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Gholami M, Sadegh M, Koroush-Arami M, Norouzi S, Arismani RJ, Asadi E, Amini M, Khodayari N. Targeting memory loss with aspirin, a molecular mechanism perspective for future therapeutic approaches. Inflammopharmacology 2023; 31:2827-2842. [PMID: 37924473 DOI: 10.1007/s10787-023-01347-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/19/2023] [Indexed: 11/06/2023]
Abstract
Acetylsalicylic acid (ASA), also known as aspirin, was discovered in 1897 as an acetylated form of salicylate. It has been widely used for its anti-inflammatory and antiplatelet effects. It is commonly used for its cardiovascular benefits and is prescribed as secondary prophylaxis after a heart attack. Furthermore, low-dose, long-term ASA is used to reduce the risk of heart attack and stroke in individuals without prior cardiovascular disease. Acetylsalicylic acid acts as a non-selective inhibitor of cyclooxygenase (COX), which inhibits the synthesis of prostaglandins and prevents pro-inflammatory cytokines. Findings suggest that targeting cytokines and growth factors could be a potential therapeutic strategy for reducing neuroinflammation and slowing down the progression of dementia. Additionally, prostaglandins contribute to synaptic plasticity and can act as retrograde messengers in synapses. Research has implicated COX-1, one of the isoforms of the enzyme, in neuroinflammation and neurodegenerative disorders. The inhibition of COX-1 might potentially prevent impairments in working memory and reduce neuroinflammation caused by beta-amyloid proteins in some conditions, such as Alzheimer's disease (AD). Cyclooxygenase-2, an inducible form of the enzyme, is expressed in cortical and hippocampal neurons and is associated with long-term synaptic plasticity. The inhibition or knockout of COX-2 has been shown to decrease long-term potentiation, a process involved in memory formation. Studies have also demonstrated that the administration of COX-2 inhibitors impairs cognitive function and memory acquisition and recall in animal models. There remains a debate regarding the effects of aspirin on dementia and cognitive decline. Although some studies suggest a possible protective effect of non-steroidal anti-inflammatory drugs, including aspirin, against the development of AD, others have shown inconsistent evidence. This review provides an overview of the effects of ASA or its active metabolite salicylate on learning, memory, and synaptic plasticity.
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Affiliation(s)
- Masoumeh Gholami
- Department of Physiology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
| | - Mehdi Sadegh
- Department of Physiology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Masoumeh Koroush-Arami
- Department of Neuroscience, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | | | - Rasoul Jafari Arismani
- Department of Urologic Surgery, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Erfan Asadi
- Medical Student, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Mohammad Amini
- Medical Student, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Nahid Khodayari
- Department of Physiology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran
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Fani Maleki A, Cisbani G, Plante MM, Préfontaine P, Laflamme N, Gosselin J, Rivest S. Muramyl dipeptide-mediated immunomodulation on monocyte subsets exerts therapeutic effects in a mouse model of Alzheimer's disease. J Neuroinflammation 2020; 17:218. [PMID: 32698829 PMCID: PMC7376735 DOI: 10.1186/s12974-020-01893-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 07/13/2020] [Indexed: 01/07/2023] Open
Abstract
Background Muramyl dipeptide (MDP) is a component derived from minimal peptidoglycan motif from bacteria, and it is a ligand for the NOD2 receptor. Peripheral administration of MDP converts Ly6Chigh into Ly6Clow monocytes. Previously, we have shown that Ly6Clow monocytes play crucial roles in the pathology of a mouse model of Alzheimer’s disease (AD). However, medications with mild immunomodulatory effects that solely target specific monocyte subsets, without triggering microglial activation, are rare. Methods Three months old APPswe/PS1 transgenic male mice and age-matched C57BL/6 J mice were used for high frequency (2 times/week) over 6 months and low frequency (once a week) over 3 months of intraperitoneally MDP (10 mg/kg) administrations. Flow cytometry analysis of monocyte subsets in blood, and behavioral and postmortem analyses were performed. Results Memory tests showed mild to a strong improvement in memory function, increased expression levels of postsynaptic density protein 95 (PSD95), and low-density lipoprotein receptor-related protein 1 (LRP1), which are involved in synaptic plasticity and amyloid-beta (Aβ) elimination, respectively. In addition, we found monocyte chemoattractant protein-1(MCP-1) levels significantly increased, whereas intercellular adhesion molecule-1(ICAM-1) significantly decreased, and microglial marker (Iba1) did not change in the treatment group compared to the control. In parallel, we discovered elevated cyclooxygenase-2 (COX2) expression levels in the treated group, which might be a positive factor for synaptic activity. Conclusions Our results demonstrate that MDP is beneficial in both the early phase and, to some extent, later phases of the pathology in the mouse model of AD. These data open the way for potential MDP-based medications for AD.
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Affiliation(s)
- Adham Fani Maleki
- Neuroscience Laboratory, CHU de Quebec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Giulia Cisbani
- Neuroscience Laboratory, CHU de Quebec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Marie-Michèle Plante
- Neuroscience Laboratory, CHU de Quebec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Paul Préfontaine
- Neuroscience Laboratory, CHU de Quebec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Nataly Laflamme
- Neuroscience Laboratory, CHU de Quebec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Jean Gosselin
- Laboratory of Innate Immunity, CHU of Quebec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada
| | - Serge Rivest
- Neuroscience Laboratory, CHU de Quebec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec City, QC, G1V 4G2, Canada.
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Guo L, Wei M, Li B, Yun Y, Li G, Sang N. The Role of Cyclooxygenases-2 in Benzo( a)pyrene-Induced Neurotoxicity of Cortical Neurons. Chem Res Toxicol 2020; 33:1364-1373. [PMID: 32115946 DOI: 10.1021/acs.chemrestox.9b00451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
With the help of particulate matter, benzo(a)pyrene (BaP) has become a widely distributed environmental contaminant. In addition to the well-known carcinogenicity, a growing number of studies have focused on the neurotoxicity of BaP, especially on adverse neurobehavioral effects. However, the molecular modulating mechanisms remain unclear. In this paper, we confirmed that BaP exposure produced a neuronal insult via its metabolite benzo(a)pyrene diol epoxide (BPDE) on the primary cultured cortical neuron in vitro and mice in vivo models, and the effects were largely achieved by activating cyclooxygenases-2 (COX-2) enhancement. Also, the action of BaP on elevating COX-2 was initiated by BPDE firmly binding to the active pockets of COX-2, then followed by the production of prostaglandin E2 (PGE2) and upregulation of its EP2 and EP4 receptors, finally stimulating the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signaling pathway. Our results reveal a mechanistic association underlying BaP exposure and increased risk for neurological dysfunction and clarify the ways to prevent and treat brain injuries in polluted environments.
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Affiliation(s)
- Lin Guo
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, P.R. China
| | - Mengjiao Wei
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, P.R. China
| | - Ben Li
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, P.R. China
| | - Yang Yun
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, P.R. China
| | - Guangke Li
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, P.R. China
| | - Nan Sang
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, P.R. China
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Matsuda S, Nishikawa H, Fukatsu A, Kurokawa Y, Tsubota M, Sekiguchi F, Tokuyama S, Kawabata A. NNC 55-0396, a T-type calcium channel blocker, protects against the brain injury induced by middle cerebral artery occlusion and reperfusion in mice. J Pharmacol Sci 2019; 140:193-196. [PMID: 31235271 DOI: 10.1016/j.jphs.2019.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 02/01/2019] [Accepted: 02/12/2019] [Indexed: 12/01/2022] Open
Abstract
We tested whether NNC 55-0396 (NNC), a T-type calcium channel (T-channel) blocker, reduces the brain injury caused by middle cerebral artery occlusion and reperfusion (MCAO/R) in mice. NNC, administered i.c.v. before the occlusion, greatly reduced the MCAO/R-induced brain infarct and neurological dysfunctions, although it, given toward the end of occlusion, was less effective. Systemic administration of NNC before the occlusion also attenuated the infarct and neurological dysfunctions. Our data imply that blood-brain-barrier-permeable T-channel blockers such as NNC are capable of reducing MCAO/R-induced brain damage, and that T-channels are involved in neuronal damage induced by ischemia rather than reperfusion.
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Affiliation(s)
- Sachi Matsuda
- Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University (formerly Kinki University), Higashi-Osaka 577-8502, Japan
| | - Hiroyuki Nishikawa
- Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University (formerly Kinki University), Higashi-Osaka 577-8502, Japan
| | - Anna Fukatsu
- Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University (formerly Kinki University), Higashi-Osaka 577-8502, Japan
| | - Yuko Kurokawa
- Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University (formerly Kinki University), Higashi-Osaka 577-8502, Japan
| | - Maho Tsubota
- Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University (formerly Kinki University), Higashi-Osaka 577-8502, Japan
| | - Fumiko Sekiguchi
- Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University (formerly Kinki University), Higashi-Osaka 577-8502, Japan
| | - Shogo Tokuyama
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 650-8586, Japan
| | - Atsufumi Kawabata
- Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University (formerly Kinki University), Higashi-Osaka 577-8502, Japan.
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Zhou M, Chen S, Peng P, Gu Z, Yu J, Zhao G, Deng Y. Dulaglutide ameliorates STZ induced AD-like impairment of learning and memory ability by modulating hyperphosphorylation of tau and NFs through GSK3β. Biochem Biophys Res Commun 2019; 511:154-160. [PMID: 30773255 DOI: 10.1016/j.bbrc.2019.01.103] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 01/24/2019] [Indexed: 01/08/2023]
Abstract
Dulaglutide, a novel long-acting glucagon-like peptide 1 (GLP-1) receptor agonist, is an incretin mimetic approved for type 2 diabetes mellitus (T2DM) treatment. Alzheimer's disease (AD) is called type 3 diabetes. The aim of this study is to explore the effects of dulaglutide on the learning and memory impairment in AD mice induced by injection of streptozocin (STZ) via intracerebroventricularly (i.c.v.). 32 male C57/BL6 mice were randomly divided into four groups: control group (CON); AD model group (STZ); dulaglutide treated (Dul); dulaglutide and exendin(9-39) (Ex). Western blotting was used to detect the levels of phosphorylated tau, neurofilament (NFs) proteins and phosphorylated PI3K/AKT/GSK3β signaling pathway. Morris water maze (MWM) test was used to assess the spatial learning and memory ability. The results displayed that the hyperphosphorylation of tau and NFs were increased in the STZ and Ex groups compared to the control and Dul groups. Dulaglutide also significantly shortened the escape latency and increased the number of hidden platform crossings in MWM test. The effects of dulaglutide on decreasing the hyperphosphorylation of tau and NFs proteins through improving the PI3K/AKT/GSK3β signaling pathway may be related to its protective effects on impairment of AD-like learning and memory.
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Affiliation(s)
- Mei Zhou
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Shuyi Chen
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Peng Peng
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Zhongya Gu
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Jing Yu
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Gang Zhao
- Department of Pathology, Tianjin Tumor Hospital, Tianjin, China
| | - Yanqiu Deng
- Pathophysiology Department, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.
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Duque A, Vinader-Caerols C, Monleón S. Indomethacin counteracts the effects of chronic social defeat stress on emotional but not recognition memory in mice. PLoS One 2017; 12:e0173182. [PMID: 28278165 PMCID: PMC5344348 DOI: 10.1371/journal.pone.0173182] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/16/2017] [Indexed: 12/15/2022] Open
Abstract
We have previously observed the impairing effects of chronic social defeat stress (CSDS) on emotional memory in mice. Given the relation between stress and inflammatory processes, we sought to study the effectiveness of the anti-inflammatory indomethacin in reversing the detrimental effects of CSDS on emotional memory in mice. The effects of CSDS and indomethacin on recognition memory were also evaluated. Male CD1 mice were randomly divided into four groups: non-stressed + saline (NS+SAL); non-stressed + indomethacin (NS+IND); stressed + saline (S+SAL); and stressed + indomethacin (S+IND). Stressed animals were exposed to a daily 10 min agonistic confrontation (CSDS) for 20 days. All subjects were treated daily with saline or indomethacin (10 mg/kg, i.p.). 24 h after the CSDS period, all the mice were evaluated in a social interaction test to distinguish between those that were resilient or susceptible to social stress. All subjects (n = 10–12 per group) were then evaluated in inhibitory avoidance (IA), novel object recognition (NOR), elevated plus maze and hot plate tests. As in control animals (NS+SAL group), IA learning was observed in the resilient groups, as well as in the susceptible mice treated with indomethacin (S+IND group). Recognition memory was observed in the non-stressed and the resilient mice, but not in the susceptible animals. Also, stressed mice exhibited higher anxiety levels. No significant differences were observed in locomotor activity or analgesia. In conclusion, CSDS induces anxiety in post-pubertal mice and impairs emotional and recognition memory in the susceptible subjects. The effects of CSDS on emotional memory, but not on recognition memory and anxiety, are reversed by indomethacin. Moreover, memory impairment is not secondary to the effects of CSDS on locomotor activity, emotionality or pain sensitivity.
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Affiliation(s)
- Aránzazu Duque
- Department of Psychobiology, University of Valencia, Valencia, Spain
| | | | - Santiago Monleón
- Department of Psychobiology, University of Valencia, Valencia, Spain
- * E-mail:
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Hermann PM, Park D, Beaulieu E, Wildering WC. Evidence for inflammation-mediated memory dysfunction in gastropods: putative PLA2 and COX inhibitors abolish long-term memory failure induced by systemic immune challenges. BMC Neurosci 2013; 14:83. [PMID: 23915010 PMCID: PMC3750374 DOI: 10.1186/1471-2202-14-83] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 08/02/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Previous studies associate lipid peroxidation with long-term memory (LTM) failure in a gastropod model (Lymnaea stagnalis) of associative learning and memory. This process involves activation of Phospholipase A2 (PLA2), an enzyme mediating the release of fatty acids such as arachidonic acid that form the precursor for a variety of pro-inflammatory lipid metabolites. This study investigated the effect of biologically realistic challenges of L. stagnalis host defense response system on LTM function and potential involvement of PLA2, COX and LOX therein. RESULTS Systemic immune challenges by means of β-glucan laminarin injections induced elevated H2O2 release from L. stagnalis circulatory immune cells within 3 hrs of treatment. This effect dissipated within 24 hrs after treatment. Laminarin exposure has no direct effect on neuronal activity. Laminarin injections disrupted LTM formation if training followed within 1 hr after injection but had no behavioural impact if training started 24 hrs after treatment. Intermediate term memory was not affected by laminarin injection. Chemosensory and motor functions underpinning the feeding response involved in this learning model were not affected by laminarin injection. Laminarin's suppression of LTM induction was reversed by treatment with aristolochic acid, a PLA2 inhibitor, or indomethacin, a putative COX inhibitor, but not by treatment with nordihydro-guaiaretic acid, a putative LOX inhibitor. CONCLUSIONS A systemic immune challenge administered shortly before behavioural training impairs associative LTM function in our model that can be countered with putative inhibitors of PLA2 and COX, but not LOX. As such, this study establishes a mechanistic link between the state of activity of this gastropod's innate immune system and higher order nervous system function. Our findings underwrite the rapidly expanding view of neuroinflammatory processes as a fundamental, evolutionary conserved cause of cognitive and other nervous system disorders.
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Affiliation(s)
- Petra M Hermann
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB T2N 1N4, Canada
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Wu A, Ying Z, Gomez-Pinilla F. The salutary effects of DHA dietary supplementation on cognition, neuroplasticity, and membrane homeostasis after brain trauma. J Neurotrauma 2011; 28:2113-22. [PMID: 21851229 DOI: 10.1089/neu.2011.1872] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The pathology of traumatic brain injury (TBI) is characterized by the decreased capacity of neurons to metabolize energy and sustain synaptic function, likely resulting in cognitive and emotional disorders. Based on the broad nature of the pathology, we have assessed the potential of the omega-3 fatty acid docosahexaenoic acid (DHA) to counteract the effects of concussive injury on important aspects of neuronal function and cognition. Fluid percussion injury (FPI) or sham injury was performed, and rats were then maintained on a diet high in DHA (1.2% DHA) for 12 days. We found that DHA supplementation, which elevates brain DHA content, normalized levels of brain-derived neurotrophic factor (BDNF), synapsin I (Syn-1), cAMP-responsive element-binding protein (CREB), and calcium/calmodulin-dependent kinase II (CaMKII), and improved learning ability in FPI rats. It is known that BDNF facilitates synaptic transmission and learning ability by modulating Syn-I, CREB, and CaMKII signaling. The DHA diet also counteracted the FPI-reduced manganese superoxide dismutase (SOD) and Sir2 (a NAD+-dependent deacetylase). Given the involvement of SOD and Sir2 in promoting metabolic homeostasis, DHA may help the injured brain by providing resistance to oxidative stress. Furthermore, DHA normalized levels of calcium-independent phospholipase A2 (iPLA2) and syntaxin-3, which may help preserve membrane homeostasis and function after FPI. The overall results emphasize the potential of dietary DHA to counteract broad and fundamental aspects of TBI pathology that may translate into preserved cognitive capacity.
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Affiliation(s)
- Aiguo Wu
- Department of Integrative Biology and Physiology, University of California at Los Angeles (UCLA), Los Angeles, California 90095, USA
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Sharma S, Ying Z, Gomez-Pinilla F. A pyrazole curcumin derivative restores membrane homeostasis disrupted after brain trauma. Exp Neurol 2010; 226:191-9. [PMID: 20816821 DOI: 10.1016/j.expneurol.2010.08.027] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/18/2010] [Accepted: 08/22/2010] [Indexed: 11/29/2022]
Abstract
We have assessed potential mechanisms associated with the deleterious effects of TBI on the integrity of plasma membranes in the hippocampus, together with consequences for behavioral function. In addition, we have investigated the efficacy of a dietary intervention based on a pyrazole curcumin derivative with demonstrated bioactivity and brain absorption, to re-establish membrane integrity. We report that moderate fluid percussion injury (FPI) increases levels of 4-Hydroxynonenal (HNE), an intermediary for the harmful effects of lipid peroxidation on neurons. A more direct action of FPI on membrane homeostasis was evidenced by a reduction in calcium-independent phospholipase A2 (iPLA₂) important for metabolism of membrane phospholipids such as DHA, and an increase in the fatty acid transport protein (FATP) involved in translocation of long-chain fatty acids across the membrane. A potential association between membrane disruption and neuronal function was suggested by reduced levels of the NR2B subunit of the transmembrane NMDA receptor, in association with changes in iPLA2 and syntaxin-3 (STX-3, involved in the action of membrane DHA on synaptic membrane expansion). In addition, changes in iPLA2, 4-HNE, and STX-3 were proportional to reduced performance in a spatial learning task. In turn, the dietary supplementation with the curcumin derivative counteracted all the effects of FPI, effectively restoring parameters of membrane homeostasis. Results show the potential of the curcumin derivative to promote membrane homeostasis following TBI, which may foster a new line of non-invasive therapeutic treatments for TBI patients by endogenous up-regulation of molecules important for neural repair and plasticity.
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Affiliation(s)
- Sandeep Sharma
- Department of Integrative Biology and Physiology, University of California, LA, CA 90095, USA
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Schaeffer EL, Forlenza OV, Gattaz WF. Phospholipase A2 activation as a therapeutic approach for cognitive enhancement in early-stage Alzheimer disease. Psychopharmacology (Berl) 2009; 202:37-51. [PMID: 18853146 DOI: 10.1007/s00213-008-1351-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 09/10/2008] [Indexed: 11/29/2022]
Abstract
RATIONALE Alzheimer disease (AD) is the leading cause of dementia in the elderly and has no known cure. Evidence suggests that reduced activity of specific subtypes of intracellular phospholipases A2 (cPLA2 and iPLA2) is an early event in AD and may contribute to memory impairment and neuropathology in the disease. OBJECTIVE The objective of this study was to review the literature focusing on the therapeutic role of PLA2 stimulation by cognitive training and positive modulators, or of supplementation with arachidonic acid (PLA2 product) in facilitating memory function and synaptic transmission and plasticity in either research animals or human subjects. METHODS MEDLINE database was searched (no date restrictions) for published articles using the keywords Alzheimer disease (mild, moderate, severe), mild cognitive impairment, healthy elderly, rats, mice, phospholipase A(2), phospholipid metabolism, phosphatidylcholine, arachidonic acid, cognitive training, learning, memory, long-term potentiation, protein kinases, dietary lipid compounds, cell proliferation, neurogenesis, and neuritogenesis. Reference lists of the identified articles were checked to select additional studies of interest. RESULTS Overall, the data suggest that PLA2 activation is induced in the healthy brain during learning and memory. Furthermore, learning seems to regulate endogenous neurogenesis, which has been observed in AD brains. Finally, PLA2 appears to be implicated in homeostatic processes related to neurite outgrowth and differentiation in both neurodevelopmental processes and response to neuronal injury. CONCLUSION The use of positive modulators of PLA2 (especially of cPLA2 and iPLA2) or supplementation with dietary lipid compounds (e.g., arachidonic acid) in combination with cognitive training could be a valuable therapeutic strategy for cognitive enhancement in early-stage AD.
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Affiliation(s)
- Evelin L Schaeffer
- Laboratory of Neuroscience (LIM-27), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, Rua Dr. Ovídio Pires de Campos 785, 05403-010 São Paulo, SP, Brazil.
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Yang H, Zhang J, Breyer RM, Chen C. Altered hippocampal long-term synaptic plasticity in mice deficient in the PGE2 EP2 receptor. J Neurochem 2008; 108:295-304. [PMID: 19012750 DOI: 10.1111/j.1471-4159.2008.05766.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Our laboratory demonstrated previously that PGE2-induced modulation of hippocampal synaptic transmission is via a pre-synaptic PGE2 EP2 receptor. However, little is known about whether the EP2 receptor is involved in hippocampal long-term synaptic plasticity and cognitive function. Here we show that long-term potentiation at the hippocampal perforant path synapses was impaired in mice deficient in the EP2 (KO), while membrane excitability and passive properties in granule neurons were normal. Importantly, escape latency in the water maze in EP2 KO was longer than that in age-matched EP2 wild-type littermates (WT). We also observed that long-term potentiation was potentiated in EP2 WT animals that received lipopolysaccharide (LPS, i.p.), but not in EP2 KO. Bath application of PGE2 or butaprost, an EP2 receptor agonist, increased synaptic transmission and decreased paired-pulses ratio in EP2 WT mice, but failed to induce the changes in EP2 KO mice. Meanwhile, synaptic transmission was elevated by application of forskolin, an adenylyl cyclase activator, both in EP2 KO and WT animals. In addition, the PGE2-enhanced synaptic transmission was significantly attenuated by application of PKA, IP3 or MAPK inhibitors in EP2 WT animals. Our results show that hippocampal long-term synaptic plasticity is impaired in mice deficient in the EP2, suggesting that PGE2-EP2 signaling is important for hippocampal long-term synaptic plasticity and cognitive function.
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Affiliation(s)
- Hongwei Yang
- Neuroscience Center of Excellence, LSU Health Sciences Center, New Orleans, Louisiana, USA
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Schaeffer EL, Zorrón Pu L, Gagliotti DAM, Gattaz WF. Conditioning training and retrieval increase phospholipase A(2) activity in the cerebral cortex of rats. J Neural Transm (Vienna) 2008; 116:41-50. [PMID: 18982240 DOI: 10.1007/s00702-008-0133-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 10/04/2008] [Indexed: 12/25/2022]
Abstract
In rats, phospholipase A(2) (PLA(2)) activity was found to be increased in the hippocampus immediately after training and retrieval of a contextual fear conditioning paradigm (step-down inhibitory avoidance [IA] task). In the present study we investigated whether PLA(2) is also activated in the cerebral cortex of rats in association with contextual fear learning and retrieval. We observed that IA training induces a rapid (immediately after training) and long-lasting (3 h after training) activation of PLA(2) in both frontal and parietal cortices. However, immediately after retrieval (measured 24 h after training), PLA(2) activity was increased just in the parietal cortex. These findings suggest that PLA(2) activity is differentially required in the frontal and parietal cortices for the mechanisms of contextual learning and retrieval. Because reduced brain PLA(2) activity has been reported in Alzheimer disease, our results suggest that stimulation of PLA(2) activity may offer new treatment strategies for this disease.
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Affiliation(s)
- E L Schaeffer
- Department and Institute of Psychiatry, University of São Paulo, Rua Doutor Ovídio Pires de Campos, São Paulo, SP, Brazil.
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Decreased phospholipase A2 activity in cerebrospinal fluid of patients with dementia. J Neural Transm (Vienna) 2008; 115:1173-9. [PMID: 18584113 DOI: 10.1007/s00702-008-0081-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2008] [Accepted: 06/05/2008] [Indexed: 10/21/2022]
Abstract
Phospholipase A2 (PLA2) is involved in important aspects of dementia, for example neurotransmission and memory processing, membrane function, choline availability, and antioxidative defense. Reduced PLA2-activity has been reported so far in blood samples and postmortem neuronal tissue in Alzheimer disease. For the first time, we studied PLA2 in cerebrospinal fluid (CSF) in Alzheimer disease (AD), vascular (VD), and mixed Alzheimer/vascular dementia (MD). Intracellular PLA2 was assessed in CSF of 16 AD, 12 VD, 15 MD patients, and 19 healthy control subjects. A fluorometric assay was applied using the PLA2-specific substrate NBDC6-HPC. Significantly reduced PLA2 activity was not only found in AD, but also in VD and MD. This finding was independent of demographic co-variates and medication. PLA2 results in CSF corroborate previous findings of impaired PLA2 function in Alzheimer's disease and extend these to patients with VD. They are likely to reflect an involvement of PLA2 impairment in a variety of pathomechanisms crucial in different dementia subtypes, in which disruption of cholinergic neurotransmission and disturbance of intact membrane function appear to be the key mechanisms.
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Abstract
Cyclooxygenase-2 (COX-2), a rate-limiting enzyme converting arachidonic acid to prostaglandins and a key player in neuroinflammation, has been implicated in the pathogenesis of neurodegenerative diseases such as multiple sclerosis, Parkinson's and Alzheimer's diseases, and in traumatic brain injury- and ischemia-induced neuronal damage, and epileptogenesis. Accumulated information suggests that the contribution of COX-2 to neuropathology is associated with its involvement in synaptic modification. Inhibition or elevation of COX-2 has been shown to suppress or enhance excitatory glutamatergic neurotransmission and long-term potentiation (LTP). These events are mainly mediated via PGE(2), the predominant reaction product of COX-2, and the PGE(2) subtype 2 receptor (EP(2))-protein kinase A pathway. Recent evidence shows that endogenous cannabinoids are substrates for COX-2 and can be oxygenated by COX-2 to form new classes of prostaglandins (prostaglandin glycerol esters and prostaglandin ethanolamides). These COX-2 oxidative metabolites of endocannabinoids, as novel signaling mediators, modulate synaptic transmission and plasticity and cause neurodegeneration. The actions of these COX-2 metabolites are likely mediated by mitogen-activated protein kinase (MAPK) and inositol 1,4,5-trisphosphate (IP(3)) signal transduction pathways. These discoveries suggest that the contributions of COX-2 to neurotransmission and brain malfunction result not only from its conversion of arachidonic acid to classic prostaglandins but also from its oxidative metabolism of endocannabinoids to novel prostaglandins. Thus, elucidation of COX-2 in synaptic signaling may provide a mechanistic basis for designing new drugs aimed at preventing, treating or alleviating neuroinflammation-associated neurological disorders.
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Affiliation(s)
- Hongwei Yang
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.
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Cholinergic and glutamatergic alterations beginning at the early stages of Alzheimer disease: participation of the phospholipase A2 enzyme. Psychopharmacology (Berl) 2008; 198:1-27. [PMID: 18392810 DOI: 10.1007/s00213-008-1092-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Accepted: 01/28/2008] [Indexed: 12/14/2022]
Abstract
RATIONALE Alzheimer disease (AD), a progressive neurodegenerative disorder, is the leading cause of dementia in the elderly. A combination of cholinergic and glutamatergic dysfunction appears to underlie the symptomatology of AD, and thus, treatment strategies should address impairments in both systems. Evidence suggests the involvement of phospholipase A(2) (PLA(2)) enzyme in memory impairment and neurodegeneration in AD via actions on both cholinergic and glutamatergic systems. OBJECTIVES To review cholinergic and glutamatergic alterations underlying cognitive impairment and neuropathology in AD and attempt to link PLA(2) with such alterations. METHODS Medline databases were searched (no date restrictions) for published articles with links among the terms Alzheimer disease (mild, moderate, severe), mild cognitive impairment, choline acetyltransferase, acetylcholinesterase, NGF, NGF receptor, muscarinic receptor, nicotinic receptor, NMDA, AMPA, metabotropic glutamate receptor, atrophy, glucose metabolism, phospholipid metabolism, sphingolipid, membrane fluidity, phospholipase A(2), arachidonic acid, attention, memory, long-term potentiation, beta-amyloid, tau, inflammation, and reactive species. Reference lists of the identified articles were checked to identify additional studies of interest. RESULTS Overall, results suggest the hypothesis that persistent inhibition of cPLA(2) and iPLA(2) isoforms at early stages of AD may play a central role in memory deficits and beta-amyloid production through down-regulation of cholinergic and glutamate receptors. As the disease progresses, beta-amyloid induced up-regulation of cPLA(2) and sPLA(2) isoforms may play critical roles in inflammation and oxidative stress, thus participating in the neurodegenerative process. CONCLUSION Activation and inhibition of specific PLA(2) isoforms at different stages of AD could be of therapeutic importance and delay cognitive dysfunction and neurodegeneration.
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Caldwell HK, Lee HJ, Macbeth AH, Young WS. Vasopressin: behavioral roles of an "original" neuropeptide. Prog Neurobiol 2007; 84:1-24. [PMID: 18053631 DOI: 10.1016/j.pneurobio.2007.10.007] [Citation(s) in RCA: 328] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 10/24/2007] [Accepted: 10/24/2007] [Indexed: 01/07/2023]
Abstract
Vasopressin (Avp) is mainly synthesized in the magnocellular cells of the hypothalamic supraoptic (SON) and paraventricular nuclei (PVN) whose axons project to the posterior pituitary. Avp is then released into the blood stream upon appropriate stimulation (e.g., hemorrhage or dehydration) to act at the kidneys and blood vessels. The brain also contains several populations of smaller, parvocellular neurons whose projections remain within the brain. These populations are located within the PVN, bed nucleus of the stria terminalis (BNST), medial amygdala (MeA) and suprachiasmatic nucleus (SCN). Since the 1950s, research examining the roles of Avp in the brain and periphery has intensified. The development of specific agonists and antagonists for Avp receptors has allowed for a better elucidation of its contributions to physiology and behavior. Anatomical, pharmacological and transgenic, including "knockout," animal studies have implicated Avp in the regulation of various social behaviors across species. Avp plays a prominent role in the regulation of aggression, generally of facilitating or promoting it. Affiliation and certain aspects of pair-bonding are also influenced by Avp. Memory, one of the first brain functions of Avp that was investigated, has been implicated especially strongly in social recognition. The roles of Avp in stress, anxiety, and depressive states are areas of active exploration. In this review, we concentrate on the scientific progress that has been made in understanding the role of Avp in regulating these and other behaviors across species. We also discuss the implications for human behavior.
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Affiliation(s)
- Heather K Caldwell
- Section on Neural Gene Expression, NIMH, NIH, DHHS, Bethesda, MD 20892, United States
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Hein AM, Stutzman DL, Bland ST, Barrientos RM, Watkins LR, Rudy JW, Maier SF. Prostaglandins are necessary and sufficient to induce contextual fear learning impairments after interleukin-1 beta injections into the dorsal hippocampus. Neuroscience 2007; 150:754-63. [PMID: 18035502 DOI: 10.1016/j.neuroscience.2007.10.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 10/01/2007] [Accepted: 10/12/2007] [Indexed: 11/19/2022]
Abstract
The intra-hippocampal administration of interleukin-1beta (IL-1beta) as well as the induction of elevated but physiological levels of IL-1beta within the hippocampus interferes with the formation of long-term memory. There is evidence suggesting that the induction of prostaglandin (PG) formation by IL-1beta is involved in impairments in working and spatial memory following IL-1beta. The present experiments extend these findings by showing that PGs are responsible for memory deficits in contextual fear conditioning that occur following IL-1beta injection into the dorsal hippocampus of Sprague-Dawley rats. Cyclooxygenase (COX) inhibition blocked the disruption in contextual fear conditioning produced by IL-1beta and COX inhibition alone also disrupted contextual memory, suggesting an inverted U-shaped relationship between PG levels and memory. In addition to demonstrating the necessity of PGs in IL-1beta-mediated memory deficits, we also show that PGs injected directly into the dorsal hippocampus are sufficient to impair context memory and significantly reduce post-conditioning levels of BDNF within the hippocampus, suggesting a possible mechanism for the memory-impairing effects of PGs.
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Affiliation(s)
- A M Hein
- Department of Psychology and The Center for Neuroscience, University of Colorado at Boulder, Campus Box 345, Boulder, CO 80309, USA.
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