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Nguyen XTA, Le TNU, Nguyen TQ, Thi Thuy Ha H, Artati A, Leong NCP, Nguyen DT, Lim PY, Susanto AV, Huang Q, Fam L, Leong LN, Bonne I, Lee A, Granadillo JL, Gooch C, Yu D, Huang H, Soong TW, Chang MW, Wenk MR, Adamski J, Cazenave-Gassiot A, Nguyen LN. MFSD7c functions as a transporter of choline at the blood-brain barrier. Cell Res 2024; 34:245-257. [PMID: 38302740 PMCID: PMC10907603 DOI: 10.1038/s41422-023-00923-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 12/26/2023] [Indexed: 02/03/2024] Open
Abstract
Mutations in the orphan transporter MFSD7c (also known as Flvcr2), are linked to Fowler syndrome. Here, we used Mfsd7c knockout (Mfsd7c-/-) mice and cell-based assays to reveal that MFSD7c is a choline transporter at the blood-brain barrier (BBB). We performed comprehensive metabolomics analysis and detected differential changes of metabolites in the brains and livers of Mfsd7c-/-embryos. Particularly, we found that choline-related metabolites were altered in the brains but not in the livers of Mfsd7c-/- embryos. Thus, we hypothesized that MFSD7c regulates the level of choline in the brain. Indeed, expression of human MFSD7c in cells significantly increased choline uptake. Interestingly, we showed that choline uptake by MFSD7c is greatly increased by choline-metabolizing enzymes, leading us to demonstrate that MFSD7c is a facilitative transporter of choline. Furthermore, single-cell patch clamp analysis showed that the import of choline by MFSD7c is electrogenic. Choline transport function of MFSD7c was shown to be conserved in vertebrates, but not in yeasts. We demonstrated that human MFSD7c is a functional ortholog of HNM1, the yeast choline importer. We also showed that several missense mutations identified in patients exhibiting Fowler syndrome had abolished or reduced choline transport activity. Mice lacking Mfsd7c in endothelial cells of the central nervous system suppressed the import of exogenous choline from blood but unexpectedly had increased choline levels in the brain. Stable-isotope tracing study revealed that MFSD7c was required for exporting choline derived from lysophosphatidylcholine in the brain. Collectively, our work identifies MFSD7c as a choline exporter at the BBB and provides a foundation for future work to reveal the disease mechanisms of Fowler syndrome.
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Affiliation(s)
- Xuan Thi Anh Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Thanh Nha Uyen Le
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Toan Q Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hoa Thi Thuy Ha
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Anna Artati
- Metabolomics and Proteomics Core, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Nancy C P Leong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Dat T Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Pei Yen Lim
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Adelia Vicanatalita Susanto
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Qianhui Huang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ling Fam
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Lo Ngah Leong
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Isabelle Bonne
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Microbiology and Immunology, Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Life Sciences Institute, Immunology Programme, National University of Singapore, Singapore, Singapore
| | - Angela Lee
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, Saint Louis, MO, USA
| | - Jorge L Granadillo
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, Saint Louis, MO, USA
| | - Catherine Gooch
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, Saint Louis, MO, USA
| | - Dejie Yu
- Electrophysiology Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hua Huang
- Electrophysiology Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Cardiovascular Diseases Program, National University of Singapore, Singapore, Singapore
| | - Tuck Wah Soong
- Electrophysiology Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Cardiovascular Diseases Program, National University of Singapore, Singapore, Singapore
| | - Matthew Wook Chang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Markus R Wenk
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Jerzy Adamski
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Amaury Cazenave-Gassiot
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Long N Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore.
- Life Sciences Institute, Immunology Programme, National University of Singapore, Singapore, Singapore.
- Cardiovascular Diseases Program, National University of Singapore, Singapore, Singapore.
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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