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Valmiki RR, Venkatesalu S, Chacko AG, Prabhu K, Thomas MM, Mathew V, Yoganathan S, Muthusamy K, Chacko G, Vanjare HA, Krothapalli SB. Phosphoproteomic analysis reveals Akt isoform-specific regulation of cytoskeleton proteins in human temporal lobe epilepsy with hippocampal sclerosis. Neurochem Int 2019; 134:104654. [PMID: 31884041 DOI: 10.1016/j.neuint.2019.104654] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/03/2019] [Accepted: 12/23/2019] [Indexed: 01/04/2023]
Abstract
Akt is one of the most important downstream effectors of phosphatidylinositol 3-kinase/mTOR pathway. Hyperactivation and expression of this pathway are seen in a variety of neurological disorders including human temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). Nevertheless, the expression and activation profiles of the Akt isoforms, Akt1, Akt2, and Akt3 and their functional roles in human TLE-HS have not been studied. We examined the protein expression and activation (phosphorylation) patterns of Akt and its isoforms in human hippocampal tissue from TLE and non-TLE patients. A phosphoproteomic approach followed by interactome analysis of each Akt isoform was used to understand protein-protein interactions and their role in TLE-HS pathology. Our results demonstrated activation of the Akt/mTOR pathway as well as activation of Akt downstream substrates like GSK3β, mTOR, and S6 in TLE-HS samples. Akt1 isoform levels were significantly increased in the TLE-HS samples as compared to the non-TLE samples. Most importantly, different isoforms were activated in different TLE-HS samples, Akt2 was activated in three samples, Akt2 and Akt1 were simultaneously activated in one sample and Akt3 was activated in two samples. Our phosphoproteomic screen across six TLE-HS samples identified 183 proteins phosphorylated by Akt isoforms, 29 of these proteins belong to cytoskeletal modification. Also, we were able to identify proteins of several other classes involved in glycolysis, neuronal development, protein folding and excitatory amino acid transport functions as Akt substrates. Taken together, our data offer clues to understand the role of Akt and its isoforms in underlying the pathology of TLE-HS and further, modulation of Akt/mTOR pathway using Akt isoforms specific inhibitors may offer a new therapeutic window for treatment of human TLE-HS.
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Affiliation(s)
- Rajesh Ramanna Valmiki
- Neurophysiology Laboratory, Department of Neurological Sciences, Christian Medical College, Vellore, 632004, Tamilnadu, India.
| | - Subhashini Venkatesalu
- Neurophysiology Laboratory, Department of Neurological Sciences, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | - Ari George Chacko
- Neurosurgery, Department of Neurological Sciences, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | - Krishna Prabhu
- Neurosurgery, Department of Neurological Sciences, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | - Maya Mary Thomas
- Department of Pediatric Neurology, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | - Vivek Mathew
- Neurology, Department of Neurological Sciences, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | - Sangeetha Yoganathan
- Department of Pediatric Neurology, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | - Karthik Muthusamy
- Department of Pediatric Neurology, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | - Geeta Chacko
- Neuropathology, Department of General Pathology, Christian Medical College, Vellore, 632004, Tamilnadu, India
| | | | - Srinivasa Babu Krothapalli
- Neurophysiology Laboratory, Department of Neurological Sciences, Christian Medical College, Vellore, 632004, Tamilnadu, India
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Rho JM, Shao LR, Stafstrom CE. 2-Deoxyglucose and Beta-Hydroxybutyrate: Metabolic Agents for Seizure Control. Front Cell Neurosci 2019; 13:172. [PMID: 31114484 PMCID: PMC6503754 DOI: 10.3389/fncel.2019.00172] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 04/11/2019] [Indexed: 01/12/2023] Open
Abstract
Current anti-seizure drugs (ASDs) are believed to reduce neuronal excitability through modulation of ion channels and transporters that regulate excitability at the synaptic level. While most patients with epilepsy respond to ASDs, many remain refractory to medical treatment but respond favorably to a high-fat, low-carbohydrate metabolism-based therapy known as the ketogenic diet (KD). The clinical effectiveness of the KD has increasingly underscored the thesis that metabolic factors also play a crucial role in the dampening neuronal hyperexcitability that is a hallmark feature of epilepsy. This notion is further amplified by the clinical utility of other related metabolism-based diets such as the modified Atkins diet and the low-glycemic index treatment (LGIT). Traditional high-fat diets are characterized by enhanced fatty acid oxidation (which produces ketone bodies such as beta-hydroxybutyrate) and a reduction in glycolytic flux, whereas the LGIT is predicated mainly on the latter observation of reduced blood glucose levels. As dietary implementation is not without challenges regarding clinical administration and patient compliance, there is an inherent desire and need to determine whether specific metabolic substrates and/or enzymes might afford similar clinical benefits, hence validating the concept of a “diet in a pill.” Here, we discuss the evidence for one glycolytic inhibitor, 2-deoxyglucose (2DG) and one metabolic substrate, β-hydroxybutyrate (BHB) exerting direct effects on neuronal excitability, highlight their mechanistic differences, and provide the strengthening scientific rationale for their individual or possibly combined use in the clinical arena of seizure management.
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Affiliation(s)
- Jong M Rho
- Section of Pediatric Neurology, Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Li-Rong Shao
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Carl E Stafstrom
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Shao LR, Rho JM, Stafstrom CE. Glycolytic inhibition: A novel approach toward controlling neuronal excitability and seizures. Epilepsia Open 2018; 3:191-197. [PMID: 30564778 PMCID: PMC6293058 DOI: 10.1002/epi4.12251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2018] [Indexed: 12/31/2022] Open
Abstract
Conventional antiseizure medications reduce neuronal excitability through effects on ion channels or synaptic function. In recent years, it has become clear that metabolic factors also play a crucial role in the modulation of neuronal excitability. Indeed, metabolic regulation of neuronal excitability is pivotal in seizure pathogenesis and control. The clinical effectiveness of a variety of metabolism‐based diets, especially for children with medication‐refractory epilepsy, underscores the applicability of metabolic approaches to the control of seizures and epilepsy. Such diets include the ketogenic diet, the modified Atkins diet, and the low‐glycemic index treatment (among others). A promising avenue to alter cellular metabolism, and hence excitability, is by partial inhibition of glycolysis, which has been shown to reduce seizure susceptibility in a variety of animal models as well as in cellular systems in vitro. One such glycolytic inhibitor, 2‐deoxy‐d‐glucose (2DG), increases seizure threshold in vivo and reduces interictal and ictal epileptiform discharges in hippocampal slices. Here, we review the role of glucose metabolism and glycolysis on neuronal excitability, with specific reference to 2DG, and discuss the potential use of 2DG and similar agents in the clinical arena for seizure management.
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Affiliation(s)
- Li-Rong Shao
- Division of Pediatric Neurology Department of Neurology Johns Hopkins University School of Medicine Baltimore Maryland U.S.A
| | - Jong M Rho
- Departments of Pediatrics, Clinical Neurosciences, Physiology and Pharmacology Alberta Children's Hospital Research Institute Hotchkiss Brain Institute Cumming School of Medicine University of Calgary Calgary Alberta Canada
| | - Carl E Stafstrom
- Division of Pediatric Neurology Department of Neurology Johns Hopkins University School of Medicine Baltimore Maryland U.S.A
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NRSF: an Angel or a Devil in Neurogenesis and Neurological Diseases. J Mol Neurosci 2014; 56:131-44. [DOI: 10.1007/s12031-014-0474-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 11/18/2014] [Indexed: 12/12/2022]
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Yang H, Wu J, Guo R, Peng Y, Zheng W, Liu D, Song Z. Glycolysis in energy metabolism during seizures. Neural Regen Res 2014; 8:1316-26. [PMID: 25206426 PMCID: PMC4107649 DOI: 10.3969/j.issn.1673-5374.2013.14.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 03/27/2013] [Indexed: 01/23/2023] Open
Abstract
Studies have shown that glycolysis increases during seizures, and that the glycolytic metabolite lactic acid can be used as an energy source. However, how lactic acid provides energy for seizures and how it can participate in the termination of seizures remains unclear. We reviewed possible mechanisms of glycolysis involved in seizure onset. Results showed that lactic acid was involved in seizure onset and provided energy at early stages. As seizures progress, lactic acid reduces the pH of tissue and induces metabolic acidosis, which terminates the seizure. The specific mechanism of lactic acid-induced acidosis involves several aspects, which include lactic acid-induced inhibition of the glycolytic enzyme 6-diphosphate kinase-1, inhibition of the N-methyl-D-aspartate receptor, activation of the acid-sensitive 1A ion channel, strengthening of the receptive mechanism of the inhibitory neurotransmitter γ-minobutyric acid, and changes in the intra- and extracellular environment.
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Affiliation(s)
- Heng Yang
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Jiongxing Wu
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Ren Guo
- Department of Pharmacy, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Yufen Peng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Wen Zheng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Ding Liu
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Zhi Song
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
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Abstract
The ketogenic diet and its newer variants are clinically useful in treating epilepsy. They can also have antiepileptogenic properties and can eventually have a role in treating other neurologic and nonneurologic conditions. Despite being nearly a century old, identifying the molecular underpinnings of the ketogenic diet has been challenging. However, recent studies provide experimental evidence for 4 distinct mechanisms that could contribute to the antiseizure and other beneficial effects of these diets. These mechanisms include carbohydrate reduction, activation of adenosine triphosphate (ATP)-sensitive potassium channels by mitochondrial metabolism, inhibition of the mammalian target of rapamycin pathway, and inhibition of glutamatergic excitatory synaptic transmission.
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Affiliation(s)
- Nika N. Danial
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston MA
| | - Adam L. Hartman
- Department of Neurology, Johns Hopkins University School of Medicine and Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Carl E. Stafstrom
- Departments of Neurology and Pediatrics, University of Wisconsin, Madison, WI
| | - Liu Lin Thio
- Departments of Neurology, Pediatrics, and Anatomy & Neurobiology, Washington University, St. Louis, MO
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Harnessing the power of metabolism for seizure prevention: focus on dietary treatments. Epilepsy Behav 2013; 26:266-72. [PMID: 23110824 PMCID: PMC3562425 DOI: 10.1016/j.yebeh.2012.09.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Accepted: 09/06/2012] [Indexed: 02/08/2023]
Abstract
The continued occurrence of refractory seizures in at least one-third of children and adults with epilepsy, despite the availability of almost 15 conventional and novel anticonvulsant drugs, speaks to a dire need to develop novel therapeutic approaches. Cellular metabolism, the critical pathway by which cells access and utilize energy, is essential for normal neuronal function. Furthermore, mounting evidence suggests direct links between energy metabolism and cellular excitability. The high-fat, low-carbohydrate ketogenic diet has been used as a treatment for drug-refractory epilepsy for almost a century. Yet, the multitude of alternative therapies to target aspects of cellular metabolism and hyperexcitability is almost untapped. Approaches discussed in this review offer a wide diversity of therapeutic targets that might be exploited by investigators in the search for safer and more effective epilepsy treatments.
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Rho JM, Stafstrom CE. The ketogenic diet: What has science taught us? Epilepsy Res 2012; 100:210-7. [DOI: 10.1016/j.eplepsyres.2011.05.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/28/2011] [Accepted: 05/01/2011] [Indexed: 01/18/2023]
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Payne NE, Cross JH, Sander JW, Sisodiya SM. The ketogenic and related diets in adolescents and adults-A review. Epilepsia 2011; 52:1941-8. [PMID: 22004525 DOI: 10.1111/j.1528-1167.2011.03287.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Natasha E Payne
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom
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