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Vanan S, Zeng X, Chia SY, Varnäs K, Jiang M, Zhang K, Saw WT, Padmanabhan P, Yu WP, Zhou ZD, Halldin C, Gulyás B, Tan EK, Zeng L. Altered striatal dopamine levels in Parkinson's disease VPS35 D620N mutant transgenic aged mice. Mol Brain 2020; 13:164. [PMID: 33261640 PMCID: PMC7706192 DOI: 10.1186/s13041-020-00704-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023] Open
Abstract
Vacuolar protein sorting 35 (VPS35) is a major component of the retromer complex that mediates the retrograde transport of cargo proteins from endosomes to the trans-Golgi network. Mutations such as D620N in the VPS35 gene have been identified in patients with autosomal dominant Parkinson's disease (PD). However, it remains poorly understood whether and how VPS35 deficiency or mutation contributes to PD pathogenesis; specifically, the studies that have examined VPS35 thus far have differed in results and methodologies. We generated a VPS35 D620N mouse model using a Rosa26-based transgene expression platform to allow expression in a spatial manner, so as to better address these discrepancies. Here, aged (20-months-old) mice were first subjected to behavioral tests. Subsequently, DAB staining analysis of substantia nigra (SN) dopaminergic neurons with the marker for tyrosine hydroxylase (TH) was performed. Next, HPLC was used to determine dopamine levels, along with levels of its two metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), in the striatum. Western blotting was also performed to study the levels of key proteins associated with PD. Lastly, autoradiography (ARG) evaluation of [3H]FE-PE2I binding to the striatal dopamine transporter DAT was carried out. We found that VPS35 D620N Tg mice displayed a significantly higher dopamine level than NTg counterparts. All results were then compared with that of current VPS35 studies to shed light on the disease pathogenesis. Our model allows future studies to explicitly control spatial expression of the transgene which would generate a more reliable PD phenotype.
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Affiliation(s)
- Sarivin Vanan
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Xiaoxia Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Sook Yoong Chia
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Katarina Varnäs
- Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet PET Centre, Karolinska Institutet, Karolinska University Hospital Solna, R5:02, 171 76, Stockholm, Sweden
| | - Mei Jiang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Ke Zhang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Wuan Ting Saw
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Wei-Ping Yu
- Animal Gene Editing Laboratory, Biological Resource Centre, A*STAR, Singapore, 138673, Singapore.,Institute of Molecular and Cell Biology, A*STAR, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore
| | - Zhi-Dong Zhou
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.,Signature Research Program in Neuroscience and Behavioral Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore
| | - Christer Halldin
- Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet PET Centre, Karolinska Institutet, Karolinska University Hospital Solna, R5:02, 171 76, Stockholm, Sweden.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Balázs Gulyás
- Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet PET Centre, Karolinska Institutet, Karolinska University Hospital Solna, R5:02, 171 76, Stockholm, Sweden.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Eng-King Tan
- Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore. .,Signature Research Program in Neuroscience and Behavioral Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore. .,Department of Neurology, National Neuroscience Institute, SGH Campus, Singapore, 169856, Singapore.
| | - Li Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore. .,Signature Research Program in Neuroscience and Behavioral Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore. .,Center for Molecular Neuropathology, Lee Kong Chian School of Medicine, Nanyang Technological University, Novena Campus, 11 Mandalay Road, Singapore, 308232, Singapore.
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