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Schuldiner S, Forrest LR. VMAT structures reveal exciting targets for drug development. Trends Pharmacol Sci 2024; 45:385-387. [PMID: 38429134 PMCID: PMC11191364 DOI: 10.1016/j.tips.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/17/2024] [Accepted: 02/16/2024] [Indexed: 03/03/2024]
Abstract
Vesicular monoamine transporter (VMAT)-2 has a crucial role in the neurotransmission of biogenic amines. Recently, Dalton et al., Pidathala et al., Wu et al., and Wang et al. individually reported cryo-electron microscopy (EM) structures of human VMAT2, offering opportunities for developing improved therapeutics and deep insights into the functioning of this protein.
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Affiliation(s)
- Shimon Schuldiner
- Department of Biological Chemistry, Institute of Life Sciences, Silberman Bldg. 1-513, Edmond J. Safra Campus, Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel.
| | - Lucy R Forrest
- Computational Structural Biology Section, 35 Convent Drive, Room 3D-991, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-8202, USA.
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Jiang X, Shao Y, Liao Y, Zheng X, Peng M, Cai Y, Wang M, Liu H, Zeng C, Lin Y, Zhang W, Liu L. Mechanisms underlying the efficacy and limitation of dopa and tetrahydrobiopterin therapies for the deficiency of GTP cyclohydrolase 1 revealed in a novel mouse model. Eur J Pharmacol 2024; 967:176379. [PMID: 38342361 DOI: 10.1016/j.ejphar.2024.176379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/13/2024]
Abstract
Dopa and tetrahydrobiopterin (BH4) supplementation are recommended therapies for the dopa-responsive dystonia caused by GTP cyclohydrolase 1 (GCH1, also known as GTPCH) deficits. However, the efficacy and mechanisms of these therapies have not been intensively studied yet. In this study, we tested the efficacy of dopa and BH4 therapies by using a novel GTPCH deficiency mouse model, Gch1KI/KI, which manifested infancy-onset motor deficits and growth retardation similar to the patients. First, dopa supplementation supported Gch1KI/KI mouse survival to adulthood, but residual motor deficits and dwarfism remained. Interestingly, RNAseq analysis indicated that while the genes participating in BH4 biosynthesis and regeneration were significantly increased in the liver, no significant changes were observed in the brain. Second, BH4 supplementation alone restored the growth of Gch1KI/KI pups only in early postnatal developmental stage. High doses of BH4 supplementation indeed restored the total brain BH4 levels, but brain dopamine deficiency remained. While total brain TH levels were relatively increased in the BH4 treated Gch1KI/KI mice, the TH in the striatum were still almost undetectable, suggesting differential BH4 requirements among brain regions. Last, the growth of Gch1KI/KI mice under combined therapy outperformed dopa or BH4 therapy alone. Notably, dopamine was abnormally high in more than half, but not all, of the treated Gch1KI/KI mice, suggesting the existence of variable synergetic effects of dopa and BH4 supplementation. Our results provide not only experimental evidence but also novel mechanistic insights into the efficacy and limitations of dopa and BH4 therapies for GTPCH deficiency.
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Affiliation(s)
- Xiaoling Jiang
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Yongxian Shao
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Yongqiang Liao
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Xiaoning Zheng
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Minzhi Peng
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Yanna Cai
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Meiyi Wang
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Huazhen Liu
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Chunhua Zeng
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China
| | - Yunting Lin
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China.
| | - Wen Zhang
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China.
| | - Li Liu
- Department of Genetics and Endocrine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, 510623, China.
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