by immunofluorescence staining and western blotting. SMI was injected intraperitoneally after 1 h of ischemia at doses of 1.42, 2.84 and 5.68 g/kg. The control group received saline as the SMI vehicle. Results Results showed that SMI (1.42, 2.84 and 5.68 g/kg) could significantly reduce the infarct volume, SMI (5.68 g/kg) could also significantly improve the neurological deficits, decreased brain water content, as well as the neuronal morphological changes. SMI (5.68g/kg) could significantly inhibit the expression of autophagy-related proteins: Beclin1 and LC3. It also reduced the increase in LC3-positive cells. SMI (5.68 g/kg) remarkably inhibited the phosphorylation of adenosine monophosphate activated protein kinase (AMPK), and down-regulated the phosphorylation of mammalian target of rapamycin (mTOR) and Jun N-terminal kinase (JNK) after 24 h of reperfusion. Discussion and conclusion The results indicate that SMI provides remarkable protection against cerebral ischemia/reperfusion injury, which may be partly due to the inhibition of autophagy and related signalling pathways.
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MESH Headings
- AMP-Activated Protein Kinases/metabolism
- Animals
- Autophagy/drug effects
- Beclin-1/metabolism
- Brain/drug effects
- Brain/enzymology
- Brain/physiopathology
- Brain/ultrastructure
- Brain Edema/prevention & control
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Combinations
- Drugs, Chinese Herbal/administration & dosage
- Enzyme Activation
- Infarction, Middle Cerebral Artery/enzymology
- Infarction, Middle Cerebral Artery/pathology
- Infarction, Middle Cerebral Artery/physiopathology
- Infarction, Middle Cerebral Artery/prevention & control
- Injections, Intraperitoneal
- JNK Mitogen-Activated Protein Kinases/metabolism
- Male
- Mice, Inbred C57BL
- Microscopy, Electron, Transmission
- Microtubule-Associated Proteins/metabolism
- Neuroprotective Agents/administration & dosage
- Phosphorylation
- Phytotherapy
- Plants, Medicinal
- Reperfusion Injury/enzymology
- Reperfusion Injury/pathology
- Reperfusion Injury/physiopathology
- Reperfusion Injury/prevention & control
- Signal Transduction/drug effects
- TOR Serine-Threonine Kinases/metabolism
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Affiliation(s)
- Haopeng Yang
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Long Li
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Kecheng Zhou
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Yuqing Wang
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Teng Guan
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Chengzhi Chai
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Junping Kou
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Boyang Yu
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
| | - Yongqing Yan
- a Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Department of Complex Prescription of TCM , China Pharmaceutical University , Nanjing , PR China
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16
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Chi OZ, Mellender SJ, Barsoum S, Liu X, Damito S, Weiss HR. Effects of rapamycin pretreatment on blood-brain barrier disruption in cerebral ischemia-reperfusion. Neurosci Lett 2016; 620:132-6. [PMID: 27037216 DOI: 10.1016/j.neulet.2016.03.053] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 03/12/2016] [Accepted: 03/28/2016] [Indexed: 02/06/2023]
Abstract
The mammalian target of rapamycin (mTOR) pathway is essential in neuronal survival and repair in cerebral ischemia. Decreases in blood-brain barrier (BBB) disruption are associated with a decrease in neuronal damage in cerebral ischemia. This study was performed to investigate how pre-inhibition of the mTOR pathway with rapamycin would affect BBB disruption and the size of the infarcted cortical area in the early stage of focal cerebral ischemia-reperfusion using quantitative analysis of BBB disruption. Rats were treated with 20mg/kg of rapamycin i.p. once a day for 2days (Rapamycin Group) or vehicle (Control Group) before transient middle cerebral artery (MCA) occlusion. After one hour of MCA occlusion and two hours of reperfusion, the transfer coefficient (Ki) of (14)C-α-aminoisobutyric acid ((14)C-AIB) to measure the degree of BBB disruption and the size of the cortical infarct were determined. Ischemia-reperfusion increased the Ki in the Rapamycin treated (+15%) as well as in the untreated control group (+13%). However, rapamycin pretreatment moderately decreased Ki in the contralateral (-30%) as well as in the ischemic-reperfused (-29%) cortex when compared with the untreated control group. Rapamycin pretreatment substantially increased the percentage of cortical infarct compared with the control group (+56%). Our data suggest that activation of mTOR pathway is necessary for neuronal survival in the early stage of cerebral ischemia-perfusion and that the reason for the enlarged cortical infarct by rapamycin pretreatment may be related to its non-BBB effects on the mTOR pathway.
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Affiliation(s)
- Oak Z Chi
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
| | - Scott J Mellender
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Sylviana Barsoum
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Xia Liu
- Department of Anesthesiology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Stacey Damito
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Harvey R Weiss
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
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17
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Yang X, Hei C, Liu P, Song Y, Thomas T, Tshimanga S, Wang F, Niu J, Sun T, Li PA. Inhibition of mTOR Pathway by Rapamycin Reduces Brain Damage in Rats Subjected to Transient Forebrain Ischemia. Int J Biol Sci 2015; 11:1424-35. [PMID: 26681922 PMCID: PMC4672000 DOI: 10.7150/ijbs.12930] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 10/21/2015] [Indexed: 12/19/2022] Open
Abstract
The aims of this study are to clarify the role of mTOR in mediating cerebral ischemic brain damage and the effects of rapamycin on ischemic outcomes. Ten minutes of forebrain ischemia was induced in rats, and their brains were sampled after 3 h, 16 h, and 7 days reperfusion for histology, immunohistochemistry and biochemical analysis. Our data demonstrated that cerebral ischemia resulted in both apoptotic and necrotic neuronal death; cerebral ischemia and reperfusion led to significant increases of mRNA and protein levels of p-mTOR and its downstream p-P70S6K and p-S6; elevation of LC3-II, and release of cytochrome c into the cytoplasm in both the cortex and hippocampus. Inhibition of mTOR by rapamycin markedly reduced ischemia-induced damage; suppressed p-Akt, p-mTOR, p-P70S6K and p-S6 protein levels; decreased LC3-II and Beclin-1; and prevented cytochrome c release in the two structures. All together, these data provide evidence that cerebral ischemia activates mTOR and autophagy pathways. Inhibition of mTOR deactivates the mTOR pathway, suppresses autophagy, prevents cytochrome c release and reduces ischemic brain damage.
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Affiliation(s)
- Xiao Yang
- 1. Neuroscience Center, General Hospital of Ningxia Medical University, Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Yinchuan 75004, China ; 2. Department of Pharmaceutical Sciences, Biomanufacturing Research Institute Biotechnology Enterprise (BRITE), North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707, USA
| | - Changhun Hei
- 2. Department of Pharmaceutical Sciences, Biomanufacturing Research Institute Biotechnology Enterprise (BRITE), North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707, USA ; 3. Department of Human Anatomy, Histology and Embryology, Ningxia Medical University, Yinchuan 75004, China
| | - Ping Liu
- 2. Department of Pharmaceutical Sciences, Biomanufacturing Research Institute Biotechnology Enterprise (BRITE), North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707, USA ; 4. Department of Endocrinology, General Hospital of Ningxia Medical University, Yinchuan 750004, China
| | - Yaozu Song
- 1. Neuroscience Center, General Hospital of Ningxia Medical University, Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Yinchuan 75004, China
| | - Taylor Thomas
- 2. Department of Pharmaceutical Sciences, Biomanufacturing Research Institute Biotechnology Enterprise (BRITE), North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707, USA
| | - Sylvie Tshimanga
- 2. Department of Pharmaceutical Sciences, Biomanufacturing Research Institute Biotechnology Enterprise (BRITE), North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707, USA
| | - Feng Wang
- 1. Neuroscience Center, General Hospital of Ningxia Medical University, Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Yinchuan 75004, China
| | - Jianguo Niu
- 1. Neuroscience Center, General Hospital of Ningxia Medical University, Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Yinchuan 75004, China
| | - Tao Sun
- 1. Neuroscience Center, General Hospital of Ningxia Medical University, Key Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Yinchuan 75004, China
| | - P Andy Li
- 2. Department of Pharmaceutical Sciences, Biomanufacturing Research Institute Biotechnology Enterprise (BRITE), North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707, USA
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18
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Specific inhibition of mTOR pathway induces anti-proliferative effect and decreases the hormone secretion in cultured pituitary adenoma cells. J Neurooncol 2015; 125:79-89. [DOI: 10.1007/s11060-015-1895-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 08/14/2015] [Indexed: 02/02/2023]
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19
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Xie R, Wang P, Cheng M, Sapolsky R, Ji X, Zhao H. Mammalian target of rapamycin cell signaling pathway contributes to the protective effects of ischemic postconditioning against stroke. Stroke 2014; 45:2769-76. [PMID: 25013017 DOI: 10.1161/strokeaha.114.005406] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Whether the mammalian target of rapamycin (mTOR) pathway is protective against brain injury from stroke or is detrimental is controversial, and whether it is involved in the protective effects of ischemic postconditioning (IPC) against stroke is unreported. Our study focuses on the protective role of mTOR against neuronal injury after stroke with and without IPC. METHODS We used both an in vitro oxygen-glucose deprivation model with a mixed neuronal culture and hypoxic postconditioning, as well as an in vivo stroke model with IPC. Rapamycin, a specific pharmacological inhibitor of mTOR, and mTOR short hairpin RNA lentiviral vectors were used to inhibit mTOR activity. A lentiviral vector expressing S6K1, a downstream molecule of mTOR, was used to confirm the protective effects of mTOR. Infarct sizes were measured and protein levels were examined by Western blot. RESULTS We report that stroke resulted in reduced levels of phosphorylated proteins in the mTOR pathway, including S6K1, S6, and 4EBP1, and that IPC increased these proteins. mTOR inhibition, both by the mTOR inhibitor rapamycin and by mTOR short hairpin RNA, worsened ischemic outcomes in vitro and in vivo and abolished the protective effects of hypoxic postconditioning and IPC on neuronal death in vitro and brain injury size in vivo. Overexpression of S6K1 mediated by lentiviral vectors significantly attenuated brain infarction. CONCLUSIONS mTOR plays a crucial protective role in brain damage after stroke and contributes to the protective effects of IPC.
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Affiliation(s)
- Rong Xie
- From the Departments of Neurosurgery (R.X., P.W., M.C., R.S., H.Z.) and Biological Sciences (M.C., R.S.), and Stanford Stroke Center (H.Z.), Stanford University, CA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China (R.X.); and Department of Neurosurgery, Xuanwu Hospital, Capital Medical School, Beijing, China (P.W., X.J.)
| | - Peng Wang
- From the Departments of Neurosurgery (R.X., P.W., M.C., R.S., H.Z.) and Biological Sciences (M.C., R.S.), and Stanford Stroke Center (H.Z.), Stanford University, CA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China (R.X.); and Department of Neurosurgery, Xuanwu Hospital, Capital Medical School, Beijing, China (P.W., X.J.)
| | - Michelle Cheng
- From the Departments of Neurosurgery (R.X., P.W., M.C., R.S., H.Z.) and Biological Sciences (M.C., R.S.), and Stanford Stroke Center (H.Z.), Stanford University, CA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China (R.X.); and Department of Neurosurgery, Xuanwu Hospital, Capital Medical School, Beijing, China (P.W., X.J.)
| | - Robert Sapolsky
- From the Departments of Neurosurgery (R.X., P.W., M.C., R.S., H.Z.) and Biological Sciences (M.C., R.S.), and Stanford Stroke Center (H.Z.), Stanford University, CA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China (R.X.); and Department of Neurosurgery, Xuanwu Hospital, Capital Medical School, Beijing, China (P.W., X.J.)
| | - Xunming Ji
- From the Departments of Neurosurgery (R.X., P.W., M.C., R.S., H.Z.) and Biological Sciences (M.C., R.S.), and Stanford Stroke Center (H.Z.), Stanford University, CA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China (R.X.); and Department of Neurosurgery, Xuanwu Hospital, Capital Medical School, Beijing, China (P.W., X.J.).
| | - Heng Zhao
- From the Departments of Neurosurgery (R.X., P.W., M.C., R.S., H.Z.) and Biological Sciences (M.C., R.S.), and Stanford Stroke Center (H.Z.), Stanford University, CA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China (R.X.); and Department of Neurosurgery, Xuanwu Hospital, Capital Medical School, Beijing, China (P.W., X.J.).
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20
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Baek SH, Noh AR, Kim KA, Akram M, Shin YJ, Kim ES, Yu SW, Majid A, Bae ON. Modulation of mitochondrial function and autophagy mediates carnosine neuroprotection against ischemic brain damage. Stroke 2014; 45:2438-2443. [PMID: 24938837 DOI: 10.1161/strokeaha.114.005183] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND PURPOSE Despite the rapidly increasing global burden of ischemic stroke, no therapeutic options for neuroprotection against stroke currently exist. Recent studies have shown that autophagy plays a key role in ischemic neuronal death, and treatments that target autophagy may represent a novel strategy in neuroprotection. We investigated whether autophagy is regulated by carnosine, an endogenous pleiotropic dipeptide that has robust neuroprotective activity against ischemic brain damage. METHODS We examined the effect of carnosine on mitochondrial dysfunction and autophagic processes in rat focal ischemia and in neuronal cultures. RESULTS Autophagic pathways such as reduction of phosphorylated mammalian target of rapamycin (mTOR)/p70S6K and the conversion of microtubule-associated protein 1 light chain 3 (LC3)-I to LC3-II were enhanced in the ischemic brain. However, treatment with carnosine significantly attenuated autophagic signaling in the ischemic brain, with improvement of brain mitochondrial function and mitophagy signaling. The protective effect of carnosine against autophagy was also confirmed in primary cortical neurons. CONCLUSIONS Taken together, our data suggest that the neuroprotective effect of carnosine is at least partially mediated by mitochondrial protection and attenuation of deleterious autophagic processes. Our findings shed new light on the mechanistic pathways that this exciting neuroprotective agent influences.
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Affiliation(s)
- Seung-Hoon Baek
- College of Pharmacy, Ajou University, Suwon, Republic of Korea
| | - Ah Reum Noh
- College of Pharmacy Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Republic of Korea
| | - Kyeong-A Kim
- College of Pharmacy Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Republic of Korea
| | - Muhammad Akram
- College of Pharmacy Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Republic of Korea
| | - Young-Jun Shin
- College of Pharmacy Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Republic of Korea
| | - Eun-Sun Kim
- College of Pharmacy Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Republic of Korea
| | - Seong Woon Yu
- Department of Brain Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Arshad Majid
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385A Glossop Road, SHEFFIELD S10 2HQ, England
| | - Ok-Nam Bae
- College of Pharmacy Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Republic of Korea
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Xiong X, Xie R, Zhang H, Gu L, Xie W, Cheng M, Jian Z, Kovacina K, Zhao H. PRAS40 plays a pivotal role in protecting against stroke by linking the Akt and mTOR pathways. Neurobiol Dis 2014; 66:43-52. [PMID: 24583056 DOI: 10.1016/j.nbd.2014.02.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 01/08/2014] [Accepted: 02/19/2014] [Indexed: 11/16/2022] Open
Abstract
The proline-rich Akt substrate of 40kDa (PRAS40) protein is not only a substrate of the protein kinase Akt but also a component of the mTOR complex 1 (mTORC1), thus it links the Akt and the mTOR pathways. We investigated the potential protective role of PRAS40 in cerebral ischemia and its underlying mechanisms by using rats with lentiviral over-expression of PRAS40 and mice with PRAS40 gene knockout (PRAS40 KO). Our results show that gene transfer of PRAS40 reduced infarction size in rats by promoting phosphorylation of Akt, FKHR (FOXO1), PRAS40, and mTOR. In contrast, PRAS40 KO increased infarction size. Although the PRAS40 KO under normal condition did not alter baseline levels of phosphorylated proteins in the Akt and mTOR pathways, PRAS40 KO that underwent stroke exhibited reduced protein levels of p-S6K and p-S6 in the mTOR pathway but not p-Akt, or p-PTEN in the Akt pathway. Furthermore, co-immunoprecipitation suggests that there were less interactive effects between Akt and mTOR in the PRAS40 KO. In conclusion, PRAS40 appears to reduce brain injury by converting cell signaling from Akt to mTOR.
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Affiliation(s)
- Xiaoxing Xiong
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Rong Xie
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Hongfei Zhang
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Lijuan Gu
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Weiying Xie
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Michelle Cheng
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Zhihong Jian
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Kristina Kovacina
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Heng Zhao
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA.
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Ström JO, Ingberg E. Impact of methodology on estrogens' effects on cerebral ischemia in rats: an updated meta-analysis. BMC Neurosci 2014; 15:22. [PMID: 24495535 PMCID: PMC3975994 DOI: 10.1186/1471-2202-15-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/29/2014] [Indexed: 12/15/2022] Open
Abstract
Background Although most animal stroke studies have demonstrated potent neuroprotective effects of estrogens, there are a number of articles reporting the opposite. In 2009, we made the case that this dichotomy was related to administered estrogen dose. Several other suggestions for the discordant results have also been propagated, including the age of the experimental animals and the length of hypoestrogenicity prior to estrogen administration. These two suggestions have gained much popularity, probably because of their kinship with the window of opportunity hypothesis, which is commonly used to explain the analogous dichotomy among human studies. We were therefore encouraged to perform an updated meta-analysis, and to improve it by including all relevant variables in a large multiple regression model, where the impact of confounders could be controlled for. Results The multiple regression model revealed an indisputable impact of estrogen administration mode on the effects of estrogens in ischemic stroke. Subcutaneous slow-release pellets differed from the injection and silastic capsule treatments in terms of impact of estrogens on ischemic stroke, showing that the first mentioned were more prone to render estrogens damaging. Neither the use of elderly animals nor the adoption of longer wash-out periods influenced estrogens’ effects on experimental ischemic stroke in rats. Conclusions We conclude that the discordant results regarding estrogens’ effects in rat models of ischemic stroke are a consequence of differences in estrogen administration modes. These results are not only of importance for the ongoing debate regarding menopausal hormone therapy, but also have an important bearing on experimental stroke methodology and the apparent translational roadblock for suggested stroke interventions.
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Affiliation(s)
- Jakob O Ström
- Vårdvetenskapligt Forskningscentrum/Centre for Health Sciences, Örebro University Hospital, County Council of Örebro, Örebro SE-703 62, Sweden.
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Strom JO, Ingberg E, Theodorsson E, Theodorsson A. Effects of high and low 17β-estradiol doses on focal cerebral ischemia: negative results. Sci Rep 2013; 3:3111. [PMID: 24177749 PMCID: PMC6505964 DOI: 10.1038/srep03111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 10/11/2013] [Indexed: 01/11/2023] Open
Abstract
The reasons why some animal studies indicate that estrogens increase focal cerebral ischemic damage while others show estrogen-induced neuroprotection has hitherto not been fully elucidated. Recent evidence indicates that discrepancies in hormone administration paradigms, resulting in highly different serum hormone concentrations, may account for the dichotomy. The current study aimed to test this hypothesis. Sixty ovariectomized female rats were randomized into three groups differing in 17β-estradiol regimens, and transient focal cerebral ischemia was subsequently induced. All animals were subjected to a small functional testing battery, and three days after MCAo they were sacrificed for infarct size assessment. Infarct sizes did not differ between groups, however clear discrepancies were seen in body weight and feeding behavior. In comparison to sham-operated animals, ovariectomized rats rapidly increased in body weight, whereas the opposite was seen in rats receiving 17beta-estradiol. The weight gain in the ovariectomized rats was paralleled by an increased food intake.
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Affiliation(s)
- Jakob O Strom
- Clinical Chemistry, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Department of Clinical Chemistry, County Council of Östergötland, Linköping, Sweden
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ZHANG HONGWEI, CUI ZHONGYI, LUO GUANGWEI, ZHANG JIAHENG, MA TAO, HU NA, CUI TIANPEN. Ghrelin attenuates intestinal ischemia/reperfusion injury in mice by activating the mTOR signaling pathway. Int J Mol Med 2013; 32:851-9. [DOI: 10.3892/ijmm.2013.1452] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/15/2013] [Indexed: 11/06/2022] Open
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Zare Mehrjerdi F, Aboutaleb N, Habibey R, Ajami M, Soleimani M, Arabian M, Niknazar S, Hossein Davoodi S, Pazoki-Toroudi H. Increased phosphorylation of mTOR is involved in remote ischemic preconditioning of hippocampus in mice. Brain Res 2013; 1526:94-101. [PMID: 23806777 DOI: 10.1016/j.brainres.2013.06.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 12/17/2022]
Abstract
Different signaling pathways are involved in tissue protection against ischemia reperfusion (IR) injury, among them mammalian target of rapamycin (mTOR) and related pathways have been examined in many recent studies. Present study evaluated the role of mTOR in remote ischemic preconditioning (RIPC) of hippocampus. Renal ischemia was induced (3 cycles of 5min occlusion and 5min reperfusion of unilateral renal artery) 24h before global brain ischemia (20min bilateral common carotid artery occlusion). Saline or rapamycin (mTOR inhibitor; 5mg/kg, i.p.) was injected 30min before RIPC. mTOR and phosphorylated mTOR (p-mTOR) expression, superoxide dismutase (SOD) activity and retention trial of passive avoidance test were determined 24h after global ischemia. Apoptosis and neuronal cell density were assessed 72h after hippocampal ischemia. RIPC decreased apoptosis (p<0.05 vs. IR), improved memory (p<0.05 vs. IR), and augmented p-mTOR expression and SOD activity after hippocampal ischemia (p<0.05 vs. IR). Rapamycin abolished all protective effects of RIPC (p<0.05 vs. RIPC+IR) suggesting a role for mTOR in RIPC induced hippocampal protection.
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Chong ZZ, Yao Q, Li HH. The rationale of targeting mammalian target of rapamycin for ischemic stroke. Cell Signal 2013; 25:1598-607. [PMID: 23563259 DOI: 10.1016/j.cellsig.2013.03.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 03/28/2013] [Indexed: 02/06/2023]
Abstract
Given the current limitation of therapeutic approach for ischemic stroke, a leading cause of disability and mortality in the developed countries, to develop new therapeutic strategies for this devastating disease is urgently necessary. As a serine/threonine kinase, mammalian target of rapamycin (mTOR) activation can mediate broad biological activities that include protein synthesis, cytoskeleton organization, and cell survival. mTOR functions through mTORC1 and mTORC2 complexes and their multiple downstream substrates, such as eukaryotic initiation factor 4E-binding protein 1, p70 ribosomal S6 kinase, sterol regulatory element-binding protein 1, hypoxia inducible factor-1, and signal transducer and activator transcription 3, Yin Ying 1, Akt, protein kinase c-alpha, Rho GTPase, serum-and gucocorticoid-induced protein kinase 1, etc. Specially, the role of mTOR in the central nervous system has been attracting considerable attention. Based on the ability of mTOR to prevent neuronal apoptosis, inhibit autophagic cell death, promote neurogenesis, and improve angiogenesis, mTOR may acquire the capability of limiting the ischemic neuronal death and promoting the neurological recovery. Consequently, to regulate the activity of mTOR holds a potential as a novel therapeutic strategy for ischemic stroke.
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Affiliation(s)
- Zhao Zhong Chong
- Department of Neurology and Neurosciences, Cancer Center, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07101, USA.
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Fortress AM, Fan L, Orr PT, Zhao Z, Frick KM. Estradiol-induced object recognition memory consolidation is dependent on activation of mTOR signaling in the dorsal hippocampus. Learn Mem 2013; 20:147-55. [PMID: 23422279 DOI: 10.1101/lm.026732.112] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The mammalian target of rapamycin (mTOR) signaling pathway is an important regulator of protein synthesis and is essential for various forms of hippocampal memory. Here, we asked whether the enhancement of object recognition memory consolidation produced by dorsal hippocampal infusion of 17β-estradiol (E(2)) is dependent on mTOR signaling in the dorsal hippocampus, and whether E(2)-induced mTOR signaling is dependent on dorsal hippocampal phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK) activation. We first demonstrated that the enhancement of object recognition induced by E(2) was blocked by dorsal hippocampal inhibition of ERK, PI3K, or mTOR activation. We then showed that an increase in dorsal hippocampal ERK phosphorylation 5 min after intracerebroventricular (ICV) E(2) infusion was also blocked by dorsal hippocampal infusion of the three cell signaling inhibitors. Next, we found that ICV infusion of E(2) increased phosphorylation of the downstream mTOR targets S6K (Thr-421) and 4E-BP1 in the dorsal hippocampus 5 min after infusion, and that this phosphorylation was blocked by dorsal hippocampal infusion of inhibitors of ERK, PI3K, and mTOR. Collectively, these data demonstrate for the first time that activation of the dorsal hippocampal mTOR signaling pathway is necessary for E(2) to enhance object recognition memory consolidation and that E(2)-induced mTOR activation is dependent on upstream activation of ERK and PI3K signaling.
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Affiliation(s)
- Ashley M Fortress
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
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Kao CH, Chang CZ, Su YF, Tsai YJ, Chang KP, Lin TK, Hwang SL, Lin CL. 17β-Estradiol attenuates secondary injury through activation of Akt signaling via estrogen receptor alpha in rat brain following subarachnoid hemorrhage. J Surg Res 2013; 183:e23-30. [PMID: 23465388 DOI: 10.1016/j.jss.2013.01.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 01/12/2013] [Accepted: 01/17/2013] [Indexed: 01/10/2023]
Abstract
BACKGROUND Apoptosis is implicated in vasospasm and the long-term sequelae of subarachnoid hemorrhage (SAH). This study tested the hypothesis that attenuation of SAH-induced apoptosis after 17β-estradiol (E2) treatment is associated with an increase in phosphorylation of Akt via estrogen receptor-α (ER-α) in rats. MATERIALS AND METHODS We examined the expression of phospho-Akt, ERα and ERβ, and apoptosis in cerebral cortex, hippocampus, and dentate gyrus in a two-hemorrhage SAH model in rats. We subcutaneously implanted other rats with a silicone rubber tube containing E2; they received daily injections of nonselective estrogen receptor antagonist (ICI 182,780), selective ERα-selective antagonist (methyl-piperidino-pyrazole), or ERβ-selective antagonist (R,R-tetrahydrochrysene) after the first hemorrhage. RESULTS At 7 d after the first SAH, protein levels of phospho-Akt and ERα were significantly decreased and caspase-3 was significantly increased in the dentate gyrus. The cell death assay revealed that DNA fragmentation was significantly increased in the dentate gyrus. Those actions were reversed by E2 and blocked by ICI 182,780 and methyl-piperidino-pyrazole, but not R,R-tetrahydrochrysene. However, there were no significant changes in the expression of the protein levels of phospho-Akt, ERα, ERβ, and caspase-3, and DNA fragmentation after SAH. CONCLUSIONS The present study shows that a beneficial effect of E2 in attenuating SAH-induced apoptosis is associated with activation of the expression of phospho-Akt and ERα, and alteration in caspase-3 protein expression via an ERα-dependent mechanism in the dentate gyrus. These data support further the investigation of E2 in the treatment of SAH in humans.
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Affiliation(s)
- Cheng-Hsing Kao
- Center for General Education, Southern Taiwan University of Technology, Tainan, Taiwan
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Sun G, Li Z, Wang X, Tang W, Wei Y. Modulation of MAPK and Akt signaling pathways in proximal segment of injured sciatic nerves. Neurosci Lett 2013; 534:205-10. [DOI: 10.1016/j.neulet.2012.12.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/26/2012] [Accepted: 12/12/2012] [Indexed: 12/18/2022]
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Korićanac G, Tepavčević S, Romić S, Živković M, Stojiljković M, Milosavljević T, Stanković A, Petković M, Kamčeva T, Žakula Z. Estradiol enhances effects of fructose rich diet on cardiac fatty acid transporter CD36 and triglycerides accumulation. Eur J Pharmacol 2012; 694:127-34. [DOI: 10.1016/j.ejphar.2012.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 08/13/2012] [Accepted: 08/18/2012] [Indexed: 12/11/2022]
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Cai M, Phan PTT, Hong JG, Kim DH, Kim JM, Park SJ, Liu X, Han JE, Park H, Choi JW, Ryu JH. The neuroprotective effect of eupatilin against ischemia/reperfusion-induced delayed neuronal damage in mice. Eur J Pharmacol 2012; 689:104-10. [DOI: 10.1016/j.ejphar.2012.05.042] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 05/23/2012] [Accepted: 05/29/2012] [Indexed: 11/30/2022]
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Pérez-Álvarez MJ, Maza MDC, Anton M, Ordoñez L, Wandosell F. Post-ischemic estradiol treatment reduced glial response and triggers distinct cortical and hippocampal signaling in a rat model of cerebral ischemia. J Neuroinflammation 2012; 9:157. [PMID: 22747981 PMCID: PMC3414748 DOI: 10.1186/1742-2094-9-157] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 05/29/2012] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Estradiol has been shown to exert neuroprotective effects in several neurodegenerative conditions, including cerebral ischemia. The presence of this hormone prior to ischemia attenuates the damage associated with such events in a rodent model (middle cerebral artery occlusion (MCAO)), although its therapeutic value when administered post-ischemia has not been assessed. Hence, we evaluated the effects of estradiol treatment after permanent MCAO (pMCAO) was induced in rats, studying the PI3K/AKT/GSK3/β-catenin survival pathway and the activation of SAPK-JNK in two brain areas differently affected by pMCAO: the cortex and hippocampus. In addition, we analyzed the effect of estradiol on the glial response to injury. METHODS Male rats were subjected to pMCAO and estradiol (0.04 mg/kg) was administered 6, 24, and 48 h after surgery. The animals were sacrificed 6 h after the last treatment, and brain damage was evaluated by immunohistochemical quantification of 'reactive gliosis' using antibodies against GFAP and Iba1. In addition, Akt, phospho-Akt(Ser473), phospho-Akt(Thr308), GSK3, phospho-GSK3(Ser21/9), β-catenin, SAPK-JNK, and pSAPK-JNK(Thr183/Tyr185) levels were determined in western blots of the ipsilateral cerebral cortex and hippocampus, and regional differences in neuronal phospho-Akt expression were determined by immunohistochemistry. RESULTS The increases in the percentage of GFAP- (5.25-fold) and Iba1- (1.8-fold) labeled cells in the cortex and hippocampus indicate that pMCAO induced 'reactive gliosis'. This effect was prevented by post-ischemic estradiol treatment; diminished the number of these cells to those comparable with control animals. pMCAO down-regulated the PI3K/AkT/GSK3/β-catenin survival pathway to different extents in the cortex and hippocampus, the activity of which was restored by estradiol treatment more efficiently in the cerebral cortex (the most affected region) than in the hippocampus. No changes in the phosphorylation of SAPK-JNK were observed 54 h after inducing pMCAO, whereas pMCAO did significantly decrease the phospho-Akt(Ser473) in neurons, an effect that was reversed by estradiol. CONCLUSION The present study demonstrates that post-pMCAO estradiol treatment attenuates ischemic injury in both neurons and glia, events in which the PI3K/AKT/GSK3/β-catenin pathway is at least partly involved. These findings indicate that estradiol is a potentially useful treatment to enhance recovery after human ischemic stroke.
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Affiliation(s)
- Maria Jose Pérez-Álvarez
- Departamento de Biología (Unidad docente Fisiología Animal), Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Centro de Biología Molecular “Severo Ochoa”, CSIC-UAM, Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Maria del Carmen Maza
- Departamento de Biología (Unidad docente Fisiología Animal), Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Centro de Biología Molecular “Severo Ochoa”, CSIC-UAM, Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Marta Anton
- Departamento de Biología (Unidad docente Fisiología Animal), Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Centro de Biología Molecular “Severo Ochoa”, CSIC-UAM, Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Lara Ordoñez
- Departamento de Biología (Unidad docente Fisiología Animal), Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Centro de Biología Molecular “Severo Ochoa”, CSIC-UAM, Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Francisco Wandosell
- Centro de Biología Molecular “Severo Ochoa”, CSIC-UAM, Univ. Autónoma de Madrid, Madrid, 28049, Spain
- Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa", CIBERNED-CSIC-UAM, Universidad Autónoma de Madrid, Cantoblanco, C/Nicolás Cabrera n° 1, Madrid, 28049, Spain
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Frick KM. Building a better hormone therapy? How understanding the rapid effects of sex steroid hormones could lead to new therapeutics for age-related memory decline. Behav Neurosci 2012; 126:29-53. [PMID: 22289043 DOI: 10.1037/a0026660] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A wealth of data collected in recent decades has demonstrated that ovarian sex-steroid hormones, particularly 17β-estradiol (E2), are important trophic factors that regulate the function of cognitive regions of the brain such as the hippocampus. The loss of hormone cycling at menopause is associated with cognitive decline and dementia in women, and the onset of memory decline in animal models. However, hormone therapy is not currently recommended to prevent or treat cognitive decline, in part because of its detrimental side effects. In this article, it is proposed that investigations of the rapid effects of E2 on hippocampal function be used to further the design of new drugs that mimic the beneficial effects of E2 on memory without the side effects of current therapies. A conceptual model is presented for elucidating the molecular and biochemical mechanisms through which sex-steroid hormones modulate memory, and a specific hypothesis is proposed to account for the rapid memory-enhancing effects of E2. Empirical support for this hypothesis is discussed as a means of stimulating the consideration of new directions for the development of hormone-based therapies to preserve memory function in menopausal women.
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Affiliation(s)
- Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, 2441 East Hartford Avenue, Milwaukee, WI 53211, USA.
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Yin Y, She H, Li W, Yang Q, Guo S, Mao Z. Modulation of Neuronal Survival Factor MEF2 by Kinases in Parkinson's Disease. Front Physiol 2012; 3:171. [PMID: 22661957 PMCID: PMC3362091 DOI: 10.3389/fphys.2012.00171] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 05/10/2012] [Indexed: 12/15/2022] Open
Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative disorder due to selective death of neurons in the substantia nigra pars compacta. The cause of cell death remains largely unknown. Myocyte enhancer factor 2 (MEF2) is a group of transcriptional factors required to regulate neuronal development, synaptic plasticity, as well as survival. Recent studies show that MEF2 functions are regulated in multiple subcellular organelles and suggest that dysregulation of MEF2 plays essential roles in the pathogenesis of PD. Many kinases associated with transcription, translation, protein misfolding, autophagy, and cellular energy homeostasis are involved in the neurodegenerative process. Following the first demonstration that mitogen-activated protein kinase p38 (p38 MAPK) directly phosphorylates and activates MEF2 to promote neuronal survival, several other kinase regulators of MEF2s have been identified. These include protein kinase A and extracellular signal regulated kinase 5 as positive MEF2 regulators, and cyclin-dependent kinase 5 (Cdk5) and glycogen synthase kinase 3β as negative regulators in response to diverse toxic signals relevant to PD. It is clear that MEF2 has emerged as a key point where survival and death signals converge to exert their regulatory effects, and dysregulation of MEF2 function in multiple subcellular organelles may underlie PD pathogenesis. Moreover, several other kinases such as leucine-rich repeat kinase 2 and PTEN-induced putative kinase 1 (PINK1) are of particular interest due to their potential interaction with MEF2.
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Affiliation(s)
- Yue Yin
- Institute of Plastic Surgery, Xijing Hospital, Fourth Military Medical University Xi'an, Shaanxi, China
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35
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Pignataro G, Capone D, Polichetti G, Vinciguerra A, Gentile A, Di Renzo G, Annunziato L. Neuroprotective, immunosuppressant and antineoplastic properties of mTOR inhibitors: current and emerging therapeutic options. Curr Opin Pharmacol 2011; 11:378-94. [PMID: 21646048 DOI: 10.1016/j.coph.2011.05.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 05/12/2011] [Accepted: 05/13/2011] [Indexed: 02/05/2023]
Abstract
The acronym mTOR defines a family of serine-threonine protein kinase called mammalian target of rapamycin. The major role of these kinases in the cell is to merge extracellular instructions with information about cellular metabolic resources and to control the rate of anabolic and catabolic processes accordingly. In mammalian cells mTOR is present in two distinct heteromeric protein complexes commonly referred to as mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), involved in the control of a wide variety of cellular processes. It has been recently reported that compounds acting modulating mTOR activity, beside mediating the well recognized processes exploited in the anticancer and immunosuppressant effects, are provided with neuroprotective properties. In fact, mTOR is involved in the mechanism of PI3K/Akt-induced upregulation of glutamate transporter 1, GLT1, that is linked to several neuronal disorders such as stroke, Alzheimer's disease, and amyotrophic lateral sclerosis. Furthermore, in adult brain mTOR is crucial for numerous physiological processes such as synaptic plasticity, learning, memory, and brain control of food uptake. Moreover, the activation of mTOR pathway is involved in neuronal development, dendrite development and spine morphogenesis.
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Affiliation(s)
- Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, School of Medicine, Federico II University of Naples, Via Pansini, 5, 80131 Naples, Italy
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Rau TF, Kothiwal A, Zhang L, Ulatowski S, Jacobson S, Brooks DM, Cardozo-Pelaez F, Chopp M, Poulsen DJ. Low dose methamphetamine mediates neuroprotection through a PI3K-AKT pathway. Neuropharmacology 2011; 61:677-86. [PMID: 21635908 DOI: 10.1016/j.neuropharm.2011.05.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 05/10/2011] [Accepted: 05/11/2011] [Indexed: 10/25/2022]
Abstract
High doses of methamphetamine induce the excessive release of dopamine resulting in neurotoxicity. However, moderate activation of dopamine receptors can promote neuroprotection. Therefore, we used in vitro and in vivo models of stroke to test the hypothesis that low doses of methamphetamine could induce neuroprotection. We demonstrate that methamphetamine does induce a robust, dose-dependent, neuroprotective response in rat organotypic hippocampal slice cultures exposed to oxygen-glucose deprivation (OGD). A similar dose dependant neuroprotective effect was observed in rats that received an embolic middle cerebral artery occlusion (MCAO). Significant improvements in behavioral outcomes were observed in rats when methamphetamine administration delayed for up to 12 h after MCAO. Methamphetamine-mediated neuroprotection was significantly reduced in slice cultures by the addition of D1 and D2 dopamine receptor antagonist. Treatment of slice cultures with methamphetamine resulted in the dopamine-mediated activation of AKT in a PI3K dependant manner. A similar increase in phosphorylated AKT was observed in the striatum, cortex and hippocampus of methamphetamine treated rats following MCAO. Methamphetamine-mediated neuroprotection was lost in rats when PI3K activity was blocked by wortmannin. Finally, methamphetamine treatment decreased both cleaved caspase 3 levels in slice cultures following OGD and TUNEL staining within the striatum and cortex in rats following transient MCAO. These data indicate that methamphetamine can mediate neuroprotection through activation of a dopamine/PI3K/AKT-signaling pathway.
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Affiliation(s)
- Thomas F Rau
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, USA
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Yoshitomi H, Iwaoka E, Kubo M, Shibata M, Gao M. Beneficial effect of Sparassis crispa on stroke through activation of Akt/eNOS pathway in brain of SHRSP. J Nat Med 2010; 65:135-41. [PMID: 21076883 PMCID: PMC2999729 DOI: 10.1007/s11418-010-0475-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 09/10/2010] [Indexed: 11/26/2022]
Abstract
Sparassis crispa (S. crispa) is a mushroom used as a natural medicine that recently became cultivatable in Japan. In this study, we investigated not only the preventive effects of S. crispa against stroke and hypertension in stroke-prone spontaneously hypertensive rats (SHRSP) but also the mechanism involved by using studies of the cerebral cortex at a young age. Six-week-old male SHRSP were divided into 2 groups, a control group and an S. crispa group administered 1.5% S. crispa in feed, and we then observed their survival. In addition, rats of the same age were treated with 1.5% S. crispa for 4 weeks and we measured body weight, blood pressure, blood flow from the tail, NOx production, and the levels of expression of several proteins in the cerebral cortex by western blot analysis. Our results showed that the S. crispa group had a delayed incidence of stroke and death and significantly decreased blood pressure and increased blood flow after the administration. Moreover, the quantity of urinary excretion and the nitrate/nitrite concentration in cerebral tissue were higher than those of control SHRSP rats. In the cerebral cortex, phosphor-eNOS (Ser1177) and phosphor-Akt (Ser473) in S. crispa-treated SHRSP were increased compared with those of control SHRSP rats. In conclusion, S. crispa could ameliorate cerebrovascular endothelial dysfunction by promoting recovery of Akt-dependent eNOS phosphorylation and increasing NO production in the cerebral cortex. S. crispa may be useful for preventing stroke and hypertension.
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Affiliation(s)
- Hisae Yoshitomi
- School of Pharmaceutical Sciences, Mukogawa Women’s University, 11-68 Koshien Kyuban-cho, Nishinomiya, Hyogo 663-8179 Japan
| | - Emiko Iwaoka
- School of Pharmaceutical Sciences, Hyogo University of Health Science, Hyogo, Japan
| | | | | | - Ming Gao
- School of Pharmaceutical Sciences, Mukogawa Women’s University, 11-68 Koshien Kyuban-cho, Nishinomiya, Hyogo 663-8179 Japan
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Chong ZZ, Shang YC, Zhang L, Wang S, Maiese K. Mammalian target of rapamycin: hitting the bull's-eye for neurological disorders. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2010; 3:374-91. [PMID: 21307646 PMCID: PMC3154047 DOI: 10.4161/oxim.3.6.14787] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The mammalian target of rapamycin (mTOR) and its associated cell signaling pathways have garnered significant attention for their roles in cell biology and oncology. Interestingly,the explosion of information in this field has linked mTOR to neurological diseases with promising initial studies. mTOR, a 289 kDa serine/threonine protein kinase, plays an important role in cell growth and proliferation and is activated through phosphorylation in response to growth factors, mitogens and hormones. Growth factors, amino acids, cellular nutrients and oxygen deficiency can downregulate mTOR activity. The function of mTOR signaling is mediated primarily through two mTOR complexes: mTORC1 and mTORC2. mTORC1 initiates cap-dependent protein translation, a rate-limiting step of protein synthesis, through the phosphorylation of the targets eukaryotic initiation factor 4E-binding protein 1 (4EBP1) and p70 ribosomal S6 kinase (p70S6K). In contrast, mTORC2 regulates development of the cytoskeleton and also controls cell survival. Although closely tied to tumorigenesis, mTOR and the downstream signaling pathways are significantly involved in the central nervous system (CNS) with synaptic plasticity, memory retention, neuroendocrine regulation associated with food intake and puberty and modulation of neuronal repair following injury. The signaling pathways of mTOR also are believed to be a significant component in a number of neurological diseases, such as Alzheimer disease, Parkinson disease and Huntington disease, tuberous sclerosis, neurofibromatosis, fragile X syndrome, epilepsy, traumatic brain injury and ischemic stroke. Here we describe the role of mTOR in the CNS and illustrate the potential for new strategies directed against neurological disorders.
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Affiliation(s)
- Zhao Zhong Chong
- Department of Neurology and Neurosciences, Cancer Center, University of Medicine and Dentistry - New Jersey Medical School, Newark, NJ, USA
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Phosphorylated endothelial NOS Ser1177 via the PI3K/Akt pathway is depressed in the brain of stroke-prone spontaneously hypertensive rat. J Stroke Cerebrovasc Dis 2010; 20:406-12. [PMID: 20813549 DOI: 10.1016/j.jstrokecerebrovasdis.2010.01.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/06/2010] [Accepted: 01/24/2010] [Indexed: 11/23/2022] Open
Abstract
Stroke-prone spontaneously hypertensive rats (SHRSP) demonstrate impaired endothelium-dependent relaxation and often develop brain injuries. We investigated whether the regulatory mechanism for endothelial NOS (eNOS) phosphorylation and activation is altered in the cerebral cortex of SHRSP at a younger age. Western blot analysis revealed a low ratio of phosphor-eNOS (Ser1177) to total eNOS in SHRSP at 10 weeks of age. In addition, urinary nitric oxide metabolites (ie, nitrate and nitrite) were decreased compared with normal control WKY rats. Likewise, Akt phosphorylation (especially Ser473) was significantly reduced, with no changes in total Akt. Furthermore, the amount of the phosphatidylinositol 3-kinase (PI3K) was upstream of Akt was diminished, although attenuation of the PI3K/Akt pathway was not an effect of mTOR, another downstream target of Akt. Our findings indicate that abnormalities of the PI3K/Akt pathway in the cerebral cortex are involved in the impaired eNOS phosphorylation and activation in SHRSP.
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NR4A orphan nuclear receptors as mediators of CREB-dependent neuroprotection. Proc Natl Acad Sci U S A 2010; 107:12317-22. [PMID: 20566846 DOI: 10.1073/pnas.1007088107] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Induced expression of neuroprotective genes is essential for maintaining neuronal integrity after stressful insults to the brain. Here we show that NR4A nuclear orphan receptors are induced after excitotoxic and oxidative stress in neurons, up-regulate neuroprotective genes, and increase neuronal survival. Moreover, we show that NR4A proteins are induced by cAMP response element binding protein (CREB) in neurons exposed to stressful insults and that they function as mediators of CREB-induced neuronal survival. Animals with null mutations in three of six NR4A alleles show increased oxidative damage, blunted induction of neuroprotective genes, and increased vulnerability in the hippocampus after treatment with kainic acid. We also demonstrate that NR4A and the transcriptional coactivator PGC-1alpha independently regulate distinct CREB-dependent neuroprotective gene programs. These data identify NR4A nuclear orphan receptors as essential mediators of neuroprotection after exposure to neuropathological stress.
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Strom JO, Theodorsson E, Holm L, Theodorsson A. Different methods for administering 17beta-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage. BMC Neurosci 2010; 11:39. [PMID: 20236508 PMCID: PMC2848231 DOI: 10.1186/1471-2202-11-39] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 03/17/2010] [Indexed: 01/26/2023] Open
Abstract
Background Numerous stroke studies have controversially shown estrogens to be either neuroprotective or neurodamaging. The discordant results observed in rat brain ischemia models may be a consequence of discrepancies in estrogen administration modes resulting in plasma concentration profiles far from those intended. To test this hypothesis we reproduced in detail and extended an earlier study from our lab using a different mode of 17β-estradiol administration; home-made silastic capsules instead of commercial slow-release 17β-estradiol pellets. Four groups of female rats (n = 12) were ovariectomized and administered 17β-estradiol or placebo via silastic capsules. All animals underwent MCAo fourteen days after ovariectomy and were sacrificed three days later. Results In contrast to our earlier results using the commercial pellets, the group receiving 17β-estradiol during the entire experiment had significantly smaller lesions than the group receiving placebo (mean ± SEM: 3.85 ± 0.70% versus 7.15 ± 0.27% of total slice area, respectively; p = 0.015). No significant neuroprotection was found when the 17β-estradiol was administered only during the two weeks before or the three days immediately after MCAo. Conclusions The results indicate that different estrogen treatment regimens result in diametrically different effects on cerebral ischemia. Thus the effects of estrogens on ischemic damage seem to be concentration-related, with a biphasic, or even more complex, dose-response relation. These findings have implications for the design of animal experiments and also have a bearing on the estrogen doses used for peri-menopausal hormone replacement therapy.
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Affiliation(s)
- Jakob O Strom
- Institution of Clinical and Experimental Medicine/Department of Clinical Chemistry, Linkoping University, Linkoping, Sweden
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Jover-Mengual T, Miyawaki T, Latuszek A, Alborch E, Zukin RS, Etgen AM. Acute estradiol protects CA1 neurons from ischemia-induced apoptotic cell death via the PI3K/Akt pathway. Brain Res 2010; 1321:1-12. [PMID: 20114038 DOI: 10.1016/j.brainres.2010.01.046] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 12/03/2009] [Accepted: 01/18/2010] [Indexed: 11/28/2022]
Abstract
Global ischemia arising during cardiac arrest or cardiac surgery causes highly selective, delayed death of hippocampal CA1 neurons. Exogenous estradiol ameliorates global ischemia-induced neuronal death and cognitive impairment in male and female rodents. However, the molecular mechanisms by which a single acute injection of estradiol administered after the ischemic event intervenes in global ischemia-induced apoptotic cell death are unclear. Here we show that acute estradiol acts via the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling cascade to protect CA1 neurons in ovariectomized female rats. We demonstrate that global ischemia promotes early activation of glycogen synthase kinase-3beta (GSK3beta) and forkhead transcription factor of the O class (FOXO)3A, known Akt targets that are related to cell survival, and activation of caspase-3. Estradiol prevents ischemia-induced dephosphorylation and activation of GSK3beta and FOXO3A, and the caspase death cascade. These findings support a model whereby estradiol acts by activation of PI3K/Akt signaling to promote neuronal survival in the face of global ischemia.
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Affiliation(s)
- Teresa Jover-Mengual
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA.
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Strom JO, Theodorsson A, Theodorsson E. Dose-related neuroprotective versus neurodamaging effects of estrogens in rat cerebral ischemia: a systematic analysis. J Cereb Blood Flow Metab 2009; 29:1359-72. [PMID: 19458604 DOI: 10.1038/jcbfm.2009.66] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Numerous studies of the effects of estrogens for stroke prevention have yielded conflicting results in human and animal studies alike. We present a systematical analysis of study design and methodological differences between 66 studies where estrogens' impact on ischemic brain damage in rat models has been investigated, providing evidence that the differences in results may be explained by high estrogen doses produced by slow-release pellets. These pellets have been used in all studies showing increased neurologic damage because of estrogens. Our data indicate that the increased neurologic damage is related to the pellets' plasma concentration profile with an early, prolonged, supraphysiological peak. Neither the method of inducing the ischemic brain lesions, the choice of variables for measuring outcome, the measured plasma concentrations of estrogens at the time of ischemia nor rat population attributes (sex, strain, age, and diseases) are factors contributing to the discrepancies in results. This suggests that the effects of estrogens for stroke prevention are concentration related with a complex dose-response curve, and underscores the importance of carefully validating the experimental methods used. Future studies of hormone-replacement therapy in women may have to take dosage and administration regimens into account.
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Affiliation(s)
- Jakob O Strom
- Department of Clinical Chemistry, Institution of Clinical and Experimental Medicine, Linköping University Hospital, Linköping, Sweden
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The mammalian target of rapamycin signaling pathway mediates epileptogenesis in a model of temporal lobe epilepsy. J Neurosci 2009; 29:6964-72. [PMID: 19474323 DOI: 10.1523/jneurosci.0066-09.2009] [Citation(s) in RCA: 386] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Understanding molecular mechanisms mediating epileptogenesis is critical for developing more effective therapies for epilepsy. We recently found that the mammalian target of rapamycin (mTOR) signaling pathway is involved in epileptogenesis, and mTOR inhibitors prevent epilepsy in a mouse model of tuberous sclerosis complex. Here, we investigated the potential role of mTOR in a rat model of temporal lobe epilepsy initiated by status epilepticus. Acute kainate-induced seizures resulted in biphasic activation of the mTOR pathway, as evident by an increase in phospho-S6 (P-S6) expression. An initial rise in P-S6 expression started approximately 1 h after seizure onset, peaked at 3-6 h, and returned to baseline by 24 h in both hippocampus and neocortex, reflecting widespread stimulation of mTOR signaling by acute seizure activity. After resolution of status epilepticus, a second increase in P-S6 was observed in hippocampus only, which started at 3 d, peaked 5-10 d, and persisted for several weeks after kainate injection, correlating with the development of chronic epileptogenesis within hippocampus. The mTOR inhibitor rapamycin, administered before kainate, blocked both the acute and chronic phases of seizure-induced mTOR activation and decreased kainate-induced neuronal cell death, neurogenesis, mossy fiber sprouting, and the development of spontaneous epilepsy. Late rapamycin treatment, after termination of status epilepticus, blocked the chronic phase of mTOR activation and reduced mossy fiber sprouting and epilepsy but not neurogenesis or neuronal death. These findings indicate that mTOR signaling mediates mechanisms of epileptogenesis in the kainate rat model and that mTOR inhibitors have potential antiepileptogenic effects in this model.
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