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Jakova E, Moutaoufik MT, Lee JS, Babu M, Cayabyab FS. Adenosine A1 receptor ligands bind to α-synuclein: implications for α-synuclein misfolding and α-synucleinopathy in Parkinson's disease. Transl Neurodegener 2022; 11:9. [PMID: 35139916 PMCID: PMC8830172 DOI: 10.1186/s40035-022-00284-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/21/2022] [Indexed: 12/20/2022] Open
Abstract
Background Accumulating α-synuclein (α-syn) aggregates in neurons and glial cells are the staples of many synucleinopathy disorders, such as Parkinson’s disease (PD). Since brain adenosine becomes greatly elevated in ageing brains and chronic adenosine A1 receptor (A1R) stimulation leads to neurodegeneration, we determined whether adenosine or A1R receptor ligands mimic the action of known compounds that promote α-syn aggregation (e.g., the amphetamine analogue 2-aminoindan) or inhibit α-syn aggregation (e.g., Rasagiline metabolite 1-aminoindan). In the present study, we determined whether adenosine, A1R receptor agonist N6-Cyclopentyladenosine (CPA) and antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) could directly interact with α-syn to modulate α-syn aggregation and neurodegeneration of dopaminergic neurons in the substantia nigra (SN). Methods Nanopore analysis and molecular docking were used to test the binding properties of CPA and DPCPX with α-syn in vitro. Sprague–Dawley rats were administered with 7-day intraperitoneal injections of the A1R ligands and 1- and 2-aminoindan, and levels of α-syn aggregation and neurodegeneration were examined in the SN pars compacta and hippocampal regions using confocal imaging and Western blotting. Results Using nanopore analysis, we showed that the A1R agonists (CPA and adenosine) interacted with the N-terminus of α-syn, similar to 2-aminoindan, which is expected to promote a “knot” conformation and α-syn misfolding. In contrast, the A1R antagonist DPCPX interacted with the N- and C-termini of α-syn, similar to 1-aminoindan, which is expected to promote a “loop” conformation that prevents α-syn misfolding. Molecular docking studies revealed that adenosine, CPA and 2-aminoindan interacted with the hydrophobic core of α-syn N-terminus, whereas DPCPX and 1-aminoindan showed direct binding to the N- and C-terminal hydrophobic pockets. Confocal imaging and Western blot analyses revealed that chronic treatments with CPA alone or in combination with 2-aminoindan increased α-syn expression/aggregation and neurodegeneration in both SN pars compacta and hippocampus. In contrast, DPCPX and 1-aminoindan attenuated the CPA-induced α-syn expression/aggregation and neurodegeneration in SN and hippocampus. Conclusions The results indicate that A1R agonists and drugs promoting a “knot” conformation of α-syn can cause α-synucleinopathy and increase neuronal degeneration, whereas A1R antagonists and drugs promoting a “loop” conformation of α-syn can be harnessed for possible neuroprotective therapies to decrease α-synucleinopathy in PD. Supplementary Information The online version contains supplementary material available at 10.1186/s40035-022-00284-3.
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Affiliation(s)
- Elisabet Jakova
- Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Mohamed Taha Moutaoufik
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK, Canada
| | - Jeremy S Lee
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Mohan Babu
- Department of Chemistry and Biochemistry, Faculty of Science, University of Regina, Regina, SK, Canada
| | - Francisco S Cayabyab
- Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
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Barker-Haliski ML, Johnson K, Billingsley P, Huff J, Handy LJ, Khaleel R, Lu Z, Mau MJ, Pruess TH, Rueda C, Saunders G, Underwood TK, Vanegas F, Smith MD, West PJ, Wilcox KS. Validation of a Preclinical Drug Screening Platform for Pharmacoresistant Epilepsy. Neurochem Res 2017; 42:1904-1918. [PMID: 28303498 DOI: 10.1007/s11064-017-2227-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/07/2017] [Accepted: 03/09/2017] [Indexed: 12/11/2022]
Abstract
The successful identification of promising investigational therapies for the treatment of epilepsy can be credited to the use of numerous animal models of seizure and epilepsy for over 80 years. In this time, the maximal electroshock test in mice and rats, the subcutaneous pentylenetetrazol test in mice and rats, and more recently the 6 Hz assay in mice, have been utilized as primary models of electrically or chemically-evoked seizures in neurologically intact rodents. In addition, rodent kindling models, in which chronic network hyperexcitability has developed, have been used to identify new agents. It is clear that this traditional screening approach has greatly expanded the number of marketed drugs available to manage the symptomatic seizures associated with epilepsy. In spite of the numerous antiseizure drugs (ASDs) on the market today, the fact remains that nearly 30% of patients are resistant to these currently available medications. To address this unmet medical need, the National Institute of Neurological Disorders and Stroke (NINDS) Epilepsy Therapy Screening Program (ETSP) revised its approach to the early evaluation of investigational agents for the treatment of epilepsy in 2015 to include a focus on preclinical approaches to model pharmacoresistant seizures. This present report highlights the in vivo and in vitro findings associated with the initial pharmacological validation of this testing approach using a number of mechanistically diverse, commercially available antiseizure drugs, as well as several probe compounds that are of potential mechanistic interest to the clinical management of epilepsy.
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Affiliation(s)
| | - Kristina Johnson
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Peggy Billingsley
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Jennifer Huff
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Laura J Handy
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Rizvana Khaleel
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Zhenmei Lu
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Matthew J Mau
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Timothy H Pruess
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Carlos Rueda
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Gerald Saunders
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Tristan K Underwood
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Fabiola Vanegas
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Misty D Smith
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA.,Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Peter J West
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA.,Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Karen S Wilcox
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, 84112, USA.,Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, 84112, USA
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