Mitochondrial GLUT10 facilitates dehydroascorbic acid import and protects cells against oxidative stress: mechanistic insight into arterial tortuosity syndrome

• Published in: Human molecular genetics 2010-10, Vol.19 (19), p.3721-3733
• Main Authors: Lee, Yi-Ching, Huang, Hsun-Yi, Chang, Chia-Jung, Cheng, Chao-Hung, Chen, Yuan-Tsong
• Format: Article
• Language: English
• Subjects: Adipocytes - drug effects; Adipocytes - metabolism; Adipocytes - pathology; Animals; Aorta - drug effects; Aorta - metabolism; Aorta - pathology; Arteries - abnormalities; Arteries - drug effects; Arteries - metabolism; Arteries - pathology; Biological and medical sciences; Biological Transport - drug effects; Complex syndromes; Cytoprotection - drug effects; Dehydroascorbic Acid - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation - drug effects; Genetics of eukaryotes. Biological and molecular evolution; Glucose Transport Proteins, Facilitative - genetics; Glucose Transport Proteins, Facilitative - metabolism; Insulin - pharmacology; Medical genetics; Medical sciences; Mice; Mitochondria - drug effects; Mitochondria - metabolism; Models, Biological; Molecular and cellular biology; Myocytes, Smooth Muscle - drug effects; Myocytes, Smooth Muscle - metabolism; NIH 3T3 Cells; Organ Specificity - drug effects; Organ Specificity - genetics; Oxidative Stress - drug effects; Reactive Oxygen Species - metabolism; Subcellular Fractions - drug effects; Subcellular Fractions - metabolism; Syndrome
• ISSN: 0964-6906; 1460-2083
• DOI: 10.1093/hmg/ddq286

Mutations in glucose transporter 10 (GLUT10) alter angiogenesis and cause arterial tortuosity syndrome (ATS); however, the mechanisms by which these mutations cause disease remain unclear. It has been reported that in most cells, mitochondria are the major source of reactive oxygen species (ROS). Moreover, mitochondria are known to incorporate as well as recycle vitamin C, which plays a critical role in redox homeostasis, although the molecular mechanism(s) underlying mitochondrial vitamin C uptake are poorly understood. We report here that GLUT10 localizes predominantly to the mitochondria of smooth muscle cells and insulin-stimulated adipocytes, where GLUT10 is highly expressed. We further demonstrate that GLUT10 facilitates transport of l-dehydroascorbic acid (DHA), the oxidized form of vitamin C, into mitochondria, and also increases cellular uptake of DHA, which in turn protects cells against oxidative stress. This protection is compromised when GLUT10 expression in mitochondria is inhibited. In addition, we found that aortic smooth muscle cells from GLUT10-mutant mice have higher ROS levels than those from wild-type mice. Our results identify the physiological role of GLUT10 as the mitochondrial DHA transporter, and demonstrate that GLUT10 protects cells from oxidative injury. Furthermore, our findings provide a mechanism to explain the ascorbate in mitochondria and show how loss-of-function GLUT10 mutations may lead to arterial abnormalities in ATS. These results also reinforce the importance of vitamin C and ROS in degenerative diseases.