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Quantitative targeted absolute proteomics of rat blood–cerebrospinal fluid barrier transporters: comparison with a human specimen
Author(s) -
Uchida Yasuo,
Zhang Zhengyu,
Tachikawa Masanori,
Terasaki Tetsuya
Publication year - 2015
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.13147
Subject(s) - choroid plexus , cerebrospinal fluid , blood–brain barrier , proteomics , transporter , biology , choroid , microbiology and biotechnology , chemistry , pathology , endocrinology , biochemistry , central nervous system , medicine , gene , retina , neuroscience
The purpose of this study was to determine absolute protein expression levels of transporters in rat choroid plexus, that is, the blood–cerebrospinal fluid barrier, and to compare them with the levels in the human choroid plexus. Plasma membrane fractions were prepared from pooled, freshly isolated choroid plexuses of 30 male Wistar rats and from frozen choroid plexus of one male human donor. Protein expression levels of 54 rat and 121 human molecules were measured, using a quantitative targeted absolute proteomics technique. In rat, oatp1a5 showed the most abundant protein expression (30.3 fmol/μg protein), and its expression level was 3.1‐, 4.5‐, 5.5‐, 8.4‐, 9.0‐, 9.9‐, 22‐, 91‐, and 95‐fold greater than those of glut1, oatp1c1, mrp1, mct1, oat3, pept2, mrp4, bcrp, and mdr1a, respectively. OATP 1A2 (a possible homolog of rat oatp1a5), OATP 1C1 and PEPT 2 were not detected in human choroid plexus. MRP 1, OAT 3, and MRP 4 showed 4.0‐, 1.8‐, and 1.7‐fold smaller expression levels in human than rat, respectively. MATE 1 was detected in human, but not rat, and its expression level (8.61 fmol/μg protein) was the highest among the xenobiotic transporters examined in human choroid plexus. These findings should be useful for understanding rat blood–cerebrospinal fluid barrier function and its differences from that in human.This is the first study clarifying the absolute protein expression levels of many transporters in the plasma membrane fractions of rat and human choroid plexuses, that is, blood cerebrospinal fluid barrier, by means of quantitative targeted absolute proteomics (QTAP) technique. This study also identified the protein expressions of some transporters including MATE1 and ABCA8 in the choroid plexus for the first time.