Pharmaceutics (Aug 2022)

Proteomics-Based Transporter Identification by the PICK Method: Involvement of TM7SF3 and LHFPL6 in Proton-Coupled Organic Cation Antiport at the Blood–Brain Barrier

  • Toshiki Kurosawa,
  • Yuma Tega,
  • Yasuo Uchida,
  • Kei Higuchi,
  • Hidetsugu Tabata,
  • Takaaki Sumiyoshi,
  • Yoshiyuki Kubo,
  • Tetsuya Terasaki,
  • Yoshiharu Deguchi

DOI
https://doi.org/10.3390/pharmaceutics14081683
Journal volume & issue
Vol. 14, no. 8
p. 1683

Abstract

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A proton-coupled organic cation (H+/OC) antiporter working at the blood–brain barrier (BBB) in humans and rodents is thought to be a promising candidate for the efficient delivery of cationic drugs to the brain. Therefore, it is important to identify the molecular entity that exhibits this activity. Here, for this purpose, we established the Proteomics-based Identification of transporter by Crosslinking substrate in Keyhole (PICK) method, which combines photo-affinity labeling with comprehensive proteomics analysis using SWATH-MS. Using preselected criteria, the PICK method generated sixteen candidate proteins. From these, knockdown screening in hCMEC/D3 cells, an in vitro BBB model, identified two proteins, TM7SF3 and LHFPL6, as candidates for the H+/OC antiporter. We synthesized a novel H+/OC antiporter substrate for functional analysis of TM7SF3 and LHFPL6 in hCMEC/D3 cells and HEK293 cells. The results suggested that both TM7SF3 and LHFPL6 are components of the H+/OC antiporter.

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