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A Warburg-like metabolic program coordinates Wnt, AMPK, and mTOR signaling pathways in epileptogenesis. PLoS One 2021; 16:e0252282. [PMID: 34358226 PMCID: PMC8345866 DOI: 10.1371/journal.pone.0252282] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 05/12/2021] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a complex neurological condition characterized by repeated spontaneous seizures and can be induced by initiating seizures known as status epilepticus (SE). Elaborating the critical molecular mechanisms following SE are central to understanding the establishment of chronic seizures. Here, we identify a transient program of molecular and metabolic signaling in the early epileptogenic period, centered on day five following SE in the pre-clinical kainate or pilocarpine models of temporal lobe epilepsy. Our work now elaborates a new molecular mechanism centered around Wnt signaling and a growing network comprised of metabolic reprogramming and mTOR activation. Biochemical, metabolomic, confocal microscopy and mouse genetics experiments all demonstrate coordinated activation of Wnt signaling, predominantly in neurons, and the ensuing induction of an overall aerobic glycolysis (Warburg-like phenomenon) and an altered TCA cycle in early epileptogenesis. A centerpiece of the mechanism is the regulation of pyruvate dehydrogenase (PDH) through its kinase and Wnt target genes PDK4. Intriguingly, PDH is a central gene in certain genetic epilepsies, underscoring the relevance of our elaborated mechanisms. While sharing some features with cancers, the Warburg-like metabolism in early epileptogenesis is uniquely split between neurons and astrocytes to achieve an overall novel metabolic reprogramming. This split Warburg metabolic reprogramming triggers an inhibition of AMPK and subsequent activation of mTOR, which is a signature event of epileptogenesis. Interrogation of the mechanism with the metabolic inhibitor 2-deoxyglucose surprisingly demonstrated that Wnt signaling and the resulting metabolic reprogramming lies upstream of mTOR activation in epileptogenesis. To augment the pre-clinical pilocarpine and kainate models, aspects of the proposed mechanisms were also investigated and correlated in a genetic model of constitutive Wnt signaling (deletion of the transcriptional repressor and Wnt pathway inhibitor HBP1). The results from the HBP1-/- mice provide a genetic evidence that Wnt signaling may set the threshold of acquired seizure susceptibility with a similar molecular framework. Using biochemistry and genetics, this paper outlines a new molecular framework of early epileptogenesis and advances a potential molecular platform for refining therapeutic strategies in attenuating recurrent seizures.
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Wang HT, Zhu ZA, Li YY, Lou SS, Yang G, Feng X, Xu W, Huang ZL, Cheng X, Xiong ZQ. CDKL5 deficiency in forebrain glutamatergic neurons results in recurrent spontaneous seizures. Epilepsia 2021; 62:517-528. [PMID: 33400301 DOI: 10.1111/epi.16805] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 12/13/2020] [Accepted: 12/13/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Mutations of the cyclin-dependent kinase-like 5 (CDKL5) gene cause severe neurodevelopmental disorders characterized by intractable epilepsy, intellectual disability, and autism. Multiple mouse models generated for mechanistic studies have exhibited phenotypes similar to some human pathological features, but none of the models has developed one of the major symptoms affecting CDKL5 deficiency disorder (CDD) patients: intractable recurrent seizures. As disrupted neuronal excitation/inhibition balance is closely associated with the activity of glutamatergic and γ-aminobutyric acidergic (GABAergic) neurons, our aim was to study the effect of the loss of CDKL5 in different types of neurons on epilepsy. METHODS Using the Cre-LoxP system, we generated conditional knockout (cKO) mouse lines allowing CDKL5 deficiency in glutamatergic or GABAergic neurons. We employed noninvasive video recording and in vivo electrophysiological approaches to study seizure activity in these Cdkl5 cKO mice. Furthermore, we conducted Timm staining to confirm a morphological alteration, mossy fiber sprouting, which occurs with limbic epilepsy in both human and mouse brains. Finally, we performed whole-cell patch clamp in dentate granule cells to investigate cell-intrinsic properties and synaptic excitatory activity. RESULTS We demonstrate that Emx1- or CamK2α-derived Cdkl5 cKO mice manifest high-frequency spontaneous seizure activities recapitulating the epilepsy of CDD patients, which ultimately led to sudden death in mice. However, Cdkl5 deficiency in GABAergic neurons does not generate such seizures. The seizures were accompanied by typical epileptic features including higher amplitude spikes for epileptiform discharges and abnormal hippocampal mossy fiber sprouting. We also found an increase in spontaneous and miniature excitatory postsynaptic current frequencies but no change in amplitudes in the dentate granule cells of Emx1-cKO mice, indicating enhanced excitatory synaptic activity. SIGNIFICANCE Our study demonstrates that Cdkl5 cKO mice, serving as an animal model to study recurrent spontaneous seizures, have potential value for the pathological study of CDD-related seizures and for therapeutic innovation.
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Affiliation(s)
- Hong-Tao Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, Xinxiang Medical University, Xinxiang, China
| | - Zi-Ai Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yi-Yan Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Sen-Sen Lou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guang Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xue Feng
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wei Xu
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Zhi-Li Huang
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xuewen Cheng
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Qi Xiong
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
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Zhang Z, Wang H, Jin Z, Cai X, Gao N, Cui X, Liu P, Zhang J, Yang S, Yang X. Downregulation of survivin regulates adult hippocampal neurogenesis and apoptosis, and inhibits spatial learning and memory following traumatic brain injury. Neuroscience 2015; 300:219-28. [PMID: 25987205 DOI: 10.1016/j.neuroscience.2015.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/09/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
Abstract
Survivin, a unique member of the inhibitor of the apoptosis protein (IAP) family, has been suggested to play a crucial role in promoting the cell cycle and mediates mitosis during embryonic development. However, the role of survivin following traumatic brain injury (TBI) in adult neurogenesis and apoptosis in the mouse dentate gyrus (DG) remains only partially understood. We adopted adenovirus-mediated RNA interference (RNAi) as a means of suppressing the expression of survivin and observed its effects on adult regeneration and neurological function in mice after brain injury. The mice were subjected to TBI, and the ipsilateral hippocampus was then examined using reverse transcription polymerase chain reaction (RT-PCR) and Western blotting analyses. Brain slices were stained for 5'-bromo-2'-deoxyuridine (BrdU) and doublecortin (DCX). Our data showed that survivin knockdown inhibits the proliferation and differentiation of neural precursor cells (NPCs) in the DG of the hippocampus soon after TBI. Furthermore, downregulation of survivin results in a significant increase in programmed cell death in the DG, as assessed using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and 4',6-diamidino-2-phenylindole (DAPI) double staining. The Morris water maze (MWM) test was adopted to evaluate neurological function, which confirmed that knockdown of survivin worsened the memory capacity that was already compromised following TBI. Survivin in adult mice brains after TBI can be successfully down-regulated by RNAi, which inhibited adult hippocampal neurogenesis, promoted apoptotic cell death, and resulted in a negative role in the recovery of dysfunction following injury.
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Affiliation(s)
- Z Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - H Wang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Z Jin
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - X Cai
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - N Gao
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - X Cui
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - P Liu
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - J Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - S Yang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - X Yang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
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