1
|
Harrington S, Pyche J, Burns AR, Spalholz T, Ryan KT, Baker RJ, Ching J, Rufener L, Lautens M, Kulke D, Vernudachi A, Zamanian M, Deuther-Conrad W, Brust P, Roy PJ. Nemacol is a small molecule inhibitor of C. elegans vesicular acetylcholine transporter with anthelmintic potential. Nat Commun 2023; 14:1816. [PMID: 37002199 PMCID: PMC10066365 DOI: 10.1038/s41467-023-37452-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 03/17/2023] [Indexed: 04/03/2023] Open
Abstract
Nematode parasites of humans and livestock pose a significant burden to human health, economic development, and food security. Anthelmintic drug resistance is widespread among parasites of livestock and many nematode parasites of humans lack effective treatments. Here, we present a nitrophenyl-piperazine scaffold that induces motor defects rapidly in the model nematode Caenorhabditis elegans. We call this scaffold Nemacol and show that it inhibits the vesicular acetylcholine transporter (VAChT), a target recognized by commercial animal and crop health groups as a viable anthelmintic target. We demonstrate that it is possible to create Nemacol analogs that maintain potent in vivo activity whilst lowering their affinity to the mammalian VAChT 10-fold. We also show that Nemacol enhances the ability of the anthelmintic Ivermectin to paralyze C. elegans and the ruminant nematode parasite Haemonchus contortus. Hence, Nemacol represents a promising new anthelmintic scaffold that acts through a validated anthelmintic target.
Collapse
Affiliation(s)
- Sean Harrington
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jacob Pyche
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Andrew R Burns
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Tina Spalholz
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
| | - Kaetlyn T Ryan
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Rachel J Baker
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Justin Ching
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Lucien Rufener
- INVENesis Sàrl, Route de Neuchâtel 15A, 2072, St Blaise (NE), Switzerland
| | - Mark Lautens
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Daniel Kulke
- Research Parasiticides, Bayer Animal Health GmbH, Monheim, Germany
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, USA
- Global Innovation, Boehringer Ingelheim Vetmedica GmbH, Binger Str. 173, 55218, Ingelheim am Rhein, Germany
| | | | - Mostafa Zamanian
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
- The Lübeck Institute of Experimental Dermatology, University Medical Center Schleswig-Holstein, 23562, Lübeck, Germany
| | - Peter J Roy
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| |
Collapse
|
2
|
Zhao HY, Zhang ST, Cheng X, Li HM, Zhang L, He H, Qin JB, Zhang WY, Sun Y, Jin GH. Long non-coding RNA GAS5 promotes PC12 cells differentiation into Tuj1-positive neuron-like cells and induces cell cycle arrest. Neural Regen Res 2019; 14:2118-2125. [PMID: 31397350 PMCID: PMC6788226 DOI: 10.4103/1673-5374.262592] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Growth arrest-specific 5 (GAS5) is an anti-oncogene that has been extensively studied in tumors. However, research on GAS5 in the context of nervous system disease is rare at present. This study aimed to investigate the role of the long non-coding RNA GAS5 in rat pheochromocytoma cells (PC12 cells). GAS5-overexpressing lentivirus was transfected into PC12 cells, and expression levels of GAS5 and C-myc were detected by real-time PCR. Ratios of cells in S phase were detected by 5-ethynyl-2′-deoxyuridine. Immunohistochemical staining was used to detect the immunoreactivity of neuron microtubule markers Tuj1, doublecortin, and microtubule-associated protein 2. Apoptosis was detected by flow cytometry, while expression of acetylcholine in cells was detected by western blot assay. We found that GAS5 can promote PC12 cells to differentiate into Tuj1-positive neuron-like cells with longer processes. In addition, cell proliferation and cell cycle were significantly suppressed by GAS5, whereas it had no effect on apoptosis of PC12 cells. Our results indicate that GAS5 could increase the expression of choline acetyltransferase and acetylcholine release. Thus, we speculate that GAS5 is beneficial to the recovery of neurons and the cholinergic nervous system.
Collapse
Affiliation(s)
- He-Yan Zhao
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Sheng-Tong Zhang
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Xiang Cheng
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Hao-Ming Li
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Lei Zhang
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Hui He
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Jian-Bing Qin
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Wei-Ye Zhang
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Yan Sun
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| | - Guo-Hua Jin
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu Province, China
| |
Collapse
|
3
|
Roslin S, De Rosa M, Deuther-Conrad W, Eriksson J, Odell LR, Antoni G, Brust P, Larhed M. Synthesis and in vitro evaluation of 5-substituted benzovesamicol analogs containing N-substituted amides as potential positron emission tomography tracers for the vesicular acetylcholine transporter. Bioorg Med Chem 2017; 25:5095-5106. [PMID: 28185725 DOI: 10.1016/j.bmc.2017.01.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 12/17/2022]
Abstract
Herein, new ligands for the vesicular acetylcholine transporter (VAChT), based on a benzovesamicol scaffold, are presented. VAChT is acknowledged as a marker for cholinergic neurons and a positron emission tomography tracer for VAChT could serve as a tool for quantitative analysis of cholinergic neuronal density. With an easily accessible triflate precursor, aminocarbonylations were utilized to evaluate the chemical space around the C5 position on the tetrahydronaphthol ring. Synthesized ligands were evaluated for their affinity and selectivity for VAChT. Small, preferably aromatic, N-substituents proved to be more potent than larger substituents. Of the fifteen compounds synthesized, benzyl derivatives (±)-7i and (±)-7l had the highest affinities for VAChT. Compound (±)-7i was chosen to investigate the importance of stereochemistry for binding to VAChT and selectivity toward the σ1 and σ2 receptors. Enantiomeric resolution gave (+)-7i and (-)-7i, and the eutomer showed seven times better affinity. Although racemate (±)-7i was initially promising, the affinity of (-)-7i for VAChT was not better than 56.7nM which precludes further preclinical evaluation. However, the nanomolar binding together with the ready synthesis of [11C]-(±)-7i shows that (-)-7i can serve as a scaffold for future optimizations to provide improved 11C-labelled VAChT PET tracers.
Collapse
Affiliation(s)
- Sara Roslin
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Maria De Rosa
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Winnie Deuther-Conrad
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Research Site Leipzig, 04318 Leipzig, Germany
| | - Jonas Eriksson
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Luke R Odell
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Gunnar Antoni
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Peter Brust
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Research Site Leipzig, 04318 Leipzig, Germany
| | - Mats Larhed
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden.
| |
Collapse
|
4
|
Barthel C, Sorger D, Deuther-Conrad W, Scheunemann M, Schweiger S, Jäckel P, Roghani A, Steinbach J, Schüürmann G, Sabri O, Brust P, Wenzel B. New systematically modified vesamicol analogs and their affinity and selectivity for the vesicular acetylcholine transporter – A critical examination of the lead structure. Eur J Med Chem 2015; 100:50-67. [DOI: 10.1016/j.ejmech.2015.05.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 12/14/2022]
|
5
|
Li H, Jin G, Zhu P, Zou L, Shi J, Yi X, Zhang X, Tian M, Qin J. Upregulation of Lhx8 increase VAChT expression and ACh release in neuronal cell line SHSY5Y. Neurosci Lett 2013; 559:184-8. [PMID: 24316404 DOI: 10.1016/j.neulet.2013.11.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/13/2013] [Accepted: 11/26/2013] [Indexed: 01/28/2023]
Abstract
Lhx8 is a transcription factor for cholinergic differentiation. Our previous experiments found upregulation of Lhx8 promoted cholinergic neuronal differentiation of hippocampal neural stem/progenitor cells or hippocampal newborn neurons in vitro. However, the role of Lhx8 in VAChT expression and ACh release is still less understood. In this report, we transfected Lhx8 cDNA into neuronal cell line SHSY5Y by lentiviral vectors to acquire the cells which stably expressed high level of Lhx8. Using this cell model, we provided experimental evidence that increasing Lhx8 upregulated the expression of ChAT and VAChT, and also increased the ACh release in culture medium. We suggested that Lhx8 overexpression is a useful strategy to increase the release of ACh and maybe of therapeutic value to neurodegenerative diseases.
Collapse
Affiliation(s)
- Haoming Li
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China
| | - Guohua Jin
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China; Department of Human Anatomy and Histoembryology, Medical School of Soochow University, Suzhou 215123, China.
| | - Peipei Zhu
- Department of Pathology, Shanghai Changzheng Hospital, Shanghai 200003, China
| | - Linqing Zou
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China; Department of Human Anatomy and Histoembryology, Medical School of Soochow University, Suzhou 215123, China
| | - Jinhong Shi
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China; Department of Human Anatomy and Histoembryology, Medical School of Soochow University, Suzhou 215123, China
| | - Xin Yi
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China; Department of Human Anatomy and Histoembryology, Medical School of Soochow University, Suzhou 215123, China
| | - Xinhua Zhang
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China
| | - Meiling Tian
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China
| | - Jianbing Qin
- Department of Human Anatomy, the Jiangsu Key Laboratory of Neuroregeneration, Medical College of Nantong University, Nantong 226001, China
| |
Collapse
|
6
|
Stepanichev MY. Current approaches and future directions of gene therapy in Alzheimer’s disease. NEUROCHEM J+ 2011. [DOI: 10.1134/s181971241103010x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
7
|
Wenzel B, Hiller A, Fischer S, Sorger D, Deuther-Conrad W, Scheunemann M, Brust P, Sabri O, Steinbach J. In vitro binding profile and radiosynthesis of a novel 18F-labeled azaspirovesamicol analog as potential ligand for imaging of the vesicular acetylcholine transporter. J Labelled Comp Radiopharm 2011. [DOI: 10.1002/jlcr.1891] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
8
|
Rana BK, Wessel J, Mahboubi V, Rao F, Haeller J, Gayen JR, Eskin E, Valle AM, Das M, Mahata SK, Taupenot L, Stridsberg M, Talley TT, Ziegler MG, Smith DW, Schork NJ, O'Connor DT, Taylor P. Natural variation within the neuronal nicotinic acetylcholine receptor cluster on human chromosome 15q24: influence on heritable autonomic traits in twin pairs. J Pharmacol Exp Ther 2009; 331:419-28. [PMID: 19671882 PMCID: PMC2775266 DOI: 10.1124/jpet.109.157271] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 08/06/2009] [Indexed: 01/18/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are combinations of subunits arranged as pentamers encircling a central cation channel. At least nine alpha and four beta subunits are expressed in the central and peripheral nervous systems; their presence in autonomic ganglia, the adrenal medulla, and central nervous system, with accompanying responses elicited by nicotinic agonists, point to their involvement in cardiovascular homeostasis. nAChRs formed by alpha3, alpha5, and beta4 subunits may regulate blood pressure (BP) by mediating release of catestatin, the endogenous nicotinic antagonist fragment of chromogranin A (CHGA) and potent inhibitor of catecholamine secretion. Genes encoding these subunits (CHRNA3, CHRNA5, and CHRNB4) are clustered on human chromosome 15q24. Because variation in this cluster may alter autonomic regulation of BP, we sequenced approximately 15 kilobase pairs in 15q24 containing their coding and 5'- and 3'-untranslated regions in 80 individuals. We identified 63 variants: 25 in coding regions of CHRNA3, CHRNA5, and CHRNB4 and 48 noncoding single-nucleotide polymorphisms (SNPs). Haplotype frequencies varied across ethnic populations. We assessed the contribution of six SNPs in the putative catestatin binding region of CHRNA3 and CHRNB4 to autonomic traits. In twins, catestatin and BP were heritable. CHRNA3 SNPs and haplotypes containing K95K (G285A) associated with circulating plasma catestatin, epinephrine levels, as well as systolic BP, suggesting altered coupling of the nAChRs to BP. Studies of chromaffin cells in vitro reveal that nicotinic agonist stimulation releases catecholamines and CHGA, a process augmented by overexpression of CHRNA3 and blocked by catestatin. These cellular events suggest a homeostatic mechanism underlying the pleiotropic actions of CHRNA3 genetic variation on autonomic function observed in twins.
Collapse
Affiliation(s)
- Brinda K Rana
- Departments of Psychiatry, University of California at San Diego, La Jolla, California 92093-0657, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Neuroimaging of the vesicular acetylcholine transporter by a novel 4-[18F]fluoro-benzoyl derivative of 7-hydroxy-6-(4-phenyl-piperidin-1-yl)-octahydro-benzo[1,4]oxazines. Nucl Med Biol 2009; 36:17-27. [PMID: 19181265 DOI: 10.1016/j.nucmedbio.2008.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 10/07/2008] [Accepted: 10/07/2008] [Indexed: 11/21/2022]
Abstract
Phenylpiperidinyl-octahydro-benzo[1,4]oxazines represent a new class of conformationally restrained vesamicol analogues. Derived from this morpholine-fused vesamicol structure, a new fluorine-18-labeled 4-fluorobenzoyl derivative ([(18)F]FBMV) was synthesized with an average specific activity of 75 GBq/micromol and a radiochemical purity of 99%. The radiolabeling method included an exchange reaction of a 4-nitro group of the precursor by fluorine-18, a reduction procedure to eliminate excess of the nitro compound, followed by a high-performance liquid chromatography purification. [(18)F]FBMV demonstrates (i) a moderate lipophilic character with a logD(pH7.0) 1.8+/-0.10; (ii) a considerable binding affinity to the vesicular acetylcholine transporter (VAChT) (K(i)=27.5 nM), as determined using PC12 cells transfected with a VAChT cDNA, and a low affinity to sigma(1,2) receptors (K(i) >3000 nM); (iii) a good uptake into the rat and pig brains; (iv) a typical accumulation in the VAChT-containing brain regions; and (v) an approximately 20% reduction in cortical tracer binding after a specific cholinergic lesion using 192IgG-saporin. [(18)F]FBMV exhibits another PET marker within the group of vesamicol derivatives that demonstrates potentials in imaging brain cholinergic deficits, while its usefulness in clinical practice must await further investigation.
Collapse
|
10
|
Sorger D, Scheunemann M, Grossmann U, Fischer S, Vercouille J, Hiller A, Wenzel B, Roghani A, Schliebs R, Brust P, Sabri O, Steinbach J. A new 18F-labeled fluoroacetylmorpholino derivative of vesamicol for neuroimaging of the vesicular acetylcholine transporter. Nucl Med Biol 2008; 35:185-95. [PMID: 18312828 DOI: 10.1016/j.nucmedbio.2007.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 08/24/2007] [Accepted: 10/10/2007] [Indexed: 11/20/2022]
Abstract
With the aim of producing selective radiotracers for in vivo imaging of the vesicular acetylcholine transporter (VAChT) using positron mission tomography (PET), here, we report synthesis and analysis of a new class of conformationally constrained vesamicol analogues with moderate lipophilicity. The sequential ring opening on trans-1,4-cyclohexadiene dioxide enabled an approach to synthesize 6-arylpiperidino-octahydrobenzo[1,4]oxazine-7-ols [morpholino vesamicols]. The radiosynthesis of the [18F]fluoroacetyl-substituted derivative ([18F]FAMV) was achieved starting from a corresponding bromo precursor [2-Bromo-1-[7-hydroxy-6-(4-phenyl-piperidin-1-yl)-octahydro-benzo[1,4]oxazin-4-yl]-ethanone] and using a modified commercial computer-controlled module system with a radiochemical yield of 27+/-4%, a high radiochemical purity (99%) and a specific activity of 35 GBq/micromol. In competitive binding assays using a PC12 cell line overexpressing VAChT and [3H]-(-) vesamicol, 2-fluoro-1-[7-hydroxy-6-(4-phenyl-piperidin-1-yl)-octahydro-benzo[1,4]oxazin-4-yl]-ethanone (FAMV) demonstrated a high selectivity for binding to VAChT (K(i): 39.9+/-5.9 nM) when compared to its binding to sigma 1/2 receptors (Ki>1500 nM). The compound showed a moderate lipophilicity (logD (pH 7)=1.9) and a plasma protein binding of 49%. The brain uptake of [18F]FAMV was about 0.1% injected dose per gram at 5 min after injection and decreased continuously with time. Notably, an increasing accumulation of radioactivity in the lateral brain ventricles was observed. After 1 h, the accumulation of [18F]FAMV, expressed as ratio to the cerebellum, was 4.5 for the striatum, 2.0 for the cortical and 1.5 for the hippocampal regions, measured on brain slices using ex vivo autoradiography. At the present time, 75% of [18F]FAMV in the plasma was shown to be metabolized to various hydrophilic compounds, as detected by high-performance liquid chromatography. The degradation of [18F]FAMV was also detected in brain extracts as early as 15 min post injection (p.i.) and increased to 50% at 1 h postinjection. In conclusion, although the chemical properties of [18F]FAMV and the selectivity of binding to VAChT appear to be promising indicators of a useful PET tracer for imaging VAChT, a low brain extraction, in combination with only moderate specific accumulation in cholinergic brain regions and an insufficient in vivo stability prevents the application of this compound for neuroimaging in humans.
Collapse
Affiliation(s)
- Dietlind Sorger
- Department of Nuclear Medicine, University of Leipzig, 04103 Leipzig, Germany.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Kallmünzer B, Sörensen B, Neuhuber WL, Wörl J. Heterogeneity of neuromuscular junctions in striated muscle of human esophagus demonstrated by triple staining for the vesicular acetylcholine transporter, α-bungarotoxin, and acetylcholinesterase. Cell Tissue Res 2006; 324:181-8. [PMID: 16437206 DOI: 10.1007/s00441-005-0154-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 12/19/2005] [Indexed: 01/22/2023]
Abstract
During studies on enteric co-innervation in the human esophagus, we found that not all acetylcholinesterase (AChE)-positive motor endplates stained for alpha-bungarotoxin (alpha-BT) and the vesicular acetylcholine transporter (VAChT), respectively. Therefore, we probed for differences in neuromuscular junctions in human esophagus by using triple staining for VAChT, alpha-BT, and AChE followed by qualitative and quantitative analysis. To exclude that the results were caused by processing artifacts, we additionally examined the influence of a number of factors including post-mortem changes and the type and duration of fixation on the staining results. Four types of neuromuscular junction could be distinguished in human esophagus: type I with VAChT-positive and type II with VAChT-negative nerve terminals on a alpha-BT-positive and AChE-positive endplate area, type III with VAChT-positive nerve terminals on a alpha-BT-negative but AChE-positive endplate area, and type IV with VAChT-negative nerve terminals on a alpha-BT-negative but AChE-positive endplate area. On average, 32% of evaluated AChE-positive motor endplates were type I, 6% type II, 24% type III, and 38% type IV. Based on these results, we suggest that, in human esophagus, (1) the most reliable method for staining motor endplates is presently AChE histochemistry, (2) alpha-BT-sensitive and alpha-BT-resistant nicotinic acetylcholine receptors exist in neuromuscular junctions, and (3) different types of VAChT or transport mechanisms for acetylcholine probably exist in neuromuscular junctions.
Collapse
Affiliation(s)
- Bernd Kallmünzer
- Institute of Anatomy, University of Erlangen-Nuremberg, Krankenhausstrasse 9, 91054, Erlangen, Germany
| | | | | | | |
Collapse
|
12
|
Pfeil U, Vollerthun R, Kummer W, Lips KS. Expression of the cholinergic gene locus in the rat placenta. Histochem Cell Biol 2004; 122:121-30. [PMID: 15278359 DOI: 10.1007/s00418-004-0687-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2004] [Indexed: 10/26/2022]
Abstract
High amounts of acetylcholine (ACh) and its synthesising enzyme choline acetyltransferase (ChAT) have been detected in the placenta. Since the placenta is not innervated by extrinsic or intrinsic cholinergic neurons, placental ACh and ChAT originate from non-neuronal sources. In neurons, cytoplasmic ACh is imported into synaptic vesicles by the vesicular acetylcholine transporter (VAChT), and released through vesicular exocytosis. In view of the coordinate expression of VAChT and ChAT from the "cholinergic gene locus" in neurons, we asked whether VAChT is coexpressed with ChAT in rat placenta, and investigated this issue by means of RT-PCR, in situ hybridisation, western blot and immunohistochemistry. Messenger RNA and protein of the common type of ChAT (cChAT), its splice variant peripheral ChAT (pChAT), and VAChT were detected in rat placenta with RT-PCR and western blot. ChAT in situ hybridisation signal and immunoreactivity for cChAT and pChAT were observed in nearly all placental cell types, while VAChT mRNA and immunolabelling were detected in the trophoblast, mesenchymal cells and the visceral yolk sac epithelial cells. While ChAT is nearly ubiquitously expressed in rat placenta, VAChT immunoreactivity is localised cell type specifically, implying that both vesicular and non-vesicular ACh release machineries prevail in placental cell types.
Collapse
Affiliation(s)
- Uwe Pfeil
- Institute for Anatomy and Cell Biology, Justus-Liebig-University, Aulweg 123, 35385 Giessen, Germany
| | | | | | | |
Collapse
|
13
|
Van der Kloot W. Loading and recycling of synaptic vesicles in the Torpedo electric organ and the vertebrate neuromuscular junction. Prog Neurobiol 2003; 71:269-303. [PMID: 14698765 DOI: 10.1016/j.pneurobio.2003.10.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In vertebrate motor nerve terminals and in the electromotor nerve terminals of Torpedo there are two major pools of synaptic vesicles: readily releasable and reserve. The electromotor terminals differ in that the reserve vesicles are twice the diameter of the readily releasable vesicles. The vesicles contain high concentrations of ACh and ATP. Part of the ACh is brought into the vesicle by the vesicular ACh transporter, VAChT, which exchanges two protons for each ACh, but a fraction of the ACh seems to be accumulated by different, unexplored mechanisms. Most of the vesicles in the terminals do not exchange ACh or ATP with the axoplasm, although ACh and ATP are free in the vesicle interior. The VAChT is controlled by a multifaceted regulatory complex, which includes the proteoglycans that characterize the cholinergic vesicles. The drug (-)-vesamicol binds to a site on the complex and blocks ACh exchange. Only 10-20% of the vesicles are in the readily releasable pool, which therefore is turned over fairly rapidly by spontaneous quantal release. The turnover can be followed by the incorporation of false transmitters into the recycling vesicles, and by the rate of uptake of FM dyes, which have some selectivity for the two recycling pathways. The amount of ACh loaded into recycling vesicles in the readily releasable pool decreases during stimulation. The ACh content of the vesicles can be varied over eight-fold range without changing vesicle size.
Collapse
Affiliation(s)
- William Van der Kloot
- Department of Physiology and Biophysics, SUNY at Stony Brook, 8661 SUNT, Stony Brook, NY 11794-8661, USA.
| |
Collapse
|