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Alattar A, Alshaman R, Althobaiti YS, Soliman GM, Ali HS, Khubrni WS, Koh PO, Rehman NU, Shah FA. Quercetin Alleviated Inflammasome-Mediated Pyroptosis and Modulated the mTOR/P70S6/P6/eIF4E/4EBP1 Pathway in Ischemic Stroke. Pharmaceuticals (Basel) 2023; 16:1182. [PMID: 37631097 PMCID: PMC10459024 DOI: 10.3390/ph16081182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/03/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Stroke ranks as the world's second most prevalent cause of mortality, and it represents a major public health concern with profound economic and social implications. In the present study, we elucidated the neuroprotective role of quercetin on NLRP3-associated pyroptosis, Nrf2-coupled anti-inflammatory, and mTOR-dependent downstream pathways. Male Sprague Dawley rats were subjected to 72 h of transient middle cerebral artery ischemia, followed by the administration of 10 mg/kg of quercetin. Our findings demonstrated that MCAO induced elevated ROS which were coupled to inflammasome-mediated pyroptosis and altered mTOR-related signaling proteins. We performed ELISA, immunohistochemistry, and Western blotting to unveil the underlying role of the Nrf2/HO-1 and PDK/AKT/mTOR pathways in the ischemic cortex and striatum. Our results showed that quercetin post-treatment activated the Nrf2/HO-1 cascade, reversed pyroptosis, and modulated the autophagy-related pathway PDK/AKT/mTOR/P70S6/P6/eIF4E/4EBP1. Further, quercetin enhances the sequestering effect of 14-3-3 and reversed the decrease in interaction between p-Bad and 14-3-3 and p-FKHR and 14-3-3. Our findings showed that quercetin exerts its protective benefits and rescues neuronal damage by several mechanisms, and it might be a viable neuroprotective drug for ischemic stroke therapy.
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Affiliation(s)
- Abdullah Alattar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk 47713, Saudi Arabia; (R.A.); (W.S.K.)
| | - Reem Alshaman
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk 47713, Saudi Arabia; (R.A.); (W.S.K.)
| | - Yusuf S. Althobaiti
- Department of Pharmacology and Toxicology, College of Pharmacy, Taif University, P.O. Box 21944, Taif 21944, Saudi Arabia;
- Addiction and Neuroscience Research Unit, Taif University, Taif 21944, Saudi Arabia
| | - Ghareb M. Soliman
- Department of Pharmaceutics, Faculty of Pharmacy, University of Tabuk, Tabuk 47713, Saudi Arabia;
| | - Howaida S. Ali
- Department of Pharmacology, Faculty of Medicine, Assuit University, Assuit 71515, Egypt;
- Department of Pharmacology, Faculty of Medicine, University of Tabuk, Tabuk 47713, Saudi Arabia
| | - Waleed Salman Khubrni
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk 47713, Saudi Arabia; (R.A.); (W.S.K.)
| | - Phil Ok Koh
- Department of Anatomy and Histology, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Republic of Korea;
| | - Najeeb Ur Rehman
- Department of Pharmacology and Toxicology, College of Pharmacy, Prince Sttam Bin Abdul Aziz University, Al-Kharj 11942, Saudi Arabia;
| | - Fawad Ali Shah
- Department of Anatomy and Histology, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Republic of Korea;
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Barrio E, Vecino R, Sánchez-Morán I, Rodríguez C, Suárez-Pindado A, Bolaños JP, Almeida A, Delgado-Esteban M. Preconditioning-Activated AKT Controls Neuronal Tolerance to Ischemia through the MDM2-p53 Pathway. Int J Mol Sci 2021; 22:ijms22147275. [PMID: 34298892 PMCID: PMC8304232 DOI: 10.3390/ijms22147275] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/29/2021] [Accepted: 07/02/2021] [Indexed: 12/28/2022] Open
Abstract
One of the most important mechanisms of preconditioning-mediated neuroprotection is the attenuation of cell apoptosis, inducing brain tolerance after a subsequent injurious ischemia. In this context, the antiapoptotic PI3K/AKT signaling pathway plays a key role by regulating cell differentiation and survival. Active AKT is known to increase the expression of murine double minute-2 (MDM2), an E3-ubiquitin ligase that destabilizes p53 to promote the survival of cancer cells. In neurons, we recently showed that the MDM2–p53 interaction is potentiated by pharmacological preconditioning, based on subtoxic stimulation of NMDA glutamate receptor, which prevents ischemia-induced neuronal apoptosis. However, whether this mechanism contributes to the neuronal tolerance during ischemic preconditioning (IPC) is unknown. Here, we show that IPC induced PI3K-mediated phosphorylation of AKT at Ser473, which in turn phosphorylated MDM2 at Ser166. This phosphorylation triggered the nuclear stabilization of MDM2, leading to p53 destabilization, thus preventing neuronal apoptosis upon an ischemic insult. Inhibition of the PI3K/AKT pathway with wortmannin or by AKT silencing induced the accumulation of cytosolic MDM2, abrogating IPC-induced neuroprotection. Thus, IPC enhances the activation of PI3K/AKT signaling pathway and promotes neuronal tolerance by controlling the MDM2–p53 interaction. Our findings provide a new mechanistic pathway involved in IPC-induced neuroprotection via modulation of AKT signaling, suggesting that AKT is a potential therapeutic target against ischemic injury.
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Affiliation(s)
- Emilia Barrio
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
| | - Rebeca Vecino
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca, CSIC, 37007 Salamanca, Spain
| | - Irene Sánchez-Morán
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
| | - Cristina Rodríguez
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca, CSIC, 37007 Salamanca, Spain
- Department of Biochemistry and Molecular Biology, University of Salamanca, 37007 Salamanca, Spain
| | - Alberto Suárez-Pindado
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
| | - Juan P. Bolaños
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca, CSIC, 37007 Salamanca, Spain
- Department of Biochemistry and Molecular Biology, University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Angeles Almeida
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca, CSIC, 37007 Salamanca, Spain
- Department of Biochemistry and Molecular Biology, University of Salamanca, 37007 Salamanca, Spain
| | - Maria Delgado-Esteban
- Institute of Functional Biology and Genomics, University of Salamanca, CSIC, 37007 Salamanca, Spain; (E.B.); (R.V.); (I.S.-M.); (C.R.); (A.S.-P.); (J.P.B.); (A.A.)
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca, CSIC, 37007 Salamanca, Spain
- Department of Biochemistry and Molecular Biology, University of Salamanca, 37007 Salamanca, Spain
- Correspondence: ; Tel.: +34-923-29-4908
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A Review on Potential Footprints of Ferulic Acid for Treatment of Neurological Disorders. Neurochem Res 2021; 46:1043-1057. [PMID: 33547615 DOI: 10.1007/s11064-021-03257-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 01/16/2021] [Accepted: 01/22/2021] [Indexed: 02/06/2023]
Abstract
Ferulic acid is being screened in preclinical settings to combat various neurological disorders. It is a naturally occurring dietary flavonoid commonly found in grains, fruits, and vegetables such as rice, wheat, oats, tomatoes, sweet corn etc., which exhibits protective effects against a number of neurological diseases such as epilepsy, depression, ischemia-reperfusion injury, Alzheimer's disease, and Parkinson's disease. Ferulic acid prevents and treats different neurological diseases pertaining to its potent anti-oxidative and anti-inflammatory effects, beside modulating unique neuro-signaling pathways. It stays in the bloodstream for longer periods than other dietary polyphenols and antioxidants and easily crosses blood brain barrier. The use of novel drug delivery systems such as solid-lipid nanoparticles (SLNs) or its salt forms (sodium ferulate, ethyl ferulate, and isopentyl ferulate) further enhance its bioavailability and cerebral penetration. Based on reported studies, ferulic acid appears to be a promising molecule for treatment of neurological disorders; however, more preclinical (in vitro and in vivo) mechanism-based studies should be planned and conceived followed by its testing in clinical settings.
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Recovery of Human Embryonic Stem Cells-Derived Neural Progenitors Exposed to Hypoxic-Ischemic-Reperfusion Injury by Indirect Exposure to Wharton’s Jelly Mesenchymal Stem Cells Through Phosphatidyl-inositol-3-Kinase Pathway. Cell Mol Neurobiol 2020; 42:1167-1188. [DOI: 10.1007/s10571-020-01007-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/11/2020] [Indexed: 12/13/2022]
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Feng C, Wan H, Zhang Y, Yu L, Shao C, He Y, Wan H, Jin W. Neuroprotective Effect of Danhong Injection on Cerebral Ischemia-Reperfusion Injury in Rats by Activation of the PI3K-Akt Pathway. Front Pharmacol 2020; 11:298. [PMID: 32218735 PMCID: PMC7078680 DOI: 10.3389/fphar.2020.00298] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/27/2020] [Indexed: 12/14/2022] Open
Abstract
Many traditional Chinese medicines, including Danhong injection (DHI), can be used to treat cerebral ischemia-reperfusion injury and have neuroprotective effects on the brain; however, few studies have explored the mechanism by which this effect is generated. In this study, we investigated the neuroprotective effect of DHI against cerebral ischemia-reperfusion injury mediated via the PI3K-Akt signaling pathway. After establishing the model of middle cerebral artery occlusion (MCAO), 60 male Sprague–Dawley rats were allocated to six groups as follows: sham, MCAO, DHI (MCAO + DHI), LY294002 (MCAO + LY294002 [PI3K-Akt pathway specific inhibitor]), DHI + LY294002 (MCAO + DHI + LY294002), and NMDP + LY294002 (MCAO + NMDP [nimodipine] + LY294002). Hematoxylin and eosin (HE) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining were used to evaluate the pathological changes of brain tissue and the degree of neuronal apoptosis. Real-time quantitative polymerase chain reaction (qRT-PCR), western blot analysis and enzyme-linked immunosorbent assays were used to measure the expression of Bad, Bax, Bcl-2, Bim, P53, MDM2, Akt, PI3K, p-Akt, p-PI3K, and Cyt-C. Compared with the MCAO group, brain tissue cell apoptosis was significantly reduced in the DHI group, and the brain function score was significantly improved. In addition, the expression of pro-apoptotic factors (Bad, Bax, and Bim) was significantly downregulated in the DHI group, while expression of the anti-apoptotic factor Bcl-2 was significantly upregulated, and expression of the apoptotic gene p53 was also significantly attenuated. Moreover, this neuroprotective effect was attenuated by the PI3K-Akt signaling pathway inhibitor (LY294002). Thus, our results confirmed the neuroprotective effects of DHI in rats with ischemia-reperfusion injury and indicate that these effects on the brain are partly generated by activation of the PI3K-Akt signaling pathway.
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Affiliation(s)
- Chen Feng
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Haofang Wan
- Academy of Chinese Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yangyang Zhang
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Li Yu
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Chongyu Shao
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yu He
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Haitong Wan
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Weifeng Jin
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
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Liu Y, Wu X, An J, Lv W, Geng Y, Lou T, Zhang Y. Glaucocalyxin B protects against oxygen-glucose-deprivation/reperfusion-induced neuronal injury in PC-12 cells. J Cell Biochem 2018; 120:6137-6144. [PMID: 30304556 DOI: 10.1002/jcb.27901] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/24/2018] [Indexed: 02/01/2023]
Abstract
Oxidative stress has been implicated in the development of cerebral ischemia/reperfusion (I/R) injury. Glaucocalyxin B (GLB), one of five ent-kauranoid diterpenoids, was reported to possess neuroprotective activity. However, the effect of GLB on oxygen-glucose-deprivation/reperfusion (OGD/R)-induced cell injury in PC-12 cells has not been explored. PC-12 cells was treated with various concentrations of GLB (0, 2.5, 5 and 10 μM), and cell viability was detected using the MTT assay. PC-12 cells were pretreated with the indicated concentration of GLB (2.5-10 μM, 2 hours pretreatment), and were maintained under OGD for 3 hours, followed by 24 hours of reoxygenation. Cell viability was assessed using the MTT assay. The levels of superoxide dismutase, malondialdehyde, and glutathione peroxidase were detected using commercially available ELISA Kits. Intracellular reactive oxygen species level was measured using the fluorescent probe 2',7'-dichlorofluorescein diacetate. The levels of Bcl-2, Bax, p-Akt, Akt, p-mTOR, mTOR were detected using Western blot. Our results revealed that GLB significantly protected PC12 cells against OGD/R-induced cell injury. In addition, GLB efficiently inhibited oxidative stress and cell apoptosis in OGD/R-stimulated PC-12 cells. Mechanistic studies revealed that pretreatment with GLB could induce the activation of Akt/mTOR signaling pathway resulting in protection of OGD-treated PC12 cells. In conclusion, our data indicate for the first time that GLB protects against OGD/R-induced neuronal injury in PC-12 cells. The mechanism of the protective effect of GLB is partially associated with activation of the Akt/mTOR signaling pathway. Thus, GLB may be a potential agent for protection against cerebral I/R injury.
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Affiliation(s)
- Yuxin Liu
- Department of Pharmacy, Huaihe Hospital of Henan University, Kaifeng, China
| | - Xianchuang Wu
- Department of Pharmacy, Huaihe Hospital of Henan University, Kaifeng, China
| | - Jihong An
- Department of Pharmacy, Huaihe Hospital of Henan University, Kaifeng, China
| | - Weiling Lv
- Department of Pharmacy, Huaihe Hospital of Henan University, Kaifeng, China
| | - Yanna Geng
- Department of Pharmacy, Huaihe Hospital of Henan University, Kaifeng, China
| | - Tingting Lou
- Department of Pharmacy, Huaihe Hospital of Henan University, Kaifeng, China
| | - Yongzhou Zhang
- Department of Pharmacy, Huaihe Hospital of Henan University, Kaifeng, China
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Yan BC, Jiang D, Wang J, Zhang Y, Zhu X, Xu P, Yu X, Won MH, Su PQ. Both decreased Akt expression and mTOR phosphorylation are related to decreased neuronal differentiation in the hippocampal alveus of aged mice. Aging Clin Exp Res 2018; 30:737-743. [PMID: 29027613 DOI: 10.1007/s40520-017-0833-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/13/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Aging is an inevitable process which results in many changes. These changes are closely related to the hippocampus which is in charge of long-term learning and episodic memory. AIM This study was to investigate age-related changes of the cell proliferation, neuroblast differentiation and Akt/mTOR signaling in the hippocampal alveus of aged mice. METHODS In the present study, we compared the differences of neurogenesis in the hippocampal alveus between adult (postnatal month 6) and aged (postnatal month 24) mice using immunohistochemistry and western blot analysis. RESULTS The cell proliferation, neuroblast differentiation, and the increased astrocyte activation in the hippocampal alveus of mice were decreased in an age-dependent manner. In addition, during normal aging, the protein level of AKT, mTOR and the phosphorylation of mTOR were all decreased. However, the protein level of AKT was increased. DISCUSSION These results indicate the neurogenesis in the immature neurons in the hippocampal alveus of aged mice was closely related to the normal aging process. In addition, during normal aging, the increased AKT phosphorylation and decreased mTOR phosphorylation in the hippocampus may play a role in aging development. CONCLUSION The result indicates that increased activation of astrocyte, increased phosphorylation of AKT and decreased phosphorylation of mTOR may be involved in the decreased cell proliferation and neuroblast differentiation in the alveus of hippocampus of aged mice.
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Affiliation(s)
- Bing Chun Yan
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou, 225001, People's Republic of China.
- Department of Neurology, Affiliated Hospital, Yangzhou University, Yangzhou, 225001, People's Republic of China.
| | - Dan Jiang
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou, 225001, People's Republic of China
| | - Jie Wang
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou, 225001, People's Republic of China
| | - Yuanyuan Zhang
- Department of Neurology, Affiliated Hospital, Yangzhou University, Yangzhou, 225001, People's Republic of China
| | - Xiaolu Zhu
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou, 225001, People's Republic of China
| | - Pei Xu
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou, 225001, People's Republic of China
| | - Xing Yu
- Department of Pharmacy, Yangzhou Maternal and Child Care Service Center, Yangzhou, 225002, People's Republic of China
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Pei Qing Su
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou, 225001, People's Republic of China
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Sun M, Izumi H, Shinoda Y, Fukunaga K. Neuroprotective effects of protein tyrosine phosphatase 1B inhibitor on cerebral ischemia/reperfusion in mice. Brain Res 2018; 1694:1-12. [PMID: 29705606 DOI: 10.1016/j.brainres.2018.04.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/10/2018] [Accepted: 04/24/2018] [Indexed: 12/11/2022]
Abstract
Akt (Protein kinase B, PKB), a serine/threonine kinase, plays a critical role in cell development, growth, and survival. Akt phosphorylation mediates a neuroprotective effect against ischemic injury. Recently, a protein-tyrosine phosphatase-1B (PTP1B) inhibitor (KY-226) was developed to elicit anti-diabetic and anti-obesity effects via enhancement of insulin signaling. Previously, we reported that the nonselective PTP1B inhibitor, sodium orthovanadate, rescued neurons from delayed neuronal death during brain ischemia. In this study, we confirmed the ameliorative effects of KY-226 on ischemia/reperfusion (I/R) injury using a murine model of middle cerebral artery occlusion (MCAO). ICR mice were subjected to MCAO for 2 h followed by reperfusion. Although KY-226 permeability was poor through the blood-brain barrier (BBB) of normal mice, it could penetrate through the BBB of mice after I/R insult. Intraperitoneal KY-226 administration elicited dose-dependent reductions in infarcted brain areas and improved neurological deficits. The neuroprotective effects of KY-266 were obtained when administered within 0.5 h after reperfusion. KY-226 (10 mg/kg) also restored reduced Akt phosphorylation and eNOS phosphorylation (Ser-1177) levels following I/R insult. Moreover, 10 mg/kg of KY-226 improved I/R-induced decreased extracellular signal-regulated kinase (ERK) phosphorylation. Furthermore, KY-226 attenuated the generation of reactive oxygen species (ROS) in mouse cortex. These results suggest that KY-226 may act as a novel therapeutic candidate for ischemic stroke. Activation of Akt and ERK possibly underlie the neuroprotective mechanism of KY-226.
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Affiliation(s)
- Meiling Sun
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai Japan
| | - Hisanao Izumi
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai Japan
| | - Yasuharu Shinoda
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai Japan
| | - Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai Japan.
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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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Chen L, Ren Z, Wei X, Wang S, Wang Y, Cheng Y, Gao H, Liu H. Losartan protects against cerebral ischemia/reperfusion-induced apoptosis through β-arrestin1-mediated phosphorylation of Akt. Eur J Pharmacol 2017; 815:98-108. [DOI: 10.1016/j.ejphar.2017.08.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 08/12/2017] [Accepted: 08/23/2017] [Indexed: 01/31/2023]
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Jiao S, Zhu H, He P, Teng J. Betulinic acid protects against cerebral ischemia/reperfusion injury by activating the PI3K/Akt signaling pathway. Biomed Pharmacother 2016; 84:1533-1537. [PMID: 27876208 DOI: 10.1016/j.biopha.2016.11.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/22/2016] [Accepted: 11/08/2016] [Indexed: 01/08/2023] Open
Abstract
Betulinic acid (BA), a naturally occurring pentacyclic lupane group triterpenoid, has been demonstrated to protect against ischemia/reperfusion-induced renal damage. However, the effects of BA on cerebral ischemia/reperfusion (I/R) injury remain unclear. Hence, this study was to investigate the effects of BA on oxygen and glucose deprivation/reperfusion (OGD/R) induced neuronal injury in rat hippocampal neurons. Our results showed that BA pretreatment greatly attenuated OGD/R-induced neuronal injury. BA also inhibited OGD/R-induced intracellular ROS production and MDA level in rat hippocampal neurons. Furthermore, the down-regulation of Bcl-2, up-regulation of Bax and the consequent activation of caspase-3 induced by OGD/R were reversed by BA pretreatment. Mechanistic studies demonstrated that BA pretreatment up-regulated the expression levels of p-PI3K and p-Akt in hippocampal neurons induced by OGD/R. Taken together, these data suggested that BA inhibits OGD/R-induced neuronal injury in rat hippocampal neurons through the activation of PI3K/Akt signaling pathway.
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Affiliation(s)
- Shujie Jiao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - Hongcan Zhu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - Ping He
- Department of Infectious Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - Junfang Teng
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China.
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Neuroprotective and Neurorestorative Processes after Spinal Cord Injury: The Case of the Bulbospinal Respiratory Neurons. Neural Plast 2016; 2016:7692602. [PMID: 27563469 PMCID: PMC4987469 DOI: 10.1155/2016/7692602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 06/29/2016] [Indexed: 11/18/2022] Open
Abstract
High cervical spinal cord injuries interrupt the bulbospinal respiratory pathways projecting to the cervical phrenic motoneurons resulting in important respiratory defects. In the case of a lateralized injury that maintains the respiratory drive on the opposite side, a partial recovery of the ipsilateral respiratory function occurs spontaneously over time, as observed in animal models. The rodent respiratory system is therefore a relevant model to investigate the neuroplastic and neuroprotective mechanisms that will trigger such phrenic motoneurons reactivation by supraspinal pathways. Since part of this recovery is dependent on the damaged side of the spinal cord, the present review highlights our current understanding of the anatomical neuroplasticity processes that are developed by the surviving damaged bulbospinal neurons, notably axonal sprouting and rerouting. Such anatomical neuroplasticity relies also on coordinated molecular mechanisms at the level of the axotomized bulbospinal neurons that will promote both neuroprotection and axon growth.
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Hami J, Kerachian MA, Karimi R, Haghir H, Sadr-Nabavi A. Effects of streptozotocin-induced type 1 maternal diabetes on PI3K/AKT signaling pathway in the hippocampus of rat neonates. J Recept Signal Transduct Res 2015; 36:254-60. [DOI: 10.3109/10799893.2015.1086884] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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14
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Lei X, Chao H, Zhang Z, Lv J, Li S, Wei H, Xue R, Li F, Li Z. Neuroprotective effects of quercetin in a mouse model of brain ischemic/reperfusion injury via anti-apoptotic mechanisms based on the Akt pathway. Mol Med Rep 2015; 12:3688-3696. [PMID: 26016839 DOI: 10.3892/mmr.2015.3857] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 04/20/2015] [Indexed: 11/05/2022] Open
Abstract
The present study provided experimental evidence for the neuroprotective effects of quercetin using a rat model of global brain ischemic/reperfusion (I/R) injury. Pre‑treatment with quercetin (5 or 10 mg/kg orally (p.o.); once daily) induced a dose‑dependent reduction in I/R‑induced hippocampal neuron cell loss, with 10 mg/kg/day being the lowest dose that achieved maximal neuroprotection. Administration of 10 mg/kg quercetin over at least 3 days prior to I/R was required to improve the survival rate of I/R rats. Fluorescence‑assisted cell sorting, hematoxylin and eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling indicated neuronal cell loss in the CA1 hippocampus. Rats that had undergone transient global cerebral ischemia for 15 min followed by 1 h of reperfusion exhibited a significant increase in reactive oxygen species (ROS) production in the hippocampus. The I/R‑induced ROS overproduction in the hippocampus at 1, 12 and 24 h following I/R was significantly decreased by quercetin pre‑treatment. Western blot analysis revealed that the neuroprotective effects of quercetin (5 and 10 mg/kg/day, p.o.) were associated with an upregulation of the I/R‑induced suppression of B‑cell lymphoma‑2 (Bcl‑2), Bcl extra large and survivin expression as well as phosphorylation of Bcl‑2‑associated death promoter. Furthermore, the neuroprotective effects of quercetin (5, 10 mg/kg/day) in the brain were associated with an upregulation of Akt signaling. These findings suggested that the inhibition of I/R‑induced brain injury by quercetin likely involves a transcriptional mechanism to enhance anti‑apoptotic signaling.
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Affiliation(s)
- Xiaoming Lei
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Hailian Chao
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Zhenni Zhang
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Jianrui Lv
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Siyuan Li
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Haidong Wei
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Rongliang Xue
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Fang Li
- Department of Anesthesiology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Zongfang Li
- Department of General Surgery, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
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15
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Palencia G, Medrano JÁN, Ortiz-Plata A, Farfán DJ, Sotelo J, Sánchez A, Trejo-Solís C. Anti-apoptotic, anti-oxidant, and anti-inflammatory effects of thalidomide on cerebral ischemia/reperfusion injury in rats. J Neurol Sci 2015; 351:78-87. [DOI: 10.1016/j.jns.2015.02.043] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/06/2015] [Accepted: 02/24/2015] [Indexed: 11/28/2022]
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16
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Inhibition of autophagy via activation of PI3K/Akt pathway contributes to the protection of ginsenoside Rb1 against neuronal death caused by ischemic insults. Int J Mol Sci 2014; 15:15426-42. [PMID: 25257523 PMCID: PMC4200757 DOI: 10.3390/ijms150915426] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/20/2014] [Accepted: 08/25/2014] [Indexed: 11/16/2022] Open
Abstract
Lethal autophagy is a pathway leading to neuronal death caused by transient global ischemia. In this study, we examined the effect of Ginsenoside Rb1 (GRb1) on ischemia/reperfusion-induced autophagic neuronal death and investigated the role of PI3K/Akt. Ischemic neuronal death in vitro was induced by using oxygen glucose deprivation (OGD) in SH-SY5Y cells, and transient global ischemia was produced by using two vessels occlusion in rats. Cellular viability of SH-SY5Y cells was assessed by MTT assay, and CA1 neuronal death was evaluated by Hematoxylin-eosin staining. Autophagic vacuoles were detected by using both fluorescent microscopy in combination with acridine orange (AO) and Monodansylcadaverine (MDC) staining and transmission electronic microscopy. Protein levels of LC3II, Beclin1, total Akt and phosphor-Akt at Ser473 were examined by western blotting analysis. GRb1 inhibited both OGD and transient ischemia-induced neuronal death and mitigated OGD-induced autophagic vacuoles in SH-SY5Y cells. By contrast, PI3K inhibitor LY294002 counteracted the protection of GRb1 against neuronal death caused by either OGD or transient ischemia. LY294002 not only mitigated the up-regulated protein level of phosphor Akt at Ser473 caused by GRb1, but also reversed the inhibitory effect of GRb1 on OGD and transient ischemia-induced elevation in protein levels of LC3II and Beclin1.
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17
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Glycoprotein nonmetastatic melanoma protein B (GPNMB) as a novel neuroprotective factor in cerebral ischemia–reperfusion injury. Neuroscience 2014; 277:123-31. [DOI: 10.1016/j.neuroscience.2014.06.065] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/26/2014] [Accepted: 06/28/2014] [Indexed: 11/18/2022]
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18
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Tetramethylpyrazine analogue CXC195 protects against cerebral ischemia/reperfusion-induced apoptosis through PI3K/Akt/GSK3β pathway in rats. Neurochem Int 2014; 66:27-32. [DOI: 10.1016/j.neuint.2014.01.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/24/2013] [Accepted: 01/09/2014] [Indexed: 12/26/2022]
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19
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Koh PO. Ferulic acid attenuates focal cerebral ischemia-induced decreases in p70S6 kinase and S6 phosphorylation. Neurosci Lett 2013; 555:7-11. [DOI: 10.1016/j.neulet.2013.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 08/29/2013] [Accepted: 09/01/2013] [Indexed: 10/26/2022]
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20
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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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21
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Ferulic acid regulates the AKT/GSK-3β/CRMP-2 signaling pathway in a middle cerebral artery occlusion animal model. Lab Anim Res 2013; 29:63-9. [PMID: 23825478 PMCID: PMC3696626 DOI: 10.5625/lar.2013.29.2.63] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/27/2013] [Accepted: 05/02/2013] [Indexed: 11/21/2022] Open
Abstract
Ferulic acid, a component of the plants Angelica sinensis (Oliv.) Diels and Ligusticum chuanxiong Hort, exerts a neuroprotective effect by regulating various signaling pathways. This study showed that ferulic acid treatment prevents the injury-induced increase of collapsin response mediator protein 2 (CRMP-2) in focal cerebral ischemia. Glycogen synthase kinase-3β (GSK-3β) regulates CRMP-2 function through phosphorylation of CRMP-2. Moreover, the pro-apoptotic activity of GSK-3β is inactivated by phosphorylation by Akt. This study investigated whether ferulic acid modulates the expression of CRMP-2 and its upstream targets, Akt and GSK-3β, in focal cerebral ischemia. Male rats were treated immediately with ferulic acid (100 mg/kg, i.v.) or vehicle after middle cerebral artery occlusion (MCAO), and then cerebral cortices were collected 24 hr after MCAO. MCAO resulted in decreased levels of phospho-Akt and phospho-GSK-3β, while ferulic acid treatment prevented the decrease in the levels of these proteins. Moreover, phospho-CRMP-2 and CRMP-2 levels increased during MCAO, whereas ferulic acid attenuated these injury-induced increases. These results demonstrate that ferulic acid regulates the Akt/GSK-3β/CRMP-2 signaling pathway in focal cerebral ischemic injury, thereby protecting against brain injury.
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22
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Chen A, Lin Z, Lan L, Xie G, Huang J, Lin J, Peng J, Tao J, Chen L. Electroacupuncture at the Quchi and Zusanli acupoints exerts neuroprotective role in cerebral ischemia-reperfusion injured rats via activation of the PI3K/Akt pathway. Int J Mol Med 2012; 30:791-6. [PMID: 22842715 DOI: 10.3892/ijmm.2012.1074] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 06/26/2012] [Indexed: 11/05/2022] Open
Abstract
The PI3K/Akt pathway, a critical mediator of cell survival, is suppressed in cerebral ischemia/reperfusion (I/R) injury; therefore, it is a major focus in treatment of ischemic stroke. Acupuncture has long been used in China to clinically treat stroke. However, the precise mechanism of its neuroprotective activities remains largely unknown. Using a focal cerebral I/R injured rat model, in the present study we evaluated the in vivo therapeutic efficacy of electroacupuncture and investigated the underlying molecular mechanisms. We found that electroacupuncture at Quchi (LI11) and Zusanli (ST36) acupoints on the contralateral paralyzed limb significantly improved neurological deficits and cerebral infarction. In addition, electroacupuncture profoundly activated PI3K/Akt signaling in ischemic cerebral tissues. Consequently, the upregulatory effect of electroacupuncture on PI3K/Akt activation resulted in the inhibition of cerebral cell apoptosis. Moreover, electroacupuncture increased the serum secretion levels of the PI3K activators BDNF and GDNF, as well as upregulated the anti-apoptotic Bcl-2/Bax ratio in ischemic cerebrum. Our data suggest that electroacupuncture at Quchi and Zusanli acupoints exerts neuroprotective function in ischemic stroke via activation of the PI3K/Akt pathway.
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Affiliation(s)
- Azhen Chen
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Minhou Shangjie, Fuzhou, Fujian 350122, PR China
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23
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De Butte-Smith M, Zukin RS, Etgen AM. Effects of global ischemia and estradiol pretreatment on phosphorylation of Akt, CREB and STAT3 in hippocampal CA1 of young and middle-aged female rats. Brain Res 2012; 1471:118-28. [PMID: 22771860 DOI: 10.1016/j.brainres.2012.06.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 06/22/2012] [Accepted: 06/25/2012] [Indexed: 01/29/2023]
Abstract
Transient global ischemia induces selective, delayed neuronal death of pyramidal neurons in the hippocampal CA1. Whereas long term treatment of middle-aged female rats with estradiol at physiological doses ameliorates neuronal death, the signaling pathways that mediate the neuroprotection are, as yet, unknown. Protein kinase B (Akt) and downstream transcription factors, the cAMP response element binding protein (CREB) and signal transducer and activator of transcription (STAT3) are critical players in cellular survival following injury. The present study was undertaken to determine whether long term estradiol alters the phosphorylation status and activity of Akt, STAT3 and CREB in ovariohysterectomized, middle-aged and young female rats subjected to global ischemia. Irrespective of either hormone or ischemic condition, middle-aged females exhibited lower levels of p-CREB and higher levels of Akt and STAT3 in CA1 than young females, as assessed by Western blot. In middle-aged animals, ischemia increased the phosphorylation status/activity of Akt and STAT3, and decreased the phosphorylation status/activity of CREB in the hippocampal CA1. Whereas estradiol did not detectably alter the phosphorylation status/activity of Akt or STAT3, it prevented the ischemia-induced decrease in nuclear p-CREB. Similar results were observed for the young females. Collectively, these data demonstrate that CREB, STAT3, and Akt are involved in the molecular response to global ischemia and that age influences the status of CREB, STAT3 and Akt activity in CA1 under physiological as well as pathological conditions, further emphasizing the importance of including older rodents in neuroprotection studies.
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Affiliation(s)
- M De Butte-Smith
- Albert Einstein College of Medicine, Dominick P. Purpura Department of Neuroscience, Bronx, NY 10461, USA
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24
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Zhang HA, Gao M, Zhang L, Zhao Y, Shi LL, Chen BN, Wang YH, Wang SB, Du GH. Salvianolic acid A protects human SH-SY5Y neuroblastoma cells against H₂O₂-induced injury by increasing stress tolerance ability. Biochem Biophys Res Commun 2012; 421:479-83. [PMID: 22516750 DOI: 10.1016/j.bbrc.2012.04.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Accepted: 04/03/2012] [Indexed: 12/29/2022]
Abstract
Salvianolic acid A (Sal A) is a polyphenol extracted from the root of the Salvia miltiorrhiza bunge. Hydrogen peroxide (H(2)O(2)) is a major reactive oxygen species (ROS), which has been implicated in stroke and other neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. In this study, we investigated the neuroprotective effects of Sal A in human SH-SY5Y neuroblastoma cells against H(2)O(2)-induced injury. Our results showed that cells pretreated with Sal A exhibited enhanced neuronal survival and that this protection was associated with an increase in adenosine triphosphate (ATP) and the stabilization of mitochondrial membrane potential. In addition, Sal A markedly decreased the excessive activation AMP-activated protein kinase (AMPK) and the serine-threonine protein kinase, Akt, in SH-SY5Ycells induced by H(2)O(2). In conclusion, our results demonstrated that Sal A protects SH-SY5Y cells against H(2)O(2)-induced oxidative stress and these protective effects are related to stress tolerance and not energy depletion via inhibition of the AMPK and Akt signaling pathway.
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Affiliation(s)
- Heng-ai Zhang
- Beijing Key Laboratory of Drug Target Identification and Drug Screening, Chinese Academy of Medical Science and Peking Union Medical College, 1 Xian Nong Tan Street, Beijing 100050, PR China
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25
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Kwak SS, Suk J, Choi JH, Yang S, Kim JW, Sohn S, Chung JH, Hong YH, Lee DH, Ahn JK, Min H, Fu YM, Meadows GG, Joe CO. Autophagy induction by tetrahydrobiopterin deficiency. Autophagy 2011; 7:1323-34. [PMID: 21795851 PMCID: PMC3242797 DOI: 10.4161/auto.7.11.16627] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 07/13/2011] [Accepted: 07/13/2011] [Indexed: 01/13/2023] Open
Abstract
Tetrahydrobiopterin (BH₄) deficiency is a genetic disorder associated with a variety of metabolic syndromes such as phenylketonuria (PKU). In this article, the signaling pathway by which BH₄ deficiency inactivates mTORC1 leading to the activation of the autophagic pathway was studied utilizing BH₄-deficient Spr(-/-) mice generated by the knockout of the gene encoding sepiapterin reductase (SR) catalyzing BH₄ synthesis. We found that mTORC1 signaling was inactivated and autophagic pathway was activated in tissues from Spr(-/-) mice. This study demonstrates that tyrosine deficiency causes mTORC1 inactivation and subsequent activation of autophagic pathway in Spr(-/-) mice. Therapeutic tyrosine diet completely rescued dwarfism and mTORC1 inhibition but inactivated autophagic pathway in Spr(-/-) mice. Tyrosine-dependent inactivation of mTORC1 was further supported by mTORC1 inactivation in Pah(enu2) mouse model lacking phenylalanine hydroxylase (Pah). NIH3T3 cells grown under the condition of tyrosine restriction exhibited autophagy induction. However, mTORC1 activation by RhebQ64L, a positive regulator of mTORC1, inactivated autophagic pathway in NIH3T3 cells under tyrosine-deficient conditions. In addition, this study first documents mTORC1 inactivation and autophagy induction in PKU patients with BH₄ deficiency.
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Affiliation(s)
- Sang Su Kwak
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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26
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Sun B, Chen L, Wei X, Xiang Y, Liu X, Zhang X. The Akt/GSK-3β pathway mediates flurbiprofen-induced neuroprotection against focal cerebral ischemia/reperfusion injury in rats. Biochem Biophys Res Commun 2011; 409:808-13. [DOI: 10.1016/j.bbrc.2011.05.095] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Accepted: 05/14/2011] [Indexed: 01/14/2023]
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27
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Kim B, Sullivan KA, Backus C, Feldman EL. Cortical neurons develop insulin resistance and blunted Akt signaling: a potential mechanism contributing to enhanced ischemic injury in diabetes. Antioxid Redox Signal 2011; 14:1829-39. [PMID: 21194385 PMCID: PMC3078499 DOI: 10.1089/ars.2010.3816] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Patients with diabetes are at higher risk of stroke and experience increased morbidity and mortality after stroke. We hypothesized that cortical neurons develop insulin resistance, which decreases neuroprotection via circulating insulin and insulin-like growth factor-I (IGF-I). Acute insulin treatment of primary embryonic cortical neurons activated insulin signaling including phosphorylation of the insulin receptor, extracellular signal-regulated kinase (ERK), Akt, p70S6K, and glycogen synthase kinase-3β (GSK-3β). To mimic insulin resistance, cortical neurons were chronically treated with 25 mM glucose, 0.2 mM palmitic acid (PA), or 20 nM insulin before acute exposure to 20 nM insulin. Cortical neurons pretreated with insulin, but not glucose or PA, exhibited blunted phosphorylation of Akt, p70S6K, and GSK-3β with no change detected in ERK. Inhibition of the phosphatidylinositol 3-kinase (PI3-K) pathway during insulin pretreatment restored acute insulin-mediated Akt phosphorylation. Cortical neurons in adult BKS-db/db mice exhibited higher basal Akt phosphorylation than BKS-db(+) mice and did not respond to insulin. Our results indicate that prolonged hyperinsulinemia leads to insulin resistance in cortical neurons. Decreased sensitivity to neuroprotective ligands may explain the increased neuronal damage reported in both experimental models of diabetes and diabetic patients after ischemia-reperfusion injury.
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Affiliation(s)
- Bhumsoo Kim
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA.
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28
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Lee HJ, Park J, Yoon OJ, Kim HW, Lee DY, Kim DH, Lee WB, Lee NE, Bonventre JV, Kim SS. Amine-modified single-walled carbon nanotubes protect neurons from injury in a rat stroke model. NATURE NANOTECHNOLOGY 2011; 6:121-125. [PMID: 21278749 PMCID: PMC4113082 DOI: 10.1038/nnano.2010.281] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 12/14/2010] [Indexed: 05/18/2023]
Abstract
Stroke results in the disruption of tissue architecture and is the third leading cause of death in the United States. Transplanting scaffolds containing stem cells into the injured areas of the brain has been proposed as a treatment strategy, and carbon nanotubes show promise in this regard, with positive outcomes when used as scaffolds in neural cells and brain tissues. Here, we show that pretreating rats with amine-modified single-walled carbon nanotubes can protect neurons and enhance the recovery of behavioural functions in rats with induced stroke. Treated rats showed less tissue damage than controls and took longer to fall from a rotating rod, suggesting better motor functions after injury. Low levels of apoptotic, angiogenic and inflammation markers indicated that amine-modified single-walled carbon nanotubes protected the brains of treated rats from ischaemic injury.
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Affiliation(s)
- Hyun Jung Lee
- Department of Anatomy and Cell Biology, College of Medicine, Chung Ang University, Seoul, 156-756, Korea
| | - Jiae Park
- Department of Anatomy and Cell Biology, College of Medicine, Chung Ang University, Seoul, 156-756, Korea
| | - Ok Ja Yoon
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology and Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Suwon, Kyunggi-do 440-746, Korea
| | - Hyun Woo Kim
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology and Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Suwon, Kyunggi-do 440-746, Korea
| | - Do Yeon Lee
- Department of Anatomy and Cell Biology, College of Medicine, Chung Ang University, Seoul, 156-756, Korea
| | - Do Hee Kim
- Department of Anatomy and Cell Biology, College of Medicine, Chung Ang University, Seoul, 156-756, Korea
| | - Won Bok Lee
- Department of Anatomy and Cell Biology, College of Medicine, Chung Ang University, Seoul, 156-756, Korea
| | - Nae-Eung Lee
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology and Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Suwon, Kyunggi-do 440-746, Korea
| | - Joseph V. Bonventre
- Renal Division, Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Sung Su Kim
- Department of Anatomy and Cell Biology, College of Medicine, Chung Ang University, Seoul, 156-756, Korea
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29
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Koh PO. Gingko biloba extract (EGb 761) prevents cerebral ischemia-induced p70S6 kinase and S6 phosphorylation. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2011; 38:727-34. [PMID: 20626058 DOI: 10.1142/s0192415x10008196] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
EGb 761 is an extract of Gingko biloba that exhibits neuroprotective effects against cerebral ischemia. The mammalian target of rapamycin (mTOR) is a critical downstream effector of Akt and a central regulator of ribosomal biogenesis and protein synthesis. We investigated whether EGb 761 regulates Akt downstream targets, including mTOR, p70S6 kinase, and S6 phosphorylation. Adult male rats were treated with vehicle or EGb 761 (100 mg/kg) prior to middle cerebral artery occlusion (MCAO). Brains were collected at 24 hours after MCAO and the cerebral cortex regions were examined. We previously showed that EGb 761 significantly reduces infarct volume and decreases the number of TUNEL-positive cells in the cerebral cortex. Ischemic brain injury induces a decrease in Akt up-stream target, PDK1 phosphorylation. The levels of phospho-mTOR, phospho-p70S6 kinase, and phospho-S6 are subsequently decreased in regions affected by ischemic injury. However, EGb 761 prevented injury-induced decreases in these protein levels. We confirmed that EGb 761 inhibits injury-induced decreases in the number of positive cells for phospho-p70S6 kinase and phospho-S6. The results of this study provide evidence that EGb 761 protects neuronal cells against ischemic brain injury by preventing injury-induced decreases in p70S6 kinase and S6 phosphorylation.
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Affiliation(s)
- Phil-Ok Koh
- Department of Anatomy, Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea.
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30
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Zhou X, Lin DS, Zheng F, Sutton MA, Wang H. Intracellular calcium and calmodulin link brain-derived neurotrophic factor to p70S6 kinase phosphorylation and dendritic protein synthesis. J Neurosci Res 2010; 88:1420-32. [PMID: 20029971 DOI: 10.1002/jnr.22321] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mammalian target of rapamycin (mTOR)/p70S6 kinase (S6K) pathway plays an important role in brain-derived neurotrophic factor (BDNF)-mediated protein synthesis and neuroplasticity. Although many aspects of neuronal function are regulated by intracellular calcium ([Ca(2+)](i)) and calmodulin (CaM), their functions in BDNF-induced phosphorylation of p70S6K and protein synthesis are largely unknown. Here, we report that BDNF, via TrkB-dependent activation of mTOR, induces sustained phosphorylation of p70S6K at Thr389 and Thr421/Ser424. BDNF-induced phosphorylation at Thr389 was dependent on PI3 kinase but independent of ERK-MAPK. The previously identified MAPK phosphorylation site at Thr421/Ser424 required both PI3K and MAPK in BDNF-stimulated neurons. Furthermore, we found that the reduction in [Ca(2+)](i), but not extracellular calcium, blocked the BDNF-induced phosphorylation of p70S6K at both sites. Inhibition of CaM by W13 also blocked p70S6K phosphorylation. In correlation, W13 inhibited BDNF-induced local dendritic protein synthesis. Interestingly, sustained elevation of [Ca(2+)](i) by membrane depolarization antagonized the BDNF-induced p70S6K phosphorylation. Finally, the BDNF-induced p70S6K phosphorylation did not require the increase of calcium level through either extracellular influx or PLC-mediated intracellular calcium release. Collectively, these results indicate that the basal level of intracellular calcium gates BDNF-induced activation of p70S6K and protein synthesis through CaM. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Xianju Zhou
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
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31
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Madathil SK, Evans HN, Saatman KE. Temporal and regional changes in IGF-1/IGF-1R signaling in the mouse brain after traumatic brain injury. J Neurotrauma 2010; 27:95-107. [PMID: 19751099 DOI: 10.1089/neu.2009.1002] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Although neurotrophic factors such as nerve growth factor, basic fibroblast growth factor, brain-derived neurotrophic factor, and neurotrophin 4/5 are elevated after traumatic brain injury (TBI), little is known about the endogenous response of insulin-like growth factor-1 (IGF-1). We evaluated IGF-1, IGF-1 receptor (IGF-1R), and total and phosphorylated Akt (p-Akt), a known downstream mediator of IGF-1 signaling, using ELISA, Western blotting, and immunohistochemistry at 1, 6, 24, 48, and 72 h following 0.5-mm controlled cortical impact brain injury in adult mice. IGF-1 was transiently upregulated in homogenates of injured cortex at 1 h, and cells with increased IGF-1 immunoreactivity were observed in and around the cortical contusion site up to 48 h. IGF-1R and total Akt levels in cortical homogenates were unchanged, although immunohistochemistry revealed regional changes. In contrast, serine p-Akt levels increased significantly in homogenates at 6 h post-injury. Interestingly, delayed increases in vascular IGF-1R, total Akt, and p-Akt immunostaining were observed in and around the cortical contusion. IGF-1 and its downstream mediators were also upregulated in the subcortical white matter. Our findings indicate that moderate TBI results in a brief induction of IGF-1 and its signaling components in the acute post-traumatic period. This may reflect an attempt at endogenous neuroprotection or repair.
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Affiliation(s)
- Sindhu Kizhakke Madathil
- Spinal Cord and Brain Injury Research Center, Department of Physiology, University of Kentucky, Lexington, Kentucky 40536-0509, USA
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Pastor MD, García-Yébenes I, Fradejas N, Pérez-Ortiz JM, Mora-Lee S, Tranque P, Moro MÁ, Pende M, Calvo S. mTOR/S6 kinase pathway contributes to astrocyte survival during ischemia. J Biol Chem 2009; 284:22067-22078. [PMID: 19535330 DOI: 10.1074/jbc.m109.033100] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neurons are highly dependent on astrocyte survival during brain damage. To identify genes involved in astrocyte function during ischemia, we performed mRNA differential display in astrocytes after oxygen and glucose deprivation (OGD). We detected a robust down-regulation of S6 kinase 1 (S6K1) mRNA that was accompanied by a sharp decrease in protein levels and activity. OGD-induced apoptosis was increased by the combined deletion of S6K1 and S6K2 genes, as well as by treatment with rapamycin that inhibits S6K1 activity by acting on the upstream regulator mTOR (mammalian target of rapamycin). Astrocytes lacking S6K1 and S6K2 (S6K1;S6K2-/-) displayed a defect in BAD phosphorylation and in the expression of the anti-apoptotic factors Bcl-2 and Bcl-xL. Furthermore reactive oxygen species were increased while translation recovery was impaired in S6K-deficient astrocytes following OGD. Rescue of either S6K1 or S6K2 expression by adenoviral infection revealed that protective functions were specifically mediated by S6K1, because this isoform selectively promoted resistance to OGD and reduction of ROS levels. Finally, "in vivo" effects of S6K suppression were analyzed in the permanent middle cerebral artery occlusion model of ischemia, in which absence of S6K expression increased mortality and infarct volume. In summary, this article uncovers a protective role for astrocyte S6K1 against brain ischemia, indicating a functional pathway that senses nutrient and oxygen levels and may be beneficial for neuronal survival.
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Affiliation(s)
- María Dolores Pastor
- Department of Medical Sciences, Medical School, Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - Isaac García-Yébenes
- Department of Pharmacology, Medical School, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Noelia Fradejas
- Department of Medical Sciences, Medical School, Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - José Manuel Pérez-Ortiz
- Department of Medical Sciences, Medical School, Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - Silvia Mora-Lee
- Department of Medical Sciences, Medical School, Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - Pedro Tranque
- Department of Medical Sciences, Medical School, Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - María Ángeles Moro
- Department of Pharmacology, Medical School, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Mario Pende
- INSERM U845, Université Paris Descartes, 75015 Paris, France
| | - Soledad Calvo
- Department of Medical Sciences, Medical School, Universidad de Castilla La Mancha, 02006 Albacete, Spain
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Zhong J, Zhao L, Du Y, Wei G, Yao WG, Lee WH. Delayed IGF-1 treatment reduced long-term hypoxia-ischemia-induced brain damage and improved behavior recovery of immature rats. Neurol Res 2009; 31:483-9. [PMID: 19500451 DOI: 10.1179/174313208x338133] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Cerebral hypoxia-ischemia during the perinatal period is the single most important cause of acute newborn mortality and chronic disability. Despite our increasing understanding of the mechanisms of neuronal injury, an effective clinical therapy has yet to be established to mitigate brain damage and improve the prognosis and well-being of these newborn patients. Insulin-like growth factor 1 (IGF-1) is a well-known neurotrophic factor, essential for the survival and functional maturation of immature neurons. This study demonstrated that subcutaneous administration of IGF-1 at 24 and 48 hours of recovery significantly reduced hypoxia-ischemia-induced injury to immature rat brains and improved long-term memory and cognitive behavior. IGF-1's therapeutic effects likely involve its ability to prevent delayed apoptosis, as we demonstrated in primary cortical neuronal cultures under oxygen and glucose deprivation. IGF-1's neuroprotective effects parallel the activities of phosphatidylinositol-3/Akt and its down-stream signaling pathway, suggesting a potential mechanistic link. Overall, evidence from this investigation strongly supports IGF-1's potential therapeutic use in the treatment of hypoxic-ischemic encephalopathy in newborn patients.
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Affiliation(s)
- Jin Zhong
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Joo EJ, Lee KY, Jeong SH, Roh MS, Kim SH, Ahn YM, Kim YS. AKT1 Gene Polymorphisms and Obstetric Complications in the Patients with Schizophrenia. Psychiatry Investig 2009; 6:102-7. [PMID: 20046382 PMCID: PMC2796044 DOI: 10.4306/pi.2009.6.2.102] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 05/07/2009] [Accepted: 05/15/2009] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE We performed a genetic association study with schizophrenic patients to investigate whether the V-akt murine thymoma viral oncogene homolog 1 (AKT1) gene plays a role in obstetric complications. METHODS One-hundred-eighty patients with schizophrenia (male, 113; female, 67) were included. All patients fulfilled DSM-IV criteria for schizophrenia. Obstetric complications were measured by the Lewis scale. Prenatal and perinatal information was retrospectively collected from the patients' mothers. We selected six single nucleotide polymorphisms (SNPs) for the AKT1 gene: SNP1 (rs3803300), SNP2 (rs1130214), SNP3 (rs3730358), SNP4 (rs 1130233), SNP5 (rs2494732), and SNPA (rs2498804). The genotype data were analyzed for an association with the Lewis total score in terms of allele, genotype, and haplotype distribution. RESULTS The mean total Lewis scores were 1.30+/-1.61 for males and 1.54+/-1.87 for females. Higher total score tended to be correlated with an earlier age of onset of schizophrenia in females. In the total sample, no SNP was associated with obstetric complications. However, the additional analyses for male and female subgroups found a significant association between SNPA and SNP4 and Lewis score in females (p=0.02 for SNPA, p=0.04 for SNP4). The SNP5-SNPA haplotype showed a positive association with obstetric complications (p=0.03) in the female patient group. CONCLUSION We found an association between SNPs in the AKT1 gene and total Lewis score measuring obstetric complications in female patients with schizophrenia. Because these findings did not survive a correction for multiple testing, the significance should be interpreted carefully and replication studies are required.
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Affiliation(s)
- Eun-Jeong Joo
- Department of Psychiatry, Eulji University School of Medicine, Daegeon, Korea
| | - Kyu-Young Lee
- Department of Psychiatry, Eulji University School of Medicine, Daegeon, Korea
| | - Seong-Hoon Jeong
- Department of Psychiatry, Dongguk University College of Medicine, Goyang, Korea
| | - Myoung-Sun Roh
- Department of Psychiatry and Behavioral Science and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Se Hyun Kim
- Department of Psychiatry and Behavioral Science and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Yong-Min Ahn
- Department of Psychiatry and Behavioral Science and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Yong Sik Kim
- Department of Psychiatry and Behavioral Science and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Korea
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Melatonin prevents ischemic brain injury through activation of the mTOR/p70S6 kinase signaling pathway. Neurosci Lett 2008; 444:74-8. [DOI: 10.1016/j.neulet.2008.08.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 07/06/2008] [Accepted: 08/08/2008] [Indexed: 12/30/2022]
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Xu X, Chua CC, Gao J, Chua KW, Wang H, Hamdy RC, Chua BHL. Neuroprotective effect of humanin on cerebral ischemia/reperfusion injury is mediated by a PI3K/Akt pathway. Brain Res 2008; 1227:12-8. [PMID: 18590709 DOI: 10.1016/j.brainres.2008.06.018] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 06/08/2008] [Accepted: 06/10/2008] [Indexed: 10/21/2022]
Abstract
Humanin (HN) is an anti-apoptotic peptide that suppresses neuronal cell death induced by Alzheimer's disease, prion protein fragments, and serum deprivation. Recently, we demonstrated that Gly14-HN (HNG), a variant of HN in which the 14th amino acid serine is replaced with glycine, can decrease apoptotic neuronal death and reduce infarct volume in a focal cerebral ischemia/reperfusion mouse model. In this study, we postulate that the mechanism of HNG's neuroprotective effect is mediated by the PI3K/Akt pathway. Oxygen-glucose deprivation (OGD) was performed in cultured mouse primary cortical neurons for 60 min. The effect of HNG and PI3K/Akt inhibitors on OGD-induced cell death was examined at 24 h after reperfusion. HNG increased cell viability after OGD in primary cortical neurons, whereas the PI3K/Akt inhibitors wortmannin and Akti-1/2 attenuated the protective effect of HNG. HNG rapidly increased Akt phosphorylation, an effect that was inhibited by wortmannin and Akti-1/2. Mouse brains were injected intraventricularly with HNG before being subjected to middle cerebral artery occlusion (MCAO). HNG treatment significantly elevated p-Akt levels after cerebral I/R injury and decreased infarct volume. The protective effect of HNG on infarct size was attenuated by wortmannin and Akti-1/2. Taken as a whole, these results suggest that PI3K/Akt activation mediates HNG's protective effect against hypoxia/ischemia reperfusion injury.
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Affiliation(s)
- Xingshun Xu
- Department of Pharmacology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA
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Koh PO, Cho JH, Won CK, Lee HJ, Sung JH, Kim MO. Estradiol attenuates the focal cerebral ischemic injury through mTOR/p70S6 kinase signaling pathway. Neurosci Lett 2008; 436:62-6. [PMID: 18378082 DOI: 10.1016/j.neulet.2008.02.061] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 02/16/2008] [Accepted: 02/27/2008] [Indexed: 01/23/2023]
Abstract
We previously showed that estradiol prevents neuronal cell death through the activation of Akt and its downstream targets Bad and FKHR. This study investigated whether estradiol modulates the survival pathway through other downstream targets of Akt, including mammalian target of rapamycin (mTOR) and p70S6 kinase. It is known that mTOR is a downstream target of Akt and a central regulator of protein synthesis, cell growth, and cell cycle progression. Adult female rats were ovariectomied and treated with estradiol prior to middle cerebral artery occlusion (MCAO). Brains were collected 24h after MCAO and infarct volumes were analyzed. We confirmed that estradiol significantly reduces infarct volume and decreases the number of positive cells for TUNEL staining in the cerebral cortex. Brain injury-induced a decrease in phospho-mTOR and phospho-p70S6 kinase. Estradiol prevented the injury-induced decrease in Akt activation and phosphorylation of mTOR and p70S6 kinases, and the subsequent decrease in S6 phosphorylation. Our findings suggest that estradiol plays a potent protective role against brain injury by preventing the injury-induced decrease of mTOR and p70S6 kinase phosphorylation.
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Affiliation(s)
- Phil-Ok Koh
- Department of Anatomy, College of Veterinary Medicine, Institute of Agriculture and Life Science, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701, South Korea.
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Li J, Lang J, Zeng Z, McCullough LD. Akt1 gene deletion and stroke. J Neurol Sci 2008; 269:105-12. [PMID: 18258266 DOI: 10.1016/j.jns.2007.12.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 10/22/2022]
Abstract
Activation of Akt has been implicated as a major contributor to neuronal survival after an ischemic insult. Numerous neuroprotective agents have been shown to augment Akt activity, suggesting that this protein represents a major mechanism of cellular salvage after injury. Estrogen is known to augment Akt, but the possibility that Akt plays a differential role in the male and female brain has yet to be evaluated. In this study, we employed both pharmacological and genetic approaches to investigate the role of Akt in stroke. Utilizing a focal stroke model we show that deletion of the Akt1 isoform does not affect stroke outcome in either male or female mice. Akt1 deficient mice had equivalent levels of phosphorylated Akt (p-Akt) when compared to their WT controls following stroke suggesting that alternative isoforms can compensate for Akt1 loss. Secondly, estrogen's neuroprotective effect is maintained in Akt1(-/-) mice and estrogen exposure did not enhance p-Akt levels in WT female mice. Thirdly, we show that inhibiting Akt using the direct pan-Akt inhibitor triciribine has no effect on stroke outcome despite dramatic reductions in p-Akt. Our study demonstrates the limitations of genetic mouse models and suggests that the importance of Akt to ischemic outcome remains unclear.
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Affiliation(s)
- Jun Li
- Department of Neurology, University of Connecticut Health Center, Farmington CT, 06030, United States
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Wakade C, Khan MM, De Sevilla LM, Zhang QG, Mahesh VB, Brann DW. Tamoxifen neuroprotection in cerebral ischemia involves attenuation of kinase activation and superoxide production and potentiation of mitochondrial superoxide dismutase. Endocrinology 2008; 149:367-79. [PMID: 17901229 PMCID: PMC2194601 DOI: 10.1210/en.2007-0899] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The purpose of this study was to enhance our understanding of the mechanisms of neuronal death after focal cerebral ischemia and the neuroprotective effects of tamoxifen (TMX). The phosphorylation state of 31 protein kinases/signaling proteins and superoxide anion (O(2)(-)) production in the contralateral and ipsilateral cortex was measured after permanent middle cerebral artery occlusion (pMCAO) in ovariectomized rats treated with placebo or TMX. The study revealed that pMCAO modulated the phosphorylation of a number of kinases/proteins in the penumbra at 2 h after pMCAO. Of significant interest, phospho-ERK1/2 (pERK1/2) was elevated significantly after pMCAO. TMX attenuated the elevation of pERK1/2, an effect correlated with reduced infarct size. In situ detection of O(2)(-) production showed a significant elevation at 1-2 h after pMCAO in the ischemic cortex with enhanced oxidative damage detected at 24 h. ERK activation may be downstream of free radicals, a suggestion supported by the findings that cells positive for O(2)(-) had high pERK activation and that a superoxide dismutase (SOD) mimetic, tempol, significantly attenuated pERK activation after MCAO. TMX treatment significantly reduced the MCAO-induced elevation of O(2)(-) production, oxidative damage, and proapoptotic caspase-3 activation. Additionally, pMCAO induced a significant reduction in the levels of manganese SOD (MnSOD), which scavenge O(2)(-), an effect largely prevented by TMX treatment, thus providing a potential mechanistic basis for the antioxidant effects of TMX. As a whole, these studies suggest that TMX neuroprotection may be achieved via an antioxidant mechanism that involves enhancement of primarily MnSOD levels, with a corresponding reduction of O(2)(-) production, and downstream kinase and caspase-3 activation.
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Affiliation(s)
- Chandramohan Wakade
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15th Street, Augusta, Georgia 30912, USA
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Kitano H, Young JM, Cheng J, Wang L, Hurn PD, Murphy SJ. Gender-specific response to isoflurane preconditioning in focal cerebral ischemia. J Cereb Blood Flow Metab 2007; 27:1377-86. [PMID: 17264860 PMCID: PMC2266686 DOI: 10.1038/sj.jcbfm.9600444] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Inhalation anesthetics are effective chemical preconditioning agents in experimental cerebral ischemia. However, previous work has been performed exclusively in male animals. We determined if there is a gender difference in ischemic outcome after isoflurane preconditioning (IsoPC), and if this sex-specific response is linked to differences in Akt phosphorylation or expression of neuronal inducible cell-death putative kinase (NIPK), a negative modulator of Akt activation. Young and middle-aged male and female mice were preconditioned for 4 h with air (sham PC) or 1.0% IsoPC and recovered for 24 h. Cortices were subdissected from preconditioned young male and female mice for measurement of Akt phosphorylation (Western blot) and NIPK mRNA (quantitative polymerase chain reaction). Additional cohorts underwent 2 h of reversible middle cerebral artery occlusion. Lastly, male and female Akt1(+/+) and Akt1(-/-) mice were studied to determine if gender differences in ischemic outcome after IsoPC is Akt1-dependent. Infarction volume was determined at 22 h reperfusion (2,3,5-triphenyltetrazolium chloride). As expected, IsoPC decreased ischemic damage as compared with sham PC in young and middle-aged male mice. In contrast, IsoPC markedly increased infarction in young female mice and had no effect in middle-aged female mice. Cortical phospho-Akt was increased by IsoPC versus sham PC only in male mice. No increase was observed in IsoPC female mice. NIPK mRNA was higher in female mice than in male mice regardless of preconditioning status. Male IsoPC neuroprotection was lost in Akt1-deficient male mice. We conclude that IsoPC is beneficial only in ischemic male brain and that sex differences in IsoPC are mediated through Akt activation and basal NIPK expression.
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Affiliation(s)
- Hideto Kitano
- Anesthesiology and Peri-Operative Medicine, Oregon Health and Science University, Portland, Oregon 97239-3098, USA
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Paccalin M, Pain-Barc S, Pluchon C, Paul C, Besson MN, Carret-Rebillat AS, Rioux-Bilan A, Gil R, Hugon J. Activated mTOR and PKR kinases in lymphocytes correlate with memory and cognitive decline in Alzheimer's disease. Dement Geriatr Cogn Disord 2007; 22:320-6. [PMID: 16954686 DOI: 10.1159/000095562] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/07/2006] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The control of translation, involving the kinases mTOR (mammalian target of rapamycin) and PKR (double-stranded RNA-dependent protein kinase), modulates cell survival and death and is altered in the brains of patients with Alzheimer's disease (AD). In AD increased susceptibility of lymphocytes to apoptosis has been reported. METHODS We investigated the level of the kinases mTOR and PKR and the eukaryotic initiation factor 2alpha (eIF2alpha) in lymphocytes of patients with AD in comparison with controls. In AD patients we also looked for a correlation between activated proteins and cognitive and memory tests. RESULTS We report significant alterations of the levels of these kinases and eIF2alpha in lymphocytes of AD patients that were also significantly correlated with cognitive and memory test scores. CONCLUSION These results suggest that the levels of mTOR, PKR and eIF2alpha in lymphocytes could follow the cognitive decline in AD.
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Affiliation(s)
- Marc Paccalin
- Brain Aging Research Group EA 3808, University of Poitiers, Poitiers, France.
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Endo H, Nito C, Kamada H, Nishi T, Chan PH. Activation of the Akt/GSK3beta signaling pathway mediates survival of vulnerable hippocampal neurons after transient global cerebral ischemia in rats. J Cereb Blood Flow Metab 2006; 26:1479-89. [PMID: 16538228 DOI: 10.1038/sj.jcbfm.9600303] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Recent studies have revealed that the phosphatidylinositol 3-kinase (PI3-K) pathway is involved in apoptotic cell death after experimental cerebral ischemia. The serine-threonine kinase, Akt, functions in the PI3-K pathway and prevents apoptosis by phosphorylation at Ser473 after a variety of cell death stimuli. After phosphorylation, activated Akt inactivates other apoptogenic factors, including glycogen synthase kinase-3beta (GSK3beta), thereby inhibiting cell death. However, the role of Akt/GSK3beta signaling in the delayed death of hippocampal neurons in the CA1 subregion after transient global cerebral ischemia (tGCI) has not been clarified. Transient global cerebral ischemia for 5 mins was induced by bilateral common carotid artery occlusion combined with hypotension. Western blot analysis showed a significant increase in phospho-Akt (Ser473) and phospho-GSK3beta (Ser9) in the hippocampal CA1 subregion after tGCI. Immunohistochemistry showed that expression of phospho-Akt (Ser473) and phospho-GSK3beta (Ser9) was markedly increased in the vulnerable CA1 subregion, but not in the ischemic-tolerant CA3 subregion. Double staining with phospho-GSK3beta (Ser9) and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling showed different cellular distributions in the CA1 subregion 3 days after tGCI. Phosphorylation of Akt and GSK3beta was prevented by LY294002, a PI3-K inhibitor, which facilitated subsequent DNA fragmentation 3 days after tGCI. Moreover, transgenic rats that overexpress copper/zinc-superoxide dismutase, which is known to be neuroprotective against delayed hippocampal CA1 injury after tGCI, had enhanced and persistent phosphorylation of both Akt and GSK3beta after tGCI. These findings suggest that activation of the Akt/GSK3beta signaling pathway may mediate survival of vulnerable hippocampal CA1 neurons after tGCI.
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Affiliation(s)
- Hidenori Endo
- Department of Neurosurgery, Program in Neurosciences, Stanford University School of Medicine, Stanford, California 94305-5487, USA
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Crespo-Biel N, Canudas AM, Camins A, Pallàs M. Kainate induces AKT, ERK and cdk5/GSK3beta pathway deregulation, phosphorylates tau protein in mouse hippocampus. Neurochem Int 2006; 50:435-42. [PMID: 17116346 DOI: 10.1016/j.neuint.2006.10.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 09/26/2006] [Accepted: 10/03/2006] [Indexed: 10/23/2022]
Abstract
Acute treatment with kainate 30 mg/kg (KA) produced behavioral alterations and reactive gliosis. However, it did not produce major death of mouse hippocampal neurons, indicating that concentrations were not cytotoxic. KA caused rapid and temporal Erk phosphorylation (at 6h) and Akt dephosphorylation (1-3 days). Concomitantly, the activation of GSK3beta was increased 1-3 days after KA. After 7 days, a reduction in GSK3beta activation was observed. Caspase-3 activity increased, but to a lesser extent than calpain activation (measured by fluorimetry and calpain-cleaved alpha-spectrin). As calpain is involved in cdk5 activation, and cdk5 is related to GSK3beta, the cdk5/p25 pathway was examined. Results showed that the p25/p35 ratio in KA-injected mice for 3 days was 73.6% higher than control levels. However, no changes in cdk5 expression were detected. Both Western blot and immunohistochemistry against p-Tau(Thr(231)) indicated an increase at this phosphorylated site of tau protein. Indeed an increase in p-Tau(Ser(199)) and p-Tau(Ser(396)) was observed by Western blot. Our results demonstrate that tau hyperphosphorylation, induced by KA, is due to an increase in GSK3beta/cdk5 activity in combination with an inactivation of Akt. This indicates that the calpain/cdk5 pathway for tau phosphorylation has a potential role in delayed apoptotic death evoked by excitotoxicity. Moreover, the subsequent activation of caspase and calpain proteases leads to dephosphorylation of tau, thus increasing microtubular destructuration. Taken together, our results provide new insights in the activation of several kinase-pathways implicated in cytoskeletal alterations that are a common feature of neurodegenerative diseases.
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Affiliation(s)
- N Crespo-Biel
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina, Universitat de Barcelona, Nucli Universitari de Pedralbes, E-08028 Barcelona, Spain
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Yu F, Sugawara T, Maier CM, Hsieh LB, Chan PH. Akt/Bad signaling and motor neuron survival after spinal cord injury. Neurobiol Dis 2005; 20:491-9. [PMID: 15896972 DOI: 10.1016/j.nbd.2005.04.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Revised: 03/28/2005] [Accepted: 04/08/2005] [Indexed: 11/18/2022] Open
Abstract
The serine-threonine kinase Akt is a cell survival signaling pathway that inactivates the proapoptotic BCL-2 family protein Bad and promotes cell survival in cerebral ischemia. Involvement of the Akt/Bad signaling pathway after spinal cord injury (SCI) is, however, uncertain. Our results showed that phospho-Akt (serine-473) and phospho-Bad (serine-136) were significantly upregulated at 1 day after SCI. In addition, phospho-Akt and phospho-Bad were colocalized in motor neurons that survived SCI and inhibition of PI3-K reduced expression of phospho-Akt and phospho-Bad. Dimerization of Bad with 14-3-3 in the cytosol was increased whereas Bad/Bcl-XL binding in the mitochondria was decreased after SCI. We further found that reduced oxidative stress by SOD1 overexpression in rats enhanced the expression of phospho-Akt, phospho-Bad, Bad/14-3-3 binding and reduced Bad/Bcl-XL binding after SCI, as compared to wild-type rats. We conclude that oxidative stress may play a role in modulating Akt/Bad signaling and subsequent motor neuron survival after SCI.
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Affiliation(s)
- Fengshan Yu
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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Abstract
1. Reactive oxygen species and oxidative state are slowly gaining acceptance in having a physiological relevance rather than just being the culprits in pathophysiological processes. The control of the redox environment of the cell provides for additional regulation in relation to signal transduction pathways. Conversely, aberrant regulation of oxidative state manifesting as oxidative stress can predispose a cell to adverse outcome. 2. The phosphatidylinositol 3-kinase/akt pathway is one such pathway that is partially regulated via oxidative state and, in an oxidative stress paradigm such as ischaemic-reperfusion injury, may be inactivated, which can lead to exacerbation of cell death. 3. Activation of nuclear factor (NF)-kappaB has been associated with oxidative stress. The role of NF-kappaB in neuronal cell death is widely debated, with major studies highlighting both a pro- and anti-apoptotic role for NF-kappaB, with the outcome being region, stimulus, dose and duration specific. 4. Oxidative state plays a key role in the regulation and control of numerous signal transduction pathways in the cell. Elucidating the mechanisms behind oxidative stress-mediated neuronal cell death is important in identifying potential putative targets for the treatment of diseases such as stroke.
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Affiliation(s)
- Juliet M Taylor
- Centre for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Melbourne, Victoria, Australia
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Kayali F, Montie HL, Rafols JA, DeGracia DJ. Prolonged translation arrest in reperfused hippocampal cornu Ammonis 1 is mediated by stress granules. Neuroscience 2005; 134:1223-45. [PMID: 16055272 DOI: 10.1016/j.neuroscience.2005.05.047] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 03/22/2005] [Accepted: 05/25/2005] [Indexed: 11/29/2022]
Abstract
Global brain ischemia and reperfusion cause phosphorylation of the alpha subunit of eukaryotic initiation factor 2alpha, a reversible event associated with neuronal translation inhibition. However, the selective vulnerability of cornu Ammonis (CA) 1 pyramidal neurons correlates with irreversible translation inhibition. Phosphorylation of eukaryotic initiation factor 2alpha also leads to the formation of stress granules, cytoplasmic foci containing, in part, components of the 48S pre-initiation complex and the RNA binding protein T cell internal antigen-1 (TIA-1). Stress granules are sites of translationally inactive protein synthesis machinery. Here we evaluated stress granules in rat hippocampal formation neurons after 10 min global brain ischemia and 10 min, 90 min or 4 h of reperfusion by double-labeling immunofluorescence for two stress granule components: small ribosomal subunit protein 6 and TIA-1. Stress granules in CA3, hilus and dentate gyrus, but not CA1, increased at 10 min reperfusion and returned to control levels by 90 min reperfusion. Dynamic changes in the nuclear distribution of TIA-1 occurred in resistant neurons. At 4 h reperfusion, small ribosomal subunit protein 6 was solely localized within stress granules only in CA1 pyramidal neurons. Both TIA-1 and small ribosomal subunit protein 6 levels decreased approximately 50% in hippocampus homogenates. Electron microscopy showed stress granules to be composed of electron dense bodies 100-200 nm in diameter, that were not membrane bound, but were associated with endoplasmic reticulum. Alterations in stress granule behavior in CA1 pyramidal neurons provide a definitive mechanism for the continued inhibition of protein synthesis in reperfused CA1 pyramidal neurons following dephosphorylation of eukaryotic initiation factor 2alpha.
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Affiliation(s)
- F Kayali
- Department of Physiology, Wayne State University, 4116 Scott Hall, Detroit, MI 48201, USA
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DeGracia DJ. Acute and persistent protein synthesis inhibition following cerebral reperfusion. J Neurosci Res 2004; 77:771-6. [PMID: 15334596 DOI: 10.1002/jnr.20225] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lack of recovery from protein synthesis inhibition (PSI) closely correlates with neuronal death following brain ischemia and reperfusion. It has therefore been suggested that understanding the mechanisms of PSI will shed light on the mechanisms of selective neuronal death following ischemia and reperfusion. It is now known that the PKR-like ER kinase (PERK)-mediated phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha) causes translation inhibition at initial reperfusion. Activation of PERK, in turn, indicates endoplasmic reticulum stress and activation of the unfolded protein response. However, phosphorylation of eIF2alpha is a transient event and can account for PSI only in the initial hours of reperfusion. Although a number of other regulators of protein synthesis, such as eIF4F, 4EBP-1, eEF-2, and S6 kinase, have been assessed following cerebral ischemia and reperfusion, the causes of prolonged PSI have yet to be fully elucidated. The purpose of the present article is to bring together the evidence indicating that, at minimum, postischemic PSI should be conceptualized as consisting of two components: an acute, transient component mediated by unfolded protein response-induced eIF2alpha phosphorylation and a longer term component that correlates with neuronal death. Ischemic tolerance appears to separate the acute and persistent components of reperfusion-induced translation inhibition. Specific models of the relationship among acute PSI, persistent PSI, and neuronal death are presented to clarify issues that have emerged from ongoing work in this area.
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Affiliation(s)
- Donald J DeGracia
- Department of Physiology, and the Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48201, USA.
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Abe T, Takagi N, Nakano M, Furuya M, Takeo S. Altered Bad localization and interaction between Bad and Bcl-xL in the hippocampus after transient global ischemia. Brain Res 2004; 1009:159-68. [PMID: 15120593 DOI: 10.1016/j.brainres.2004.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2004] [Indexed: 11/28/2022]
Abstract
Accumulating evidence indicates that the mitochondrial cell-death pathway, which involves the release of cytochrome c from mitochondria, participates in neuronal cell death after transient cerebral ischemia. However, the upstream events, that induce cytochrome c release after transient global ischemia are not fully understood. Bad is a pro-apoptotic member of the bcl-2 gene family that promotes apoptosis by binding to and inhibiting functions of anti-apoptotic proteins Bcl-2 and Bcl-xL. We investigated the effects of transient (15 min) global ischemia on the intracellular localization of Bad and the interaction of Bad with calcineurin, Akt or Bcl-xL in the vulnerable CA1 and resistant CA3/dentate gyrus of the hippocampus. Immunoblotting analysis revealed that the amount of Bad in mitochondria significantly increased after ischemia. Co-immunoprecipitation studies showed decreased interactions of Bad with Akt and calcineurin in the cytosol and increased binding with Bcl-xL in the mitochondrial fraction of hippocampal CA1, but not in the CA3/dentate gyrus region. Further, we examined the effect of recombinant Bad on the cytochrome c release from isolated mitochondria. Treatment with both recombinant Bad and calcium, but not with recombinant Bad alone, induced cytochrome c release. These results suggest that changes in localization and complex formation by Bad are, at least in part, involved in the vulnerability of cells after transient global ischemia.
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Affiliation(s)
- Tsutomu Abe
- Faculty of Pharmaceutical Sciences, Department of Pharmacology, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
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Hasegawa Y, Hamada JI, Morioka M, Yano S, Kawano T, Kai Y, Fukunaga K, Ushio Y. Neuroprotective effect of postischemic administration of sodium orthovanadate in rats with transient middle cerebral artery occlusion. J Cereb Blood Flow Metab 2003; 23:1040-51. [PMID: 12973020 DOI: 10.1097/01.wcb.0000085160.71791.3f] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Orthovanadate is a competitive inhibitor of protein tyrosine phosphatases. Some of its reported biologic effects are its insulin mimetic property and its activation of phosphoinositide 3-kinase and extracellular-signal regulated kinase (ERK). The authors previously reported its neuroprotective effect on delayed neuronal death of gerbil hippocampal CA1 neurons via Akt and ERK activation after transient forebrain ischemia. In the present study, the neuroprotective effect of postischemic intraperitoneal administration of sodium orthovanadate (2 l/kg of 50-mmol/l sodium orthovanadate in saline) was investigated in rats with transient middle cerebral artery occlusion. Ischemic neuronal injury was evaluated 1 day and 28 days after ischemia. The neuroprotective effect of orthovanadate was significant in the cortex but not the caudate putamen (ischemic core) at both 1 and 28 days after ischemia. In orthovanadate group, the activities of Akt and ERK were maintained after reperfusion; they were decreased in saline group. Blood glucose level decreased but within normal range. Regional cerebral blood flow was lower than that of saline group only at 0 hours after reperfusion. These data suggest that orthovanadate has neuroprotective effects in rats with transient middle cerebral artery occlusion and that these effects are mediated by Akt and ERK activation. Furthermore, low blood glucose levels and gradual recovery of regional cerebral blood flow may contribute to neuroprotection.
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Affiliation(s)
- Yu Hasegawa
- Department of Neurosurgery, Kumamoto University School of Medicine, Kumamoto, Japan
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Arsham AM, Howell JJ, Simon MC. A novel hypoxia-inducible factor-independent hypoxic response regulating mammalian target of rapamycin and its targets. J Biol Chem 2003; 278:29655-60. [PMID: 12777372 DOI: 10.1074/jbc.m212770200] [Citation(s) in RCA: 354] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Hypoxia triggers a reversible inhibition of protein synthesis thought to be important for energy conservation in O2-deficient environments. The mammalian target of rapamycin (mTOR) pathway integrates multiple environmental cues to regulate translation in response to nutrient availability and stress, suggesting it as a candidate for O2 regulation. We show here that hypoxia rapidly and reversibly triggers hypophosphorylation of mTOR and its effectors 4E-BP1, p70S6K, rpS6, and eukaryotic initiation factor 4G. Hypoxic regulation of these translational control proteins is dominant to activation via multiple distinct signaling pathways such as insulin, amino acids, phorbol esters, and serum and is independent of Akt/protein kinase B and AMP-activated protein kinase phosphorylation, ATP levels, ATP:ADP ratios, and hypoxia-inducible factor-1 (HIF-1). Finally, hypoxia appears to repress phosphorylation of translational control proteins in a manner analogous to rapamycin and independent of phosphatase 2A (PP2A) activity. These data demonstrate a new mode of regulation of the mTOR pathway and position this pathway as a powerful point of control by O2 of cellular metabolism and energetics.
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Affiliation(s)
- Andrew M Arsham
- Committee on Genetics, University of Chicago, Chicago, Illinois 60615, USA
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