title: Molecular and functional characterization of choline transporter in the human trophoblastic cell line JEG-3 cells.
abstract: BACKGROUND
  Choline is essential for the synthesis of the major membrane phospholipid phosphatidylcholine (PC), the methyl donor betaine and the neurotransmitter acetylcholine (ACh), which is involved in several vital biological functions that play key roles in fetal development. In this study, we examined the molecular and functional characteristics of choline uptake in the human trophoblastic cell line JEG-3.
  
  
  METHODS
  We examined [(3)H]choline uptake in the human trophoblastic cell line JEG-3. The expression of CTL1 and CTL2 was evaluated by quantitative real-time PCR, western blotting and immunocytochemistry.
  
  
  RESULTS
  We demonstrated that JEG-3 cells take up [(3)H] choline by a saturable process that is mediated by a Na(+)-independent and pH-dependent transport system. The cells have two different [(3)H] choline transport systems, high- and low-affinity, with Km values of 28.4 ± 5.0 μM and 210.6 ± 55.1 μM, respectively. Cationic compounds and hemicholinium-3 (HC-3) inhibited choline uptake. Choline transporter-like protein 1 (CTL1) and CTL2 mRNA and protein were highly expressed in JEG-3 cells and were localized to the plasma membrane.
  
  
  CONCLUSIONS
  The present results suggest that choline is mainly transported via a high-affinity choline transport system (CTL1) and a low-affinity choline transport system (CTL2) in human trophoblastic JEG-3 cells. These transporters play an important role in the growth of the fetus.
authors.affiliation: Department of Anesthesiology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yara
authors.affiliation: Department of Psychiatry, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: B
authors.initials: B
authors.lastname: Iwao
authors.affiliation: Department of Anesthesiology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hara
authors.affiliation: Department of Preventive Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamanaka
authors.affiliation: Department of Anesthesiology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Uchino
authors.affiliation: Department of Preventive Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan; Institute of Medical Science, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan. Electronic address: inazu@tokyo-med.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Inazu
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D002794:Choline / Q000494:pharmacology*; D005260:Female; D006426:Hemicholinium 3 / Q000494:pharmacology; D006801:Humans; D026901:Membrane Transport Proteins / Q000378:metabolism*; D011247:Pregnancy; D014327:Trophoblasts / Q000187:drug effects / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; C065637:choline transporter; D006426:Hemicholinium 3; D002794:Choline
keywords: Blood placenta barrier; Choline; Choline transporter-like protein; JEG-3 cells; Transporter