[Molecular Mechanism Underlying the Function and Disintegration of the Central Nerve System Barrier Unraveled by Proteo-typing of Membrane Proteins].

Although 82% of the cerebrospinal fluid (CSF) is localized in the subarachnoid space, the function of the blood-arachnoid barrier (BAB) has not been elucidated. We found an abundance of drug efflux transporter proteins in the BAB. Moreover, several transporter proteins, including organic anion transporters and organic cation transporters have been found in the BAB. Significant in vivo transport activity of the BAB has been observed, suggesting that the BAB plays a pivotal role in the CNS barrier. Using quantitative targeted absolute proteomic analysis, we determined the similarities and differences in transport function and tight junction formation among the BBB, BAB, blood-CSF barrier (BCSFB), and blood-spinal cord barrier (BSCB). Furthermore, we proposed several hypotheses regarding the molecular mechanism underlying CNS barrier disintegration in the presence of oxidative stress, TNF-α release, and multiple sclerosis.