The University of Tokyo group has unveiled for the first time in the world an excretory transporter responsible for transporting vitamin C from intracellular to extracellular.
While Vitamin C is known as an essential nutrient for survival, little is known about its pharmacokinetic control to reach every corner of the body.In particular, although the brain is an organ rich in vitamin C, it is separated from blood by barrier tissues, so it is thought that there is a molecular mechanism that controls the transfer of vitamin C from blood to the brain.
The only vitamin C transporters identified so far are sodium-dependent vitamin C transporters (SVCT1 and SVCT2), and in the epithelial cells of the choroidal flora that form the blood cerebrospinal fluid barrier, the cell membrane on the blood side. Above, SVCT functions as the entrance to vitamin C (incorporating vitamin C from outside the cell into the cell).In this study, we considered that there is an unknown vitamin C transporter that functions as an exit on the cell membrane on the cerebrospinal fluid side, which is a companion to this, and we have proceeded with the study.
As a result, it was found that the SLC2A12 transporter expressed in the choroid plexus is responsible for the intracellular to extracellular transport (excretion) of vitamin C. In mice lacking the SLC2A12 gene, the vitamin C concentration in the brain was reduced to about half that of normal mice.In addition, the vitamin C concentration in the choroid plexus increased significantly, while the vitamin C concentration in the cerebrospinal fluid decreased significantly.This indicates that the exit of vitamin C from the choroid plexus to the cerebrospinal fluid is lost, and that vitamin C excretion-type transport by SLC2A12 is a physiologically important pathway for vitamin C supply to the brain. Can be done.
Named "Vitamin C Excreting Protein: VCEP", this transporter is the first excretory transporter of vitamin C transporters previously known to be only uptake. The VCEP gene-deficient mouse is said to be the first animal model that can significantly reduce the vitamin C concentration in the brain, and is considered to be a great achievement in clarifying the role of vitamin C in the brain.
Paper information:[IScience] Identification of an exporter that regulates vitamin C supply from bloodto the brain
