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Yuliani T, Lobentanzer S, Klein J. Central cholinergic function and metabolic changes in streptozotocin-induced rat brain injury. J Neurochem 2020; 158:1307-1319. [PMID: 33448390 DOI: 10.1111/jnc.15155] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 11/29/2022]
Abstract
As glucose hypometabolism in the brain is an early sign of Alzheimer´s dementia (AD), the diabetogenic drug streptozotocin (STZ) has been used to induce Alzheimer-like pathology in rat brain by intracereboventricular injection (icv-STZ). However, many details of the pathological mechanism of STZ in this AD model remain unclear. Here, we report metabolic and cholinergic effects of icv-STZ using microdialysis in freely moving animals. We found that icv-STZ at a dose of 3 mg/kg (2 × 1.5 mg/kg) causes overt toxicity reflected in body weight loss. Three weeks after STZ administration, histological examination revealed a high number of glial fibrillary acidic protein reactive cells in the hippocampus, accompanied by Fluoro-Jade C-positive cells in the CA1 region. Glucose and lactate levels in microdialysates were unchanged, but mitochondrial respiration measured ex vivo was reduced by 9%-15%. High-affinity choline uptake, choline acetyltransferase, and acetylcholine esterase (AChE) activities in the hippocampus were reduced by 16%, 28%, and 30%, respectively. Importantly, extracellular acetylcholine (ACh) levels in the hippocampus were unchanged and responded to behavioral and pharmacological challenges. In comparison, extracellular ACh levels and cholinergic parameters in the striatum were unchanged or slightly increased. We conclude that the icv-STZ model poorly reflects central cholinergic dysfunction, an important characteristic of dementia. The icv-STZ model may be more aptly described as an animal model of hippocampal gliosis.
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Affiliation(s)
- Tri Yuliani
- Institute of Pharmacology and Clinical Pharmacy, College of Pharmacy, Goethe University, Frankfurt am Main, Germany.,Research Center for Chemistry, Indonesian Institute of Sciences (LIPI), Tangerang Selatan, Banten, Indonesia
| | - Sebastian Lobentanzer
- Institute of Pharmacology and Clinical Pharmacy, College of Pharmacy, Goethe University, Frankfurt am Main, Germany
| | - Jochen Klein
- Institute of Pharmacology and Clinical Pharmacy, College of Pharmacy, Goethe University, Frankfurt am Main, Germany
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Li J, Chen Y, Zhang X, Ye S, Yi J, Chen Q, Liu Q. Inhibition of acetylcholinesterase attenuated retinal inflammation via suppressing NF-κB activation. Exp Eye Res 2020; 195:108003. [PMID: 32184102 DOI: 10.1016/j.exer.2020.108003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 01/10/2020] [Accepted: 03/11/2020] [Indexed: 11/29/2022]
Abstract
Elevated inflammatory cytokines contribute to the pathogenesis of various retinal diseases such as diabetic retinopathy, retinal vasculitis and retinitis. However, the underlying mechanism of retinal inflammation remains largely unknown. Recent studies demonstrated that acetylcholinesterase (ACHE) is an inflammatory indicator in central neural system. This study was aimed to dissect the role of ACHE in retinal inflammation, and its mechanism of action. Retinal inflammation was induced by intravitreal injection of tumor necrosis factor-α (TNF-α) in heterozygous ACHE knockdown mice (ACHE+/-) and wild type mice (ACHE+/+). Donepezil, a well-known ACHE inhibitor, was administrated by daily gavage. Expression of ACHE and intercellular adherent molecule-1 (ICAM-1), infiltration of CD11b+ inflammatory cells, retinal leukostasis and vascular leakage was determined in both ACHE+/- and ACHE+/+ mice. ARPE-19 cells, a human retinal pigment epithelial cell line, were cultured for in vitro assay. Knockdown of ACHE was achieved by lipofectamine-mediated siRNA transfection and pharmaceutical suppression of ACHE was manipulated by donepezil. Cellular expression and distribution of ACHE, ICAM-1, and phosphorylation of NF-κB, IκB and IKKα/β were detected by western-blot analysis or immunocytochemistry. Retinal expression of ACHE was dramatically upregulated, in parallel with increased ICAM-1 expression, enhanced leukostasis and augmented CD11b+ inflammatory cell infiltration as well as vascular hyperpermeability in ACHE+/+ mice injected with TNF-α. However, TNF-α-injected ACHE+/- mice showed lower level of ICAM-1, less leukostasis and fewer infiltrated CD11b+ cells. Moreover, TNF-α-induced retinal vascular leakage was significantly reduced in ACHE+/- mice. Similarly, TNF-α-induced retinal inflammatory response were also attenuated by donepezil intervention. In addition, TNF-α treatment resulted in significant induction of ACHE, upregulation of ICAM-1 and nuclear translocation of NF-κB, phosphorylation of IκB and IKKα/β in ARPE-19 cells. However, inhibition of ACHE reduced TNF-α-induced phosphorylation of NF-κB, IκB and IKKα/β in ARPE-19 cells. The present study reveals a pivotal role of ACHE in retinal inflammation. Inhibition of ACHE attenuates retinal inflammation and retinal leakage likely through suppressing NF-κB signaling activation.
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Affiliation(s)
- Jingming Li
- Affiliated Eye Hospital of Nanchang University, Nanchang University, Nanchang, China.
| | - Yingying Chen
- Department of Ophthalmology, Hainan People's Hospital, Haikou, China
| | - Xian Zhang
- Affiliated Eye Hospital of Nanchang University, Nanchang University, Nanchang, China
| | - Sihao Ye
- Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Jinglin Yi
- Affiliated Eye Hospital of Nanchang University, Nanchang University, Nanchang, China
| | - Qian Chen
- Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China.
| | - Qiuping Liu
- Affiliated Eye Hospital of Nanchang University, Nanchang University, Nanchang, China.
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Miller JV, LeBouf RF, Kelly KA, Michalovicz LT, Ranpara A, Locker AR, Miller DB, O'Callaghan JP. The Neuroinflammatory Phenotype in a Mouse Model of Gulf War Illness is Unrelated to Brain Regional Levels of Acetylcholine as Measured by Quantitative HILIC-UPLC-MS/MS. Toxicol Sci 2019; 165:302-313. [PMID: 29846716 DOI: 10.1093/toxsci/kfy130] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Many veterans of the 1991 Persian Gulf War (GW) returned with a chronic multisymptom illness that has been termed Gulf War Illness (GWI). Previous GWI studies have suggested that exposure to acetylcholinesterase inhibitors (AChEIs) in theater, such as sarin and/or pesticides, may have contributed to the symptomatology of GWI. Additionally, concomitant high physiological stress experienced during the war may have contributed to the initiation of the GWI phenotype. Although inhibition of AChE leading to accumulation of acetylcholine (ACh) will activate the cholinergic anti-inflammatory pathway, the signature symptomatology of GWI has been shown to be associated with neuroinflammation. To investigate the relationship between ACh and neuroinflammation in discrete brain regions, we used our previously established mouse model of GWI, which combines an exposure to a high physiological stress mimic, corticosterone (CORT), with GW-relevant AChEIs. The AChEIs used in this study were diisopropyl fluorophosphate (DFP), chlorpyrifos oxon (CPO), and physostigmine (PHY). After AChEI exposure, ACh concentrations for cortex (CTX), hippocampus (HIP), and striatum (STR) were determined using hydrophilic interaction liquid chromatography with ultraperformance liquid chromatography-tandem-mass spectrometry (MS/MS). CORT pretreatment ameliorated the DFP-induced ACh increase in HIP and STR, but not CTX. CORT pretreatment did not significantly alter ACh levels for CPO and PHY. Further analysis of STR neuroinflammatory biomarkers revealed an exacerbated CORT + AChEI response, which does not correspond to measured brain ACh. By utilizing this new analytical method for discrete brain region analysis of ACh, this work suggests the exacerbated neuroinflammatory effects in our mouse model of GWI are not driven by the accumulation of brain region-specific ACh.
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Affiliation(s)
| | - Ryan F LeBouf
- Respiratory Health Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505
| | | | | | - Anand Ranpara
- Respiratory Health Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505
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Meller S, Brandt C, Theilmann W, Klein J, Löscher W. Commonalities and differences in extracellular levels of hippocampal acetylcholine and amino acid neurotransmitters during status epilepticus and subsequent epileptogenesis in two rat models of temporal lobe epilepsy. Brain Res 2019; 1712:109-123. [DOI: 10.1016/j.brainres.2019.01.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/09/2019] [Accepted: 01/26/2019] [Indexed: 02/06/2023]
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Baccus B, Auvin S, Dorandeu F. Electro-behavioral phenotype and cell injury following exposure to paraoxon-ethyl in mice: Effect of the genetic background. Chem Biol Interact 2018; 290:119-125. [PMID: 29800574 DOI: 10.1016/j.cbi.2018.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/14/2018] [Accepted: 05/21/2018] [Indexed: 10/16/2022]
Abstract
Organophosphorus compounds (OP) are irreversible inhibitors of both central and peripheral cholinesterases (ChE). They still represent a major health issue in some countries as well as a terrorist and military threat. In order to design appropriate medical counter-measures, a better understanding of the pathophysiology of the poisoning is needed. Little to nothing is known regarding the impact of the genetic background on OP-induced seizures and seizure-related cell injury. Using two different mouse strains, Swiss and C57BL/6J, exposed to a convulsing dose of the OP pesticide paraoxon-ethyl (POX), our study focused on seizure susceptibility, especially the occurrence of SE and related mortality. We also evaluated the initial neuropathological response and SE-induced cell injury. Following the administration of 2.4 mg/kg POX, more Swiss mice experienced SE than C57BL/6J (55.6% versus 17.2%) but the duration of their SE, based on EEG recordings, was shorter (64.3 ± 19.5 min versus 180.8 ± 36.8 min). No significant difference was observed between strains regarding mortality (33% versus 14%). In both strains limited cell injury was observed in the medial temporal cortex, the dentate gyrus and the CA3 field without inter-strain differences (Fluorojade C-positive cells/mm2). Conversely, only C57BL/6J mice showed cell injury in the CA1 field. There was no obvious correlation between the number of Fluorojade C-positive cells and the duration of the EEG discharges. Our work suggests some differences between Swiss and C57BL/6J mice and lay ground to further studies on the impact of strains in the development of central nervous system toxicity of OP.
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Affiliation(s)
- Benjamin Baccus
- Institut de recherche biomédicale des armées (French armed forces biomedical research institute), 1 Place Général Valérie André, BP 73, 91223 Brétigny sur Orge cedex, France; Inserm U1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France; Ecole du Val de Grâce, 1 Place Alphonse Laveran, 75005 Paris, France.
| | - Stéphane Auvin
- Inserm U1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France
| | - Frédéric Dorandeu
- Institut de recherche biomédicale des armées (French armed forces biomedical research institute), 1 Place Général Valérie André, BP 73, 91223 Brétigny sur Orge cedex, France; Ecole du Val de Grâce, 1 Place Alphonse Laveran, 75005 Paris, France
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Stoichiometry of the Heteromeric Nicotinic Receptors of the Renshaw Cell. J Neurosci 2018; 38:4943-4956. [PMID: 29724797 DOI: 10.1523/jneurosci.0070-18.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/21/2018] [Accepted: 03/27/2018] [Indexed: 01/05/2023] Open
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are pentamers built from a variety of subunits. Some are homomeric assemblies of α subunits, others heteromeric assemblies of α and β subunits which can adopt two stoichiometries (2α:3β or 3α:2β). There is evidence for the presence of heteromeric nAChRs with the two stoichiometries in the CNS, but it has not yet been possible to identify them at a given synapse. The 2α:3β receptors are highly sensitive to agonists, whereas the 3α:2β stoichiometric variants, initially described as low sensitivity receptors, are indeed activated by low and high concentrations of ACh. We have taken advantage of the discovery that two compounds (NS9283 and Zn) potentiate selectively the 3α:2β nAChRs to establish (in mice of either sex) the presence of these variants at the motoneuron-Renshaw cell (MN-RC) synapse. NS9283 prolonged the decay of the two-component EPSC mediated by heteromeric nAChRs. NS9283 and Zn also prolonged spontaneous EPSCs involving heteromeric nAChRs, and one could rule out prolongations resulting from AChE inhibition by NS9283. These results establish the presence of 3α:2β nAChRs at the MN-RC synapse. At the functional level, we had previously explained the duality of the EPSC by assuming that high ACh concentrations in the synaptic cleft account for the fast component and that spillover of ACh accounts for the slow component. The dual ACh sensitivity of 3α:2β nAChRs now allows to attribute to these receptors both components of the EPSC.SIGNIFICANCE STATEMENT Heteromeric nicotinic receptors assemble α and β subunits in pentameric structures, which can adopt two stoichiometries: 3α:2β or 2α:3β. Both stoichiometric variants are present in the CNS, but they have never been located and characterized functionally at the level of an identified synapse. Our data indicate that 3α:2β receptors are present at the spinal cord synapses between motoneurons and Renshaw cells, where their dual mode of activation (by high concentrations of ACh for synaptic receptors, by low concentrations of ACh for extrasynaptic receptors) likely accounts for the biphasic character of the synaptic current. More generally, 3α:2β nicotinic receptors appear unique by their capacity to operate both in the cleft of classical synapses and at extrasynaptic locations.
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The Eukaryotic Elongation Factor 1 Alpha (eEF1α) from the Parasite Leishmania infantum Is Modified with the Immunomodulatory Substituent Phosphorylcholine (PC). Molecules 2017; 22:molecules22122094. [PMID: 29186074 PMCID: PMC6149742 DOI: 10.3390/molecules22122094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 11/24/2017] [Indexed: 01/11/2023] Open
Abstract
Proteins and glycolipids have been found to be decorated with phosphorylcholine (PC) both in protozoa and nematodes that parasitize humans and animals. PC epitopes can provoke various effects on immune cells leading to an immunomodulation of the host’s immune system that allows long-term persistence of the parasites. So far, only a limited number of PC-modified proteins, mainly from nematodes, have been identified. Infections caused by Leishmania spp. (e.g., L. infantum in southern Europe) affect about 12 million people worldwide and are characterized by a wide spectrum of clinical forms in humans, ranging from cutaneous to fatal visceral leishmaniasis. To establish and maintain the infection, these protozoa are dependent on the secretion of effector molecules into the host for modulating their immune system. In this project, we analyzed the PC modification of L. infantum promastigotes by 2D-gel based proteomics. Western blot analysis with the PC-specific antibody TEPC-15 revealed one PC-substituted protein in this organism, identified as eEF1α. We could demonstrate that the binding of eEF1α to one of its downstream effectors is dependent on its PC-modification. In this study we provide evidence that in this parasite the modification of eEF1α with PC may be essential for its function as an important virulence factor.
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Zhao C, Zhang H, Li H, Lv C, Liu X, Li Z, Xin W, Wang Y, Zhang W. Geniposide ameliorates cognitive deficits by attenuating the cholinergic defect and amyloidosis in middle-aged Alzheimer model mice. Neuropharmacology 2016; 116:18-29. [PMID: 27940040 DOI: 10.1016/j.neuropharm.2016.12.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 11/30/2016] [Accepted: 12/03/2016] [Indexed: 01/18/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by memory deficits and cognitive decline. Amyloid-β (Aβ) deposition and cholinergic defect are widely thought to be the underlying mechanism of learning and memory impairment. Geniposide, which is the main active component of the traditional Chinese herbal Gardenia jasminoides Ellis, elicits neuroprotective effects by alleviating inflammation responses and oxidative damages. In this study, we investigated the protective effect of geniposide on levels of cholinergic markers, RAGE, RAGE-dependent signalling pathways and amyloid accumulation in the APPswe/PS1dE9 AD model mouse. Geniposide suppressed MAPK signaling over-activation mediated by Aβ-RAGE interaction, resulting in reduced Aβ accumulation and amelioration of cholinergic deficits in the cerebral hippocampus. Furthermore, geniposide inhibited the toxic effect of oligomeric Aβ1-42 induced cholinergic deficit by increasing ChAT levels and activity but decreasing AChE activity in cultured primary hippocampal neurons. These results indicated that geniposide enhanced cholinergic neurotransmission, which likely contributes to its memory enhancing effect.
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Affiliation(s)
- Chunhui Zhao
- Beijing Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Beijing 100875, China; Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China.
| | - Haijing Zhang
- Beijing Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Beijing 100875, China; Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China; College of Resources Science Technology, Beijing Normal University, Beijing 100875, China.
| | - Hang Li
- Beijing Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Beijing 100875, China; Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China; College of Resources Science Technology, Beijing Normal University, Beijing 100875, China.
| | - Cui Lv
- Beijing Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Beijing 100875, China; College of Resources Science Technology, Beijing Normal University, Beijing 100875, China; Laboratory of Immunology for Environment and Health, Shandong Analysis and Test Center, Shandong Academy of Science, Jinan 250014, China.
| | - Xiaoli Liu
- Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China; College of Resources Science Technology, Beijing Normal University, Beijing 100875, China.
| | - Zhi Li
- Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China.
| | - Wenfeng Xin
- Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China; Engineering Research Center of Sanqi Biotechnology and Pharmaceutical, Yun Nan Province, Kunming 650000, China.
| | - Yongyan Wang
- Beijing Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Beijing 100875, China; Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China; College of Resources Science Technology, Beijing Normal University, Beijing 100875, China.
| | - Wensheng Zhang
- Beijing Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Beijing 100875, China; Engineering Research Center of Natural Medicine, Ministry of Education, Beijing Normal University, Beijing 100875, China; College of Resources Science Technology, Beijing Normal University, Beijing 100875, China; Engineering Research Center of Sanqi Biotechnology and Pharmaceutical, Yun Nan Province, Kunming 650000, China.
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Beckmann J, Dittmann N, Schütz I, Klein J, Lips KS. Effect of M3 muscarinic acetylcholine receptor deficiency on collagen antibody-induced arthritis. Arthritis Res Ther 2016; 18:17. [PMID: 26785775 PMCID: PMC4719200 DOI: 10.1186/s13075-016-0926-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 01/07/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND There is increasing evidence that the non-neuronal cholinergic system might be of importance for the pathology of rheumatoid arthritis. The role of M3 muscarinic acetylcholine receptor (M3R) in this regard has, however, not been investigated to date. Thus, in the present study we analyzed if M3R deficiency might have a protective effect on experimentally induced arthritis. METHODS Collagen antibody-induced arthritis (CAIA) was evoked in M3R-deficient (M3R(-/-)) mice and wild-type (WT) littermates. Severity of arthritis was assessed by scoring of paw swelling. The joints of arthritic and nonarthritic animals were analyzed for histopathological changes regarding synovial tissue, cartilage degradation and bone destruction. Further, gene expression analysis of respective markers was performed. Systemic and local inflammatory response was determined by flow cytometry and immunohistochemistry for leukocytes as well as mRNA and protein measurements for pro-inflammatory cytokines and chemokines. RESULTS In arthritic M3R(-/-) mice the number of leukocytes, specifically neutrophils, was enhanced even though clinical arthritis score was not significantly different between WT and M3R(-/-) mice with CAIA. In M3R(-/-) mice, levels of neutrophil chemoattractant chemokine C-X-C-motif ligand 2 (CXCL2) as well as the pro-inflammatory cytokine interleukin-6 were already strongly increased in mice with low arthritis score, whereas WT mice only showed prominent expression of these markers when reaching high arthritis scores. Furthermore, arthritic M3R(-/-) mice displayed a stronger degradation of collagen II in the articular cartilage and, most strikingly, histopathological evaluation revealed more severe bone destruction in arthritic mice with M3R deficiency compared to WT littermates. Moreover, in M3R(-/-) mice, gene expression of markers for bone degradation (matrix metalloproteinase 13, cathepsin K and receptor activator of nuclear factor-κB ligand) was already increased in mice with low arthritis score. CONCLUSIONS Taken together, the present study shows that while M3R(-/-) mice were not protected from CAIA, they had a tendency toward a higher inflammatory response after arthritis induction than WT mice. Further, arthritis-induced joint destruction was significantly stronger in mice with M3R deficiency, indicating that stimulation of M3R might have protective effects on arthritis.
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Affiliation(s)
- Janet Beckmann
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkraderstrasse 9, 35394, Giessen, Germany.
| | - Nicole Dittmann
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkraderstrasse 9, 35394, Giessen, Germany.
| | - Iris Schütz
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkraderstrasse 9, 35394, Giessen, Germany.
| | - Jochen Klein
- Department of Pharmacology, School of Pharmacy, Goethe-University Frankfurt, Max-von-Laue Strasse 9, 60438, Frankfurt am Main, Germany.
| | - Katrin Susanne Lips
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkraderstrasse 9, 35394, Giessen, Germany.
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Lietsche J, Imran I, Klein J. Extracellular levels of ATP and acetylcholine during lithium-pilocarpine induced status epilepticus in rats. Neurosci Lett 2015; 611:69-73. [PMID: 26610905 DOI: 10.1016/j.neulet.2015.11.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 11/12/2015] [Accepted: 11/17/2015] [Indexed: 01/23/2023]
Abstract
Acetylcholine (ACh) and ATP are rapidly acting neurotransmitters with a putative role in epileptic seizures. In the present study we investigated extracellular concentrations of both neurotransmitters in parallel by microdialysis in rat hippocampus. We found that infusion of neostigmine increases, while calcium-free perfusion and infusion of tetrodotoxin (TTX) decreases, ACh levels. Calcium-free perfusion also decreased ATP levels which were, however, not affected by neostigmine or TTX. During status epilepticus, ACh levels were increased threefold but returned to baseline after the termination of seizures by diazepam. ATP levels were unchanged during status epilepticus but a several-fold increase was seen when AOPCP, an inhibitor of 5'-endonucleotidase, was infused. The results demonstrate an increase of ATP levels during epileptic seizures which, however, was not of neuronal origin.
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Affiliation(s)
- Jana Lietsche
- Department of Pharmacology, College of Pharmacy, Goethe University of Frankfurt, Germany
| | - Imran Imran
- Faculty of Pharmacy, Bahauddin Zakariya University, Multan, Pakistan
| | - Jochen Klein
- Department of Pharmacology, College of Pharmacy, Goethe University of Frankfurt, Germany.
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11
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Mohr F, Krejci E, Zimmermann M, Klein J. Dysfunctional Presynaptic M2 Receptors in the Presence of Chronically High Acetylcholine Levels: Data from the PRiMA Knockout Mouse. PLoS One 2015; 10:e0141136. [PMID: 26506622 PMCID: PMC4624712 DOI: 10.1371/journal.pone.0141136] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/05/2015] [Indexed: 12/31/2022] Open
Abstract
The muscarinic M2 receptor (M2R) acts as a negative feedback regulator in central cholinergic systems. Activation of the M2 receptor limits acetylcholine (ACh) release, especially when ACh levels are increased because acetylcholinesterase (AChE) activity is acutely inhibited. Chronically high ACh levels in the extracellular space, however, were reported to down-regulate M2R to various degrees. In the present study, we used the PRiMA knockout mouse which develops severely reduced AChE activity postnatally to investigate ACh release, and we used microdialysis to investigate whether the function of M2R to reduce ACh release in vivo was impaired in adult PRiMA knockout mice. We first show that striatal and hippocampal ACh levels, while strongly increased, still respond to AChE inhibitors. Infusion or injection of oxotremorine, a muscarinic M2 agonist, reduced ACh levels in wild-type mice but did not significantly affect ACh levels in PRiMA knockout mice or in wild-type mice in which ACh levels were artificially increased by infusion of neostigmine. Scopolamine, a muscarinic antagonist, increased ACh levels in wild-type mice receiving neostigmine, but not in wild-type mice or in PRiMA knockout mice. These results demonstrate that M2R are dysfunctional and do not affect ACh levels in PRiMA knockout mice, likely because of down-regulation and/or loss of receptor-effector coupling. Remarkably, this loss of function does not affect cognitive functions in PRiMA knockout mice. Our results are discussed in the context of AChE inhibitor therapy as used in dementia.
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Affiliation(s)
- Franziska Mohr
- Department of Pharmacology, School of Pharmacy, Goethe University, Frankfurt am Main, Germany
| | - Eric Krejci
- Centre d'Etude de la Sensorimotricité, Université Paris Descartes, CNRS UMR 8194, Paris, France
| | - Martina Zimmermann
- Department of Pharmacology, School of Pharmacy, Goethe University, Frankfurt am Main, Germany; Centre for the Humanities and Health, Department of English, King´s College, London, United Kingdom
| | - Jochen Klein
- Department of Pharmacology, School of Pharmacy, Goethe University, Frankfurt am Main, Germany
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12
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Hecker A, Küllmar M, Wilker S, Richter K, Zakrzewicz A, Atanasova S, Mathes V, Timm T, Lerner S, Klein J, Kaufmann A, Bauer S, Padberg W, Kummer W, Janciauskiene S, Fronius M, Schweda EKH, Lochnit G, Grau V. Phosphocholine-Modified Macromolecules and Canonical Nicotinic Agonists Inhibit ATP-Induced IL-1β Release. THE JOURNAL OF IMMUNOLOGY 2015. [PMID: 26202987 DOI: 10.4049/jimmunol.1400974] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IL-1β is a potent proinflammatory cytokine of the innate immune system that is involved in host defense against infection. However, increased production of IL-1β plays a pathogenic role in various inflammatory diseases, such as rheumatoid arthritis, gout, sepsis, stroke, and transplant rejection. To prevent detrimental collateral damage, IL-1β release is tightly controlled and typically requires two consecutive danger signals. LPS from Gram-negative bacteria is a prototypical first signal inducing pro-IL-1β synthesis, whereas extracellular ATP is a typical second signal sensed by the ATP receptor P2X7 that triggers activation of the NLRP3-containing inflammasome, proteolytic cleavage of pro-IL-1β by caspase-1, and release of mature IL-1β. Mechanisms controlling IL-1β release, even in the presence of both danger signals, are needed to protect from collateral damage and are of therapeutic interest. In this article, we show that acetylcholine, choline, phosphocholine, phosphocholine-modified LPS from Haemophilus influenzae, and phosphocholine-modified protein efficiently inhibit ATP-mediated IL-1β release in human and rat monocytes via nicotinic acetylcholine receptors containing subunits α7, α9, and/or α10. Of note, we identify receptors for phosphocholine-modified macromolecules that are synthesized by microbes and eukaryotic parasites and are well-known modulators of the immune system. Our data suggest that an endogenous anti-inflammatory cholinergic control mechanism effectively controls ATP-mediated release of IL-1β and that the same mechanism is used by symbionts and misused by parasites to evade innate immune responses of the host.
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Affiliation(s)
- Andreas Hecker
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Mira Küllmar
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Sigrid Wilker
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Katrin Richter
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany; Institute of Animal Physiology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany
| | - Anna Zakrzewicz
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Srebrena Atanasova
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Verena Mathes
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Thomas Timm
- Protein Analytics, Institute of Biochemistry, Justus-Liebig-University Giessen, D-35392 Giessen, Germany
| | - Sabrina Lerner
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Jochen Klein
- Department of Pharmacology, Goethe University College of Pharmacy, D-60438 Frankfurt, Germany
| | - Andreas Kaufmann
- Institute for Immunology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - Stefan Bauer
- Institute for Immunology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - Winfried Padberg
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany
| | - Wolfgang Kummer
- Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany
| | - Sabina Janciauskiene
- Department of Respiratory Medicine, Hannover Medical School, D-30625 Hannover, Germany
| | - Martin Fronius
- Institute of Animal Physiology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany; Department of Physiology, University of Otago, Dunedin 9054, New Zealand; and
| | - Elke K H Schweda
- Division of Chemistry, Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping, Sweden
| | - Günter Lochnit
- Protein Analytics, Institute of Biochemistry, Justus-Liebig-University Giessen, D-35392 Giessen, Germany
| | - Veronika Grau
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, D-35385 Giessen, Germany;
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Timm T, Lenz C, Merkel D, Sadiffo C, Grabitzki J, Klein J, Lochnit G. Detection and site localization of phosphorylcholine-modified peptides by NanoLC-ESI-MS/MS using precursor ion scanning and multiple reaction monitoring experiments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:460-471. [PMID: 25487775 DOI: 10.1007/s13361-014-1036-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/17/2014] [Accepted: 10/22/2014] [Indexed: 06/04/2023]
Abstract
Phosphorylcholine (PC)-modified biomolecules like lipopolysaccharides, glycosphingolipids, and (glyco)proteins are widespread, highly relevant antigens of parasites, since this small hapten shows potent immunomodulatory capacity, which allows the establishment of long-lasting infections of the host. Especially for PC-modified proteins, structural data is rare because of the zwitterionic nature of the PC substituent, resulting in low sensitivities and unusual but characteristic fragmentation patterns. We have developed a targeted mass spectrometric approach using hybrid triple quadrupole/linear ion trap (QTRAP) mass spectrometry coupled to nanoflow chromatography for the sensitive detection of PC-modified peptides from complex proteolytic digests, and the localization of the PC-modification within the peptide backbone. In a first step, proteolytic digests are screened using precursor ion scanning for the marker ions of choline (m/z 104.1) and phosphorylcholine (m/z 184.1) to establish the presence of PC-modified peptides. Potential PC-modified precursors are then subjected to a second analysis using multiple reaction monitoring (MRM)-triggered product ion spectra for the identification and site localization of the modified peptides. The approach was first established using synthetic PC-modified synthetic peptides and PC-modified model digests. Following the optimization of key parameters, we then successfully applied the method to the detection of PC-peptides in the background of a proteolytic digest of a whole proteome. This methodological invention will greatly facilitate the detection of PC-substituted biomolecules and their structural analysis.
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Affiliation(s)
- Thomas Timm
- Protein Analytics, Institute of Biochemistry, Faculty of Medicine, Justus-Liebig-University Giessen, 35392, Giessen, Germany
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Self-built microdialysis probes with improved recoveries of ATP and neuropeptides. J Neurosci Methods 2014; 237:1-8. [PMID: 25172804 DOI: 10.1016/j.jneumeth.2014.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/09/2014] [Accepted: 08/14/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Microdialysis is an established technique for collecting small molecular weight substances (e.g. neurotransmitter and energy metabolites) from the extracellular space. The major element of microdialysis is the probe which contains a semi-permeable membrane and is exposed to the interstitial space. As the microdialysis technique has major advantages, e.g. versatility and use in awake animals, commercially produced probes are in great demand. NEW METHOD We here present the design of a probe assembly step by step which will enable researchers to build custom-made probes. Probe recoveries of substances with different molecular weight (ranging from 100 to 1600 Da) were compared for three different probes (CMA 12 Elite probe, custom-made 10 kDa and 30 kDa probes). Recoveries of glucose, lactate, acetylcholine, choline, ATP and the neuropeptides angiotensin II, substance P and somatostatin are presented. RESULTS We found that the 10 kDa probe is only useful for compounds up to 1000 Da while recoveries of the CMA-12 Elite Probe are variable and apparently dependent on ionic charges of analytes. The recovery of the custom-made 30 kDa probe is highest and evidently not influenced by physicochemical parameters of analytes. In a further optimization step, we describe the use of ZipTip(®) μC-18 collection tips to replace the outlet tubing when purifying the dialysate for MALDI-MS measurements of neuropeptides. COMPARISON WITH EXISTING METHODS The results show that self-built microdialysis probes can be equally or more effective than commercially available probes. CONCLUSIONS Self-built microdialysis probes with large pore-membranes are capable of dialyzing ATP and neuropeptides.
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Zimmermann M. Neuronal AChE splice variants and their non-hydrolytic functions: redefining a target of AChE inhibitors? Br J Pharmacol 2014; 170:953-67. [PMID: 23991627 DOI: 10.1111/bph.12359] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 08/04/2013] [Accepted: 08/12/2013] [Indexed: 12/11/2022] Open
Abstract
AChE enzymatic inhibition is a core focus of pharmacological intervention in Alzheimer's disease (AD). Yet, AChE has also been ascribed non-hydrolytic functions, which seem related to its appearance in various isoforms. Neuronal AChE presents as a tailed form (AChE-T) predominantly found on the neuronal synapse, and a facultatively expressed readthough form (AChE-R), which exerts short to medium-term protective effects. Notably, this latter form is also found in the periphery. While these non-hydrolytic functions of AChE are most controversially discussed, there is evidence for them being additional targets of AChE inhibitors. This review aims to provide clarification as to the role of these AChE splice variants and their interplay with other cholinergic parameters and their being targets of AChE inhibition: AChE-R is particularly involved in the mediation of (anti-)apoptotic events in cholinergic cells, involving adaptation of various cholinergic parameters and a time-dependent link to the expression of neuroprotective factors. The AChE-T C-terminus is central to AChE activity regulation, while isolated AChE-T C-terminal fragments mediate toxic effects via the α7 nicotinic acetylcholine receptor. There is direct evidence for roles of AChE-T and AChE-R in neurodegeneration and neuroprotection, with these roles involving AChE as a key modulator of the cholinergic system: in vivo data further encourages the use of AChE inhibitors in the treatment of neurodegenerative conditions such as AD since effects on both enzymatic activity and the enzyme's non-hydrolytic functions can be postulated. It also suggests that novel AChE inhibitors should enhance protective AChE-R, while avoiding the concomitant up-regulation of AChE-T.
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Affiliation(s)
- M Zimmermann
- Department of Pharmacology, School of Pharmacy, Goethe University Frankfurt, Frankfurt am Main, Germany
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Hillert MH, Imran I, Zimmermann M, Lau H, Weinfurter S, Klein J. Dynamics of hippocampal acetylcholine release during lithium-pilocarpine-induced status epilepticus in rats. J Neurochem 2014; 131:42-52. [PMID: 24909269 DOI: 10.1111/jnc.12787] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 01/30/2023]
Abstract
The lithium-pilocarpine model is a rat model of epilepsy that mimics status epilepticus in humans. Here, we report changes of acetylcholine (ACh) release in the hippocampus before, during and after status epilepticus as monitored by microdialysis in unanesthetized rats. Administration of pilocarpine (30 mg/kg s.c.) to rats pretreated with lithium chloride (127 mg/kg i.p.) caused a massive, six-fold increase of hippocampal ACh release, paralleling the development of tonic seizures. When seizures were stopped by administration of diazepam (10 mg/kg i.p.) or ketamine (75 mg/kg i.p.), ACh levels returned to normal. Extracellular concentrations of glutamate remained unchanged during this procedure. Administration of atropine (1 mg/kg i.p.) 2 h after pilocarpine caused a further increase of ACh but did not affect seizures, whereas injection of mecamylamine (5 mg/kg i.p.) reduced ACh levels and seizures in a delayed fashion. Local infusion of tetrodotoxin, 1 μM locally) or hemicholinium (10 μM locally) strongly reduced ACh release and had delayed effects on seizures. Administration of glucose or inositol (250 mg/kg each i.p.) had no visible consequences. In parallel experiments, lithium-pilocarpine-induced status epilepticus also enhanced striatal ACh release, and hippocampal ACh levels equally increased when status epilepticus was induced by kainate (30 mg/kg i.p.). Taken together, our results demonstrate that seizure development in status epilepticus models is accompanied by massive increases of extracellular ACh, but not glutamate, levels. Treatments that reduce seizure activity also reliably reduce extracellular ACh levels.
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Affiliation(s)
- Markus H Hillert
- Department of Pharmacology, School of Pharmacy, Biocenter N260, Goethe University Frankfurt, Frankfurt am Main, Germany
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Burkhardt U, Stegner D, Hattingen E, Beyer S, Nieswandt B, Klein J. Impaired brain development and reduced cognitive function in phospholipase D-deficient mice. Neurosci Lett 2014; 572:48-52. [DOI: 10.1016/j.neulet.2014.04.052] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/29/2014] [Accepted: 04/30/2014] [Indexed: 01/04/2023]
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Bitter triggers acetylcholine release from polymodal urethral chemosensory cells and bladder reflexes. Proc Natl Acad Sci U S A 2014; 111:8287-92. [PMID: 24843119 DOI: 10.1073/pnas.1402436111] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chemosensory cells in the mucosal surface of the respiratory tract ("brush cells") use the canonical taste transduction cascade to detect potentially hazardous content and trigger local protective and aversive respiratory reflexes on stimulation. So far, the urogenital tract has been considered to lack this cell type. Here we report the presence of a previously unidentified cholinergic, polymodal chemosensory cell in the mammalian urethra, the potential portal of entry for bacteria and harmful substances into the urogenital system, but not in further centrally located parts of the urinary tract, such as the bladder, ureter, and renal pelvis. Urethral brush cells express bitter and umami taste receptors and downstream components of the taste transduction cascade; respond to stimulation with bitter (denatonium), umami (monosodium glutamate), and uropathogenic Escherichia coli; and release acetylcholine to communicate with other cells. They are approached by sensory nerve fibers expressing nicotinic acetylcholine receptors, and intraurethral application of denatonium reflexively increases activity of the bladder detrusor muscle in anesthetized rats. We propose a concept of urinary bladder control involving a previously unidentified cholinergic chemosensory cell monitoring the chemical composition of the urethral luminal microenvironment for potential hazardous content.
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Bader S, Klein J, Diener M. Choline acetyltransferase and organic cation transporters are responsible for synthesis and propionate-induced release of acetylcholine in colon epithelium. Eur J Pharmacol 2014; 733:23-33. [PMID: 24698650 DOI: 10.1016/j.ejphar.2014.03.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/20/2014] [Accepted: 03/03/2014] [Indexed: 01/11/2023]
Abstract
Acetylcholine is not only a neurotransmitter, but is found in a variety of non-neuronal cells. For example, the enzyme choline acetyltransferase (ChAT), catalyzing acetylcholine synthesis, is expressed by the colonic epithelium of different species. These cells release acetylcholine across the basolateral membrane after luminal exposure to propionate, a short-chain fatty acid. The functional consequence is the induction of chloride secretion, measurable as increase in short-circuit current (Isc) in Ussing chamber experiments. It is unclear how acetylcholine is produced and released by colonic epithelium. Therefore, the aim of the present study was the identification (on mRNA and protein level) and functional characterization (in Ussing chamber experiments combined with HPLC detection of acetylcholine) of transporters/enzymes in the cholinergic system of rat colonic epithelium. Immunohistochemical staining as well as RT-PCR revealed the expression of high-affinity choline transporter, ChAT, carnitine acetyltransferase (CarAT), vesicular acetylcholine transporter (VAChT), and organic cation transporters (OCT 1, 2, 3) in colonic epithelium. In contrast to blockade of ChAT with bromoacetylcholine, inhibition of CarAT with mildronate did not inhibit the propionate-induced increase in Isc, suggesting a predominant synthesis of epithelial acetylcholine by ChAT. Although being expressed, blockade of VAChT with vesamicol was ineffective, whereas inhibition of OCTs with omeprazole and corticosterone inhibited propionate-induced Isc and the release of acetylcholine into the basolateral compartment. In summary, OCTs seem to be involved in regulated acetylcholine release by colonic epithelium, which is assumed to be involved in chemosensing of luminal short-chain fatty acids by the intestinal epithelium.
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Affiliation(s)
- Sandra Bader
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, 35392, Germany
| | - Jochen Klein
- Institute of Pharmacology, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Martin Diener
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, 35392, Germany.
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Modeling fall propensity in Parkinson's disease: deficits in the attentional control of complex movements in rats with cortical-cholinergic and striatal-dopaminergic deafferentation. J Neurosci 2013; 33:16522-39. [PMID: 24133257 DOI: 10.1523/jneurosci.2545-13.2013] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cognitive symptoms, complex movement deficits, and increased propensity for falls are interrelated and levodopa-unresponsive symptoms in patients with Parkinson's disease (PD). We developed a test system for the assessment of fall propensity in rats and tested the hypothesis that interactions between loss of cortical cholinergic and striatal dopaminergic afferents increase fall propensity. Rats were trained to traverse stationary and rotating rods, placed horizontally or at inclines, and while exposed to distractors. Rats also performed an operant Sustained Attention Task (SAT). Partial cortical cholinergic and/or caudate dopaminergic deafferentation were produced by bilateral infusions of 192 IgG-saporin (SAP) into the basal forebrain and/or 6-hydroxydopamine (6-OHDA) into the caudate nucleus, respectively, modeling the lesions seen in early PD. Rats with dual cholinergic-dopaminergic lesions (DL) fell more frequently than SAP or 6-OHDA rats. Falls in DL rats were associated with incomplete rebalancing after slips and low traversal speed. Ladder rung walking and pasta handling performance did not indicate sensorimotor deficits. SAT performance was impaired in DL and SAP rats; however, SAT performance and falls were correlated only in DL rats. Furthermore, in DL rats, but not in rats with only dopaminergic lesions, the placement and size of dopaminergic lesion correlated significantly with fall rates. The results support the hypothesis that after dual cholinergic-dopaminergic lesions, attentional resources can no longer be recruited to compensate for diminished striatal control of complex movement, thereby "unmasking" impaired striatal control of complex movements and yielding falls.
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Reassessment of the Role of the Central Cholinergic System. J Mol Neurosci 2013; 53:352-8. [DOI: 10.1007/s12031-013-0164-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 10/24/2013] [Indexed: 12/18/2022]
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