1
|
Orock A, Logan S, Deak F. Age-Related Cognitive Impairment: Role of Reduced Synaptobrevin-2 Levels in Deficits of Memory and Synaptic Plasticity. J Gerontol A Biol Sci Med Sci 2021; 75:1624-1632. [PMID: 30649208 DOI: 10.1093/gerona/glz013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Indexed: 01/02/2023] Open
Abstract
Cognitive impairment in the aging population is quickly becoming a health care priority, for which currently no disease-modifying treatment is available. Multiple domains of cognition decline with age even in the absence of neurodegenerative diseases. The cellular and molecular changes leading to cognitive decline with age remain elusive. Synaptobrevin-2 (Syb2), the major vesicular SNAP receptor protein, highly expressed in the cerebral cortex and hippocampus, is essential for synaptic transmission. We have analyzed Syb2 protein levels in mice and found a decrease with age. To investigate the functional consequences of lower Syb2 expression, we have used adult Syb2 heterozygous mice (Syb2+/-) with reduced Syb2 levels. This allowed us to mimic the age-related decrease of Syb2 in the brain in order to selectively test its effects on learning and memory. Our results show that Syb2+/- animals have impaired learning and memory skills and they perform worse with age in the radial arm water maze assay. Syb2+/- hippocampal neurons have reduced synaptic plasticity with reduced release probability and impaired long-term potentiation in the CA1 region. Syb2+/- neurons also have lower vesicular release rates when compared to WT controls. These results indicate that reduced Syb2 expression with age is sufficient to cause cognitive impairment.
Collapse
Affiliation(s)
- Albert Orock
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Sreemathi Logan
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Ferenc Deak
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City.,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City.,Department of Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City
| |
Collapse
|
2
|
Pharmacological upregulation of GLT-1 alleviates the cognitive impairments in the animal model of temporal lobe epilepsy. PLoS One 2021; 16:e0246068. [PMID: 33507976 PMCID: PMC7842975 DOI: 10.1371/journal.pone.0246068] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 01/12/2021] [Indexed: 02/07/2023] Open
Abstract
It is known that hippocampal epileptogenesis is accompanied by hyperexcitability, glutamate-related neuronal dysfunctions and consequently cognitive deficits. However, the neuroprotective role of astrocytic glutamate uptake through the Glutamate Transporter-1 (GLT-1) remains to be unknown in these processes. Therefore, to assess the effect of glutamate uptake, pharmacological upregulation of GLT-1 using ceftriaxone administration (200 mg/kg/day, i.p, 5 days) was utilized in Li-PIL animal models of temporal lobe epilepsy (TLE). Glutamate concentration and glutamine synthetase activity were analyzed using biochemical assays. In addition, GLT-1 gene expression was assessed by RT-qPCR. Finally, cognitive function was studied using Morris water maze (MWM) test and novel object recognition task (NORT). Our results demonstrated that the acute phase of epileptogenesis (first 72 hours after Status Epilepticus) was accompanied by an increase in the hippocampal glutamate and downregulation of GLT-1 mRNA expression compared to controls. Ceftriaxone administration in epileptic animals led to a reduction of glutamate along with elevation of the level of glutamine synthetase activity and GLT-1 expression in the acute phase. In the chronic phase of epileptogenesis (4 weeks after Status Epilepticus), glutamate levels and GLT-1 expression were decreased compared to controls. Ceftriaxone treatment increased the levels of GLT-1 expression. Furthermore, impaired learning and memory ability in the chronic phase of epileptogenesis was rescued by Ceftriaxone administration. This study shows that astrocytic glutamate uptake can profoundly impact the processes of hippocampal epileptogenesis through the reduction of glutamate-induced excitotoxicity and consequently rescuing of cognitive deficits caused by epilepsy.
Collapse
|
3
|
Schulze F, Müller S, Guli X, Schumann L, Brehme H, Riffert T, Rohde M, Goerss D, Rackow S, Einsle A, Kirschstein T, Köhling R. CK2 Inhibition Prior to Status Epilepticus Persistently Enhances K Ca2 Function in CA1 Which Slows Down Disease Progression. Front Cell Neurosci 2020; 14:33. [PMID: 32174814 PMCID: PMC7054465 DOI: 10.3389/fncel.2020.00033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/04/2020] [Indexed: 12/19/2022] Open
Abstract
Purpose Epilepsy therapy is currently based on anti-seizure drugs that do not modify the course of the disease, i.e., they are not anti-epileptogenic in nature. Previously, we observed that in vivo casein kinase 2 (CK2) inhibition with 4,5,6,7-tetrabromotriazole (TBB) had anti-epileptogenic effects in the acute epilepsy slice model. Methods Here, we pretreated rats with TBB in vivo prior to the establishment of a pilocarpine-induced status epilepticus (SE) in order to analyze the long-term sequelae of such a preventive TBB administration. Results We found that TBB pretreatment delayed onset of seizures after pilocarpine and slowed down disease progression during epileptogenesis. This was accompanied with a reduced proportion of burst firing neurons in the CA1 area. Western blot analyses demonstrated that CA1 tissue from TBB-pretreated epileptic animals contained significantly less CK2 than TBB-pretreated controls. On the transcriptional level, TBB pretreatment led to differential gene expression changes of KCa2.2, but also of HCN1 and HCN3 channels. Thus, in the presence of the HCN channel blocker ZD7288, pretreatment with TBB rescued the afterhyperpolarizing potential (AHP) as well as spike frequency adaptation in epileptic animals, both of which are prominent functions of KCa2 channels. Conclusion These data indicate that TBB pretreatment prior to SE slows down disease progression during epileptogenesis involving increased KCa2 function, probably due to a persistently decreased CK2 protein expression.
Collapse
Affiliation(s)
- Felix Schulze
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Steffen Müller
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Xiati Guli
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Lukas Schumann
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Hannes Brehme
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Till Riffert
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Marco Rohde
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Doreen Goerss
- Department of Psychosomatic Medicine, Rostock University Medical Center, Rostock, Germany.,German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Simone Rackow
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Anne Einsle
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.,Center of Transdisciplinary Neurosciences Rostock, University of Rostock, Rostock, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.,Center of Transdisciplinary Neurosciences Rostock, University of Rostock, Rostock, Germany
| |
Collapse
|